0000950170-24-036396 | 10-K | XBRL Viewer

Income Taxes

12 Months Ended

Dec. 31, 2023

12. Income Taxes

The provision for income taxes for the years ended December 31, 2023 and 2022 was comprised as follows (in thousands):


	Year Ended December 31,
	2023		2022
Current taxes:
Federal	$	—	$	—
State		27		10
Total current taxes		27		10
Deferred taxes:
Federal		—		—
State		—		—
Total deferred taxes		—		—
Total provision for income taxes	$	27	$	10

A reconciliation of the federal statutory income tax rate to the Company’s effective tax rate is as follows:


	December 31,
	2023			2022
Income tax computed at federal statutory rate		21.0	%		21.0	%
State taxes, net of federal benefit		7.1	%		6.1	%
Tax credit carryforwards		3.6	%		6.2	%
Permanent items		(1.0	)%		(0.2	)%
Change in valuation allowance		(30.8	)%		(32.7	)%
Other		0.1	%		(0.4	)%
Effective tax rate		—	%		—	%

The principal components of the Company’s deferred tax assets and liabilities as of December 31, 2023 and 2022 were comprised as follows (in thousands):


	December 31,
	2023			2022
Deferred tax assets:
Net operating loss carryforwards	$	80,385		$	19,580
Tax credit carryforwards		22,474			5,477
Capitalized research and development		34,395			10,279
Stock-based compensation		4,494			319
Amortization		1,138			—
Operating lease liability		9,052			855
Accrued expenses and other temporary differences		1,543			707
Total deferred tax assets		153,481			37,217
Less: valuation allowance		(145,766	)		(36,094	)
Net deferred tax assets		7,715			1,123
Deferred tax liabilities:
Operating right-of-use asset		(7,401	)		(552	)
Depreciation		(314	)		(571	)
Total deferred tax liabilities		(7,715	)		(1,123	)
Net deferred taxes	$	—		$	—

As of December 31, 2023, the Company had federal and state net operating loss (“NOL”) carryforwards of $302.5 million and $266.3 million, respectively. Under current law, the Company's federal NOLs generated in taxable years ending after December 31, 2017, may be carried forward indefinitely, but the deductibility of such federal NOLs is limited to 80% of the Company's taxable income annually for tax years beginning after December 31, 2018. Federal NOLs generated in taxable years ending on or prior to December 31, 2017, however, have a 20-year carryforward period, but are not subject to the 80% limitation. The Company has federal NOLs of $22.4 million that are subject to expiration between 2036 and 2037 and has $280.1 million of federal NOLs that do not expire.

State NOLs expire at various dates from 2035 through 2043. As of December 31, 2023, the Company had federal research and development tax credit carryforwards of $15.6 million that expire at various dates from 2036 through 2043. In addition, as of December 31, 2023, the Company had state research and development tax credit carryforwards of $8.7 million that expire at various dates from 2032 through 2038.

The Company has evaluated the positive and negative evidence bearing upon the realizability of its deferred tax assets, which primarily pertain to NOL carryforwards, tax credit carryforwards and capitalized research and development. The Company has determined that it is more likely than not that it will not realize the benefits of its deferred tax assets, and as a result, a valuation allowance of $145.8 million has been established at December 31, 2023. The increase in the valuation allowance of $109.7 million during the year ended December 31, 2023 was primarily due to the additional operating loss generated by the Company and the combination of deferred tax assets as a result of the Merger.

NOL and tax credit carryforwards are subject to review and possible adjustment by the Internal Revenue Service and may become subject to an annual limitation in the event of certain cumulative changes in the ownership interest of significant shareholders over a three-year period in excess of 50% as defined under Sections 382 and 383 in the IRC. This could limit the amount of tax attributes that can be utilized annually to offset future taxable income or tax liabilities. The amount of the annual limitation is determined based on the Company’s value immediately prior to the ownership change. As a result of ownership changes in the Company from its inception through December 31, 2023, the Company’s NOL and tax credit carryforwards allocable to the periods preceding each such ownership change could be subject to limitations under IRC Section 382, however the Company has not yet completed an IRC Section 382 study.

The Company had no unrecognized tax benefits as of either December 31, 2023 or 2022. The Company has not conducted a study of its research and development credit carryforwards generated during any year. This study, once completed, may result in an adjustment to the Company’s research and development credit carryforwards.

However, until a study is completed and any adjustment is known, no amounts are being presented as an uncertain tax position. A full valuation allowance has been provided against the Company’s research and development credit carryforwards, and if an adjustment is required, this adjustment would be offset by an adjustment to the valuation allowance. Thus, there would be no impact to the consolidated statements of operations and comprehensive loss if an adjustment were required.

The Company files income tax returns in the United States federal tax jurisdiction and the Connecticut and Massachusetts state tax jurisdictions. Because the Company is in a loss carryforward position, it is generally subject to examination by federal and state tax authorities for all tax years in which a loss carryforward is available.

As of December 31, 2023, the Company has not incurred any material interest or penalty charges.

- Definition

The entire disclosure for income taxes. Disclosures may include net deferred tax liability or asset recognized in an enterprise's statement of financial position, net change during the year in the total valuation allowance, approximate tax effect of each type of temporary difference and carryforward that gives rise to a significant portion of deferred tax liabilities and deferred tax assets, utilization of a tax carryback, and tax uncertainties information.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 13
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480990/946-20-50-13

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 235
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(h)(2))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480678/235-10-S99-1

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-Name Accounting Standards Codification
-Publisher FASB
-URI https://asc.fasb.org//740/tableOfContent

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 14
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482685/740-10-50-14

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 21
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482685/740-10-50-21

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-SubTopic 270
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482526/740-270-50-1

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 17
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482685/740-10-50-17

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SAB TOPIC 6.I.5.Q1)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479360/740-10-S99-1

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 2
-Subparagraph (SAB Topic 11.C)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479360/740-10-S99-2

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482603/740-30-50-2

+ Details

Net Loss per Share - Schedule of Basic And Diluted Net Loss per Share Attributable to Common Stockholders (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Numerator:
Net loss	$ (81,172)	$ (58,032)
Denominator:
Weighted-average shares used in computing net loss per share, basic	1,529,321	255,175
Weighted-average shares used in computing net loss per share, diluted	1,529,321	255,175
Net loss per share, basic	$ (53.08)	$ (227.42)
Net loss per share, diluted	$ (53.08)	$ (227.42)

- Definition

The amount of net income (loss) for the period per each share of common stock or unit outstanding during the reporting period.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 250
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483443/250-10-50-3

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 260
-SubTopic 10
-Name Accounting Standards Codification
-Section 55
-Paragraph 15
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482635/260-10-55-15

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 815
-SubTopic 40
-Name Accounting Standards Codification
-Section 65
-Paragraph 1
-Subparagraph (e)(4)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480175/815-40-65-1

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 815
-SubTopic 40
-Name Accounting Standards Codification
-Section 65
-Paragraph 1
-Subparagraph (f)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480175/815-40-65-1

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 250
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 11
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483443/250-10-50-11

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Topic 250
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 11
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483443/250-10-50-11

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Topic 250
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 7
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483443/250-10-50-7

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Topic 260
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 2
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482689/260-10-45-2

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Topic 260
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 60B
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482689/260-10-45-60B

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Topic 250
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 4
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483443/250-10-50-4

Reference 11: http://www.xbrl.org/2003/role/disclosureRef
-Topic 260
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482662/260-10-50-1

Reference 12: http://www.xbrl.org/2003/role/disclosureRef
-Topic 260
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 10
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482689/260-10-45-10

Reference 13: http://www.xbrl.org/2003/role/disclosureRef
-Topic 220
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03(25))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483621/220-10-S99-2

Reference 14: http://www.xbrl.org/2003/role/disclosureRef
-Topic 942
-SubTopic 220
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-04(27))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483589/942-220-S99-1

Reference 15: http://www.xbrl.org/2003/role/disclosureRef
-Topic 944
-SubTopic 220
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-04(23))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483586/944-220-S99-1

Reference 16: http://www.xbrl.org/2003/role/exampleRef
-Topic 260
-SubTopic 10
-Name Accounting Standards Codification
-Section 55
-Paragraph 52
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482635/260-10-55-52

Reference 17: http://www.xbrl.org/2003/role/disclosureRef
-Topic 260
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 7
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482689/260-10-45-7

+ Details

- Definition

The amount of net income (loss) for the period available to each share of common stock or common unit outstanding during the reporting period and to each share or unit that would have been outstanding assuming the issuance of common shares or units for all dilutive potential common shares or units outstanding during the reporting period.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 250
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483443/250-10-50-3

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 260
-SubTopic 10
-Name Accounting Standards Codification
-Section 55
-Paragraph 15
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482635/260-10-55-15

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 815
-SubTopic 40
-Name Accounting Standards Codification
-Section 65
-Paragraph 1
-Subparagraph (e)(4)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480175/815-40-65-1

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 815
-SubTopic 40
-Name Accounting Standards Codification
-Section 65
-Paragraph 1
-Subparagraph (f)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480175/815-40-65-1

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 250
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 11
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483443/250-10-50-11

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Topic 250
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 11
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483443/250-10-50-11

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Topic 250
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 7
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483443/250-10-50-7

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Topic 260
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 2
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482689/260-10-45-2

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Topic 260
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 60B
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482689/260-10-45-60B

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Topic 250
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 4
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483443/250-10-50-4

Reference 11: http://www.xbrl.org/2003/role/disclosureRef
-Topic 260
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482662/260-10-50-1

Reference 12: http://www.xbrl.org/2003/role/disclosureRef
-Topic 220
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03(25))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483621/220-10-S99-2

Reference 13: http://www.xbrl.org/2003/role/disclosureRef
-Topic 942
-SubTopic 220
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-04(27))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483589/942-220-S99-1

Reference 14: http://www.xbrl.org/2003/role/disclosureRef
-Topic 944
-SubTopic 220
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-04(23))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483586/944-220-S99-1

Reference 15: http://www.xbrl.org/2003/role/exampleRef
-Topic 260
-SubTopic 10
-Name Accounting Standards Codification
-Section 55
-Paragraph 52
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482635/260-10-55-52

Reference 16: http://www.xbrl.org/2003/role/disclosureRef
-Topic 260
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 7
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482689/260-10-45-7

+ Details

- Definition

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 235
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(g)(1)(ii))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480678/235-10-S99-1

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 323
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481687/323-10-50-3

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 825
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 28
-Subparagraph (f)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482907/825-10-50-28

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 220
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 6
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482765/220-10-50-6

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 250
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483443/250-10-50-3

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Topic 250
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (b)(2)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483443/250-10-50-1

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Topic 815
-SubTopic 40
-Name Accounting Standards Codification
-Section 65
-Paragraph 1
-Subparagraph (f)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480175/815-40-65-1

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Topic 250
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 8
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483443/250-10-50-8

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Topic 250
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 9
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483443/250-10-50-9

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Topic 250
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 11
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483443/250-10-50-11

Reference 11: http://www.xbrl.org/2003/role/disclosureRef
-Topic 250
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 11
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483443/250-10-50-11

Reference 12: http://www.xbrl.org/2003/role/disclosureRef
-Topic 250
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 4
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483443/250-10-50-4

Reference 13: http://www.xbrl.org/2003/role/exampleRef
-Topic 946
-SubTopic 830
-Name Accounting Standards Codification
-Section 55
-Paragraph 10
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480167/946-830-55-10

Reference 14: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 220
-Name Accounting Standards Codification
-Section 45
-Paragraph 7
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483581/946-220-45-7

Reference 15: http://www.xbrl.org/2003/role/disclosureRef
-Topic 944
-SubTopic 220
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-04(18))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483586/944-220-S99-1

Reference 16: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 22
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-22

Reference 17: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 220
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.6-07(9))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483575/946-220-S99-1

Reference 18: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 220
-Name Accounting Standards Codification
-Section S99
-Paragraph 3
-Subparagraph (SX 210.6-09(1)(d))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483575/946-220-S99-3

Reference 19: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1A
-Subparagraph (SX 210.13-01(a)(4)(i))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480097/470-10-S99-1A

Reference 20: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 470
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1A
-Subparagraph (SX 210.13-01(a)(4)(ii))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480097/470-10-S99-1A

Reference 21: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1A
-Subparagraph (SX 210.13-01(a)(4)(iii)(A))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480097/470-10-S99-1A

Reference 22: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1A
-Subparagraph (SX 210.13-01(a)(4)(iv))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480097/470-10-S99-1A

Reference 23: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1A
-Subparagraph (SX 210.13-01(a)(5))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480097/470-10-S99-1A

Reference 24: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1B
-Subparagraph (SX 210.13-02(a)(4)(i))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480097/470-10-S99-1B

Reference 25: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1B
-Subparagraph (SX 210.13-02(a)(4)(iii)(A))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480097/470-10-S99-1B

Reference 26: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1B
-Subparagraph (SX 210.13-02(a)(4)(iii)(B))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480097/470-10-S99-1B

Reference 27: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1B
-Subparagraph (SX 210.13-02(a)(4)(iv))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480097/470-10-S99-1B

Reference 28: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1B
-Subparagraph (SX 210.13-02(a)(5))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480097/470-10-S99-1B

Reference 29: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 30
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-30

Reference 30: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 32
-Subparagraph (f)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-32

Reference 31: http://www.xbrl.org/2003/role/disclosureRef
-Topic 260
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 60B
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482689/260-10-45-60B

Reference 32: http://www.xbrl.org/2003/role/exampleRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 31
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-31

Reference 33: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 32
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-32

Reference 34: http://www.xbrl.org/2003/role/disclosureRef
-Topic 205
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 7
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483499/205-20-50-7

Reference 35: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 230
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 28
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482740/230-10-45-28

Reference 36: http://www.xbrl.org/2003/role/disclosureRef
-Topic 220
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 1A
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482790/220-10-45-1A

Reference 37: http://www.xbrl.org/2003/role/disclosureRef
-Topic 220
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 1B
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482790/220-10-45-1B

Reference 38: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 220
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03(20))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483621/220-10-S99-2

Reference 39: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 942
-SubTopic 220
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-04(22))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483589/942-220-S99-1

+ Details

Stock-based Compensation (Tables)

12 Months Ended

Dec. 31, 2023

Share-Based Payment Arrangement [Abstract]

Summary of Stock-based Compensation Expense

Total stock-based compensation expense recognized in the consolidated statements of operations and comprehensive loss for the years ended December 31, 2023 and 2022 was as follows (in thousands):


	Year Ended December 31,
	2023		2022
Research and development	$	759	$	243
General and administrative		1,622		897
Total stock-based compensation expense	$	2,381	$	1,140

Summary of Restricted Common Stock Activity

The following table summarizes Legacy Korro restricted common stock activity during the year ended December 31, 2023:


	Shares		Weighted- Average Grant Date Fair Value per Share
Unvested as of December 31, 2022		2,902	$	0.59
Granted		—	$	—
Vested		2,902	$	0.23
Repurchased		—	$	—
Unvested as of December 31, 2023		—	$	—

Summary of Stock Option Weighted-Average Assumptions

The fair value of stock options granted during the years ended December 31, 2023 and 2022 was calculated on the date of grant using the following weighted-average assumptions:


	Year Ended December 31,
	2023			2022
Risk-free interest rate		4.3	%		2.5	%
Expected dividend yield	—%			—%
Expected term (in years)		6.0			6.0
Expected volatility		72.8	%		72.9	%

Summary of Stock Option Activity

The following table summarizes changes in stock option activity during the year ended December 31, 2023 (in thousands, except per share amounts):


	Options			Weighted- Average Exercise Price		Weighted- Average Remaining Contractual Term (in years)		Aggregate Intrinsic Value
Outstanding at December 31, 2022		461,100		$	14.95		8.0	$	2,953
Assumed in reverse recapitalization		93,153		$	121.91
Granted		835,839		$	17.33
Exercised		(39,395	)	$	16.41
Forfeited		(20,091	)	$	20.07
Cancelled		(7,455	)	$	18.85
Outstanding as of December 31, 2023		1,323,151		$	23.49		8.4	$	36,310
Exercisable at December 31, 2023		368,036		$	34.60		6.7	$	8,457

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Current assets:
Cash and cash equivalents	$ 166,150	$ 36,333
Short-term investments	0	18,915
Restricted cash	3,563	603
Prepaid expenses and other current assets	3,015	1,232
Total current assets	172,728	57,083
Property and equipment, net	15,665	9,866
Operating lease right-of-use assets	27,150	2,024
Restricted Cash, net of current portion	3,406	4,541
Other non-current assets	2,714	228
Total assets	221,663	73,742
Current Liabilities
Accounts payable	7,280	2,605
Accrued expenses and other current liabilities	10,212	3,175
Operating lease liabilities, current portion	1,991	2,921
Total current liabilities	19,483	8,701
Operating lease liabilities, net of current portion	31,216	209
Other non-current liabilities	1,053	0
Total liabilities	51,752	8,910
Commitments and contingencies (Note 13)
Stockholders' equity (deficit)
Preferred stock, $0.001 par value; 10,000,000 shares and no shares authorized at December 31, 2023 and 2022; no shares issued and outstanding at December 31, 2023 and 2022	0	0
Common stock, $0.001 par value; 200,000,000 and 5,755,759 shares authorized at December 31, 2023 and 2022; 8,016,516 and 271,371 shares issued at December 31, 2023 and 2022, respectively; 8,016,516 and 268,468 shares outstanding at December 31, 2023 and 2022	8	0
Additional paid-in capital	352,908	2,807
Accumulated other comprehensive loss	0	(5)
Accumulated deficit	(183,005)	(101,833)
Total stockholders' equity (deficit)	169,911	(99,031)
Total liabilities, convertible preferred stock and stockholders' equity (deficit)	221,663	73,742
Series Seed Convertible Preferred Stock [Member]
Current Liabilities
Temporary equity, convertible preferred stock	0	15,924
Series A Preferred Stock [Member]
Current Liabilities
Temporary equity, convertible preferred stock	0	77,736
Series B-1 Preferred Stock [Member]
Current Liabilities
Temporary equity, convertible preferred stock	0	57,703
Series B-2 Preferred Stock [Member]
Current Liabilities
Temporary equity, convertible preferred stock	$ 0	$ 12,500

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Net loss	$ (81,172)	$ (58,032)
Adjustments to reconcile net loss to net cash used in operating activities:
Non-cash lease expense	3,610	1,396
Stock-based compensation expense	2,381	1,140
Depreciation expense	3,630	2,511
Non-cash interest expense	0	118
Net amortization of premiums and discounts on investments	(80)	(145)
Loss on disposal of property and equipment	65	0
Changes in operating assets and liabilities:
Prepaid expenses and other current assets	559	(28)
Accounts payable	3,100	1,755
Accrued expenses	1,270	(39)
Operating lease liabilities	1,341	(2,198)
Other non-current assets	(1,987)	(123)
Net cash used in operating activities	(67,283)	(53,645)
Investing Activities
Purchases of investments		(37,213)
Proceeds from maturities of investments	19,000	53,485
Purchases of property and equipment	(7,836)	(5,136)
Advance payments for property and equipment not yet received		(76)
Net cash provided by (used in) investing activities	11,164	11,060
Financing Activities
Proceeds from exercises of stock options	702	62
Proceeds from the issuance of common stock in pre-closing financing	117,250	0
Cash acquired in connection with the reverse recapitalization	36,600	0
Payment of reverse recapitalization transaction costs	(12,247)	0
Other financing activities, net	(2)	(44)
Net cash provided by financing activities	187,761	18
Net (decrease) increase in cash, cash equivalents, and restricted cash	131,642	(42,567)
Cash, cash equivalents and restricted cash, beginning of period	41,477	84,044
Cash, cash equivalents and restricted cash, end of period	173,119	41,477
Noncash Investing and Financing Items [Abstract]
Property and equipment capitalized under tenant improvement allowance	2,271	0
Purchases of property and equipment in accounts payable and accrued expenses	1,983	402
Operating Lease Liabilities Arising From Right-Of-Use Assets	26,777	5,629
Operating lease liabilities arising from lease modification	1,959	0
Supplemental cash flow information
Cash paid for income taxes	27	11
Cash paid for operating lease liabilities	2,978	2,335
Series B-2 Preferred Stock [Member]
Financing Activities
Proceeds from Series convertible preferred stock, net of issuance costs	$ 45,458	$ 0

Accrued Expenses and Other Current Liabilities - Schedule of Accrued Expenses and Other Current Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Payables and Accruals [Abstract]
Other employee compensation and benefits	$ 7,896	$ 2,624
External research and development services	1,255	274
Other operating expenses	447	207
CVR Liability, Current	395	0
Professional fees	219	70
Total accrued expenses and other current liabilities	$ 10,212	$ 3,175

Genevant Agreement

12 Months Ended

Dec. 31, 2023

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Genevant Agreement

13. Genevant Agreement

In March 2023, Legacy Korro entered into a collaboration and license agreement (the “Genevant Agreement”) with Genevant Sciences GmbH (“Genevant”). Key financial terms under the Genevant Agreement are as follows:

•

The Company made a $2.5 million payment to Genevant in March 2023 upon execution of the Genevant Agreement and recorded the payment within research and development expense in the consolidated statement of operations for the year ended December 31, 2023.

•

The Company will reimburse Genevant for certain out-of-pocket and full-time equivalent costs incurred as a result of research and development activities performed under the Genevant Agreement.

•

Genevant is entitled to receive payments from the Company upon the achievement of certain milestones, including potential clinical milestone payments of up to $13.5 million, potential regulatory and development milestone payments of up to $27.0 million, and potential commercial milestone payments up to an aggregate total of $57.0 million.

•

Genevant is eligible to receive royalties at percentage rates in the mid-single-digits, based on future annual net sales of licensed products within the scope of the Genevant Agreement.

