Verve Therapeutics (VERV) 10-Q 7 Nov 23 2023 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2023	Oct. 31, 2023
Cover [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2023
Document Fiscal Year Focus	2023
Document Fiscal Period Focus	Q3
Entity Registrant Name	VERVE THERAPEUTICS, INC.
Entity Central Index Key	0001840574
Trading Symbol	VERV
Current Fiscal Year End Date	--12-31
Entity Current Reporting Status	Yes
Entity Shell Company	false
Entity Filer Category	Non-accelerated Filer
Entity Emerging Growth Company	true
Entity Ex Transition Period	false
Entity Small Business	true
Entity Common Stock, Shares Outstanding		63,752,748
Entity Interactive Data Current	Yes
Security Exchange Name	NASDAQ
Title of 12(b) Security	Common stock, par value $0.001 per share
Entity File Number	001-40489
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	82-4800132
Entity Address, Address Line One	201 Brookline Avenue, Suite 601
Entity Address, City or Town	Boston
Entity Address, State or Province	MA
Entity Address, Postal Zip Code	02215
City Area Code	617
Local Phone Number	603-0070
Document Quarterly Report	true
Document Transition Report	false

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Current assets:
Cash and cash equivalents	$ 78,370	$ 115,412
Marketable securities	406,856	439,396
Collaboration receivable	3,145	1,012
Prepaid expenses and other current assets	9,890	7,339
Total current assets	498,261	563,159
Property and equipment, net	20,803	18,778
Restricted cash	4,774	4,824
Operating lease right-of-use assets	87,041	91,877
Other long term assets	1,528	585
Total assets	612,407	679,223
Current liabilities:
Accounts payable	1,054	2,424
Accrued expenses	23,403	20,767
Lease liability, current portion	10,118	11,904
Total current liabilities	34,575	35,095
Long-term lease liability	66,689	70,014
Success Payment Liability	2,007	2,885
Deferred revenue non-current	48,554	20,014
Other long term liabilities	213	283
Total liabilities	152,038	128,291
Commitments and contingencies (See Note 7 and Note 8)
Stockholders' equity:
Preferred stock, $0.001 par value; 5,000,000 shares authorized; no shares issued and outstanding	0	0
Common stock, $0.001 par value; 200,000,000 shares authorized, 62,064,279 and 61,730,816 shares issued and outstanding at June 30, 2023 and December 31, 2022, respectively	64	62
Additional paid-in capital	956,855	895,801
Accumulated other comprehensive loss	(597)	(694)
Accumulated deficit	(495,953)	(344,237)
Total stockholders equity	460,369	550,932
Total liabilities and stockholders' equity	$ 612,407	$ 679,223

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Parenthetical) - $ / shares	Sep. 30, 2023	Dec. 31, 2022
Statement of Financial Position [Abstract]
Preferred stock, par value	$ 0.001	$ 0.001
Preferred stock, shares authorized	5,000,000	5,000,000
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	200,000,000
Common stock shares issued	63,737,089	61,730,816
Common stock, shares outstanding	63,737,089	61,730,816

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations and Comprehensive Loss - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Income Statement [Abstract]
Collaboration Revenue	$ 3,117	$ 929	$ 6,614	$ 929
Operating expenses:
Research and development	43,765	35,197	138,135	92,811
General and administrative	11,686	9,592	37,655	26,095
Total operating expenses	55,451	44,789	175,790	118,906
Loss from operations	(52,334)	(43,860)	(169,176)	(117,977)
Other (expense) income:
Change in fair value of success payment liability	802	(3,306)	878	(691)
Interest and other income, net	5,841	1,976	16,825	2,366
Total other income, net	6,643	(1,330)	17,703	1,675
Loss before provision for income taxes	(45,691)	(45,190)	(151,473)	(116,302)
Provision for income taxes	(67)	0	(243)	0
Net loss	$ (45,758)	$ (45,190)	$ (151,716)	$ (116,302)
Net loss per common share attributable to common stockholders, basic	$ (0.72)	$ (0.79)	$ (2.43)	$ (2.26)
Net loss per common share attributable to common stockholders, diluted	$ (0.72)	$ (0.79)	$ (2.43)	$ (2.26)
Weighted-average common shares used in net loss per share attributable to common stockholders, basic	63,211,849	57,207,125	62,322,965	51,516,037
Weighted-average common shares used in net loss per share attributable to common stockholders, diluted	63,211,849	57,207,125	62,322,965	51,516,037
Comprehensive Loss:
Net loss	$ (45,758)	$ (45,190)	$ (151,716)	$ (116,302)
Other comprehensive income (loss):
Unrealized income (loss) on marketable securities	157	18	97	(692)
Comprehensive loss	$ (45,601)	$ (45,172)	$ (151,619)	$ (116,994)

Condensed Consolidated Statem_2

Condensed Consolidated Statement of Convertible Preferred Stock and Stockholders' Equity (Deficit) - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-In Capital	Accumulated Other Comprehensive Loss	Accumulated Deficit
Beginning Balance at Dec. 31, 2021	$ 357,352	$ 49	$ 544,381	$ (228)	$ (186,850)
Beginning Balance (in shares) at Dec. 31, 2021		48,511,735
Exercise of stock options	505		505
Exercise of stock options (in shares)		143,506
Unrealized loss on available-for-sale securities	(504)			(504)
Stock-based compensation	4,203		4,203
Net loss	(30,166)				(30,166)
Ending Balance at Mar. 31, 2022	331,390	$ 49	549,089	(732)	(217,016)
Ending balance (in shares) at Mar. 31, 2022		48,655,241
Beginning Balance at Dec. 31, 2021	357,352	$ 49	544,381	(228)	(186,850)
Beginning Balance (in shares) at Dec. 31, 2021		48,511,735
Net loss	(116,302)
Ending Balance at Sep. 30, 2022	547,943	$ 61	851,954	(920)	(303,152)
Ending balance (in shares) at Sep. 30, 2022		60,443,175
Beginning Balance at Mar. 31, 2022	331,390	$ 49	549,089	(732)	(217,016)
Beginning Balance (in shares) at Mar. 31, 2022		48,655,241
Exercise of stock options	120		120
Exercise of stock options (in shares)		29,193
Issuance of common stock under Employee Stock Purchase Plan, shares		25,218
Issuance of common stock under Employee Stock Purchase Plan	325		325
Unrealized loss on available-for-sale securities	(206)			(206)
Stock-based compensation	5,650		5,650
Net loss	(40,946)				(40,946)
Ending Balance at Jun. 30, 2022	296,333	$ 49	555,184	(938)	(257,962)
Ending balance (in shares) at Jun. 30, 2022		48,709,652
Exercise of stock options	1,107		1,107
Exercise of stock options (in shares)		413,503
Unrealized loss on available-for-sale securities	18			18
Stock-based compensation	5,920		5,920
Issuance of common stock in connection with the Vertex Agreement, shares		1,519,756
Issuance of common stock from At-the-Market offering, net of issuance costs, shares		216,930
Issuance of common stock from follow-on public offering, net of issuance costs,shares		9,583,334
Issuance of common stock in connection with the Vertex Agreement	39,987	$ 2	39,985
Issuance of common stock from follow-on public offering, net of issuance Cost	242,848	10	242,838
Issuance of common stock from At-the-Market offering, net of issuance costs	6,920		6,920
Net loss	(45,190)				(45,190)
Ending Balance at Sep. 30, 2022	547,943	$ 61	851,954	(920)	(303,152)
Ending balance (in shares) at Sep. 30, 2022		60,443,175
Beginning Balance at Dec. 31, 2022	$ 550,932	$ 62	895,801	(694)	(344,237)
Beginning Balance (in shares) at Dec. 31, 2022	61,730,816	61,730,816
Exercise of stock options	$ 116		116
Exercise of stock options (in shares)		29,010
Unrealized loss on available-for-sale securities	457			457
Stock-based compensation	8,024		8,024
Issuance of common stock from At-the-Market offering, net of issuance costs, shares		103,184
Issuance of common stock from At-the-Market offering, net of issuance costs	1,922		1,922
Net loss	(51,975)				(51,975)
Ending Balance at Mar. 31, 2023	509,476	$ 62	905,863	(237)	(396,212)
Ending balance (in shares) at Mar. 31, 2023		61,863,010
Beginning Balance at Dec. 31, 2022	$ 550,932	$ 62	895,801	(694)	(344,237)
Beginning Balance (in shares) at Dec. 31, 2022	61,730,816	61,730,816
Exercise of stock options (in shares)	171,037
Net loss	$ (151,716)
Ending Balance at Sep. 30, 2023	$ 460,369	$ 64	956,855	(597)	(495,953)
Ending balance (in shares) at Sep. 30, 2023	63,737,089	63,737,089
Beginning Balance at Mar. 31, 2023	$ 509,476	$ 62	905,863	(237)	(396,212)
Beginning Balance (in shares) at Mar. 31, 2023		61,863,010
Vesting of restricted stock units (in shares)		50,537
Exercise of stock options	548		548
Exercise of stock options (in shares)		98,598
Issuance of common stock under Employee Stock Purchase Plan, shares		52,134
Issuance of common stock under Employee Stock Purchase Plan	685		685
Unrealized loss on available-for-sale securities	(517)			(517)
Stock-based compensation	9,013		9,013
Net loss	(53,983)				(53,983)
Ending Balance at Jun. 30, 2023	465,222	$ 62	916,109	(754)	(450,195)
Ending balance (in shares) at Jun. 30, 2023		62,064,279
Vesting of restricted stock units (in shares)		76,586
Exercise of stock options	213		213
Exercise of stock options (in shares)		43,429
Unrealized loss on available-for-sale securities	157			157
Stock-based compensation	8,825		8,825
Issuance of common stock in connection with the Lilly Agreement ,Shares		1,552,795
Issuance of common stock in connection with the Lilly Agreement,Cost	31,710	$ 2	31,708
Net loss	(45,758)				(45,758)
Ending Balance at Sep. 30, 2023	$ 460,369	$ 64	$ 956,855	$ (597)	$ (495,953)
Ending balance (in shares) at Sep. 30, 2023	63,737,089	63,737,089