As of December 31, 2023, no milestones have been achieved and the Company has recorded payments to Genevant of $1.2 million within research and development expense in the consolidated statement of operations during the year ended December 31, 2023.

Related Party Transactions (Additional Information) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Related Party Transaction [Line Items]
Incurred expenses	$ 0	$ 0
Affiliate amount related to consulting services	0	$ 0
Maximum [Member]
Related Party Transaction [Line Items]
Incurred expenses	$ 100

Commitments and Contingencies - Schedule of Lease Costs (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Commitments and Contingencies Disclosure [Abstract]
Operating lease liabilities arising from lease modification	$ 5,948	$ 1,675
Variable Lease Costs	1,211	732
Short-term Lease Costs	921	626
Total Lease Costs	$ 8,080	$ 3,033

Reverse Merger

12 Months Ended

Dec. 31, 2023

Business Combination and Asset Acquisition [Abstract]

Reverse Merger

3. Reverse Merger

As described in Note 1, Legacy Korro merged with Frequency on November 3, 2023. The merger was accounted for as a reverse recapitalization with Legacy Korro as the accounting acquirer. The primary pre-combination assets of Frequency were cash and cash equivalents. Under reverse recapitalization accounting, the assets and liabilities of Frequency were recorded at their fair value which approximated book value due to the short-term nature of the accounts. No goodwill or intangible assets were recognized. Consequently, the consolidated financial statements of the Company reflect the operations of Legacy Korro for accounting purposes, together with a deemed issuance of shares equivalent to the shares held by the former stockholders of Frequency, the legal acquirer, and a recapitalization of the equity of Legacy Korro, the accounting acquirer.

As part of the reverse recapitalization, the Company acquired $36.6 million of cash and cash equivalents. The Company also obtained prepaids and other assets of $1.9 million and assumed accounts payable and accrued expenses of $5.4 million. Frequency’s development programs had ceased prior to the merger and were deemed to be de minimis in value at the transaction date.

In addition, the Company recognized $0.3 million in share-based compensation expense as a result of the acceleration of vesting of stock options, performance stock units and restricted stock units at the time of merger. This amount was recorded in general and administrative expense in the accompanying consolidated statements of operations and comprehensive loss for the year ended December 31, 2023. The company recognized $2.5 million in personnel cost related to the severance payment to Frequency employees and this amount was recorded in general and administrative expense in the accompanying consolidated statements of operations and comprehensive loss for the year ended December 31, 2023. The Company also incurred transaction costs of $12.2 million and this amount is recorded in additional paid-in capital in the accompanying consolidated statements of convertible preferred stock and stockholders’ equity (deficit) for the year ended December 31, 2023.

Preferred Stock (Additional Information) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2023	Nov. 03, 2023	Dec. 31, 2022
Class of Stock [Line Items]
Preferred stock, shares issued	0		0
Preferred Stock, Shares Authorized	10,000,000		0
Preferred stock, par value	$ 0.001		$ 0.001
Preferred Stock, Shares Outstanding	0		0
Preferred Stock, Convertible, Conversion Ratio	4.9688%
Preferred Stock [Member]
Class of Stock [Line Items]
Percentage of outstanding shares of Preferred Stock	66.00%
Preferred Stock, Dividend Rate, Percentage	8.00%
Preferred Stock, Convertible, Conversion Ratio	4.9688%
Preferred Stock [Member] \| Minimum [Member]
Class of Stock [Line Items]
Sale of Stock, Price Per Share	$ 111.9
Proceeds from Issuance Initial Public Offering	$ 75,000
Percentage of outstanding shares of Preferred Stock	66.00%
Series A Convertible Preferred Stock [Member]
Class of Stock [Line Items]
Sale of Stock, Price Per Share	$ 45.08
Preferred Stock, Shares Outstanding	0		2,029,666
Preferred Stock, Convertible, Conversion Price	$ 45.08
Series B Preferred Stock
Class of Stock [Line Items]
Preferred Stock, Shares Outstanding	0		1,104,178
Series B-1 Preferred Stock [Member]
Class of Stock [Line Items]
Sale of Stock, Price Per Share	$ 52.53
Preferred Stock, Convertible, Conversion Price	52.53
Series B-2 Preferred Stock [Member]
Class of Stock [Line Items]
Sale of Stock, Price Per Share	55.95
Preferred Stock, Convertible, Conversion Price	55.95
Series Seed Preferred Stock [Member]
Class of Stock [Line Items]
Sale of Stock, Price Per Share	$ 20.13
Preferred Stock, Shares Outstanding	0		684,739
Preferred Stock, Convertible, Conversion Price	$ 20.13
Series Seed-3 Preferred Stock [Member]
Class of Stock [Line Items]
Sale of Stock, Price Per Share	26.16
Preferred Stock, Convertible, Conversion Price	$ 26.16
Legacy Korro [Member]
Class of Stock [Line Items]
Preferred stock, shares issued			4,042,000
Preferred Stock, Shares Authorized			4,855,239
Preferred Stock, Shares Outstanding			4,042,000
Legacy Korro [Member] \| Preferred Stock [Member]
Class of Stock [Line Items]
Preferred stock, shares issued			0
Preferred Stock, Shares Authorized			10,000,000
Preferred stock, par value			$ 0.001
Preferred Stock, Shares Outstanding			0
Preferred Stock, Convertible, Conversion Ratio		4.9688%
Legacy Korro [Member] \| Series A Convertible Preferred Stock [Member]
Class of Stock [Line Items]
Preferred stock, shares issued			2,029,666
Preferred Stock, Shares Authorized			2,029,666
Preferred Stock, Shares Outstanding			2,029,666
Legacy Korro [Member] \| Series B-1 Preferred Stock [Member]
Class of Stock [Line Items]
Preferred stock, shares issued			1,104,178
Preferred Stock, Shares Authorized			1,104,178
Preferred Stock, Shares Outstanding			1,104,178
Legacy Korro [Member] \| Series B-2 Preferred Stock [Member]
Class of Stock [Line Items]
Preferred stock, shares issued			223,417
Preferred Stock, Shares Authorized			1,036,656
Preferred Stock, Shares Outstanding			223,417
Legacy Korro [Member] \| Series Seed Preferred Stock [Member]
Class of Stock [Line Items]
Preferred stock, shares issued			684,739
Preferred Stock, Shares Authorized			684,739
Preferred Stock, Shares Outstanding			684,739

Stock-based Compensation - Summary of Restricted Common Stock Activity (Details) - Restricted Stock Units (RSUs) [Member]	12 Months Ended
	Dec. 31, 2023 $ / shares shares
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Unvested as of December 31, 2022 \| shares	2,902
Granted \| shares	0
Vested \| shares	2,902
Repurchased \| shares	0
Unvested as of December 31, 2023 \| shares	0
Weighted average fair value, Unvested as of December 31, 2022 \| $ / shares	$ 0.59
Weighted average fair value, Granted \| $ / shares	0
Weighted average fair value, Vested \| $ / shares	0.23
Weighted average fair value, Repurchased \| $ / shares	0
Weighted average fair value, Unvested as of December 31, 2023 \| $ / shares	$ 0

The Company and Liquidity (Additional Information) (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2023	Nov. 03, 2023	Dec. 31, 2022
Date of incorporation	Nov. 30, 2014
Common stock, shares issued	8,016,516		271,371
Exchange Ratio	4.9688%
Cash and cash equivalents	$ 166,150	$ 36,600	$ 36,333
Accumulated deficit	(183,005)		$ (101,833)
MS APA Asset [Member]
Initial Consideration Amount	500
MS APA Asset [Member] \| Minimum [Member]
Future Milestone Payments	700
MS APA Asset [Member] \| Maximum [Member]
Future Milestone Payments	$ 17,500
Common Stock [Member] \| Legacy Korro [Member]
Ownership	91.00%
Common Stock [Member] \| Legacy Korro [Member] \| Accredited Investors [Member]
Common stock, shares issued		42,176,255
Common Stock, Value, Subscriptions		$ 117,300
Sale of Stock, Price Per Share		$ 2.78
Common Stock [Member] \| Frequency [Member]
Common stock, shares issued	8,623,645	7,848,776
Ownership	9.00%
Preferred Stock [Member]
Exchange Ratio	4.9688%
Preferred Stock [Member] \| Minimum [Member]
Sale of Stock, Price Per Share	$ 111.9
Preferred Stock [Member] \| Legacy Korro [Member]
Exchange Ratio		4.9688%

Restricted Cash (Tables)

12 Months Ended

Dec. 31, 2023

Cash and Cash Equivalents [Abstract]

Schedule of Reconciliation of Cash, Cash Equivalents and Restricted Cash

The following table provides a reconciliation of cash, cash equivalents and restricted cash as of December 31, 2023 and 2022 that sums to the total of the same amounts shown in the consolidated statements of cash flows (in thousands):


	December 31,
	2023		2022
Cash and cash equivalents	$	166,150	$	36,333
Restricted cash		6,969		5,144
Cash, cash equivalents and restricted cash	$	173,119	$	41,477

Investments (Additional Information) (Details) $ in Millions	Dec. 31, 2022 USD ($) Securities
Investments [Abstract]
Fair value of securities in unrealized loss position for less than twelve \| $	$ 4.0
Number of position of securities in unrealized loss position for less than twelve \| Securities	0

Basis of Presentation and Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2023
Accounting Policies [Abstract]
Basis of Presentation and Consolidation	Basis of Presentation and Consolidation The accompanying consolidated financial statements have been prepared in accordance with generally accepted accounting principles in the United States of America (“GAAP”). These consolidated financial statements have been prepared on the going concern basis of accounting, which assumes continuity of operations, realization of assets and satisfaction of liabilities in the ordinary course of business. The consolidated financial statements include the accounts of Korro Bio, Inc. and its wholly-owned subsidiaries. All intercompany transactions and balances have been eliminated in consolidation.
Segment Information	Segment Information Operating segments are defined as components of an enterprise about which separate discrete information is available for evaluation by the chief operating decision-maker in deciding how to allocate resources and assess performance. The Company and the Company’s chief operating decision maker, the Company’s chief executive officer, views the Company’s operations and manages its business as a single operating segment. The Company operates only in the United States.
Use of Estimates	Use of Estimates The preparation of the Company’s consolidated financial statements requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the consolidated financial statements and the reported amounts of expenses during the reporting period. Significant estimates and assumptions reflected in these consolidated financial statements include, but are not limited to the fair value of the common stock prior to the effective date of the merger; the fair value of the CVR liability and the incremental borrowing rate for determining lease liabilities and right-of-use assets. The Company bases its estimates on historical experience, known trends and other market-specific or other relevant factors that it has concluded to be reasonable under the circumstances. On an ongoing basis, management evaluates its estimates as there are changes in circumstances, facts and experience. Changes in estimates are recorded in the period in which they become known. Actual results may differ materially from those estimates or assumptions.
Fair Value of Financial Instruments	Fair Value of Financial Instruments ASC Topic 820, Fair Value Measurement, (“ASC 820”) establishes a fair value hierarchy for instruments measured at fair value that distinguishes between assumptions based on market data (observable inputs) and the Company’s own assumptions (unobservable inputs). Observable inputs are inputs that market participants would use in pricing the asset or liability based on market data obtained from sources independent of the Company. Unobservable inputs are inputs that reflect the Company’s assumptions about the inputs that market participants would use in pricing the asset or liability and are developed based on the best information available in the circumstances. ASC 820 identifies fair value as the exchange price, or exit price, representing the amount that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants. As a basis for considering market participant assumptions in fair value measurements, ASC 820 establishes a three-tier fair value hierarchy that distinguishes between the following: • Level 1 inputs are quoted prices (unadjusted) in active markets for identical assets or liabilities. • Level 2 inputs are inputs other than quoted prices included within Level 1 that are observable for the asset or liability, either directly or indirectly. • Level 3 inputs are unobservable inputs that reflect the Company’s own assumptions about the assumptions market participants would use in pricing the asset or liability. Financial assets and liabilities are classified in their entirety based on the lowest level of input that is significant to the fair value measurement. To the extent that the valuation is based on models or inputs that are less observable or unobservable in the market, the determination of fair value requires more judgment. Accordingly, the degree of judgment exercised by the Company in determining fair value is greatest for instruments categorized in Level 3. A financial instrument’s level within the fair value hierarchy is based on the lowest level of any input that is significant to the fair value measurement.
Cash Equivalents	Cash Equivalents Cash equivalents are highly-liquid investments that are readily convertible into cash with original maturities of three months or less when purchased. These assets include investments in money market funds that invest in U.S. Treasury obligations. Cash equivalents are reflected at fair value based on quoted market prices, as further described in Note 3, “Fair Value Measurements”.
Investments	Investments Investments consist of securities with original maturities greater than three months when purchased. Short-term investments consist of investments that are available for use in current operations. Long-term investments consist of investments with maturities of greater than one year that are not available for use in current operations. The Company did not maintain any long-term investments as of December 31, 2023 or 2022. The Company classifies all of its investments as available-for-sale securities. Accordingly, these investments are recorded at fair value. Realized gains and losses and amortization and accretion of discounts and premiums are included in “Other income, net”. Unrealized gains and losses on available-for-sale securities are included in “Accumulated other comprehensive loss” as a component of stockholders’ deficit until realized. The Company reviews its investment portfolio to identify and evaluate investments that have indicators of possible other-than-temporary impairment. Factors considered in determining whether a loss is other-than-temporary include the length of time and extent to which fair value has been less than the cost basis, the financial condition of the issuer and the Company’s intent and ability to hold the investment for a period of time sufficient to allow for any anticipated recovery in market value.
Property and Equipment	Property and Equipment Property and equipment are recorded at cost and consists of laboratory equipment, furniture and office equipment, computer equipment, leasehold improvements, and construction in progress. The Company capitalizes property and equipment that is acquired for research and development activities and that has alternative future use. Expenditures for repairs and maintenance are recorded to expense as incurred, whereas major betterments are capitalized as additions to property and equipment. Property and equipment not yet placed into service is capitalized as construction in progress and is depreciated once placed into service. Leasehold improvements are depreciated over the lesser of their useful lives or the term of the lease. Depreciation, including depreciation for assets recorded under finance leases, is calculated over the estimated useful lives of the assets using the straight-line method.
Impairment of Long-lived Assets	Impairment of Long-lived Assets The Company reviews long-lived assets when events or changes in circumstances indicate that the carrying value of an asset may not be recoverable. Recoverability is measured by comparing the carrying value of the asset to the future undiscounted cash flows from the use and eventual disposition of the asset. If an asset is considered to be impaired, the impairment loss to be recognized is measured as the amount by which the carrying value of the asset exceeds its fair value. Leases Under ASC Topic 842, Leases (“ASC 842”), the Company determines whether an arrangement is or contains a lease at inception. For leases with a term of 12 months or less, the Company does not recognize a right-of-use asset or lease liability. The Company’s operating leases are recognized on its consolidated balance sheets as noncurrent assets, current liabilities and noncurrent liabilities. The Company does not have any finance leases. Right-of-use assets represent the Company’s right to use an underlying asset for the lease term and lease liabilities represent the Company’s obligation to make lease payments arising from the lease. Operating lease right-of-use assets and liabilities are recognized at the lease commencement date based on the present value of lease payments over the lease term. As the Company’s leases typically do not provide an implicit rate, the Company uses an estimate of its incremental borrowing rate based on the information available at the lease commencement date in determining the present value of lease payments. Lease expense is recognized on a straight-line basis over the lease term. The Company typically only includes an initial lease term in its assessment of a lease arrangement. Options to renew or options to terminate a lease are not included in the Company’s assessment unless there is reasonable certainty that the Company will exercise such options, respectively. The Company has elected to account for the lease and non-lease components together for existing classes of underlying assets. Preferred Stock The Company applies the guidance of ASC Topic 480, Distinguishing Liabilities from Equity (“ASC 480”), when determining the classification and measurement of its preferred stock. Preferred stock subject to mandatory redemption (if any) are classified as liability instruments and are measured at fair value. The Company classifies contingently redeemable preferred stock (if any), which includes preferred stock that features redemption rights that are either within the control of the holder or subject to redemption upon the occurrence of uncertain events not solely within the Company’s control, as temporary equity. At all other times, the Company classifies its preferred stock in stockholders’ equity (deficit). Prior to the merger, Legacy Korro classified its convertible preferred stock as temporary equity due to terms that allowed for redemption of the shares upon the occurrence of a contingent event that was not solely within the Legacy Korro’s control. Legacy Korro did not accrete the carrying values of the preferred stock to the redemption values since the contingent event was not considered probable.
Leases	Leases Under ASC Topic 842, Leases (“ASC 842”), the Company determines whether an arrangement is or contains a lease at inception. For leases with a term of 12 months or less, the Company does not recognize a right-of-use asset or lease liability. The Company’s operating leases are recognized on its consolidated balance sheets as noncurrent assets, current liabilities and noncurrent liabilities. The Company does not have any finance leases. Right-of-use assets represent the Company’s right to use an underlying asset for the lease term and lease liabilities represent the Company’s obligation to make lease payments arising from the lease. Operating lease right-of-use assets and liabilities are recognized at the lease commencement date based on the present value of lease payments over the lease term. As the Company’s leases typically do not provide an implicit rate, the Company uses an estimate of its incremental borrowing rate based on the information available at the lease commencement date in determining the present value of lease payments. Lease expense is recognized on a straight-line basis over the lease term. The Company typically only includes an initial lease term in its assessment of a lease arrangement. Options to renew or options to terminate a lease are not included in the Company’s assessment unless there is reasonable certainty that the Company will exercise such options, respectively. The Company has elected to account for the lease and non-lease components together for existing classes of underlying assets.
Preferred Stock	Preferred Stock The Company applies the guidance of ASC Topic 480, Distinguishing Liabilities from Equity (“ASC 480”), when determining the classification and measurement of its preferred stock. Preferred stock subject to mandatory redemption (if any) are classified as liability instruments and are measured at fair value. The Company classifies contingently redeemable preferred stock (if any), which includes preferred stock that features redemption rights that are either within the control of the holder or subject to redemption upon the occurrence of uncertain events not solely within the Company’s control, as temporary equity. At all other times, the Company classifies its preferred stock in stockholders’ equity (deficit). Prior to the merger, Legacy Korro classified its convertible preferred stock as temporary equity due to terms that allowed for redemption of the shares upon the occurrence of a contingent event that was not solely within the Legacy Korro’s control. Legacy Korro did not accrete the carrying values of the preferred stock to the redemption values since the contingent event was not considered probable.
Research and Development Expenses	Research and Development Expenses Expenditures relating to research and development are expensed as incurred. Research and development expenses include external expenses incurred under arrangements with third parties, academic and non-profit institutions and consultants; salaries and personnel-related costs, including non-cash stock-based compensation expense; license fees to acquire in-process technology and other expenses, which include direct and allocated expenses for laboratory, facilities and other costs. Non-refundable advance payments for goods and services that will be used in future research and development activities are expensed when the activity has been performed or when the goods have been received rather than when the payment is made. As part of the process of preparing the consolidated financial statements, the Company is required to estimate its accrued research and development expenses as of each balance sheet date. In accruing service fees, the Company estimates the time period over which services will be performed and the level of effort to be expended in each period. This process involves reviewing open contracts and purchase orders, communicating with internal personnel to identify services that have been performed on the Company’s behalf and estimating the level of service performed and the associated cost incurred for the service when the Company has not yet been invoiced or otherwise notified of the actual cost. The Company periodically confirms the accuracy of its estimates with its service providers and makes adjustments if necessary. The majority of the Company’s service providers invoice monthly in arrears for services performed or when contractual milestones are met. The financial terms of agreements with these service providers are subject to negotiation, vary from contract-to-contract and may result in uneven payment flows. In circumstances where amounts have been paid in excess of costs incurred, the Company records a prepaid expense.
Intellectual Property Expenses	Intellectual Property Expenses The Company expenses legal costs related to patent applications as they are incurred. Such costs are classified as general and administrative expenses within the consolidated statements of operations and comprehensive loss.
Stock-based Compensation	Stock-based Compensation The Company accounts for stock-based payments in accordance with ASC Topic 718, Compensation—Stock Compensation (“ASC 718”). This guidance requires all stock-based payments, including grants of stock options and restricted common stock, to be recognized as expense in the consolidated statements of operations and comprehensive loss based on their grant date fair values. For stock options granted to employees, non-employees and members of the Company’s Board of Directors for their services on the Board of Directors, the Company estimates the grant date fair value of each stock option using the Black-Scholes option-pricing model. For restricted common stock granted to employees and non-employees, the Company estimates the grant date fair value of each award using the intrinsic value, which is based on the value of the underlying common stock less any purchase price. For stock-based payments subject to service-based vesting conditions, the Company recognizes stock-based compensation expense equal to the grant date fair value of stock-based payment on a straight-line basis over the requisite service period. Prior to the merger, due to the absence of an active market for Legacy Korro’s common stock, Legacy Korro and its Board were required to determine the fair value of Legacy Korro’s common stock at the time of each grant of a stock-based award. Legacy Korro estimated the grant date fair value of its common stock using an appropriate valuation methodology, in accordance with the framework of the American Institute of Certified Public Accountants’ Technical Practice Aid, Valuation of Privately-Held Company Equity Securities Issued as Compensation. Historically, the Company has utilized a market approach to determine its total equity value and the option pricing method (“OPM”) to allocate this equity value among various classes of securities. The OPM treats common stock and convertible preferred stock as call options on the total equity value of a company, with exercise prices based on the value thresholds at which the allocation among the various holders of a company’s securities changes. Under the OPM, the common stock has value only if the funds available for distribution to stockholders exceeds the value of the convertible preferred stock liquidation preferences at the time of the liquidity event, such as a strategic sale or a merger. A discount for lack of marketability of the common stock is then applied to arrive at an indication of value for the common stock. Each valuation methodology includes estimates and assumptions that required the Legacy Korro’s judgment. These estimates and assumptions include a number of objective and subjective factors, including external market conditions, guideline public company information, the prices at which Legacy Korro sold convertible preferred stock to third parties in arms’ length transactions, the rights and preferences of securities senior to Legacy Korro’s common stock at the time and the likelihood of achieving a liquidity event such as an initial public offering or sale. Significant changes to the assumptions used in the valuations could result in different fair values of stock options and restricted stock at each valuation date, as applicable. In addition to the grant date fair value of the Company’s common stock, the Black-Scholes option pricing model requires the input of certain subjective assumptions, including (i) the calculation of expected term of the stock-based payment, (ii) the risk-free interest rate, (iii) the expected stock price volatility and (iv) the expected dividend yield. The Company uses the simplified method as proscribed by SEC Staff Accounting Bulletin No. 107 to calculate the expected term for stock options granted to employees as the Company does not have sufficient historical exercise data to provide a reasonable basis upon which to estimate the expected term. The Company determines the risk-free interest rate based on a treasury instrument whose term is consistent with the expected term of the stock options. Due to the lack of Company-specific historical and implied volatility data, the Company bases its estimates of expected volatility on the historical volatility of a group of publicly-traded companies with similar characteristics to itself, including stage of product development and therapeutic focus within the life sciences industry. The expected volatility has been determined using a weighted-average of the historical volatility measures of this group of companies. The Company expects to continue to do so until such time as it has adequate historical data regarding the volatility of its own traded stock price. Historical volatility is calculated over a period of time commensurate with the expected term of the stock-based payment. The Company uses an assumed dividend yield of zero as the Company has never paid dividends on its common stock, nor does it expect to pay dividends on its common stock in the foreseeable future. The Company accounts for forfeitures of all stock-based payments when such forfeitures occur.
Income Taxes	Income Taxes Income taxes are recorded in accordance with ASC Topic 740, Income Taxes, which provides for deferred taxes using an asset and liability approach. The Company recognizes deferred tax assets and liabilities for the expected future tax consequences of events that have been included in the consolidated financial statements or tax returns. Deferred tax assets and liabilities are determined based on the difference between the financial statement and tax bases of assets and liabilities using enacted tax rates in effect for the year in which the differences are expected to reverse. A valuation allowance against deferred tax assets is recorded if, based on the weight of the available evidence, it is more likely than not that some or all of the deferred tax assets will not be realized. The Company accounts for uncertain tax positions using a more-likely-than-not threshold for recognizing and resolving uncertain tax positions. The evaluation of uncertain tax positions is based on factors, including, but not limited to, changes in the law, the measurement of tax positions taken or expected to be taken in tax returns, the effective settlement of matters subject to audit, new audit activity and changes in facts or circumstances related to a tax position. Interest and penalty charges, if any, related to income taxes would be classified as a component of the “Provision for income taxes” in the consolidated statements of operations and comprehensive loss.
Net Loss per Share	Net Loss per Share Net loss per share attributable to common stockholders is calculated using the two-class method, which is an earnings allocation formula that determines net loss per share for the holders of the Company’s common shares and participating securities. The Company’s Preferred Stock contains participation rights in any dividend paid by the Company and is deemed to be a participating security. Net income attributable to common stockholders and participating preferred shares are allocated to each share as if all of the earnings for the period had been distributed. The participating securities do not include a contractual obligation to share in losses of the Company and are not included in the calculation of net loss per share in the periods in which a net loss is recorded. Net loss attributable to common stockholders is equal to the net loss for the period. Diluted net loss per share is computed using the more dilutive of (a) the two-class method or (b) the treasury stock method and if-converted method. The Company allocates earnings first to preferred stockholders based on dividend rights and then to common and preferred stockholders based on ownership interests. The weighted-average number of common shares included in the computation of diluted net loss gives effect to all potentially dilutive common equivalent shares, including outstanding stock options and Preferred Stock. Common stock equivalent shares are excluded from the computation of diluted net loss per share if their effect is antidilutive. In periods in which the Company reports a net loss attributable to common stockholders, diluted net loss per share attributable to common stockholders is generally the same as basic net loss per share attributable to common stockholders since dilutive common shares are not assumed to have been issued if their effect is anti-dilutive.
Concentration of Credit Risk and Off-Balance Sheet Risk	Concentration of Credit Risk and Off-Balance Sheet Risk Financial instruments that potentially expose the Company to concentrations of credit risk primarily consist of cash, cash equivalents and investments. Cash balances are deposited with federally-insured financial institutions in the United States and may, at times, exceed federally-insured limits. The Company maintains its cash, cash equivalents and investments with high-quality financial institutions and, consequently, the Company believes that such funds are subject to minimal credit risk. The Company’s cash equivalents are comprised of money market funds that are invested in U.S. Treasury and government agency obligations. The Company’s investments are comprised of commercial paper and government securities. Credit risk in these securities is reduced as a result of the Company’s investment policy to limit the amount invested in any single issuer and to only invest in securities of a high credit quality. The Company relies, and expects to continue to rely, on a small number of vendors to manufacture supplies and to process its product candidates for its development programs. These programs could be adversely affected by a significant interruption in the manufacturing process or supply chain. The Company has no significant off-balance sheet risk such as foreign exchange contracts, option contracts or other foreign hedging arrangements.
Emerging growth company status	Emerging growth company status The Company qualifies as an “emerging growth company” (“EGC”), as defined in the Jumpstart Our Business Startups Act (“JOBS Act”), and may take advantage of certain exemptions from various reporting requirements that are applicable to other public companies that are not EGCs. The Company may take advantage of these exemptions until it is no longer an EGC under Section 107 of the JOBS Act, which provides that an EGC can take advantage of the extended transition period afforded by the JOBS Act for the implementation of new or revised accounting standards. The Company has elected to avail itself of the extended transition period and, therefore, while the Company is an EGC it will not be subject to new or revised accounting standards the same time that they become applicable to other public companies that are not EGCs, unless it chooses to early adopt a new or revised accounting standard. As a result of this election, the consolidated financial statements may not be comparable to companies that comply with public company FASB standards’ effective dates.
Recently Adopted Accounting Pronouncements	Recently Adopted Accounting Pronouncements In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments, which has been subsequently amended by ASU 2018-19, ASU 2019-04, ASU 2019-05, ASU 2019-10, ASU 2019-11, ASU 2020-03, and ASU 2022-02 (“ASU 2016-13”). This standard requires that credit losses be recorded using an expected losses model rather than the incurred losses model that was previously used and establishes additional credit risk disclosures associated with financial assets. The amendments in this standard should be applied on a modified retrospective basis to all periods presented. The Company adopted ASU 2016-13 on January 1, 2023 using the modified retrospective approach. The adoption of this standard did not have a material effect on the Company’s financial position, results of operations or disclosures. Recent Accounting Pronouncements—Yet to be Adopted Other accounting standards that have been issued or proposed by the FASB or other standards-setting bodies that do not require adoption until a future date are not expected to have a material impact on the Company’s consolidated financial statements upon adoption. In November 2023, the FASB issued Accounting Standards Update ("ASU") 2023-07, Segment Reporting (Topic 280), Improvements to Reportable Segment Disclosures, which is intended to provide enhanced segment disclosures. The standard will require disclosures about significant segment expenses and other segment items and identifying the Chief Operating Decision Maker and how they use the reported segment profitability measures to assess segment performance and allocate resources. These enhanced disclosures are required for all public entities on an interim and annual basis, even if they have only a single reportable segment. The standard is effective for years beginning after December 15, 2023, and interim periods within annual periods beginning after December 15, 2024. Early adoption is permitted. The Company is evaluating this standard to determine if adoption will have a material impact on the Company's consolidated financial statements.
Recent Accounting Pronouncements - Yet to be Adopted	Recent Accounting Pronouncements—Yet to be Adopted Other accounting standards that have been issued or proposed by the FASB or other standards-setting bodies that do not require adoption until a future date are not expected to have a material impact on the Company’s consolidated financial statements upon adoption. In November 2023, the FASB issued Accounting Standards Update ("ASU") 2023-07, Segment Reporting (Topic 280), Improvements to Reportable Segment Disclosures, which is intended to provide enhanced segment disclosures. The standard will require disclosures about significant segment expenses and other segment items and identifying the Chief Operating Decision Maker and how they use the reported segment profitability measures to assess segment performance and allocate resources. These enhanced disclosures are required for all public entities on an interim and annual basis, even if they have only a single reportable segment. The standard is effective for years beginning after December 15, 2023, and interim periods within annual periods beginning after December 15, 2024. Early adoption is permitted. The Company is evaluating this standard to determine if adoption will have a material impact on the Company's consolidated financial statements

Fair Value Measurements

12 Months Ended

Dec. 31, 2023

Fair Value Disclosures [Abstract]

Fair Value Measurements

4. Fair Value Measurements

The Company measures the fair value of money market funds based on quoted prices in active markets for identical securities. Investments also include commercial paper and government securities that are valued either based on recent trades of securities in inactive markets or based on quoted market prices of similar instruments and other significant inputs derived from or corroborated by observable market data. The carrying amounts reflected in the consolidated balance sheets for cash, prepaid expenses and other current assets, accounts payable and accrued expenses approximate their fair values, due to their short-term nature.

Assets measured at fair value on a recurring basis as of December 31, 2023 were as follows (in thousands):


	Total		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Money market funds, included in cash and cash equivalents	$	158,706	$	158,706	$	—	$	—
MS APA asset	$	1,448	$	—	$	—	$	1,448
Total	$	160,154	$	158,706	$	—	$	1,448

Assets measured at fair value on a recurring basis as of December 31, 2022 were as follows (in thousands):


	Total		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Money market funds, included in cash and cash equivalents	$	14,904	$	14,904	$	—	$	—
Short-term investments:
Commercial paper	$	14,935		—		14,935		—
Government securities	$	3,980		—		3,980		—
Total	$	33,819	$	14,904	$	18,915	$	—

As noted previously in Note 1, at the effective time of the Transaction, the Company entered into the CVR Agreement providing for the payment of certain contingent cash payments equal to the net amount of proceeds actually received by the Company or its subsidiaries after the end of each fiscal quarter following the first anniversary of the closing of the Transaction related to the disposition of assets related to the Company’s former multiple sclerosis programs, with the time periods and subject to deductions as provided therein. The Company concluded that the CVR is a derivative liability and is accounted for at fair value, which was $1.4 million as of December 31, 2023 of which $0.4 million is included in accrued expenses and other current liabilities and the remaining $1.0 million in other non-current liabilities in the consolidated balance sheet. Concurrently, the Company entered into the MS APA with Progentos, whereby Progentos acquired the rights, title and interest in certain assets related to the Company’s MS program. The MS APA included initial consideration of $0.5 million in proceeds that were settled through net cash at the merger closing and will be entitled to future milestone payments of up to $17.5 million as well as a $0.7 million payment in the event of Progentos closing of an equity financing at or above a specified amount. The Company concluded that the MS APA is a derivative asset and is accounted for at fair value, which was $1.4 million as of December 31, 2023 of which $0.4 million is included in prepaid and other current assets and the remaining $1.0 million in other long-term assets in the consolidated balance sheet.

The fair value of the CVR liability and the MS APA are based on significant unobservable inputs, which represent Level 3 measurements within the fair value hierarchy. In determining the fair value of the CVR liability and the MS APA asset, the Company used the income approach, primarily discounted cash flow models. The discounted cash flow models require the use of significant judgment, estimates and assumptions, including the probability of technical and regulatory success, and discount rates. For the year ended December 31, 2023, the aggregate change in fair value of the CVR liability and MS APA asset was $0.08 million.

There were no liabilities measured at fair value on a recurring basis as of December 31, 2022.

There were no changes in valuation techniques, nor were there any transfers among the fair value hierarchy levels during the years ended December 31, 2023 or 2022.

- Definition

The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.

+ References + Details

Stock-based Compensation - Summary of Stock-based Compensation Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Stock-based compensation	$ 2,381	$ 1,140
Research and Development Expense [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Stock-based compensation	759	243
General and Administrative Expense [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Stock-based compensation	$ 1,622	$ 897

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 35
-Paragraph 1D
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480483/718-10-35-1D

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 35
-Paragraph 3
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480483/718-10-35-3

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (a)(1)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (a)(2)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (a)(3)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(i)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(ii)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(iii)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(iv)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(iv)(01)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Reference 11: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(iv)(02)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Reference 12: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(iv)(03)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Reference 13: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(iv)(04)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Reference 14: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)(2)(i)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Reference 15: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)(2)(ii)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Reference 16: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)(2)(iii)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Reference 17: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)(2)(iii)(01)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Reference 18: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)(2)(iii)(02)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Reference 19: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)(2)(iii)(03)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Reference 20: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (d)(1)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Reference 21: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (d)(2)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Reference 22: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (e)(1)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Reference 23: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (e)(2)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Reference 24: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (f)(2)(i)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Reference 25: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (f)(2)(ii)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Reference 26: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (f)(2)(iii)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Reference 27: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (f)(2)(iv)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Reference 28: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (f)(2)(v)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

+ Details

Property and Equipment, Net - Schedule of Property and Equipment (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Property, Plant and Equipment [Line Items]
Total property and equipment, gross	$ 23,507	$ 14,121
Less: accumulated depreciation	(7,842)	(4,255)
Total property and equipment, net	$ 15,665	$ 9,866
Property, Plant and Equipment, Dispositions	Shorter of useful life or remaining lease term	Shorter of useful life or remaining lease term
Laboratory equipment
Property, Plant and Equipment [Line Items]
Total property and equipment, gross	$ 11,187	$ 8,441
Estimated Useful Life (in Years)	5 years	5 years
Furniture and office equipment
Property, Plant and Equipment [Line Items]
Total property and equipment, gross	$ 481	$ 477
Estimated Useful Life (in Years)	4 years	4 years
Computer equipment
Property, Plant and Equipment [Line Items]
Total property and equipment, gross	$ 241	$ 213
Estimated Useful Life (in Years)	3 years	3 years
Leasehold improvements
Property, Plant and Equipment [Line Items]
Total property and equipment, gross	$ 3,356	$ 2,941
Construction in progress
Property, Plant and Equipment [Line Items]
Total property and equipment, gross	$ 8,242	$ 2,049

Stock-based Compensation (Additional Information) (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Nov. 30, 2023	Mar. 31, 2023
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Common stock, reserved for future issuance	1,675,396	5,487,208
Share-Based Compensation Arrangement by Share-Based Payment Award, Description	In addition, the number of shares of common stock available for issuance under the 2023 Plan will be automatically increased on the first day of each calendar year during the ten-year term of the 2023 Plan, beginning with January 1, 2024 and ending with January 1, 2033, by the amount equal to 5% of the outstanding number of shares of the Company’s common stock on December 31 of the preceding calendar year or such lesser amount as determined by the Company’s board of directors.
Number of Outstanding Option	1,323,151	461,100
Weighted-average grant date fair value of stock options granted	$ 23.49	$ 14.95
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Exercises in Period, Intrinsic Value	$ 0.3	$ 0.1
Total unrecognized stock-based compensation expense relating to unvested stock options	$ 10.1
Unrecognized unvested stock options, weighted-average period	3 years 1 month 6 days
Options vesting period	4 years
Options expiration period	10 years
Restricted Stock Units (RSUs) [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Fair value of restricted common stock	$ 0.1	$ 0.5
2019 Stock Incentive Plan Member
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Common stock, reserved for future issuance	600,977	683,156
2019 Stock Incentive Plan
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Common stock, reserved for future issuance	110,285
Common stock authorized under plan				747,752
2019 Incentive Award Plan [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Common stock authorized under plan	154,032
2023 Stock Option and Incentive Plan
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Common stock, reserved for future issuance	889,922		885,028
Common stock, shares available for future grants	255,694
2019 Stock Incentive Plan
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Number of Outstanding Option	51,491
2014 Stock Incentive Plan
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Common stock, reserved for future issuance	424,853
Common stock, shares available for future grants	0
Number of Outstanding Option	36,455
Legacy Korro [Member] \| 2019 Stock Incentive Plan
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Common stock, shares available for future grants	0	159,890

Net Loss per Share

12 Months Ended

Dec. 31, 2023

Earnings Per Share [Abstract]

Net Loss per Share

17. Net Loss per Share

The following common stock equivalents have been excluded from the calculation of diluted net loss per share because their effect would be anti-dilutive:


	Year Ended December 31,
	2023		2022
Legacy Korro Series Seed Preferred Stock		—		684,739
Legacy Korro Series A Preferred Stock		—		2,029,666
Legacy Korro Series B-1 Preferred Stock		—		1,104,178
Legacy Korro Series B-2 Preferred Stock		—		223,417
Unvested Legacy Korro restricted common stock		—		2,902
Outstanding Legacy Korro stock options		1,323,151		461,100
Outstanding Legacy Korro warrant		8,049		8,049
Total		1,331,200		4,514,051

Basic and diluted loss per share is computed by dividing net loss by the weighted-average common shares outstanding. The following table sets forth the computation of the Company's basic and diluted net loss per share (in thousands, except share and per share data):


	Years Ended December 31,
	2023			2022
Numerator:
Net loss	$	(81,172	)	$	(58,032	)
Denominator:
Weighted-average number of shares outstanding, basic and diluted		1,529,321			255,175
Net loss per share, basic and diluted	$	(53.08	)	$	(227.42	)

Commitments and Contingencies - Schedule of Future Minimum Rental Payments (Details) $ in Thousands	Dec. 31, 2023 USD ($)
Lessee, Lease, Description [Line Items]
2024	$ (7,227)
2025	6,247
2026	7,341
2027	7,557
Thereafter	52,498
Total Future Minimum Leases Payments	66,416
amount of lease payments representing interest	(33,209)
Present Value of Operating Lease Liabilities	$ 33,207

The Company and Liquidity

12 Months Ended

Dec. 31, 2023

Organization, Consolidation and Presentation of Financial Statements [Abstract]

The Company and Liquidity

1. The Company and Liquidity

Nature of Business

Korro Bio, Inc. (together with its subsidiaries, the “Company”) is a biopharmaceutical company with a mission to discover, develop and commercialize a new class of genetic medicines based on editing RNA, enabling the treatment of both rare and highly prevalent diseases. The Company was incorporated in November 2014 as a Delaware corporation. The Company's principal offices are in Cambridge, Massachusetts.

Risks and Uncertainties

The Company is subject to risks common to companies in the biotechnology industry including, but not limited to, new technological innovations, protection of proprietary technology, dependence on key personnel, compliance with government regulations and the need to obtain additional financing. Product candidates currently under development will require significant additional research and development efforts, including extensive pre-clinical and clinical testing and regulatory approval, prior to commercialization. These efforts will require significant amounts of additional capital, adequate personnel infrastructure and extensive compliance-reporting capabilities. Even if the Company’s product development efforts are successful, it is uncertain when, if ever, the Company will realize revenue from product sales.

Reverse Merger with Legacy Korro

On July 14, 2023, Frequency Merger Sub, Inc.(“Merger Sub”) a Delaware corporation, a wholly-owned subsidiary of Frequency Therapeutics, Inc. (“Frequency”), a Delaware corporation and Korro Bio, Inc (“Legacy Korro”), a Delaware corporation, entered into an Agreement and Plan of Merger (the “Merger Agreement”). The merger was completed on November 3, 2023 (the “Merger” or the "Transaction"). In accordance with the Merger Agreement, the Merger Sub merged with and into Legacy Korro, with Legacy Korro surviving as a wholly-owned subsidiary of the Company. In connection with the completion of the Merger, the Company changed its name from Frequency Therapeutics, Inc. to Korro Bio, Inc. On November 6, 2023, the combined company’s common stock began trading on The Nasdaq Capital Market under the ticker symbol “KRRO”.

Except as otherwise indicated, references herein to the “Company,” or the “combined company”, refer to Korro Bio, Inc. on a post-merger basis, and the term “Legacy Korro” refers to the business of privately held Korro Bio, Inc., prior to completion of the merger. References to Frequency refer to Frequency Therapeutics, Inc. prior to completion of the merger.

Concurrently with the execution and delivery of the Merger Agreement, Legacy Korro entered into a subscription agreement with a number of accredited investors. Immediately prior to consummation of the Merger, Legacy Korro issued and sold an aggregate of 42,176,255 shares of its common stock at a purchase price of approximately $2.78 per share, for an aggregate purchase price of approximately $117.3 million. Shares of Legacy Korro common stock issued pursuant to the Pre-Closing Financing were converted into shares of the Company’s common stock based on an exchange ratio (as defined below).

Pursuant to the terms of the Merger Agreement, immediately prior to the effective time of the Merger, each share of Legacy Korro preferred stock was converted into a share of Legacy Korro common stock, and then exchanged in the Merger for shares of Frequency common stock using an exchange ratio of 0.049688 (the “Exchange Ratio”).

At the effective time of the Merger, the Company issued (or reserved for issuance upon exercise of options assumed in the Merger) an aggregate of approximately 7,848,776 shares of its common stock to Legacy Korro securityholders (before eliminating fractions), calculated as provided in the Merger Agreement, (the “Exchange”), resulting in approximately 8,623,645 shares of its common stock being issued and outstanding on a fully diluted basis immediately following the effective time of the Merger. This number includes shares of the Company’s common stock that was issued upon vesting and settlement of certain outstanding equity awards at the effective time of the Merger. Immediately following the completion of the Merger, Frequency securityholders prior to the Merger owned approximately 9% of the outstanding shares of common stock on a fully diluted basis and Legacy Korro’s securityholders, including those securityholders who purchased shares in Legacy Korro’s pre-closing financing, owned approximately 91% of the outstanding shares on a fully diluted basis. The Merger was intended to qualify for federal income tax purposes as a tax-free reorganization under the provisions of Section 368(a) of the Internal Revenue Code of 1986, as amended (the "IRC").