Condensed Consolidated Statem_3

Condensed Consolidated Statement of Convertible Preferred Stock and Stockholders' Equity (Deficit) (Parenthetical) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2023	Sep. 30, 2022
Statement of Stockholders' Equity [Abstract]
Issuance of common stock from At-the-Market offering	$ 126	$ 0.6
Issuance of common stock from follow-on public offering		$ 15.9

Condensed Consolidated Statem_4

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022
Cash flows from operating activities:
Net loss	$ (151,716)	$ (116,302)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation	3,938	1,879
Non-cash lease expense	5,046	2,279
Net amortization of premium (accretion of discount) on marketable securities	(11,044)	1,114
Stock-based compensation	25,862	15,773
Change in fair value of success payments liabilities	(878)	691
Changes in operating assets and liabilities:
Collaboration receivable	(3,117)	(929)
Prepaid expenses and other assets	(2,587)	(9,368)
Accounts payable	(589)	(6,411)
Accrued expenses and other liabilities	2,996	4,661
Operating lease liabilities	(5,320)	(2,841)
Deferred revenue	28,540	20,014
Net cash used in operating activities	(108,869)	(89,440)
Cash flows from investing activities:
Purchases of property and equipment	(7,098)	(8,264)
Purchases of marketable securities	(394,817)	(222,078)
Maturities of marketable securities	438,498	242,700
Net cash provided by investing activities	36,583	12,358
Cash flows from financing activities:
Proceeds from the issuance of common stock in connection with collaboration agreements	31,710	39,986
Proceeds from issuance of common stock, net of commissions	1,987	247,919
Payment of equity offering costs	(65)	(605)
Proceeds from exercise of stock options	877	1,733
Issuance of common stock under employee stock purchase plan	685	325
Net cash provided by financing activities	35,194	289,358
Increase (decrease) in cash, cash equivalents and restricted cash	(37,092)	212,276
Cash, cash equivalents and restricted cash—beginning of period	120,236	69,567
Cash, cash equivalents and restricted cash—end of period	83,144	281,843
Supplemental disclosure of noncash investing and financing activities:
Property and equipment additions included in accounts payable and accrued expenses	495	2,025
Offering costs included in accounts payable and accrued liabilities	0	175
Right-of-use assets obtained in exchange for new operating lease liabilities	$ 0	$ 81,244

Nature of the Business and Basi

Nature of the Business and Basis of Presentation	9 Months Ended
	Sep. 30, 2023
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Nature of the Business and Basis of Presentation	1. Nature of the business and basis of presentation Organization Verve Therapeutics, Inc. (the “Company” or “Verve”) is a clinical-stage genetic medicines company pioneering a new approach to the care of cardiovascular disease, transforming treatment from chronic management to single-course gene editing medicines. The Company was incorporated on March 9, 2018 as Endcadia, Inc., a Delaware corporation, and began operations shortly thereafter. In January 2019, the Company amended its certificate of incorporation to change its name to Verve Therapeutics, Inc. The Company’s principal offices are located in Boston, Massachusetts. Liquidity and capital resources Since its inception, the Company has devoted its efforts principally to research and development and raising capital. The Company is subject to risks and uncertainties common to early-stage companies in the biotechnology industry including, but not limited to, technical risks associated with the successful research, development and manufacturing of product candidates, development by competitors of new technological innovations, dependence on key personnel, protection of proprietary technology, compliance with government regulations and the ability to secure additional capital to fund operations. Current and future programs will require significant research and development efforts, including extensive preclinical and clinical testing and regulatory approval prior to commercialization. These efforts require significant amounts of additional capital, adequate personnel and infrastructure and extensive compliance-reporting capabilities. Even if the Company’s development efforts are successful, it is uncertain when, if ever, the Company will realize significant revenue from product sales. The accompanying condensed consolidated financial statements have been prepared on a going concern basis, which contemplates the realization of assets and the satisfaction of liabilities and commitments in the ordinary course of business. The Company expects that its cash, cash equivalents and marketable securities of $ 485.2 million as of September 30, 2023 will be sufficient to fund its operations and capital expenditure requirements beyond the next 12 months from the date of issuance of these financial statements. The Company will need additional financing to support its continuing operations and pursue its growth strategy. Until such time as the Company can generate significant revenue from product sales, if ever, it expects to finance its operations through a combination of equity offerings, debt financings, collaborations, strategic alliances and marketing, distribution or licensing arrangements. The Company may be unable to raise additional funds or enter into such other agreements when needed on favorable terms or at all. The inability to raise capital as and when needed could have a negative impact on the Company’s financial condition and its ability to pursue its business strategy. The Company will need to generate significant revenue to achieve profitability, and it may never do so. Basis of presentation The accompanying condensed consolidated financial statements have been prepared in accordance with United States generally accepted accounting principles (“GAAP”) and pursuant to the rules and regulations of the Securities and Exchange Commission ("SEC"). Any reference in these notes to applicable guidance is meant to refer to the authoritative GAAP as found in the Accounting Standards Codification (“ASC”) and Accounting Standards Update (“ASU”) of the Financial Accounting Standards Board (“FASB”). Certain information and footnote disclosures normally included in financial statements prepared in accordance with GAAP have been condensed or omitted pursuant to such rules and regulations. The unaudited condensed consolidated financial statements have been prepared on the same basis as the audited consolidated financial statements. In the opinion of the Company’s management, the accompanying unaudited condensed consolidated financial statements contain all adjustments that are necessary to present fairly the Company’s financial position as of September 30, 2023, the results of its operations and other comprehensive loss for the three and nine months ended September 30, 2023 and 2022, stockholders’ equity for the three and nine months ended September 30, 2023 and 2022 and cash flows for the nine months ended September 30, 2023 and 2022. Such adjustments are of a normal and recurring nature. The results for the three and nine months ended September 30, 2023 are not necessarily indicative of the results for the year ending December 31, 2023, or for any future period. These interim financial statements should be read in conjunction with the audited consolidated financial statements as of and for the year ended December 31, 2022 , and the notes thereto, included in the Company’s Annual Report on Form 10-K filed with the SEC on March 2, 2023.