Upon closing of the Merger, the Company assumed the Legacy Korro 2019 Stock Incentive Plan, and each outstanding and unexercised option to purchase Legacy Korro shares at such time, each of which converted into an option to purchase shares of the Company’s common stock, with necessary adjustments to the number of shares and exercise price to reflect the Exchange Ratio. In addition, upon the closing of the Merger, the Company assumed each outstanding and unexercised warrant to purchase

Legacy Korro shares at such time, each of which converted into a warrant to purchase shares of the Company’s common stock, with necessary adjustments to the number of shares and exercise price to reflect the Exchange Ratio.

At the effective time of the Merger, the Company entered into a contingent value rights agreement (the “CVR Agreement”) with Computershare Trust Company, N.A. and Computershare Inc., collectively as rights agent providing for the payment of certain contingent cash payments equal to the net amount (calculated in accordance with GAAP consistently applied) of proceeds actually received by the Company or its subsidiaries after the end of each fiscal quarter following the first anniversary of the closing of the Transaction related to the disposition of assets related to Frequency’s former multiple sclerosis programs, with the time periods and subject to deductions as provided therein. Concurrently, the Company entered into an asset purchase agreement with Progentos Therapeutics (“Progentos”), whereby Progentos acquired the rights, title and interest in certain assets related to Freqeuncy’s MS program ("MS APA"). The MS APA included initial consideration of $0.5 million in proceeds that were settled through net cash at the merger closing and will be entitled to future milestone payments of up to $17.5 million as well as a $0.7 million payment in the event of Progentos closing of an equity financing at or above a specified amount.

The Merger was accounted for as a reverse recapitalization in accordance with U.S. GAAP. For accounting purposes, Legacy Korro was considered to be acquiring the assets and liabilities of Frequency in the Merger based on the terms of the Merger Agreement and other factors, including: (i) Legacy Korro controlling the majority of outstanding voting shares; (ii) Legacy Korro controlling the Board of Directors; (iii) Legacy Korro’s executive management team became the management of the combined company; and (iv) the pre-combination assets of Frequency were primarily cash and cash equivalents and other non-operating assets. Accordingly, the Merger was treated as the equivalent of Legacy Korro issuing stock to acquire the net assets of Frequency. As a result of Legacy Korro being treated as the accounting acquirer, Legacy Korro’s assets and liabilities were recorded at their pre-combination carrying amounts. Frequency’s assets and liabilities were measured and recognized at their fair values, which approximated their carrying values as of the effective date of the Merger, and combined with the assets, liabilities, and results of operations of Legacy Korro after the consummation of the Merger. As a result, upon consummation the historical financial statements of Legacy Korro became the historical consolidated financial statements of the combined company.

Reverse Stock Split and Exchange Ratio

In connection with, and prior to the completion of, the merger, Frequency effected a one-for-fifty reverse stock split of its then outstanding common stock (the “Reverse Stock Split”). The par value and the authorized shares of the common stock were not adjusted as a result of the Reverse Stock Split. All issued and outstanding Legacy Korro common stock, convertible preferred stock and options prior to the effective date of the merger have been retroactively adjusted to reflect the merger 0.049688 Exchange Ratio, which reflects the impact of the reverse stock split, for all periods presented.

Liquidity and Capital Resources

The Company’s consolidated financial statements have been prepared on the basis of the Company continuing as a going concern. The Company expects that its existing cash and cash equivalents as of December 31, 2023 of $166.1 million will enable the Company to fund its planned operating expense and capital expenditure requirements for at least twelve months from the date of issuance of these consolidated financial statements. The Company has incurred recurring losses and negative cash flows from operations since inception. As of December 31, 2023, the Company had an accumulated deficit of $183.0 million. The Company expects its operating losses and negative operating cash flows to continue into the foreseeable future. The future viability of the Company is dependent on its ability to generate cash from operating activities or to raise additional capital to finance its operations. There can be no assurance that the Company will ever earn revenues or achieve profitability, or if achieved, that the revenues or profitability will be sustained on a continuing basis. In addition, the Company’s preclinical and clinical development activities, manufacturing and commercialization of the Company’s product candidates, if approved, will require significant additional financing. However, if the Company is unable to obtain additional financing, the Company would be forced to delay, reduce or eliminate its research and development programs and/or relinquish valuable rights to its technology and product candidates. There is no assurance that the Company will be successful in obtaining sufficient financing on acceptable terms to continue funding its operations.

Restricted Cash (Additional Information) (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Cash and Cash Equivalents [Abstract]
Restricted Cash, Current	$ 3,563	$ 603
Restricted Cash, Noncurrent	$ 3,400	$ 4,500

Income taxes (Additional Information) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Operating Loss Carryforwards [Line Items]
Net Operating Loss Carryforwards, Limitations on Use	Under current law, the Company's federal NOLs generated in taxable years ending after December 31, 2017, may be carried forward indefinitely, but the deductibility of such federal NOLs is limited to 80% of the Company's taxable income annually for tax years beginning after December 31, 2018. Federal NOLs generated in taxable years ending on or prior to December 31, 2017, however, have a 20-year carryforward period, but are not subject to the 80% limitation
Net Operating Loss Carryforwards Expiration without Limitation	$ 280,100
Tax Credit Carryforward, Amount	22,474	$ 5,477
Valuation Allowance	145,766	36,094
Change in Valuation Allowance Amount	$ 109,700
Explanation of Change in Valuation Allowance	the additional operating loss generated by the Company and the combination of deferred tax assets as a result of the Merger
Unrecognized Tax Benefits	$ 0	$ 0
Penalties Charges and Interest Expense	$ 0
Internal Revenue Service (IRS) [Member]
Operating Loss Carryforwards [Line Items]
Period of Cumulative Change in Ownership	3 years
Maximum [Member]
Operating Loss Carryforwards [Line Items]
Net Operating Loss Carryforwards, Expiration Year	2037
Minimum [Member]
Operating Loss Carryforwards [Line Items]
Net Operating Loss Carryforwards, Expiration Year	2036
Minimum [Member] \| Internal Revenue Service (IRS) [Member]
Operating Loss Carryforwards [Line Items]
Cumulative Change In Ownership Percentage	50.00%
State [Member]
Operating Loss Carryforwards [Line Items]
Net Operating Loss Carryforwards	$ 266,300
State [Member] \| Research and Development Tax Credit Carryforward [Member]
Operating Loss Carryforwards [Line Items]
Tax Credit Carryforward, Amount	$ 8,700
State [Member] \| Maximum [Member]
Operating Loss Carryforwards [Line Items]
Net Operating Loss Carryforwards, Expiration Year	2043
State [Member] \| Maximum [Member] \| Research and Development Tax Credit Carryforward [Member]
Operating Loss Carryforwards [Line Items]
Tax Credit Carryforward, Expiration Year	2038
State [Member] \| Minimum [Member]
Operating Loss Carryforwards [Line Items]
Net Operating Loss Carryforwards, Expiration Year	2035
State [Member] \| Minimum [Member] \| Research and Development Tax Credit Carryforward [Member]
Operating Loss Carryforwards [Line Items]
Tax Credit Carryforward, Expiration Year	2032
Federal [Member]
Operating Loss Carryforwards [Line Items]
Net Operating Loss Carryforwards	$ 302,500
Net Operating Loss Carryforwards Expiration with Limitation	22,400
Federal [Member] \| Research and Development Tax Credit Carryforward [Member]
Operating Loss Carryforwards [Line Items]
Tax Credit Carryforward, Amount	$ 15,600
Federal [Member] \| Maximum [Member] \| Research and Development Tax Credit Carryforward [Member]
Operating Loss Carryforwards [Line Items]
Tax Credit Carryforward, Expiration Year	2043
Federal [Member] \| Minimum [Member] \| Research and Development Tax Credit Carryforward [Member]
Operating Loss Carryforwards [Line Items]
Tax Credit Carryforward, Expiration Year	2036

Stock-based Compensation - Summary of Stock Option Weighted-Average Assumptions (Details)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Share-Based Payment Arrangement [Abstract]
Risk-free interest rate	4.30%	2.50%
Expected dividend yield	0.00%	0.00%
Expected term (in years)	6 years	6 years
Expected volatility	72.80%	72.90%

Investments

12 Months Ended

Dec. 31, 2023

Investments [Abstract]

Investments

5. Investments

The Company did not have investments as of December 31, 2023.

Short-term investments as of December 31, 2022 were comprised as follows (in thousands):


	Amortized Cost		Unrealized Gains		Unrealized Losses			Fair Value
Commercial paper	$	14,935	$	—	$	—		$	14,935
Government securities		3,985		—		(5	)		3,980
Total	$	18,920	$	—	$	(5	)	$	18,915

As of December 31, 2022, the aggregate fair value of securities that were in an unrealized loss position for less than twelve months was $4.0 million. As of December 31, 2022, the Company held no securities that were in an unrealized loss position for more than twelve months. As of December 31, 2022, the Company did not intend to sell, and would not be more likely than not required to sell, the securities in an unrealized loss position before recovery of their amortized cost bases. Furthermore, the Company determined that there was no material change in the credit risk of these securities. As a result, the Company determined it did not hold any securities with any other-than-temporary impairment as of December 31, 2022.

Commitments and Contingencies (Tables)

12 Months Ended

Dec. 31, 2023

Commitments and Contingencies Disclosure [Abstract]

Schedule of Future Minimum Rental Payments

Future minimum lease payments for all three leases, net of $10.8 million expected to be received and intended to be used related to the remaining tenant improvement allowance and rent credits associated with the 60 First Street Lease, as of December 31, 2023 were as follows (in thousands):


	As of December 31, 2023
2024		(7,227	)
2025		6,247
2026		7,341
2027		7,557
Thereafter		52,498
Total Future Minimum Leases Payments		66,416
Less: Interest		33,209
Present Value of Operating Lease Liabilities		33,207

Schedule of Lease Costs

The following table summarizes the effect of lease costs in the Company’s consolidated statement of operations and comprehensive loss of its operating leases (in thousands):


	Year Ended December 31,
	2023		2022
Operating lease costs	$	5,948	$	1,675
Variable Lease Costs		1,211		732
Short-term Lease Costs		921		626
Total Lease Costs	$	8,080	$	3,033

Preferred Stock (Tables)

12 Months Ended

Dec. 31, 2023

Class of Stock Disclosures [Abstract]

Schedule of Preferred Stock authorized, issued and outstanding Table

As of December 31, 2022, Legacy Korro Preferred Stock authorized, issued and outstanding consisted of the following (in thousands, except share amounts):


	December 31, 2022
	Preferred Stock Authorized		Preferred Stock Issued and Outstanding		Carrying Value		Liquidation Value		Common Stock Issuable Upon Conversion
Legacy Korro Series Seed Preferred Stock		684,739		684,739		15,924	$	16,115		684,739
Legacy Korro Series A Preferred Stock		2,029,666		2,029,666		77,736		91,500		2,029,666
Legacy Korro Series B-1 Preferred Stock		1,104,178		1,104,178		57,703		58,000		1,104,178
Legacy Korro Series B-2 Preferred Stock		1,036,656		223,417		12,500		12,500		223,417
Total		4,855,239		4,042,000	$	163,863	$	178,115		4,042,000

Property and Equipment, Net (Additional Information) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Property, Plant and Equipment [Abstract]
Depreciation	$ 3,630	$ 2,511
Construction in progress	$ 8,200	$ 2,000

Income Taxes (Tables)

12 Months Ended

Dec. 31, 2023

Income Tax Disclosure [Abstract]

Schedule of Provision for Income Taxes

The provision for income taxes for the years ended December 31, 2023 and 2022 was comprised as follows (in thousands):


	Year Ended December 31,
	2023		2022
Current taxes:
Federal	$	—	$	—
State		27		10
Total current taxes		27		10
Deferred taxes:
Federal		—		—
State		—		—
Total deferred taxes		—		—
Total provision for income taxes	$	27	$	10

Schedule of Reconciliation of U.S. Federal Statutory Income Tax Rate

A reconciliation of the federal statutory income tax rate to the Company’s effective tax rate is as follows:


	December 31,
	2023			2022
Income tax computed at federal statutory rate		21.0	%		21.0	%
State taxes, net of federal benefit		7.1	%		6.1	%
Tax credit carryforwards		3.6	%		6.2	%
Permanent items		(1.0	)%		(0.2	)%
Change in valuation allowance		(30.8	)%		(32.7	)%
Other		0.1	%		(0.4	)%
Effective tax rate		—	%		—	%

Schedule of Deferred Tax Assets and Liabilities

The principal components of the Company’s deferred tax assets and liabilities as of December 31, 2023 and 2022 were comprised as follows (in thousands):


	December 31,
	2023			2022
Deferred tax assets:
Net operating loss carryforwards	$	80,385		$	19,580
Tax credit carryforwards		22,474			5,477
Capitalized research and development		34,395			10,279
Stock-based compensation		4,494			319
Amortization		1,138			—
Operating lease liability		9,052			855
Accrued expenses and other temporary differences		1,543			707
Total deferred tax assets		153,481			37,217
Less: valuation allowance		(145,766	)		(36,094	)
Net deferred tax assets		7,715			1,123
Deferred tax liabilities:
Operating right-of-use asset		(7,401	)		(552	)
Depreciation		(314	)		(571	)
Total deferred tax liabilities		(7,715	)		(1,123	)
Net deferred taxes	$	—		$	—

Stock-based Compensation

12 Months Ended

Dec. 31, 2023

Share-Based Payment Arrangement [Abstract]

Stock-based Compensation

11. Stock-based Compensation

2023 Stock Option and Incentive Plan

In November 2023, the Company’s board of directors adopted the Company’s 2023 Stock Option and Incentive Plan (the “2023 Plan”). The 2023 Plan was approved by the Company’s stockholders in November 2023 and became effective in November 2023

in connection with completion of the Merger. The 2023 Plan initially reserved 885,028 shares for the issuance of stock awards. In addition, the number of shares of common stock available for issuance under the 2023 Plan will be automatically increased on the first day of each calendar year during the ten-year term of the 2023 Plan, beginning with January 1, 2024 and ending with January 1, 2033, by the amount equal to 5% of the outstanding number of shares of the Company’s common stock on December 31 of the preceding calendar year or such lesser amount as determined by the Company’s board of directors. Awards granted under the 2023 Plan expire no later than ten years from the date of grant. For stock options, the option price shall generally not be less than 100% of the fair market value on the day of grant. As of December 31, 2023, there were in aggregate 889,922 shares of common stock reserved for issuance and 255,694 shares available to grant under the 2023 Plan.

2019 Stock Incentive Plan

In January 2019, the Legacy Korro's Board of Directors adopted the 2019 Stock Incentive Plan (as amended from time to time, the “Legacy Korro Plan”). The Legacy Korro Plan provides for the grant of stock options, stock awards and restricted stock units to employees, members of the Company’s Board of Directors and non-employee consultants and advisors. The Legacy Korro Plan initially provided for the issuance of up to 110,285 shares of common stock. The Legacy Korro Plan was subsequently amended in May 2019, June 2020, October 2020, April 2021, November 2021 and March 2023 to modify the number of shares of common stock issuable under the Legacy Korro Plan. Subsequent to the March 2023 amendment to the Legacy Korro Plan, Legacy Korro could issue up to 747,752 shares of common stock under the Legacy Korro Plan.

In connection with the merger, each option to purchase shares of Legacy Korro common stock that was outstanding and unexercised under the Legacy Korro Plan immediately prior to the Effective Time, whether or not vested, was converted into an option to purchase shares of the Company’s common stock and became eligible to be registered on Form S-8. The Company assumed each outstanding option to purchase shares of Legacy Korro common stock in accordance with the terms (as in effect as of the date of the Merger Agreement) of the Legacy Korro Plan and the terms of the stock option agreement by which such option to purchase shares of Legacy Korro common stock is evidenced. The number of shares under the Legacy Korro Plan subject to outstanding awards as of the effective date of the 2023 Plan that are subsequently canceled, forfeited or repurchased by the Company will be added to the shares reserved under the 2023 Plan.

The number of shares of common stock reserved for issuance pursuant to outstanding awards under the Legacy Korro Plan as of December 31, 2023 and 2022 was 600,977 shares and 683,156 shares, respectively. The number of shares available for grant under the Legacy Korro Plan was 0 and 159,890 at December 31, 2023 and 2022, respectively. Upon completion of the Merger and effectiveness of the 2023 Plan, the Company ceased granting awards under the Legacy Korro Plan.

2014 Stock Incentive Plan

On November 13, 2014, Frequency adopted the 2014 Stock Incentive Plan (as amended from time to time,the "2014 Plan"). All of Frequency’s employees, officers, directors, and consultants were eligible to be granted options to purchase common shares, restricted stock units and restricted stock under the terms of the 2014 Plan. Frequency, reserved an aggregate of 424,853 shares of common stock for issuance under the 2014 Plan. The number of shares under the 2014 Plan subject to outstanding awards as of the effective date of the 2023 Plan that are subsequently canceled, forfeited or repurchased by the Company will be added to the shares reserved under the 2023 Plan. As of December 31, 2023, there were no shares of common stock available for future grants under the 2014 Plan and there were 36,455 shares subject to outstanding option awards under the 2014 Plan.

2019 Incentive Award Plan

On September 17, 2019, Frequency’s board of directors and on September 19, 2019, its stockholders approved and adopted the 2019 Incentive Award Plan (the "2019 Plan"). Under the 2019 Plan, Frequency may grant stock options, stock appreciation rights, restricted stock, restricted stock units, and other stock and cash-based awards to individuals who are then employees, officers, directors or consultants of the Company, and employees and consultants of the Company’s subsidiaries. A total of 154,032 shares of common stock were approved to be initially reserved for issuance under the 2019 plan. The number of shares under the 2019 Plan subject to outstanding awards as of the effective date of the 2023 Plan that are subsequently canceled, forfeited or repurchased by the Company will be added to the shares reserved under the 2023 Plan. Upon completion of the Merger and effectiveness of the 2023 Plan, the Company ceased granting awards under the 2019 Plan. Accordingly, as of December 31, 2023, there were no shares of common stock available for future grants under the 2019 Plan and there were 51,491 shares subject to outstanding option awards under the 2019 Plan.

All stock option grants are non-statutory stock options except option grants to employees (including officers and directors) intended to qualify as incentive stock options under the IRC. Incentive stock options may not be granted at less than the fair

market value of the Company’s common stock on the date of grant. Nonqualified stock options may be granted at an exercise price established by the Board of Directors at its sole discretion (which has not been less than fair market value on the date of grant) and the vesting periods may vary. Vesting periods are generally four years and are determined by the Board of Directors. Stock options generally become exercisable as they vest. Options granted under the Legacy Korro Plan, 2014 Plan and the 2019 Plan expire no more than ten years from the date of grant.

Stock-based Compensation Expense

Total stock-based compensation expense recognized in the consolidated statements of operations and comprehensive loss for the years ended December 31, 2023 and 2022 was as follows (in thousands):


	Year Ended December 31,
	2023		2022
Research and development	$	759	$	243
General and administrative		1,622		897
Total stock-based compensation expense	$	2,381	$	1,140

Restricted Common Stock Activity

Prior to the adoption of the 2019 Plan, Legacy Korro issued shares of restricted common stock to its founders as well as to certain employees. The restrictions on the common stock generally lapse over two to four years. In the event that a recipient ceases to provide service to Legacy Korro, Legacy Korro has the right to repurchase any unvested shares of restricted common stock at their original purchase price. As a result of this repurchase right, Legacy Korro recorded the issuance of such restricted common stock as a liability in the consolidated balance sheets. Amounts are reclassified to common stock at par and additional paid-in capital as the restricted common stock vests and restrictions lapse.

The following table summarizes Legacy Korro restricted common stock activity during the year ended December 31, 2023:


	Shares		Weighted- Average Grant Date Fair Value per Share
Unvested as of December 31, 2022		2,902	$	0.59
Granted		—	$	—
Vested		2,902	$	0.23
Repurchased		—	$	—
Unvested as of December 31, 2023		—	$	—

The aggregate fair value of Legacy Korro restricted common stock that vested during the years ended December 31, 2023 and 2022, based upon the fair value of the underlying restricted common stock on the day of vesting, was $0.1 million and $0.5 million, respectively.

Stock Option Activity

The fair value of stock options granted during the years ended December 31, 2023 and 2022 was calculated on the date of grant using the following weighted-average assumptions:


	Year Ended December 31,
	2023			2022
Risk-free interest rate		4.3	%		2.5	%
Expected dividend yield	—%			—%
Expected term (in years)		6.0			6.0
Expected volatility		72.8	%		72.9	%

Using the Black-Scholes option pricing model, the weighted-average grant date fair value of stock options granted during the years ended December 31, 2023 and 2022 was $23.49 and $14.95 per share, respectively.

The following table summarizes changes in stock option activity during the year ended December 31, 2023 (in thousands, except per share amounts):


	Options			Weighted- Average Exercise Price		Weighted- Average Remaining Contractual Term (in years)		Aggregate Intrinsic Value
Outstanding at December 31, 2022		461,100		$	14.95		8.0	$	2,953
Assumed in reverse recapitalization		93,153		$	121.91
Granted		835,839		$	17.33
Exercised		(39,395	)	$	16.41
Forfeited		(20,091	)	$	20.07
Cancelled		(7,455	)	$	18.85
Outstanding as of December 31, 2023		1,323,151		$	23.49		8.4	$	36,310
Exercisable at December 31, 2023		368,036		$	34.60		6.7	$	8,457

The aggregate intrinsic value of options is calculated as the difference between the exercise price of the stock options and the fair value of the Company’s common stock for those stock options that had exercise prices lower than the fair value of the common stock as of the end of the period. The aggregate intrinsic value of stock options exercised during the years ended December 31, 2023 and 2022 was $0.3 million and $0.1 million, respectively.