Summary of Significant Accounti

Summary of Significant Accounting Policies	9 Months Ended
	Sep. 30, 2023
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	2. S ummary of significant accounting policies The Company's significant accounting policies are disclosed in Note 2, "Summary of significant accounting policies," in the audited consolidated financial statements for the year ended December 31, 2022, and notes thereto, included in the Company’s Annual Report on Form 10-K filed with the SEC on March 2, 2023. Since the date of those financial statements, there have been no changes to the Company's significant accounting policies. Cash, cash equivalents and restricted cash Restricted cash represents collateral provided for letters of credit issued as security deposits in connection with the Company’s leases of its corporate facilities. A reconciliation of the cash, cash equivalents, and restricted cash reported within the condensed consolidated balance sheet that sum to the total of the same amounts shown in the condensed consolidated statements of cash flows is as follows: September 30, September 30, (in thousands) 2023 2022 Cash and cash equivalents $ 78,370 $ 277,019 Restricted cash 4,774 4,824 Total cash, cash equivalents and restricted cash $ 83,144 $ 281,843 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. The standard requires that credit losses be reported using an expected losses model rather than the incurred losses model that was previously used, and establishes additional disclosures related to credit risks. For available-for-sale debt securities with unrealized losses, this standard requires allowances to be recorded instead of reducing the amortized cost of the investment. The Company adopted the new standard on January 1, 2023. Based upon the Company's analysis, the adoption of this new standard did not have a material impact on the Company's financial statements.

Marketable Securities

Marketable Securities	9 Months Ended
	Sep. 30, 2023
Investments, Debt and Equity Securities [Abstract]
Marketable Securities	3. Marketable securities Marketable securities by security type consisted of the following: September 30, 2023 (in thousands) Amortized Gross Gross Fair U.S. treasury bills and notes $ 112,735 $ 2 $ ( 84 ) $ 112,653 U.S. agency securities 294,718 21 ( 536 ) 294,203 Total $ 407,453 $ 23 $ ( 620 ) $ 406,856 December 31, 2022 (in thousands) Amortized Gross Gross Fair U.S. treasury bills and notes $ 228,432 $ 13 $ ( 301 ) $ 228,144 U.S. agency securities 211,658 68 ( 474 ) 211,252 Total $ 440,090 $ 81 $ ( 775 ) $ 439,396 The remaining contractual maturities of all marketable securities were less than 15 months as of September 30, 2023 and 18 months as of December 31, 2022.The gross unrealized losses on the Company’s marketable securities of $ 0.6 million and $ 0.8 million as of September 30, 2023 and December 31, 2022, respectively, were caused by interest rate increases which resulted in the decrease in market value of these securities. Because the decline in fair value is attributable to changes in interest rates and not credit quality, and because the Company does not intend to sell the investments and it is not more likely than not that the Company will be required to sell the investments before recovery of their amortized cost bases, which may be maturity, the Company does not consider those marketable securities to be impaired at September 30, 2023 or December 31, 2022 . The Company has not recorded any allowance for credit losses. None of the Company’s marketable securities have been in a continuous unrealized loss position for 12 months or greater as of September 30, 2023 or December 31, 2022 .

Property and equipment, net

Property and equipment, net	9 Months Ended
	Sep. 30, 2023
Property, Plant and Equipment [Abstract]
Property and equipment, net	4. P roperty and equipment, net Property and equipment, net, consisted of the following: (in thousands) September 30, 2023 December 31, 2022 Lab equipment $ 25,649 $ 20,379 Leasehold improvements 746 266 Furniture and fixtures 2,323 2,294 Computer equipment 970 826 Total property and equipment 29,688 23,765 Less accumulated depreciation ( 8,885 ) ( 4,987 ) Property and equipment, net $ 20,803 $ 18,778 The following table summarizes depreciation expense incurred: Three months ended September 30, Nine months ended September 30, (in thousands) 2023 2022 2023 2022 Depreciation expense $ 1,474 $ 717 $ 3,938 $ 1,879

Fair value of financial instrum

Fair value of financial instruments	9 Months Ended
	Sep. 30, 2023
Fair Value Disclosures [Abstract]
Fair value of financial instruments	5. f air value of financial instruments The Company’s financial instruments that are measured at fair value on a recurring basis consist of money market funds, marketable securities, and a derivative liability (success payment liability) pursuant to the Company's license agreement with the President and Fellows of Harvard College ("Harvard") and The Broad Institute, Inc. (“Broad”), which license agreement is referred to herein as the Harvard/Broad License Agreement. The following tables set forth the fair value of the Company’s financial instruments by level within the fair value hierarchy: As of September 30, 2023 (in thousands) Fair Level 1 Level 2 Level 3 Assets Money market funds $ 57,567 $ 57,567 $ — $ — Marketable securities: U.S. treasury bills and notes 112,653 — 112,653 — U.S. agency securities 294,203 — 294,203 — Total assets $ 464,423 $ 57,567 $ 406,856 $ — Liabilities Success payment liability $ 2,007 $ — $ — $ 2,007 Total liabilities $ 2,007 $ — $ — $ 2,007 As of December 31, 2022 (in thousands) Fair Level 1 Level 2 Level 3 Assets Money market funds $ 105,303 $ 105,303 $ — $ — Marketable securities: U.S. treasury bills and notes 228,144 — 228,144 — U.S. agency securities 211,252 — 211,252 — Total assets $ 544,699 $ 105,303 $ 439,396 $ — Liabilities Success payment liability $ 2,885 $ — $ — $ 2,885 Total liabilities $ 2,885 $ — $ — $ 2,885 Cash Equivalents —Cash equivalents of $ 57.6 million and $ 105.3 million as of September 30, 2023 and December 31, 2022, respectively, consisted of money market funds and are classified within Level 1 of the fair value hierarchy because they are valued using quoted market prices in active markets. Marketable Securities —The Company measures its marketable securities at fair value on a recurring basis and classifies those instruments within Level 2 of the fair value hierarchy. Marketable securities are classified within Level 2 of the fair value hierarchy because pricing inputs are other than quoted prices in active markets, which are either directly or indirectly observable as of the reporting date, and fair value is determined through the use of models or other valuation methodologies. Success Payment Liability —The Company is obligated to pay to Harvard and Broad tiered success payments in the event its average market capitalization exceeds specified thresholds for a specified period of time ascending from a high nine-digit dollar amount to $ 10.0 billion, or in the event of a sale of the Company for consideration in excess of those thresholds. In the event of a change of control or a sale of the Company, the Company is required to pay success payments in cash within a specified period following such event. Otherwise, the success payments may be settled at the Company’s option in either cash or shares of common stock, or a combination of cash and shares of common stock. The maximum aggregate success payments that could be payable by the Company is $ 31.3 million. The success payment liability is stated at fair value and is classified in Level 3 of the fair value hierarchy because its fair value measurement is based, in part, on significant inputs not observed in the market. The Company used a Monte Carlo simulation model, which models the value of the liability based on several key variables, including probability of event occurrence, timing of event occurrence, as well as the value of the Company’s common stock. The Company remeasured the liability at fair value with decreases of $ 0.8 million and $ 0.9 million recorded to other income for the three and nine months ended September 30, 2023, respectively, and increases of $ 3.3 million and $ 0.7 million recorded to other expense for the three and nine months ended September 30, 2022, respectively. The primary inputs used in valuing the success payment liability at September 30, 2023 and December 31, 2022, were as follows: At At Fair value of common stock (per share) $ 13.26 $ 19.35 Equity volatility 84 % 84 % The reconciliation of change in the fair value of financial instruments based on Level 3 inputs for the nine months ended September 30, 2023 is as follows: (in thousands) Success Balance at December 31, 2022 $ 2,885 Changes in fair value ( 878 ) Balance at September 30, 2023 $ 2,007 The reconciliation of change in the fair value of financial instruments based on Level 3 inputs for the nine months ended September 30, 2022 is as follows: (in thousands) Success Balance at December 31, 2021 $ 4,371 Changes in fair value 691 Balance at September 30, 2022 $ 5,062