As of December 31, 2023, there was unrecognized stock-based compensation expense related to unvested stock options of $10.1 million, which the Company expects to recognize over a weighted-average period of approximately 3.1 years.

Income Taxes - Schedule of Reconciliation of U.S. Federal Statutory Income Tax Rate (Details)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Income Tax Disclosure [Abstract]
Income tax computed at federal statutory rate	21.00%	21.00%
State taxes, net of federal benefit	7.10%	6.10%
Tax credit carryforwards	3.60%	6.20%
Permanent items	(1.00%)	(0.20%)
Change in valuation allowance	(30.80%)	(32.70%)
Other	0.10%	(0.40%)
Effective tax rate	0.00%	0.00%

Consolidated Statements of Convertible Preferred Stock and Stockholders' Deficit - USD ($) $ in Thousands	Total	Series Seed Convertible Preferred Stock [Member]	Series A Convertible Preferred Stock [Member]	Series B-1 Convertible Preferred Stock [Member]	Series B-2 Convertible Preferred Stock [Member]	Common Stock [Member]	Additional Paid-In Capital [Member]	Accumulated Other Comprehensive Loss [Member]	Accumulated Deficit [Member]
Temporary equity, beginning balance (in share) at Dec. 31, 2021		684,739	2,029,666	1,104,178	223,417
Temporary equity, beginning balance at Dec. 31, 2021		$ 15,924	$ 77,736	$ 57,703	$ 12,500
Beginning balance (in share) at Dec. 31, 2021						237,803
Beginning balance at Dec. 31, 2021	$ (42,208)						$ 1,600	$ (7)	$ (43,801)
Issuance of common stock for services rendered (in share)						497
Issuance of common stock for services rendered	11						11
Exercises of stock options (in shares)						8,722
Exercises of stock options	62						62
Vesting of restricted common stock (in share)						21,377
Vesting of restricted common stock	5						5
Stock-based compensation expense	1,129						1,129
Other comprehensive income	2							2
Net loss	$ (58,032)								(58,032)
Ending balance (in share) at Dec. 31, 2022	268,468					268,399
Ending balance at Dec. 31, 2022	$ (99,031)						2,807	(5)	(101,833)
Temporary equity, beginning balance (in share) at Dec. 31, 2022		684,739	2,029,666	1,104,178	223,417
Temporary equity, ending balance at Dec. 31, 2022		$ 15,924	$ 77,736	$ 57,703	$ 12,500
Issuance of common stock for services rendered (in share)						292
Issuance of common stock for services rendered	$ 6						6
Exercises of stock options (in shares)	39,395					73,394
Exercises of stock options	$ 702						702
Vesting of restricted common stock (in share)						2,902
Stock-based compensation expense	2,375						2,375
Issuance of Series B-2 convertible preferred stock, net of issuance costs (in share)					813,239
Issuance of Series B-2 convertible preferred stock, net of issuance costs					$ 45,458
Issuance of common stock for cash in PIPE financing (in share)						2,077,864
Issuance of common stock for cash in PIPE financing	117,252					$ 2	117,250
Conversion of preferred stock to common stock (in share)		(684,739)	(2,029,666)	(1,104,178)	(1,036,656)	4,855,208
Conversion of preferred stock to common stock	209,320	$ (15,924)	$ (77,736)	$ (57,703)	$ (57,958)	$ 5	209,315
Issuance of common stock to Frequency shareholders in reverse recapitalization (in share)						738,457
Issuance of common stock to Frequency shareholders in reverse recapitalization	32,701					$ 1	32,700
Reverse recapitalization transaction costs	(12,247)						(12,247)
Other comprehensive income	5							$ 5
Net loss	$ (81,172)								(81,172)
Ending balance (in share) at Dec. 31, 2023	8,016,516					8,016,516
Ending balance at Dec. 31, 2023	$ 169,911					$ 8	$ 352,908		$ (183,005)
Temporary equity, beginning balance (in share) at Dec. 31, 2023		0	0	0	0
Temporary equity, ending balance at Dec. 31, 2023		$ 0	$ 0	$ 0	$ 0

Income Taxes - Schedule of Provision for Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Current taxes:
Federal	$ 0	$ 0
State	27	10
Total current taxes	27	10
Deferred taxes:
Federal	0	0
State	0	0
Total deferred taxes	0	0
Total provision for income taxes	$ 27	$ 10

- Definition

Amount of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

+ References + Details

Investments - Schedule of Fair Value of Cash Equivalents and Short-Term Investments (Details) $ in Thousands	Dec. 31, 2022 USD ($)
Cash and Cash Equivalents [Line Items]
Amortized Cost	$ 18,920
Unrealized Gains	0
Unrealized Losses	(5)
Fair Value	18,915
Government Securities [Member]
Cash and Cash Equivalents [Line Items]
Amortized Cost	3,985
Unrealized Gains	0
Unrealized Losses	(5)
Fair Value	3,980
Commercial Paper [Member]
Cash and Cash Equivalents [Line Items]
Amortized Cost	14,935
Unrealized Gains	0
Unrealized Losses	0
Fair Value	$ 14,935

Common Stock (Tables)

12 Months Ended

Dec. 31, 2023

Equity [Abstract]

Schedule of Number of Shares Reserved for Future Issuance

As of December 31, 2023 and 2022, the Company had reserved for future issuance the following number of shares of common stock:


	December 31,
	2023		2022
Conversion of outstanding Legacy Korro Series Seed Preferred Stock		—		684,739
Conversion of outstanding Legacy Korro Series A Preferred Stock		—		2,029,666
Conversion of outstanding Legacy Korro Series B-1 Preferred Stock		—		1,104,178
Conversion of outstanding Legacy Korro Series B-2 Preferred Stock		—		223,417
Future issuances of Legacy Korro Series B-2 Preferred Stock		—		813,239
Vesting of restricted common stock		—		2,902
Exercises of outstanding stock options		1,323,151		461,128
Exercise of outstanding warrant		8,049		8,049
Future issuances under 2019 Stock Incentive Plan		—		159,890
Future issuances under 2023 Stock Incentive Plan		255,694		—
Future issuances under 2023 ESPP Plan		88,502		—
Total reserved for future issuance		1,675,396		5,487,208

Property and Equipment, Net (Tables)

12 Months Ended

Dec. 31, 2023

Property, Plant and Equipment [Abstract]

Schedule of Property and Equipment

Property and equipment, net, as of December 31, 2023 and 2022 was comprised as follows (in thousands):


		December 31,
	Estimated Useful Life (in Years)	2023			2022
Laboratory equipment	5	$	11,187		$	8,441
Furniture and office equipment	4		481			477
Computer equipment	3		241			213
Leasehold improvements	Shorter of useful life or remaining lease term		3,356			2,941
Construction in progress			8,242			2,049
Total property and equipment, gross			23,507			14,121
Less: accumulated depreciation			(7,842	)		(4,255	)
Total property and equipment, net		$	15,665		$	9,866

Basis of Presentation and Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2023
Accounting Policies [Abstract]
Basis of Presentation and Summary of Significant Accounting Policies	2. Basis of Presentation and Summary of Significant Accounting Policies Basis of Presentation and Consolidation The accompanying consolidated financial statements have been prepared in accordance with generally accepted accounting principles in the United States of America (“GAAP”). These consolidated financial statements have been prepared on the going concern basis of accounting, which assumes continuity of operations, realization of assets and satisfaction of liabilities in the ordinary course of business. The consolidated financial statements include the accounts of Korro Bio, Inc. and its wholly-owned subsidiaries. All intercompany transactions and balances have been eliminated in consolidation. Segment Information Operating segments are defined as components of an enterprise about which separate discrete information is available for evaluation by the chief operating decision-maker in deciding how to allocate resources and assess performance. The Company and the Company’s chief operating decision maker, the Company’s chief executive officer, views the Company’s operations and manages its business as a single operating segment. The Company operates only in the United States. Use of Estimates The preparation of the Company’s consolidated financial statements requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the consolidated financial statements and the reported amounts of expenses during the reporting period. Significant estimates and assumptions reflected in these consolidated financial statements include, but are not limited to the fair value of the common stock prior to the effective date of the merger; the fair value of the CVR liability and the incremental borrowing rate for determining lease liabilities and right-of-use assets. The Company bases its estimates on historical experience, known trends and other market-specific or other relevant factors that it has concluded to be reasonable under the circumstances. On an ongoing basis, management evaluates its estimates as there are changes in circumstances, facts and experience. Changes in estimates are recorded in the period in which they become known. Actual results may differ materially from those estimates or assumptions. Fair Value of Financial Instruments ASC Topic 820, Fair Value Measurement, (“ASC 820”) establishes a fair value hierarchy for instruments measured at fair value that distinguishes between assumptions based on market data (observable inputs) and the Company’s own assumptions (unobservable inputs). Observable inputs are inputs that market participants would use in pricing the asset or liability based on market data obtained from sources independent of the Company. Unobservable inputs are inputs that reflect the Company’s assumptions about the inputs that market participants would use in pricing the asset or liability and are developed based on the best information available in the circumstances. ASC 820 identifies fair value as the exchange price, or exit price, representing the amount that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants. As a basis for considering market participant assumptions in fair value measurements, ASC 820 establishes a three-tier fair value hierarchy that distinguishes between the following: • Level 1 inputs are quoted prices (unadjusted) in active markets for identical assets or liabilities. • Level 2 inputs are inputs other than quoted prices included within Level 1 that are observable for the asset or liability, either directly or indirectly. • Level 3 inputs are unobservable inputs that reflect the Company’s own assumptions about the assumptions market participants would use in pricing the asset or liability. Financial assets and liabilities are classified in their entirety based on the lowest level of input that is significant to the fair value measurement. To the extent that the valuation is based on models or inputs that are less observable or unobservable in the market, the determination of fair value requires more judgment. Accordingly, the degree of judgment exercised by the Company in determining fair value is greatest for instruments categorized in Level 3. A financial instrument’s level within the fair value hierarchy is based on the lowest level of any input that is significant to the fair value measurement. Cash Equivalents Cash equivalents are highly-liquid investments that are readily convertible into cash with original maturities of three months or less when purchased. These assets include investments in money market funds that invest in U.S. Treasury obligations. Cash equivalents are reflected at fair value based on quoted market prices, as further described in Note 3, “Fair Value Measurements”. Investments Investments consist of securities with original maturities greater than three months when purchased. Short-term investments consist of investments that are available for use in current operations. Long-term investments consist of investments with maturities of greater than one year that are not available for use in current operations. The Company did not maintain any long-term investments as of December 31, 2023 or 2022. The Company classifies all of its investments as available-for-sale securities. Accordingly, these investments are recorded at fair value. Realized gains and losses and amortization and accretion of discounts and premiums are included in “Other income, net”. Unrealized gains and losses on available-for-sale securities are included in “Accumulated other comprehensive loss” as a component of stockholders’ deficit until realized. The Company reviews its investment portfolio to identify and evaluate investments that have indicators of possible other-than-temporary impairment. Factors considered in determining whether a loss is other-than-temporary include the length of time and extent to which fair value has been less than the cost basis, the financial condition of the issuer and the Company’s intent and ability to hold the investment for a period of time sufficient to allow for any anticipated recovery in market value. Property and Equipment Property and equipment are recorded at cost and consists of laboratory equipment, furniture and office equipment, computer equipment, leasehold improvements, and construction in progress. The Company capitalizes property and equipment that is acquired for research and development activities and that has alternative future use. Expenditures for repairs and maintenance are recorded to expense as incurred, whereas major betterments are capitalized as additions to property and equipment. Property and equipment not yet placed into service is capitalized as construction in progress and is depreciated once placed into service. Leasehold improvements are depreciated over the lesser of their useful lives or the term of the lease. Depreciation, including depreciation for assets recorded under finance leases, is calculated over the estimated useful lives of the assets using the straight-line method. Impairment of Long-lived Assets The Company reviews long-lived assets when events or changes in circumstances indicate that the carrying value of an asset may not be recoverable. Recoverability is measured by comparing the carrying value of the asset to the future undiscounted cash flows from the use and eventual disposition of the asset. If an asset is considered to be impaired, the impairment loss to be recognized is measured as the amount by which the carrying value of the asset exceeds its fair value. Leases Under ASC Topic 842, Leases (“ASC 842”), the Company determines whether an arrangement is or contains a lease at inception. For leases with a term of 12 months or less, the Company does not recognize a right-of-use asset or lease liability. The Company’s operating leases are recognized on its consolidated balance sheets as noncurrent assets, current liabilities and noncurrent liabilities. The Company does not have any finance leases. Right-of-use assets represent the Company’s right to use an underlying asset for the lease term and lease liabilities represent the Company’s obligation to make lease payments arising from the lease. Operating lease right-of-use assets and liabilities are recognized at the lease commencement date based on the present value of lease payments over the lease term. As the Company’s leases typically do not provide an implicit rate, the Company uses an estimate of its incremental borrowing rate based on the information available at the lease commencement date in determining the present value of lease payments. Lease expense is recognized on a straight-line basis over the lease term. The Company typically only includes an initial lease term in its assessment of a lease arrangement. Options to renew or options to terminate a lease are not included in the Company’s assessment unless there is reasonable certainty that the Company will exercise such options, respectively. The Company has elected to account for the lease and non-lease components together for existing classes of underlying assets. Preferred Stock The Company applies the guidance of ASC Topic 480, Distinguishing Liabilities from Equity (“ASC 480”), when determining the classification and measurement of its preferred stock. Preferred stock subject to mandatory redemption (if any) are classified as liability instruments and are measured at fair value. The Company classifies contingently redeemable preferred stock (if any), which includes preferred stock that features redemption rights that are either within the control of the holder or subject to redemption upon the occurrence of uncertain events not solely within the Company’s control, as temporary equity. At all other times, the Company classifies its preferred stock in stockholders’ equity (deficit). Prior to the merger, Legacy Korro classified its convertible preferred stock as temporary equity due to terms that allowed for redemption of the shares upon the occurrence of a contingent event that was not solely within the Legacy Korro’s control. Legacy Korro did not accrete the carrying values of the preferred stock to the redemption values since the contingent event was not considered probable. Research and Development Expenses Expenditures relating to research and development are expensed as incurred. Research and development expenses include external expenses incurred under arrangements with third parties, academic and non-profit institutions and consultants; salaries and personnel-related costs, including non-cash stock-based compensation expense; license fees to acquire in-process technology and other expenses, which include direct and allocated expenses for laboratory, facilities and other costs. Non-refundable advance payments for goods and services that will be used in future research and development activities are expensed when the activity has been performed or when the goods have been received rather than when the payment is made. As part of the process of preparing the consolidated financial statements, the Company is required to estimate its accrued research and development expenses as of each balance sheet date. In accruing service fees, the Company estimates the time period over which services will be performed and the level of effort to be expended in each period. This process involves reviewing open contracts and purchase orders, communicating with internal personnel to identify services that have been performed on the Company’s behalf and estimating the level of service performed and the associated cost incurred for the service when the Company has not yet been invoiced or otherwise notified of the actual cost. The Company periodically confirms the accuracy of its estimates with its service providers and makes adjustments if necessary. The majority of the Company’s service providers invoice monthly in arrears for services performed or when contractual milestones are met. The financial terms of agreements with these service providers are subject to negotiation, vary from contract-to-contract and may result in uneven payment flows. In circumstances where amounts have been paid in excess of costs incurred, the Company records a prepaid expense. Intellectual Property Expenses The Company expenses legal costs related to patent applications as they are incurred. Such costs are classified as general and administrative expenses within the consolidated statements of operations and comprehensive loss. Stock-based Compensation The Company accounts for stock-based payments in accordance with ASC Topic 718, Compensation—Stock Compensation (“ASC 718”). This guidance requires all stock-based payments, including grants of stock options and restricted common stock, to be recognized as expense in the consolidated statements of operations and comprehensive loss based on their grant date fair values. For stock options granted to employees, non-employees and members of the Company’s Board of Directors for their services on the Board of Directors, the Company estimates the grant date fair value of each stock option using the Black-Scholes option-pricing model. For restricted common stock granted to employees and non-employees, the Company estimates the grant date fair value of each award using the intrinsic value, which is based on the value of the underlying common stock less any purchase price. For stock-based payments subject to service-based vesting conditions, the Company recognizes stock-based compensation expense equal to the grant date fair value of stock-based payment on a straight-line basis over the requisite service period. Prior to the merger, due to the absence of an active market for Legacy Korro’s common stock, Legacy Korro and its Board were required to determine the fair value of Legacy Korro’s common stock at the time of each grant of a stock-based award. Legacy Korro estimated the grant date fair value of its common stock using an appropriate valuation methodology, in accordance with the framework of the American Institute of Certified Public Accountants’ Technical Practice Aid, Valuation of Privately-Held Company Equity Securities Issued as Compensation. Historically, the Company has utilized a market approach to determine its total equity value and the option pricing method (“OPM”) to allocate this equity value among various classes of securities. The OPM treats common stock and convertible preferred stock as call options on the total equity value of a company, with exercise prices based on the value thresholds at which the allocation among the various holders of a company’s securities changes. Under the OPM, the common stock has value only if the funds available for distribution to stockholders exceeds the value of the convertible preferred stock liquidation preferences at the time of the liquidity event, such as a strategic sale or a merger. A discount for lack of marketability of the common stock is then applied to arrive at an indication of value for the common stock. Each valuation methodology includes estimates and assumptions that required the Legacy Korro’s judgment. These estimates and assumptions include a number of objective and subjective factors, including external market conditions, guideline public company information, the prices at which Legacy Korro sold convertible preferred stock to third parties in arms’ length transactions, the rights and preferences of securities senior to Legacy Korro’s common stock at the time and the likelihood of achieving a liquidity event such as an initial public offering or sale. Significant changes to the assumptions used in the valuations could result in different fair values of stock options and restricted stock at each valuation date, as applicable. In addition to the grant date fair value of the Company’s common stock, the Black-Scholes option pricing model requires the input of certain subjective assumptions, including (i) the calculation of expected term of the stock-based payment, (ii) the risk-free interest rate, (iii) the expected stock price volatility and (iv) the expected dividend yield. The Company uses the simplified method as proscribed by SEC Staff Accounting Bulletin No. 107 to calculate the expected term for stock options granted to employees as the Company does not have sufficient historical exercise data to provide a reasonable basis upon which to estimate the expected term. The Company determines the risk-free interest rate based on a treasury instrument whose term is consistent with the expected term of the stock options. Due to the lack of Company-specific historical and implied volatility data, the Company bases its estimates of expected volatility on the historical volatility of a group of publicly-traded companies with similar characteristics to itself, including stage of product development and therapeutic focus within the life sciences industry. The expected volatility has been determined using a weighted-average of the historical volatility measures of this group of companies. The Company expects to continue to do so until such time as it has adequate historical data regarding the volatility of its own traded stock price. Historical volatility is calculated over a period of time commensurate with the expected term of the stock-based payment. The Company uses an assumed dividend yield of zero as the Company has never paid dividends on its common stock, nor does it expect to pay dividends on its common stock in the foreseeable future. The Company accounts for forfeitures of all stock-based payments when such forfeitures occur. Income Taxes Income taxes are recorded in accordance with ASC Topic 740, Income Taxes, which provides for deferred taxes using an asset and liability approach. The Company recognizes deferred tax assets and liabilities for the expected future tax consequences of events that have been included in the consolidated financial statements or tax returns. Deferred tax assets and liabilities are determined based on the difference between the financial statement and tax bases of assets and liabilities using enacted tax rates in effect for the year in which the differences are expected to reverse. A valuation allowance against deferred tax assets is recorded if, based on the weight of the available evidence, it is more likely than not that some or all of the deferred tax assets will not be realized. The Company accounts for uncertain tax positions using a more-likely-than-not threshold for recognizing and resolving uncertain tax positions. The evaluation of uncertain tax positions is based on factors, including, but not limited to, changes in the law, the measurement of tax positions taken or expected to be taken in tax returns, the effective settlement of matters subject to audit, new audit activity and changes in facts or circumstances related to a tax position. Interest and penalty charges, if any, related to income taxes would be classified as a component of the “Provision for income taxes” in the consolidated statements of operations and comprehensive loss. Net Loss per Share Net loss per share attributable to common stockholders is calculated using the two-class method, which is an earnings allocation formula that determines net loss per share for the holders of the Company’s common shares and participating securities. The Company’s Preferred Stock contains participation rights in any dividend paid by the Company and is deemed to be a participating security. Net income attributable to common stockholders and participating preferred shares are allocated to each share as if all of the earnings for the period had been distributed. The participating securities do not include a contractual obligation to share in losses of the Company and are not included in the calculation of net loss per share in the periods in which a net loss is recorded. Net loss attributable to common stockholders is equal to the net loss for the period. Diluted net loss per share is computed using the more dilutive of (a) the two-class method or (b) the treasury stock method and if-converted method. The Company allocates earnings first to preferred stockholders based on dividend rights and then to common and preferred stockholders based on ownership interests. The weighted-average number of common shares included in the computation of diluted net loss gives effect to all potentially dilutive common equivalent shares, including outstanding stock options and Preferred Stock. Common stock equivalent shares are excluded from the computation of diluted net loss per share if their effect is antidilutive. In periods in which the Company reports a net loss attributable to common stockholders, diluted net loss per share attributable to common stockholders is generally the same as basic net loss per share attributable to common stockholders since dilutive common shares are not assumed to have been issued if their effect is anti-dilutive. Concentration of Credit Risk and Off-Balance Sheet Risk Financial instruments that potentially expose the Company to concentrations of credit risk primarily consist of cash, cash equivalents and investments. Cash balances are deposited with federally-insured financial institutions in the United States and may, at times, exceed federally-insured limits. The Company maintains its cash, cash equivalents and investments with high-quality financial institutions and, consequently, the Company believes that such funds are subject to minimal credit risk. The Company’s cash equivalents are comprised of money market funds that are invested in U.S. Treasury and government agency obligations. The Company’s investments are comprised of commercial paper and government securities. Credit risk in these securities is reduced as a result of the Company’s investment policy to limit the amount invested in any single issuer and to only invest in securities of a high credit quality. The Company relies, and expects to continue to rely, on a small number of vendors to manufacture supplies and to process its product candidates for its development programs. These programs could be adversely affected by a significant interruption in the manufacturing process or supply chain. The Company has no significant off-balance sheet risk such as foreign exchange contracts, option contracts or other foreign hedging arrangements. Emerging growth company status The Company qualifies as an “emerging growth company” (“EGC”), as defined in the Jumpstart Our Business Startups Act (“JOBS Act”), and may take advantage of certain exemptions from various reporting requirements that are applicable to other public companies that are not EGCs. The Company may take advantage of these exemptions until it is no longer an EGC under Section 107 of the JOBS Act, which provides that an EGC can take advantage of the extended transition period afforded by the JOBS Act for the implementation of new or revised accounting standards. The Company has elected to avail itself of the extended transition period and, therefore, while the Company is an EGC it will not be subject to new or revised accounting standards the same time that they become applicable to other public companies that are not EGCs, unless it chooses to early adopt a new or revised accounting standard. As a result of this election, the consolidated financial statements may not be comparable to companies that comply with public company FASB standards’ effective dates. Recently Adopted Accounting Pronouncements In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments, which has been subsequently amended by ASU 2018-19, ASU 2019-04, ASU 2019-05, ASU 2019-10, ASU 2019-11, ASU 2020-03, and ASU 2022-02 (“ASU 2016-13”). This standard requires that credit losses be recorded using an expected losses model rather than the incurred losses model that was previously used and establishes additional credit risk disclosures associated with financial assets. The amendments in this standard should be applied on a modified retrospective basis to all periods presented. The Company adopted ASU 2016-13 on January 1, 2023 using the modified retrospective approach. The adoption of this standard did not have a material effect on the Company’s financial position, results of operations or disclosures. Recent Accounting Pronouncements—Yet to be Adopted Other accounting standards that have been issued or proposed by the FASB or other standards-setting bodies that do not require adoption until a future date are not expected to have a material impact on the Company’s consolidated financial statements upon adoption. In November 2023, the FASB issued Accounting Standards Update ("ASU") 2023-07, Segment Reporting (Topic 280), Improvements to Reportable Segment Disclosures, which is intended to provide enhanced segment disclosures. The standard will require disclosures about significant segment expenses and other segment items and identifying the Chief Operating Decision Maker and how they use the reported segment profitability measures to assess segment performance and allocate resources. These enhanced disclosures are required for all public entities on an interim and annual basis, even if they have only a single reportable segment. The standard is effective for years beginning after December 15, 2023, and interim periods within annual periods beginning after December 15, 2024. Early adoption is permitted. The Company is evaluating this standard to determine if adoption will have a material impact on the Company's consolidated financial statements.