Accrued expenses

Accrued expenses	9 Months Ended
	Sep. 30, 2023
Payables and Accruals [Abstract]
Accrued expenses	6. Accrued expenses Accrued expenses consisted of the following: (in thousands) September 30, December 31, Employee compensation and related benefits $ 9,322 $ 9,124 Accrued external research and development expenses 9,995 8,919 Professional fees 2,665 1,193 License and milestone payments 348 310 Other 1,073 1,221 Total $ 23,403 $ 20,767

Leases

Leases	9 Months Ended
	Sep. 30, 2023
Leases [Abstract]
Leases	7. Leases The Company’s operating lease activity is comprised of non-cancelable facility leases for office and laboratory space in Boston, Massachusetts. The Company has also entered into multiple contract research and contract manufacturing service agreements with third parties which contain embedded leases within the scope of ASC Topic 842, "Leases". The embedded leases are considered short term leases, as the contractual terms are 12 months or less. Accordingly, no lease liability or right-of-use asset has been recorded. The Company has recognized $ 0.4 million and $ 0.9 million of short term lease costs associated with the embedded leases during the three and nine months ended September 30, 2023 , respectively. The Company has recognized $ 0.2 million and $ 0.6 million of short term lease costs associ ated with the embedded leases during the three and nine months ended September 30, 2022, respectively. The components of operating lease cost were as follows: Three months ended September 30, Nine months ended September 30, (in thousands) 2023 2022 2023 2022 Operating lease costs $ 3,234 $ 1,356 $ 9,702 $ 2,366 Variable lease costs 1,127 428 2,775 885 Total $ 4,361 $ 1,784 $ 12,477 $ 3,251 Supplemental cash flow information related to operating leases was as follows: Nine months ended September 30, (in thousands) 2023 2022 Cash paid for amounts included in the measurements of lease liabilities: Operating cash flows related to operating leases $ 9,983 $ 2,898 As of September 30, 2023, the Company’s operating leases were measured using a weighted-average incremental borrowing rate of 7.89 % over a weighted-average remaining lease term of 9.3 years. Future minimum commitments under non-cancelable leases as of September 30, 2023 were as follows: Years ending December 31, Amount (in thousands) Remainder of 2023 $ 2,567 2024 10,563 2025 10,868 2026 11,183 2027 11,506 Thereafter 62,735 Total lease payments $ 109,422 Less: interest ( 32,615 ) Present value of operating lease liabilities $ 76,807