Income Taxes - Schedule of Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Deferred tax assets:
Net operating loss carryforwards	$ 80,385	$ 19,580
Tax credit carryforwards	22,474	5,477
Capitalized research and development	34,395	10,279
Stock-based compensation	4,494	319
Amortization	1,138	0
Operating lease liability	9,052	855
Accrued expenses and other temporary differences	1,543	707
Total deferred tax assets	153,481	37,217
Less: valuation allowance	(145,766)	(36,094)
Net deferred tax assets	7,715	1,123
Deferred tax liabilities:
Operating right-of-use asset	(7,401)	(552)
Depreciation	(314)	(571)
Total deferred tax liabilities	(7,715)	(1,123)
Net deferred taxes	$ 0	$ 0

Accrued Expenses and Other Current Liabilities (Tables)

12 Months Ended

Dec. 31, 2023

Payables and Accruals [Abstract]

Schedule of Accrued Expenses and Other Current Liabilities

Accrued expenses and other current liabilities as of December 31, 2023 and 2022 were comprised as follows (in thousands):


	December 31,
	2023		2022
Employee compensation and benefits	$	7,896	$	2,624
External research and development services		1,255		274
Other operating expenses		447		207
CVR liability, current		395		—
Professional fees		219		70
Total accrued expenses and other current liabilities	$	10,212	$	3,175

401(k) Savings Plan

12 Months Ended

Dec. 31, 2023

Retirement Benefits [Abstract]

401(k) Savings Plan

15. 401(k) Savings Plan

The Company has a defined-contribution savings plan under Section 401(k) of the IRC (the “401(k) Plan”). The 401(k) Plan covers all employees who meet defined minimum age and service requirements and allows participants to defer a portion of their annual compensation, subject to statutory limitations. Beginning on April 1, 2022, the Company matches 100% of an employee’s 401(k) contributions up to a maximum of 3% of the participant’s salary, subject to employer match limitations under the IRC. As such, the Company made $0.5 million and $0.2 million of matching contributions to the 401(k) Plan during the year ended December 31, 2023 and December 31, 2022, respectively.

Commitments and Contingencies

12 Months Ended

Dec. 31, 2023

Commitments and Contingencies Disclosure [Abstract]

Commitments and Contingencies

14. Commitments and Contingencies

Leases

The Company is party to an operating lease at One Kendall Square, Cambridge, Massachusetts and occupies 22,561 square feet of laboratory and office space (the “OKS Facility”). On October 20, 2023, the Company entered into an amendment to the Lease Agreement that extended the lease expiration date from December 31, 2023 to September 30, 2024 and provided the Company with no option to further extend the lease expiration date. The Company is also party to an operating sublease agreement at Cummings Park in Woburn, Massachusetts and occupies 18,148 square feet of laboratory and office space (the “Cummings Park Sublease”) which expires on July 31, 2024.

The Company is party to an operating lease for 50,453 square feet of office and laboratory space at 60 First Street, Cambridge, Massachusetts (the “60 First Street Lease”). In May 2023, the Company obtained control over the space and the Company recognized the operating lease right-of-use asset and the operating lease liability of $26.8 million on the commencement date of the lease. The total rental payments over the 11 year lease are expected to be $62.1 million, including rent credits and other lease incentives per the terms of the lease. Specifically, the 60 First Street Lease provides the Company with a tenant improvement allowance of $13.1 million. The Company utilized $2.3 million of the $13.1 million tenant improvement allowance as of December 31, 2023. The lease has remaining term approximately 10 years. The Company has an option to extend the lease for an additional period of five years with the rent during the option period being the then fair market rent.


	As of December 31, 2023
2024		(7,227	)
2025		6,247
2026		7,341
2027		7,557
Thereafter		52,498
Total Future Minimum Leases Payments		66,416
Less: Interest		33,209
Present Value of Operating Lease Liabilities		33,207

As of December 31, 2023, the weighted average remaining lease term was 10.0 years and the weighted average incremental borrowing rate used to determine the operating lease liability was 11.2%.

The Company combines the lease and non-lease components of fixed costs in its lease arrangements as a single lease component. Variable costs, such as utilities and maintenance costs, are not included in the measurement of right-of-use assets and lease liabilities, but rather are expensed when the event determining the amount of variable consideration to be paid occurs.

The following table summarizes the effect of lease costs in the Company’s consolidated statement of operations and comprehensive loss of its operating leases (in thousands):


	Year Ended December 31,
	2023		2022
Operating lease costs	$	5,948	$	1,675
Variable Lease Costs		1,211		732
Short-term Lease Costs		921		626
Total Lease Costs	$	8,080	$	3,033

Legal Contingencies

The Company accrues a liability for legal contingencies when it believes that it is both probable that a liability has been incurred and that the Company can reasonably estimate the amount of the loss. The Company reviews these accruals and adjusts them to reflect ongoing negotiations, settlements, rulings, advice of legal counsel and other relevant information. To the extent new information is obtained and the views on the probable outcomes of claims, suits, assessments, investigations or legal proceedings change, changes in the Company’s accrued liabilities would be recorded in the period in which such determination is made.

In addition, in accordance with the relevant authoritative guidance, for any matters in which the likelihood of material loss is at least reasonably possible, the Company will provide disclosure of the possible loss or range of loss. If a reasonable estimate cannot be made, however, the Company will provide disclosure to that effect. The Company expenses legal costs as they are incurred.

On June 3, 2021 and June 22, 2021, purported stockholders of the Company filed putative class action lawsuits in the U.S. District Court for the District of Massachusetts against the Frequency and the Frequency’s Chief Executive Officer, President, and Director, David Lucchino. On March 21, 2022, the two lawsuits were consolidated into a single lawsuit, Quinones et al. v. Frequency Therapeutics, Inc. et al. and on May 16, 2022, the Company’s Chief Development Officer, Dr. Carl Le Bel, was added as a defendant. The plaintiffs alleged violations of Sections 10(b), 20(a) and Rule 10b5 of the Securities Exchange Act of 1934, as amended (the Exchange Act), due to allegedly false and misleading statements and omissions about the Company’s Phase 2a clinical trial (FX-322-202) for its product candidate FX-322 in the Company’s public disclosures between October 29, 2020 and March 22,2021. The lawsuit sought, among other things, damages in connection with the Company’s allegedly artificially inflated stock price between October 29,2020 and March 22, 2021 as a result of those allegedly false and misleading statements and omissions, as well as interest, attorneys’ fees and costs. The Company filed a motion to dismiss the Amended Complaint on July 15, 2022. On March 29, 2023, the Company’s motion to dismiss was granted and the lawsuit was dismissed in its entirety. On April 27, 2023, Plaintiff filed a notice of appeal to the United States Court of Appeals for the First Circuit from the order dismissing the lawsuit. On August 2, 2023, Plaintiff-Appellant submitted its opening brief to the First Circuit. The Company filed its response brief on October 27, 2023. The First Circuit heard oral argument on January 8, 2024, and has not yet issued a decision on plaintiff’s appeal. This matter is at the very early stages of the legal process, and as a result, the Company is not able to estimate a range of possible loss. Since an estimate of the possible loss or range of loss cannot be made at this time, no accruals have been recorded as of December 31, 2023.

Indemnifications

The Company indemnifies each of its officers and directors for certain events or occurrences, subject to certain limits, while the officer or director is or was serving at the Company’s request in such capacity, as permitted under Delaware law and in accordance with the Company’s amended and restated certificate of incorporation and bylaws. The term of the indemnification period lasts as long as an officer or director may be subject to any proceeding arising out of acts or omissions of such officer or director in such capacity.

The maximum amount of potential future indemnification is unlimited; however, the Company currently holds director and officer liability insurance. This insurance allows the transfer of risk associated with the Company’s exposure and may enable the Company to recover a portion of any future amounts paid. The Company believes that the fair value of these potential indemnification obligations is minimal. Accordingly, the Company has not recognized any liabilities relating to these obligations for any period presented.

Net Loss per Share - Computation of Diluted Net Loss per Share Attributable to Common Stockholders (Details) - Legacy Korro [Member] - shares	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Antidilutive securities excluded from computation of earnings per share	1,331,200	4,514,051
Outstanding Warrant [Member]
Antidilutive securities excluded from computation of earnings per share	8,049	8,049
Unvested Restricted Stock Units [Member]
Antidilutive securities excluded from computation of earnings per share	0	2,902
Outstanding Stock Options [Member]
Antidilutive securities excluded from computation of earnings per share	1,323,151	461,100
Series Seed Preferred Stock [Member]
Antidilutive securities excluded from computation of earnings per share	0	684,739
Series A Convertible Preferred Stock [Member]
Antidilutive securities excluded from computation of earnings per share	0	2,029,666
Series B-1 Preferred Stock [Member]
Antidilutive securities excluded from computation of earnings per share	0	1,104,178
Series B-2 Preferred Stock [Member]
Antidilutive securities excluded from computation of earnings per share	0	223,417

Document and Entity Information - USD ($)	12 Months Ended
Document and Entity Information - USD ($)	Dec. 31, 2023	Mar. 21, 2024	Jun. 30, 2023
Cover [Abstract]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2023
Document Fiscal Year Focus	2023
Current Fiscal Year End Date	--12-31
Document Fiscal Period Focus	FY
Document Annual Report	true
Entity File Number	001-39062
Entity Registrant Name	Korro Bio, Inc.
Entity Central Index Key	0001703647
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	47-2324450
Entity Address, Address Line One	One Kendall Square
Entity Address, Address Line Two	Building 600-700
Entity Address, Address Line Three	Suite 6-401
Entity Address, City or Town	Cambridge
Entity Address, State or Province	MA
Entity Address, Postal Zip Code	02139
City Area Code	617
Local Phone Number	468-1999
Title of 12(b) Security	Common stock, par value $0.001 per share
Trading Symbol	KRRO
Security Exchange Name	NASDAQ
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Emerging Growth Company	true
Document Transition Report	false
Entity Small Business	true
Entity Ex Transition Period	false
Entity Shell Company	false
Document Financial Statement Error Correction [Flag]	false
ICFR Auditor Attestation Flag	false
Entity Public Float			$ 12,148,224
Entity Common Stock, Shares Outstanding		8,021,946
Auditor Firm ID	42
Auditor Name	Ernst & Young LLP
Auditor Location	Boston, Massachusetts

Reverse Merger (Additional Information) (Details) - USD ($) $ in Thousands		12 Months Ended
	Nov. 03, 2023	Dec. 31, 2023	Dec. 31, 2022
Business Combination and Asset Acquisition [Abstract]
Goodwill or intangible assets	$ 0
Cash and cash equivalents	36,600	$ 166,150	$ 36,333
Prepaid expense and other assets	1,900
Accounts payable and accrued expenses	$ 5,400
Employee Benefits and Share-Based Compensation		300
Severance payment		2,500
Transaction costs		$ 12,247

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Statement [Table]
Preferred stock, par value	$ 0.001	$ 0.001
Preferred stock, shares authorized	10,000,000	0
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value	$ 0.001	$ 0.001
Common stock, shares authorized	200,000,000	5,755,759
Common stock, shares issued	8,016,516	271,371
Common stock, shares outstanding	8,016,516	268,468
Series Seed Convertible Preferred Stock [Member]
Statement [Table]
Temporary equity, preferred stock, par value	$ 0.001	$ 0.001
Temporary equity, preferred stock, shares authorized	0	684,739
Temporary equity, preferred stock, shares issued	0	684,739
Temporary equity, preferred stock, shares outstanding	0	684,739
Temporary equity, preferred stock, liquidation preference	$ 0	$ 16,115
Series A Convertible Preferred Stock [Member]
Statement [Table]
Temporary equity, preferred stock, par value	$ 0.001	$ 0.001
Temporary equity, preferred stock, shares authorized	0	2,029,666
Temporary equity, preferred stock, shares issued	0	2,029,666
Temporary equity, preferred stock, shares outstanding	0	2,029,666
Temporary equity, preferred stock, liquidation preference	$ 0	$ 91,500
Preferred stock, shares outstanding	0	2,029,666
Series B-1 Preferred Stock [Member]
Statement [Table]
Temporary equity, preferred stock, par value	$ 0.001	$ 0.001
Temporary equity, preferred stock, shares authorized	0	1,104,178
Temporary equity, preferred stock, shares issued	0	1,104,178
Temporary equity, preferred stock, shares outstanding	0	1,104,178
Temporary equity, preferred stock, liquidation preference	$ 0	$ 58,000
Series B-2 Preferred Stock [Member]
Statement [Table]
Temporary equity, preferred stock, par value	$ 0.001	$ 0.001
Temporary equity, preferred stock, shares authorized	0	1,036,656
Temporary equity, preferred stock, shares issued	0	223,417
Temporary equity, preferred stock, shares outstanding	0	223,417
Temporary equity, preferred stock, liquidation preference	$ 0	$ 12,500

Restricted Cash - Schedule of Reconciliation of Cash, Cash Equivalents and Restricted Cash (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Nov. 03, 2023	Dec. 31, 2022
Cash and Cash Equivalents [Abstract]
Cash and cash equivalents	$ 166,150	$ 36,600	$ 36,333
Restricted Cash	6,969		5,144
Cash, cash equivalents and restricted cash	$ 173,119		$ 41,477

Consolidated Statements of Operations and Comprehensive Loss - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Operating expenses:
Research and development	$ 57,250	$ 42,201
General and administrative	27,284	16,797
Total operating expenses	84,534	58,998
Loss from operations	(84,534)	(58,998)
Other income:
Other income, net	3,389	976
Total other income, net	3,389	976
Loss before provision for income taxes	(81,145)	(58,022)
Provision for income taxes	27	10
Net loss	(81,172)	(58,032)
Other comprehensive income
Unrealized gain on available-for-sale investments	0	2
Comprehensive loss	$ (81,172)	$ (58,030)
Net loss per share, basic	$ (53.08)	$ (227.42)
Net loss per share, diluted	$ (53.08)	$ (227.42)
Weighted-average shares used in computing net loss per share, basic	1,529,321	255,175
Weighted-average shares used in computing net loss per share, diluted	1,529,321	255,175

Common Stock (Additional Information) (Details) - $ / shares	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Common stock, shares authorized	200,000,000	5,755,759
Common stock, par value	$ 0.001	$ 0.001
Korros [Member]
Dividends Declared	$ 0
Korros [Member] \| Common Stock [Member]
Common stock, shares authorized	200,000,000
Common stock, par value	$ 0.001

Restricted Cash

12 Months Ended

Dec. 31, 2023

Cash and Cash Equivalents [Abstract]

Restricted Cash

6. Restricted Cash

As of December 31, 2023, the Company maintained current restricted cash of $3.6 million and non-current restricted cash of $3.4 million. As of December 31, 2022, the Company maintained current restricted cash of $0.6 million and non-current restricted cash of $4.5 million. All restricted cash amounts are comprised solely of letters of credit required pursuant to the Company’s facility leases.


	December 31,
	2023		2022
Cash and cash equivalents	$	166,150	$	36,333
Restricted cash		6,969		5,144
Cash, cash equivalents and restricted cash	$	173,119	$	41,477

Preferred Stock - Schedule Of Preferred Stock Authorized, Issued And Outstanding Table (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Class of Stock [Line Items]
Preferred stock, shares authorized	10,000,000	0
Preferred Stock Outstanding	0	0
Preferred Stock Issued	0	0
Preferred stock, $0.001 par value; 10,000,000 shares and no shares authorized at December 31, 2023 and 2022; no shares issued and outstanding at December 31, 2023 and 2022	$ 0	$ 0
Series Seed Preferred Stock [Member]
Class of Stock [Line Items]
Preferred Stock Outstanding	0	684,739
Series A Preferred Stock [Member]
Class of Stock [Line Items]
Preferred Stock Outstanding	0	2,029,666
Legacy Korro [Member]
Class of Stock [Line Items]
Preferred stock, shares authorized		4,855,239
Preferred Stock Outstanding		4,042,000
Preferred Stock Issued		4,042,000
Preferred stock, $0.001 par value; 10,000,000 shares and no shares authorized at December 31, 2023 and 2022; no shares issued and outstanding at December 31, 2023 and 2022		$ 163,863
Liquidation Value		$ 178,115
Common Stock Issuable Upon Conversion		4,042,000
Legacy Korro [Member] \| Series Seed Preferred Stock [Member]
Class of Stock [Line Items]
Preferred stock, shares authorized		684,739
Preferred Stock Outstanding		684,739
Preferred Stock Issued		684,739
Preferred stock, $0.001 par value; 10,000,000 shares and no shares authorized at December 31, 2023 and 2022; no shares issued and outstanding at December 31, 2023 and 2022		$ 15,924
Liquidation Value		$ 16,115
Common Stock Issuable Upon Conversion		684,739
Legacy Korro [Member] \| Series A Preferred Stock [Member]
Class of Stock [Line Items]
Preferred stock, shares authorized		2,029,666
Preferred Stock Outstanding		2,029,666
Preferred Stock Issued		2,029,666
Preferred stock, $0.001 par value; 10,000,000 shares and no shares authorized at December 31, 2023 and 2022; no shares issued and outstanding at December 31, 2023 and 2022		$ 77,736
Liquidation Value		$ 91,500
Common Stock Issuable Upon Conversion		2,029,666
Legacy Korro [Member] \| Series B-1 Preferred Stock [Member]
Class of Stock [Line Items]
Preferred stock, shares authorized		1,104,178
Preferred Stock Outstanding		1,104,178
Preferred Stock Issued		1,104,178
Preferred stock, $0.001 par value; 10,000,000 shares and no shares authorized at December 31, 2023 and 2022; no shares issued and outstanding at December 31, 2023 and 2022		$ 57,703
Liquidation Value		$ 58,000
Common Stock Issuable Upon Conversion		1,104,178
Legacy Korro [Member] \| Series B-2 Preferred Stock [Member]
Class of Stock [Line Items]
Preferred stock, shares authorized		1,036,656
Preferred Stock Outstanding		223,417
Preferred Stock Issued		223,417
Preferred stock, $0.001 par value; 10,000,000 shares and no shares authorized at December 31, 2023 and 2022; no shares issued and outstanding at December 31, 2023 and 2022		$ 12,500
Liquidation Value		$ 12,500
Common Stock Issuable Upon Conversion		223,417

401(k) Savings Plan (Additional Information) (Details) - USD ($) $ in Millions		12 Months Ended
	Apr. 01, 2022	Dec. 31, 2023	Dec. 31, 2022
Defined Contribution Plan [Table]
Defined Contribution Plan, Employer Matching Contribution, Percent of Match	3.00%
Defined Contribution Plan, Cost		$ 0.5	$ 0.2
Maximum [Member]
Defined Contribution Plan [Table]
Defined Contribution Plan, Employer Matching Contribution, Percent of Match	100.00%

Preferred Stock

12 Months Ended

Dec. 31, 2023

Class of Stock Disclosures [Abstract]

Preferred Stock

10. Preferred Stock

As of December 31, 2023, the Company was authorized to issue up to 10,000,000 shares of preferred stock at a par value of $0.001 with no preferred stock shares issued or outstanding.

Pursuant to the terms of the Merger Agreement, immediately prior to closing of the Merger, each share of Legacy Korro's Preferred Stock issued and outstanding immediately prior to the Closing of the Merger was converted into shares of the Legacy Korro’s common stock, and then exchanged in the Merger for shares of the Company's common stock using an exchange ratio of 0.049688. The conversion was approved by greater than 66% of the then-outstanding shares of Preferred Stock, voting as a single class on an as-converted to common stock basis.

As of December 31, 2022, Legacy Korro was authorized to issue up to 10,000,000 shares of preferred stock at a par value of $0.001 with no preferred stock shares issued or outstanding. As of December 31, 2022, Legacy Korro Preferred Stock authorized, issued and outstanding consisted of the following (in thousands, except share amounts):


	December 31, 2022
	Preferred Stock Authorized		Preferred Stock Issued and Outstanding		Carrying Value		Liquidation Value		Common Stock Issuable Upon Conversion
Legacy Korro Series Seed Preferred Stock		684,739		684,739		15,924	$	16,115		684,739
Legacy Korro Series A Preferred Stock		2,029,666		2,029,666		77,736		91,500		2,029,666
Legacy Korro Series B-1 Preferred Stock		1,104,178		1,104,178		57,703		58,000		1,104,178
Legacy Korro Series B-2 Preferred Stock		1,036,656		223,417		12,500		12,500		223,417
Total		4,855,239		4,042,000	$	163,863	$	178,115		4,042,000

Rights, Preferences and Privileges of Legacy Korro Preferred Stock

The Legacy Korro Preferred Stock as of December 31, 2022 had the following rights and preferences. In the discussion below, the Legacy Korro Series Seed Preferred Stock and the Legacy Korro Series A Preferred Stock, the Legacy Korro Series B-1 Preferred Stock and the Legacy Korro Series B-2 Preferred Stock are collectively referred to as the “ Legacy Korro Preferred Stock” unless specifically noted.

Conversion

Each share of Legacy Korro Preferred Stock were convertible, at the option of the holder thereof, at any time and from time to time, and without the payment of additional consideration by the holder thereof, into such number of fully paid and non-assessable shares of common stock as is determined by dividing the original issuance price by the conversion price in effect at the time of conversion. The original conversion price of the Legacy Korro Series Seed 1 Preferred Stock and Legacy Korro Series Seed 2 Preferred Stock was $20.13, the original conversion price of the Legacy Korro Series Seed 3 Preferred Stock was $26.16, the original conversion price of the Legacy Korro Series A Preferred Stock was $45.08, the original conversion price of the Legacy Korro Series B-1 Preferred Stock was $52.53 and the original conversion price of the Legacy Korro Series B-2 Preferred Stock was $55.95. Shares of Legacy Korro preferred stock are subject to adjustments to reflect the issuance of common stock,

options, warrants, or other rights to subscribe for or to purchase common stock for a consideration per share, less than the conversion price then in effect and subsequent stock dividends, stock splits, combinations, or recapitalizations.

The Legacy Korro Preferred Stock was subject to mandatory conversion upon the closing of a sale of common stock to the public at a price of at least $111.90 per share (subject to appropriate adjustment in the event of a stock dividend, stock split, combination or other similar recapitalization) in a firm-commitment underwritten public offering resulting in at least $75.0 million of gross proceeds to Legacy Korro. The Legacy Korro Preferred Stock was also subject to mandatory conversion upon the vote or written consent of the holders of at least 66% of the then-outstanding shares of Legacy Korro Preferred Stock, voting as a single class on an as-converted to common stock basis.

Dividends

The holders of Legacy Korro Preferred Stock, in preference to common stockholders, were entitled to receive, when, as and if declared by the Company’s Board of Directors, dividends at a rate of 8% annually. Dividends on Legacy Korro Preferred Stock were non-cumulative and were payable only when and if declared by Legacy Korro’s Board of Directors. The holders of Legacy Korro Preferred Stock were entitled to participate in dividends on common stock on an as-converted basis when and if declared by Legacy Korro's Board of Directors. Since Legacy Korro’s inception, no dividends have been declared.

Liquidation Preference

In the event of any voluntary or involuntary liquidation, dissolution, winding up or deemed liquidation event of Legacy Korro, the holders of shares of Legacy Korro Preferred Stock then outstanding were entitled to be paid out of the assets of Legacy Korro available for distribution to its stockholders before any payment shall be made to the holders of common stock, an amount equal to the original issue price per share plus any dividends declared but unpaid thereon. For clarity, the original issue price of the Legacy Korro Series Seed 1 Preferred Stock and Legacy Korro Series Seed 2 Preferred Stock was $20.13 per share, the original issue price of the Legacy Korro Series Seed 3 Preferred Stock was $26.16 per share, the original issue price of the Legacy Korro Series A Preferred Stock was $45.08 per share, the original issue price of the Legacy Korro Series B-1 Preferred Stock was $52.53 per share and the original issue price of the Legacy Korro Series B-2 Preferred Stock was $55.95 per share.

If upon any voluntary or involuntary liquidation, dissolution, winding up or deemed liquidation event of Legacy Korro, the assets of Legacy Korro available for distribution were insufficient to pay the holders of Legacy Korro Preferred Stock the full amount to which they were entitled, the holders of shares of Legacy Korro Preferred Stock shall share ratably in any distribution of the assets available for distribution in proportion to the respective amounts that would otherwise be payable in respect of the shares held by them upon such distribution if all amounts payable on or with respect to such shares were paid in full.

Redemption

The Legacy Korro Preferred Stock was contingently redeemable upon the occurrence of a deemed liquidation event, which included a merger or a sale of substantially all of the assets of Legacy Korro. As of December 31, 2022, a deemed liquidation event was not considered to be probable.

Voting Rights

The holders of Legacy Korro Preferred Stock were entitled to vote based on the number of common shares that their preferred shares converted into on as-converted basis at the time of such vote. Except in specific circumstances, holders of Legacy Korro Preferred Stock shall vote as a single class with the common stockholders.

The holders of record of the shares of the Legacy Korro Series Seed Preferred Stock, voting exclusively and as a separate class on an as-converted to common stock basis, were entitled to elect two members to Legacy Korro’s Board of Directors. The holders of record of the shares of the Legacy Korro Series A Preferred Stock, voting exclusively and as a separate class on an as-converted to common stock basis, were entitled to elect two members to the Legacy Korro’s Board of Directors. The holders of record of the shares of the Legacy Korro Series B Preferred Stock, voting exclusively and as a separate class on an as-converted to common stock basis, were entitled to elect two members to the Legacy Korro’s Board of Directors.

Stock-based Compensation - Summary of Stock Option Activity (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Number of shares Options , Beginning balance	461,100
Number of Share Option, Reverse Recapitalization	93,153
Number of shares Options , Granted	835,839
Number of shares Options, Exercised	(39,395)
Number of shares Options, Forfeited	(20,091)
Number of shares Options, Cancelled	(7,455)
Number of shares Options, Ending balance	1,323,151	461,100
Exercisable at December 31, 2023	368,036
Weighted average exercise price, Beginning balance	$ 14.95
Weighted- Average Exercise Price Reverse Recapitalization	121.91
Weighted average exercise price, Granted	17.33
Weighted average exercise price, Exercised	16.41
Weighted average exercise price, Fofeited	20.07
Weighted- Average Exercise Price Cancelled	18.85
Weighted average exercise price, Ending balance	23.49	$ 14.95
Weighted average exercise price, OptionsExercisable at December 31, 2022	$ 34.6
Weighted average remaining contractual term (in years), Outstanding	8 years 4 months 24 days	8 years
Weighted average remaining contractual term (in years), Options exercisable as of December 31, 2022	6 years 8 months 12 days
Aggregate intrinsic value, Outstanding as of December 31, 2021	$ 2,953
Aggregate intrinsic value, Outstanding as of December 31, 2022	36,310	$ 2,953
Aggregate intrinsic value, Options exercisable as of Exercisable at December 31, 2022	$ 8,457

Genevant Agreement (Additional Information) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Research and Development Expense, Total	$ 57,250	$ 42,201
Reimbursements with in Research and Development Expense	1,200
Genevant Agreement [Member]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Research and Development Expense, Total	2,500
Revenue recognized commercialization milestone payments to receive	57,000
Genevant Agreement [Member] \| Maximum [Member] \| Phase 3 Clinical Trial
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Milestone payment	13,500
Genevant Agreement [Member] \| Maximum [Member] \| Phase2b Clinical Trial
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Milestone payment	$ 27,000

Investments (Tables)

12 Months Ended

Dec. 31, 2023

Investments [Abstract]

Schedule of Fair Value of Cash Equivalents and Short-Term Investments

Short-term investments as of December 31, 2022 were comprised as follows (in thousands):


	Amortized Cost		Unrealized Gains		Unrealized Losses			Fair Value
Commercial paper	$	14,935	$	—	$	—		$	14,935
Government securities		3,985		—		(5	)		3,980
Total	$	18,920	$	—	$	(5	)	$	18,915

Basis of Presentation and Summary of Significant Accounting Policies - Schedule of Financial Statement Affected by Adoption of ASC (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Operating lease right-of-use assets	$ 27,150	$ 2,024
Operating lease liabilities, current portion	$ 1,991	$ 2,921

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 405
-SubTopic 50
-Name Accounting Standards Codification
-Section 65
-Paragraph 1
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147477123/405-50-65-1

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 820
-SubTopic 10
-Name Accounting Standards Codification
-Section 65
-Paragraph 13
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482477/820-10-65-13

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 820
-SubTopic 10
-Name Accounting Standards Codification
-Section 65
-Paragraph 13
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482477/820-10-65-13

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 10
-Name Accounting Standards Codification
-Section 65
-Paragraph 5
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479654/326-10-65-5

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 10
-Name Accounting Standards Codification
-Section 65
-Paragraph 5
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479654/326-10-65-5

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 10
-Name Accounting Standards Codification
-Section 65
-Paragraph 5
-Subparagraph (b)(1)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479654/326-10-65-5

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 10
-Name Accounting Standards Codification
-Section 65
-Paragraph 5
-Subparagraph (c)(2)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479654/326-10-65-5

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Topic 815
-SubTopic 20
-Name Accounting Standards Codification
-Section 65
-Paragraph 6
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480528/815-20-65-6

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Topic 815
-SubTopic 20
-Name Accounting Standards Codification
-Section 65
-Paragraph 6
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480528/815-20-65-6

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Topic 815
-SubTopic 20
-Name Accounting Standards Codification
-Section 65
-Paragraph 6
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480528/815-20-65-6

Reference 11: http://www.xbrl.org/2003/role/disclosureRef
-Topic 815
-SubTopic 20
-Name Accounting Standards Codification
-Section 65
-Paragraph 6
-Subparagraph (e)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480528/815-20-65-6

Reference 12: http://www.xbrl.org/2003/role/disclosureRef
-Topic 815
-SubTopic 20
-Name Accounting Standards Codification
-Section 65
-Paragraph 6
-Subparagraph (f)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480528/815-20-65-6

Reference 13: http://www.xbrl.org/2003/role/disclosureRef
-Topic 815
-SubTopic 20
-Name Accounting Standards Codification
-Section 65
-Paragraph 6
-Subparagraph (h)(1)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480528/815-20-65-6

Reference 14: http://www.xbrl.org/2003/role/disclosureRef
-Topic 815
-SubTopic 20
-Name Accounting Standards Codification
-Section 65
-Paragraph 6
-Subparagraph (h)(1)(i)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480528/815-20-65-6

Reference 15: http://www.xbrl.org/2003/role/disclosureRef
-Topic 815
-SubTopic 20
-Name Accounting Standards Codification
-Section 65
-Paragraph 6
-Subparagraph (h)(1)(iii)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480528/815-20-65-6

Reference 16: http://www.xbrl.org/2003/role/disclosureRef
-Topic 815
-SubTopic 20
-Name Accounting Standards Codification
-Section 65
-Paragraph 6
-Subparagraph (h)(1)(iv)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480528/815-20-65-6

Reference 17: http://www.xbrl.org/2003/role/disclosureRef
-Topic 815
-SubTopic 20
-Name Accounting Standards Codification
-Section 65
-Paragraph 6
-Subparagraph (i)(2)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480528/815-20-65-6

Reference 18: http://www.xbrl.org/2003/role/disclosureRef
-Topic 815
-SubTopic 20
-Name Accounting Standards Codification
-Section 65
-Paragraph 6
-Subparagraph (i)(3)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480528/815-20-65-6

Reference 19: http://www.xbrl.org/2003/role/disclosureRef
-Topic 832
-SubTopic 10
-Name Accounting Standards Codification
-Section 65
-Paragraph 1
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483482/832-10-65-1

Reference 20: http://www.xbrl.org/2003/role/disclosureRef
-Topic 832
-SubTopic 10
-Name Accounting Standards Codification
-Section 65
-Paragraph 1
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483482/832-10-65-1

Reference 21: http://www.xbrl.org/2003/role/disclosureRef
-Topic 805
-SubTopic 20
-Name Accounting Standards Codification
-Section 65
-Paragraph 3
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479845/805-20-65-3

Reference 22: http://www.xbrl.org/2003/role/disclosureRef
-Topic 805
-SubTopic 20
-Name Accounting Standards Codification
-Section 65
-Paragraph 3
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479845/805-20-65-3

Reference 23: http://www.xbrl.org/2003/role/disclosureRef
-Topic 805
-SubTopic 20
-Name Accounting Standards Codification
-Section 65
-Paragraph 3
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479845/805-20-65-3

Reference 24: http://www.xbrl.org/2003/role/disclosureRef
-Topic 842
-SubTopic 10
-Name Accounting Standards Codification
-Section 65
-Paragraph 5
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479832/842-10-65-5

Reference 25: http://www.xbrl.org/2003/role/disclosureRef
-Topic 842
-SubTopic 10
-Name Accounting Standards Codification
-Section 65
-Paragraph 5
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479832/842-10-65-5

Reference 26: http://www.xbrl.org/2003/role/disclosureRef
-Topic 842
-SubTopic 10
-Name Accounting Standards Codification
-Section 65
-Paragraph 5
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479832/842-10-65-5

Reference 27: http://www.xbrl.org/2003/role/disclosureRef
-Topic 842
-SubTopic 10
-Name Accounting Standards Codification
-Section 65
-Paragraph 5
-Subparagraph (d)(1)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479832/842-10-65-5

Reference 28: http://www.xbrl.org/2003/role/disclosureRef
-Topic 815
-SubTopic 40
-Name Accounting Standards Codification
-Section 65
-Paragraph 2
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480175/815-40-65-2

Reference 29: http://www.xbrl.org/2003/role/disclosureRef
-Topic 848
-SubTopic 10
-Name Accounting Standards Codification
-Section 65
-Paragraph 2
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483550/848-10-65-2

Reference 30: http://www.xbrl.org/2003/role/disclosureRef
-Topic 848
-SubTopic 10
-Name Accounting Standards Codification
-Section 65
-Paragraph 2
-Subparagraph (a)(1)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483550/848-10-65-2

Reference 31: http://www.xbrl.org/2003/role/disclosureRef
-Topic 848
-SubTopic 10
-Name Accounting Standards Codification
-Section 65
-Paragraph 2
-Subparagraph (a)(2)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483550/848-10-65-2

Reference 32: http://www.xbrl.org/2003/role/disclosureRef
-Topic 848
-SubTopic 10
-Name Accounting Standards Codification
-Section 65
-Paragraph 2
-Subparagraph (a)(3)(iii)(01)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483550/848-10-65-2

Reference 33: http://www.xbrl.org/2003/role/disclosureRef
-Topic 848
-SubTopic 10
-Name Accounting Standards Codification
-Section 65
-Paragraph 2
-Subparagraph (a)(3)(iii)(03)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483550/848-10-65-2

Reference 34: http://www.xbrl.org/2003/role/disclosureRef
-Topic 105
-SubTopic 10
-Name Accounting Standards Codification
-Section 65
-Paragraph 6
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479343/105-10-65-6

Reference 35: http://www.xbrl.org/2003/role/disclosureRef
-Topic 105
-SubTopic 10
-Name Accounting Standards Codification
-Section 65
-Paragraph 6
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479343/105-10-65-6

Reference 36: http://www.xbrl.org/2003/role/disclosureRef
-Topic 105
-SubTopic 10
-Name Accounting Standards Codification
-Section 65
-Paragraph 6
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479343/105-10-65-6

Reference 37: http://www.xbrl.org/2003/role/disclosureRef
-Topic 105
-SubTopic 10
-Name Accounting Standards Codification
-Section 65
-Paragraph 6
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479343/105-10-65-6

Reference 38: http://www.xbrl.org/2003/role/disclosureRef
-Topic 105
-SubTopic 10
-Name Accounting Standards Codification
-Section 65
-Paragraph 6
-Subparagraph (e)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479343/105-10-65-6

Reference 39: http://www.xbrl.org/2003/role/disclosureRef
-Topic 944
-SubTopic 40
-Name Accounting Standards Codification
-Section 65
-Paragraph 2
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480016/944-40-65-2

Reference 40: http://www.xbrl.org/2003/role/disclosureRef
-Topic 944
-SubTopic 40
-Name Accounting Standards Codification
-Section 65
-Paragraph 2
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480016/944-40-65-2

Reference 41: http://www.xbrl.org/2003/role/disclosureRef
-Topic 944
-SubTopic 40
-Name Accounting Standards Codification
-Section 65
-Paragraph 2
-Subparagraph (e)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480016/944-40-65-2

Reference 42: http://www.xbrl.org/2003/role/disclosureRef
-Topic 944
-SubTopic 40
-Name Accounting Standards Codification
-Section 65
-Paragraph 2
-Subparagraph (f)(1)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480016/944-40-65-2

Reference 43: http://www.xbrl.org/2003/role/disclosureRef
-Topic 944
-SubTopic 40
-Name Accounting Standards Codification
-Section 65
-Paragraph 2
-Subparagraph (f)(2)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480016/944-40-65-2

Reference 44: http://www.xbrl.org/2003/role/disclosureRef
-Topic 944
-SubTopic 40
-Name Accounting Standards Codification
-Section 65
-Paragraph 2
-Subparagraph (g)(1)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480016/944-40-65-2

Reference 45: http://www.xbrl.org/2003/role/disclosureRef
-Topic 944
-SubTopic 40
-Name Accounting Standards Codification
-Section 65
-Paragraph 2
-Subparagraph (g)(2)(i)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480016/944-40-65-2

Reference 46: http://www.xbrl.org/2003/role/disclosureRef
-Topic 944
-SubTopic 40
-Name Accounting Standards Codification
-Section 65
-Paragraph 2
-Subparagraph (g)(2)(ii)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480016/944-40-65-2

Reference 47: http://www.xbrl.org/2003/role/disclosureRef
-Topic 944
-SubTopic 40
-Name Accounting Standards Codification
-Section 65
-Paragraph 2
-Subparagraph (g)(2)(iii)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480016/944-40-65-2

Reference 48: http://www.xbrl.org/2003/role/disclosureRef
-Topic 944
-SubTopic 40
-Name Accounting Standards Codification
-Section 65
-Paragraph 2
-Subparagraph (g)(2)(iv)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480016/944-40-65-2

Reference 49: http://www.xbrl.org/2003/role/disclosureRef
-Topic 944
-SubTopic 40
-Name Accounting Standards Codification
-Section 65
-Paragraph 2
-Subparagraph (h)(1)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480016/944-40-65-2

Reference 50: http://www.xbrl.org/2003/role/disclosureRef
-Topic 944
-SubTopic 40
-Name Accounting Standards Codification
-Section 65
-Paragraph 2
-Subparagraph (h)(2)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480016/944-40-65-2

Reference 51: http://www.xbrl.org/2003/role/disclosureRef
-Topic 250
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 5
-Subparagraph (SAB Topic 11.M.Q2)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480530/250-10-S99-5

Reference 52: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 10
-Name Accounting Standards Codification
-Section 65
-Paragraph 4
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479654/326-10-65-4

Reference 53: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 10
-Name Accounting Standards Codification
-Section 65
-Paragraph 4
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479654/326-10-65-4

Reference 54: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 10
-Name Accounting Standards Codification
-Section 65
-Paragraph 4
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479654/326-10-65-4

Reference 55: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-SubTopic 10
-Name Accounting Standards Codification
-Section 65
-Paragraph 8
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482615/740-10-65-8

Reference 56: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-SubTopic 10
-Name Accounting Standards Codification
-Section 65
-Paragraph 8
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482615/740-10-65-8

Reference 57: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-SubTopic 10
-Name Accounting Standards Codification
-Section 65
-Paragraph 8
-Subparagraph (d)(2)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482615/740-10-65-8

Reference 58: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-SubTopic 10
-Name Accounting Standards Codification
-Section 65
-Paragraph 8
-Subparagraph (d)(3)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482615/740-10-65-8

Reference 59: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 10
-Name Accounting Standards Codification
-Section 65
-Paragraph 4
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479654/326-10-65-4

Reference 60: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 10
-Name Accounting Standards Codification
-Section 65
-Paragraph 4
-Subparagraph (e)(3)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479654/326-10-65-4

Reference 61: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 10
-Name Accounting Standards Codification
-Section 65
-Paragraph 4
-Subparagraph (e)(4)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479654/326-10-65-4

Reference 62: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 65
-Paragraph 15
-Subparagraph (e)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480336/718-10-65-15

Reference 63: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 65
-Paragraph 15
-Subparagraph (f)(1)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480336/718-10-65-15

Reference 64: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 65
-Paragraph 15
-Subparagraph (f)(2)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480336/718-10-65-15

Reference 65: http://www.xbrl.org/2003/role/disclosureRef
-Topic 926
-SubTopic 20
-Name Accounting Standards Codification
-Section 65
-Paragraph 2
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483194/926-20-65-2

Reference 66: http://www.xbrl.org/2003/role/disclosureRef
-Topic 926
-SubTopic 20
-Name Accounting Standards Codification
-Section 65
-Paragraph 2
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483194/926-20-65-2

Reference 67: http://www.xbrl.org/2003/role/disclosureRef
-Topic 926
-SubTopic 20
-Name Accounting Standards Codification
-Section 65
-Paragraph 2
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483194/926-20-65-2

Reference 68: http://www.xbrl.org/2003/role/disclosureRef
-Topic 250
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483443/250-10-50-3

Reference 69: http://www.xbrl.org/2003/role/disclosureRef
-Topic 250
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (b)(2)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483443/250-10-50-1

Reference 70: http://www.xbrl.org/2003/role/disclosureRef
-Topic 250
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (b)(3)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483443/250-10-50-1

Reference 71: http://www.xbrl.org/2003/role/disclosureRef
-Topic 250
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (b)(4)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483443/250-10-50-1

Reference 72: http://www.xbrl.org/2003/role/disclosureRef
-Topic 250
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (c)(2)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483443/250-10-50-1

Reference 73: http://www.xbrl.org/2003/role/disclosureRef
-Topic 260
-SubTopic 10
-Name Accounting Standards Codification
-Section 55
-Paragraph 15
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482635/260-10-55-15

Reference 74: http://www.xbrl.org/2003/role/disclosureRef
-Topic 250
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 6
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483421/250-10-45-6

Reference 75: http://www.xbrl.org/2003/role/disclosureRef
-Topic 825
-SubTopic 10
-Name Accounting Standards Codification
-Section 65
-Paragraph 6
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482833/825-10-65-6

Reference 76: http://www.xbrl.org/2003/role/disclosureRef
-Topic 825
-SubTopic 10
-Name Accounting Standards Codification
-Section 65
-Paragraph 6
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482833/825-10-65-6

Reference 77: http://www.xbrl.org/2003/role/disclosureRef
-Topic 825
-SubTopic 10
-Name Accounting Standards Codification
-Section 65
-Paragraph 6
-Subparagraph (c)(1)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482833/825-10-65-6

Reference 78: http://www.xbrl.org/2003/role/disclosureRef
-Topic 825
-SubTopic 10
-Name Accounting Standards Codification
-Section 65
-Paragraph 6
-Subparagraph (c)(2)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482833/825-10-65-6

Reference 79: http://www.xbrl.org/2003/role/disclosureRef
-Topic 815
-SubTopic 40
-Name Accounting Standards Codification
-Section 65
-Paragraph 1
-Subparagraph (a)(1)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480175/815-40-65-1

Reference 80: http://www.xbrl.org/2003/role/disclosureRef
-Topic 815
-SubTopic 40
-Name Accounting Standards Codification
-Section 65
-Paragraph 1
-Subparagraph (a)(2)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480175/815-40-65-1

Reference 81: http://www.xbrl.org/2003/role/disclosureRef
-Topic 815
-SubTopic 40
-Name Accounting Standards Codification
-Section 65
-Paragraph 1
-Subparagraph (a)(3)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480175/815-40-65-1

Reference 82: http://www.xbrl.org/2003/role/disclosureRef
-Topic 815
-SubTopic 40
-Name Accounting Standards Codification
-Section 65
-Paragraph 1
-Subparagraph (b)(1)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480175/815-40-65-1

Reference 83: http://www.xbrl.org/2003/role/disclosureRef
-Topic 815
-SubTopic 40
-Name Accounting Standards Codification
-Section 65
-Paragraph 1
-Subparagraph (b)(2)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480175/815-40-65-1

Reference 84: http://www.xbrl.org/2003/role/disclosureRef
-Topic 815
-SubTopic 40
-Name Accounting Standards Codification
-Section 65
-Paragraph 1
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480175/815-40-65-1

Reference 85: http://www.xbrl.org/2003/role/disclosureRef
-Topic 815
-SubTopic 40
-Name Accounting Standards Codification
-Section 65
-Paragraph 1
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480175/815-40-65-1

Reference 86: http://www.xbrl.org/2003/role/disclosureRef
-Topic 815
-SubTopic 40
-Name Accounting Standards Codification
-Section 65
-Paragraph 1
-Subparagraph (e)(2)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480175/815-40-65-1

Reference 87: http://www.xbrl.org/2003/role/disclosureRef
-Topic 815
-SubTopic 40
-Name Accounting Standards Codification
-Section 65
-Paragraph 1
-Subparagraph (e)(3)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480175/815-40-65-1

Reference 88: http://www.xbrl.org/2003/role/disclosureRef
-Topic 815
-SubTopic 40
-Name Accounting Standards Codification
-Section 65
-Paragraph 1
-Subparagraph (e)(4)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480175/815-40-65-1

Reference 89: http://www.xbrl.org/2003/role/disclosureRef
-Topic 815
-SubTopic 40
-Name Accounting Standards Codification
-Section 65
-Paragraph 1
-Subparagraph (f)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480175/815-40-65-1

Reference 90: http://www.xbrl.org/2003/role/disclosureRef
-Topic 310
-SubTopic 20
-Name Accounting Standards Codification
-Section 65
-Paragraph 2
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481925/310-20-65-2

Reference 91: http://www.xbrl.org/2003/role/disclosureRef
-Topic 310
-SubTopic 20
-Name Accounting Standards Codification
-Section 65
-Paragraph 2
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481925/310-20-65-2

Reference 92: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480424/946-10-50-3

+ Details

Property and Equipment , Net

12 Months Ended

Dec. 31, 2023

Property, Plant and Equipment [Abstract]

Property and Equipment, Net

7. Property and Equipment, Net

Property and equipment, net, as of December 31, 2023 and 2022 was comprised as follows (in thousands):


		December 31,
	Estimated Useful Life (in Years)	2023			2022
Laboratory equipment	5	$	11,187		$	8,441
Furniture and office equipment	4		481			477
Computer equipment	3		241			213
Leasehold improvements	Shorter of useful life or remaining lease term		3,356			2,941
Construction in progress			8,242			2,049
Total property and equipment, gross			23,507			14,121
Less: accumulated depreciation			(7,842	)		(4,255	)
Total property and equipment, net		$	15,665		$	9,866

As of December 31, 2023 and 2022, the Company had construction in progress of $8.2 million and $2.0 million, predominately related to laboratory equipment received but not yet installed and capitalizable costs related to the Company’s future corporate headquarters.

Depreciation expense for the years ended December 31, 2023 and 2022 was $3.6 million and $2.5 million, respectively.

Accrued Expenses and Other Current Liabilities

12 Months Ended

Dec. 31, 2023

Payables and Accruals [Abstract]

Accrued Expenses and Other Current Liabilities

8. Accrued Expenses and Other Current Liabilities

Accrued expenses and other current liabilities as of December 31, 2023 and 2022 were comprised as follows (in thousands):


	December 31,
	2023		2022
Employee compensation and benefits	$	7,896	$	2,624
External research and development services		1,255		274
Other operating expenses		447		207
CVR liability, current		395		—
Professional fees		219		70
Total accrued expenses and other current liabilities	$	10,212	$	3,175

Related Party Transactions

12 Months Ended

Dec. 31, 2023

Related Party Transactions

16. Related Party Transactions

As a result of Atlas’ ownership of the Legacy Korro’s Series Seed Preferred Stock, Series A Preferred Stock and Series B Preferred Stock which was exchanged in the Merger for the Company's common stock, Atlas represents an affiliate of the Company. During the years ended December 31, 2023 and 2022, the Company incurred no expense and expenses of less than $0.1 million, respectively, related to consulting services provided by an affiliate of Atlas. As of December 31, 2023 and 2022, the Company had no amounts due to this affiliate.

- Definition

The entire disclosure for related party transactions. Examples of related party transactions include transactions between (a) a parent company and its subsidiary; (b) subsidiaries of a common parent; (c) and entity and its principal owners; and (d) affiliates.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480990/946-20-50-2

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 5
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480990/946-20-50-5

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 6
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480990/946-20-50-6

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 235
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481062/946-235-50-2

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 235
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (e)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481062/946-235-50-2

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Topic 850
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483326/850-10-50-1

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 220
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.6-07(2)(g)(3))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483575/946-220-S99-1

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 220
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.6-07(2)(c))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483575/946-220-S99-1

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 220
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.6-07(2)(e))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483575/946-220-S99-1

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Topic 850
-Name Accounting Standards Codification
-Publisher FASB
-URI https://asc.fasb.org//850/tableOfContent

Reference 11: http://www.xbrl.org/2003/role/disclosureRef
-Topic 850
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 6
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483326/850-10-50-6

Reference 12: http://www.xbrl.org/2003/role/disclosureRef
-Topic 850
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483326/850-10-50-1

Reference 13: http://www.xbrl.org/2003/role/disclosureRef
-Topic 850
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483326/850-10-50-1

+ Details

Common Stock - Schedule of Number of Shares Reserved for Future Issuance (Details) - shares	Dec. 31, 2023	Dec. 31, 2022
Preferred stock, shares outstanding	0	0
Future issuance of share	8,016,516	271,371
Total reserved for future issuance	1,675,396	5,487,208
Exercises of outstanding Shares	8,016,516	268,468
2019 Stock Incentive Plan
Future issuance of share	0	159,890
Total reserved for future issuance	110,285
2023 Stock Incentive Plan
Future issuance of share	255,694	0
Employee Stock Purchase Plan
Future issuance of share	88,502	0
Outstanding Warrant [Member]
Exercises of outstanding Shares	8,049	8,049
Stock Options
Exercises of outstanding Shares	1,323,151	461,128
Restricted Common Stock
Future issuance of share	0	2,902
Series Seed Preferred Stock
Preferred stock, shares outstanding	0	684,739
Series A Preferred Stock
Preferred stock, shares outstanding	0	2,029,666
Series B-1 Preferred Stock
Preferred stock, shares outstanding	0	1,104,178
Series B-2 Preferred Stock
Preferred stock, shares outstanding	0	223,417
Future issuance of share	0	813,239

Commitments and Contingencies (Additional Information) (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2023 USD ($) ft²	Sep. 30, 2023 USD ($)	May 31, 2023 USD ($)	Dec. 31, 2022 USD ($)
Lessee, Lease, Description [Line Items]
Operating lease right-of-use assets	$ 27,150			$ 2,024
Operating lease liability	33,207
Lease rental payments	$ 66,416
Weighted average remaining lease term	10 years
Weighted average remaining lease discount rate	11.20%
Loss contingency accrual	$ 0
OKS Facility [Member]
Lessee, Lease, Description [Line Items]
Lease area of land \| ft²	22,561
Lease expiration date	Oct. 20, 2023
Cummings Park Sublease [Member]
Lessee, Lease, Description [Line Items]
Lease area of land \| ft²	18,148
Lease expiration date	Jul. 31, 2024
60 First Street Lease [Member]
Lessee, Lease, Description [Line Items]
Lease remaining terms	10 years
Lease area of land \| ft²	50,453
Operating lease right-of-use assets			$ 26,800
Operating lease liability			26,800
Lease rental payments			62,100
Lessee, Operating Lease, Remaining Lease Term	10 years
Tenant improvement allowance	$ 13,100		$ 13,100
Tenant improvement allowance utilized	$ 2,300
Future minimum lease payments receivable		$ 10,800

Fair Value Measurements (Tables)

12 Months Ended

Dec. 31, 2023

Fair Value Disclosures [Abstract]

Schedule of Financial Assets Measured at Fair Value on Recurring Basis

Assets measured at fair value on a recurring basis as of December 31, 2023 were as follows (in thousands):


	Total		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Money market funds, included in cash and cash equivalents	$	158,706	$	158,706	$	—	$	—
MS APA asset	$	1,448	$	—	$	—	$	1,448
Total	$	160,154	$	158,706	$	—	$	1,448

Assets measured at fair value on a recurring basis as of December 31, 2022 were as follows (in thousands):


	Total		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Money market funds, included in cash and cash equivalents	$	14,904	$	14,904	$	—	$	—
Short-term investments:
Commercial paper	$	14,935		—		14,935		—
Government securities	$	3,980		—		3,980		—
Total	$	33,819	$	14,904	$	18,915	$	—

Fair Value Measurements (Additional Information) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Tranfer of assets among fair value hierarchy levels	$ 0	$ 0
Prepaid Expense and Other Assets, Current	3,015,000	1,232,000
Other non-current liabilities	$ 1,053,000	$ 0
MS APA Asset [Member]
Derivative Liability, Statement of Financial Position [Extensible Enumeration]	Liabilities
Derivative Liability	$ 1,400,000
Other current liabilities	400,000
Initial Consideration Amount	$ 500,000
Derivative Asset, Statement of Financial Position [Extensible Enumeration]	Assets
Derivative Asset	$ 1,400,000
Other Assets, Current	1,000,000
Prepaid Expense and Other Assets, Current	400,000
Other non-current liabilities	1,000,000
Maximum [Member] \| MS APA Asset [Member]
Future Milestone Payments	17,500,000
Minimum [Member] \| MS APA Asset [Member]
Future Milestone Payments	700,000
Fair Value, Inputs, Level 3 [Member] \| MS APA Asset [Member]
Change in fair value of CVR liability	$ 80,000.00

Net Loss per Share (Tables)

12 Months Ended

Dec. 31, 2023

Earnings Per Share [Abstract]

Computation of Diluted Net Loss per Share

The following common stock equivalents have been excluded from the calculation of diluted net loss per share because their effect would be anti-dilutive:


	Year Ended December 31,
	2023		2022
Legacy Korro Series Seed Preferred Stock		—		684,739
Legacy Korro Series A Preferred Stock		—		2,029,666
Legacy Korro Series B-1 Preferred Stock		—		1,104,178
Legacy Korro Series B-2 Preferred Stock		—		223,417
Unvested Legacy Korro restricted common stock		—		2,902
Outstanding Legacy Korro stock options		1,323,151		461,100
Outstanding Legacy Korro warrant		8,049		8,049
Total		1,331,200		4,514,051

Schedule of Basic and Diluted Net Loss per Share


	Years Ended December 31,
	2023			2022
Numerator:
Net loss	$	(81,172	)	$	(58,032	)
Denominator:
Weighted-average number of shares outstanding, basic and diluted		1,529,321			255,175
Net loss per share, basic and diluted	$	(53.08	)	$	(227.42	)

Basis of Presentation and Summary of Significant Accounting Policies (Additional Information) (Details)	12 Months Ended
	Dec. 31, 2023 USD ($)
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Increase in right-of-use asset	$ 0

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

+ Details

Common Stock

12 Months Ended

Dec. 31, 2023

Equity [Abstract]

Common Stock

9. Common Stock

At the closing of the merger, the shares of Legacy Korro common stock were converted into shares of the Company's common stock based on the exchange ratio determined in the Merger Agreement.

As of December 31, 2023, the Company was authorized to issue 200,000,000 shares of common stock, $0.001 per value per share. Prior to the merger, the holders of Legacy Korro’s common stock were subject to and qualified by the rights, powers and preferences of the holders of the Preferred Stock set forth in Note 10. Holders of common stock are entitled to one vote per share. In addition, holders of common stock are entitled to receive dividends, if and when declared by the Company’s Board of Directors. As of December 31, 2023, no dividends had been declared.

As of December 31, 2023 and 2022, the Company had reserved for future issuance the following number of shares of common stock:


	December 31,
	2023		2022
Conversion of outstanding Legacy Korro Series Seed Preferred Stock		—		684,739
Conversion of outstanding Legacy Korro Series A Preferred Stock		—		2,029,666
Conversion of outstanding Legacy Korro Series B-1 Preferred Stock		—		1,104,178
Conversion of outstanding Legacy Korro Series B-2 Preferred Stock		—		223,417
Future issuances of Legacy Korro Series B-2 Preferred Stock		—		813,239
Vesting of restricted common stock		—		2,902
Exercises of outstanding stock options		1,323,151		461,128
Exercise of outstanding warrant		8,049		8,049
Future issuances under 2019 Stock Incentive Plan		—		159,890
Future issuances under 2023 Stock Incentive Plan		255,694		—
Future issuances under 2023 ESPP Plan		88,502		—
Total reserved for future issuance		1,675,396		5,487,208

- Definition

The entire disclosure for equity.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 505
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 13
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481112/505-10-50-13

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 505
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 13
-Subparagraph (h)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481112/505-10-50-13

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 505
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 14
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481112/505-10-50-14

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 235
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481062/946-235-50-2

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 235
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481062/946-235-50-2

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 505
-Name Accounting Standards Codification
-Section 50
-Paragraph 6
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481004/946-505-50-6

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Topic 815
-SubTopic 40
-Name Accounting Standards Codification
-Section 50
-Paragraph 6
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480237/815-40-50-6

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Topic 505
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.3-04)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480008/505-10-S99-1

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Topic 235
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(e)(1))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480678/235-10-S99-1

Reference 10: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 505
-Name Accounting Standards Codification
-Publisher FASB
-URI https://asc.fasb.org//505/tableOfContent

Reference 11: http://www.xbrl.org/2003/role/disclosureRef
-Topic 505
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 13
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481112/505-10-50-13

Reference 12: http://www.xbrl.org/2003/role/disclosureRef
-Topic 505
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 13
-Subparagraph (g)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481112/505-10-50-13

Reference 13: http://www.xbrl.org/2003/role/disclosureRef
-Topic 505
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 13
-Subparagraph (i)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481112/505-10-50-13

Reference 14: http://www.xbrl.org/2003/role/disclosureRef
-Topic 505
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 14
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481112/505-10-50-14

Reference 15: http://www.xbrl.org/2003/role/disclosureRef
-Topic 505
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 14
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481112/505-10-50-14

Reference 16: http://www.xbrl.org/2003/role/disclosureRef
-Topic 505
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 16
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481112/505-10-50-16

Reference 17: http://www.xbrl.org/2003/role/disclosureRef
-Topic 505
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 18
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481112/505-10-50-18

Reference 18: http://www.xbrl.org/2003/role/disclosureRef
-Topic 505
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 18
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481112/505-10-50-18

Reference 19: http://www.xbrl.org/2003/role/disclosureRef
-Topic 505
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 18
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481112/505-10-50-18

+ Details

Stock-based Compensation - Summary of Restricted Common Stock Activity (Details) - Restricted Stock Units (RSUs) [Member]	12 Months Ended
	Dec. 31, 2023 $ / shares shares
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Unvested as of December 31, 2022 \| shares	2,902
Granted \| shares	0
Vested \| shares	2,902
Repurchased \| shares	0
Unvested as of December 31, 2023 \| shares	0
Weighted average fair value, Unvested as of December 31, 2022 \| $ / shares	$ 0.59
Weighted average fair value, Granted \| $ / shares	0
Weighted average fair value, Vested \| $ / shares	0.23
Weighted average fair value, Repurchased \| $ / shares	0
Weighted average fair value, Unvested as of December 31, 2023 \| $ / shares	$ 0

Fair Value Measurements - Schedule of Financial Assets Measured at Fair Value on Recurring Basis (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair market value		$ 18,915
Fair Value Measurements Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair market value	$ 160,154	33,819
Fair Value, Inputs, Level 1 [Member] \| Fair Value Measurements Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair market value	158,706	14,904
Fair Value, Inputs, Level 2 [Member] \| Fair Value Measurements Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair market value	0	18,915
Fair Value, Inputs, Level 3 [Member] \| Fair Value Measurements Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair market value	1,448	0
Money Market Funds [Member] \| Fair Value Measurements Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair market value	158,706	14,904
Money Market Funds [Member] \| Fair Value, Inputs, Level 1 [Member] \| Fair Value Measurements Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair market value	158,706	14,904
Money Market Funds [Member] \| Fair Value, Inputs, Level 2 [Member] \| Fair Value Measurements Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair market value	0	0
Money Market Funds [Member] \| Fair Value, Inputs, Level 3 [Member] \| Fair Value Measurements Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair market value	0	0
MS APA Asset [Member] \| Fair Value Measurements Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair market value	1,448
MS APA Asset [Member] \| Fair Value, Inputs, Level 1 [Member] \| Fair Value Measurements Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair market value	0
MS APA Asset [Member] \| Fair Value, Inputs, Level 2 [Member] \| Fair Value Measurements Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair market value	0
MS APA Asset [Member] \| Fair Value, Inputs, Level 3 [Member] \| Fair Value Measurements Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair market value	$ 1,448
Commercial Paper [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair market value		14,935
Commercial Paper [Member] \| Fair Value Measurements Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair market value		14,935
Commercial Paper [Member] \| Fair Value, Inputs, Level 1 [Member] \| Fair Value Measurements Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair market value		0
Commercial Paper [Member] \| Fair Value, Inputs, Level 2 [Member] \| Fair Value Measurements Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair market value		14,935
Commercial Paper [Member] \| Fair Value, Inputs, Level 3 [Member] \| Fair Value Measurements Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair market value		0
Government Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair market value		3,980
Government Securities [Member] \| Fair Value Measurements Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair market value		3,980
Government Securities [Member] \| Fair Value, Inputs, Level 1 [Member] \| Fair Value Measurements Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair market value		0
Government Securities [Member] \| Fair Value, Inputs, Level 2 [Member] \| Fair Value Measurements Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair market value		3,980
Government Securities [Member] \| Fair Value, Inputs, Level 3 [Member] \| Fair Value Measurements Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair market value		$ 0