License Agreements

License Agreements	9 Months Ended
	Sep. 30, 2023
License Agreement [Abstract]
License Agreement	8. License agreements The Company's significant license agreements are disclosed in Note 8, "License agreements," to the audited consolidated financial statements for the year ended December 31, 2022, included in the Company’s Annual Report on Form 10-K filed with the SEC on March 2, 2023. Since the date of those financial statements, there have been no changes to its license agreements, except as noted below. Harvard/Broad license agreement In March 2019, the Company entered into the Harvard/Broad License Agreement for certain base editing technologies pursuant to which the Company received exclusive, worldwide, sublicensable, royalty-bearing licenses under specified patent rights to develop and commercialize licensed products and nonexclusive, worldwide, sublicensable, royalty-bearing licenses under certain patent rights to research and develop licensed products. To the extent achieved, the Company is obligated to pay up to an aggregate of $ 23.1 million and $ 54.0 million in development and sales-based milestones, respectively, pursuant to the Harvard/Broad License Agreement. In 2022 , the first milestone was triggered and amounts due to Harvard and Broad totaled $ 0.3 million. These amounts remain payable as of September 30, 2023. Beam license agreement In April 2019, the Company and Beam Therapeutics Inc. ("Beam") entered into a collaboration and license agreement (the “Beam Agreement”), which was amended and restated in July 2022 when the Company entered into an Amended and Restated Collaboration and License Agreement with Beam (the “Amended Beam Agreement”). The Company concluded the receipt of any milestone or royalty payments under the Amended Beam Agreement was not probable as of September 30, 2023. On October 27, 2023, Beam and Eli Lilly and Company entered into a transfer and delegation agreement (the "TDA"), pursuant to which Lilly acquired certain assets and other rights from Beam under the Amended Beam Agreement, including Beam's opt-in rights to co-develop and co-commercialize the Company's base editing programs for cardiovascular disease, which consist of programs targeting PCSK9 , ANGPTL3 and an undisclosed liver-mediated, cardiovascular target, which is further described in Note 15, "Subsequent events." The terms of the TDA have no impact on the Company's financial statements or accounting analysis of the Amended Beam Agreement. Beam materials exchange letter agreement In October 2020, the Company and Beam entered into a materials exchange agreement wherein the parties agreed that Beam would provide certain mRNA, gRNA, and protein to the Company and that the Company would provide certain gRNAs to Beam at an agreed upon price per each material provided. For the three and nine months ended September 30, 2023 and 2022 , the Company did not purchase any materials from Beam or sell any materials to Beam. Novartis license agreement In October 2021, the Company entered into a license agreement with Novartis Pharma AG to obtain a non-exclusive license to lipid technology the Company is using in connection with the research and development of certain product candidates, including VERVE-102 and VERVE-201. The license agreement requires the Company to pay up to an aggregate of $ 10.0 million in clinical and regulatory milestones and $ 35.0 million in sales-based milestones for products that incorporate the licensed lipid technology. The milestones have not been achieved and no expense has been recorded for these milestones as of September 30, 2023 .

Collaboration and License Agree

Collaboration and License Agreements	9 Months Ended
	Sep. 30, 2023
Collaboration and License Agreements [Abstract]
Collaboration and License Agreements	9. Collaboration and license agreements Vertex Agreement Summary of Agreement In July 2022, the Company entered into a Strategic Collaboration and License Agreement (the "Vertex Agreement") with Vertex Pharmaceuticals Incorporated ("Vertex") for an exclusive, four-year worldwide research collaboration focused on developing in vivo gene editing candidates toward an undisclosed target for the treatment of a single liver disease. Additionally, in connection with the execution of the Vertex Agreement, the Company entered into a stock purchase agreement (the "Vertex Stock Purchase Agreement") with Vertex, pursuant to which the Company sold 1,519,756 shares of its common stock to Vertex at a price of $ 23.03 per share, for an aggregate purchase price of $ 35.0 million. Pursuant to the Vertex Agreement, the Company is responsible for discovery, research and certain preclinical development of novel in vivo gene editing development candidates for the target of interest. The Company’s research activities are focused on (i) identifying and engineering specific gene editing systems and in vivo delivery systems directed to the target and (ii) evaluating and optimizing development candidates to achieve criteria specified in the Vertex Agreement. Vertex is obligated to reimburse the Company’s research expenses consistent with a mutually agreed-upon research plan and budget (“Vertex Research Plan”). The research term has an initial term of four years and may be extended by Vertex for up to one additional year (“Vertex Research Term”). The Vertex Research Plan is overseen by a Joint Research Committee (“Vertex JRC”) as detailed in the Vertex Agreement. Any material amendments to the Vertex Research Plan are required to be mutually agreed to by the Vertex JRC. During the Vertex Research Term, Vertex may select certain gene editing systems and in vivo delivery systems directed at the target to become a licensed agent. Upon the designation of the licensed agent, Vertex shall receive a license to exploit the licensed agent, and the licensed agent will continue to be developed under the Vertex Research Plan in order to achieve certain development candidate criteria agreed to by the Vertex JRC. Following the Vertex Research Term, Vertex will be solely responsible for subsequent development, manufacturing and commercialization of any product candidate resulting from the licensed agent. The Company received an upfront payment from Vertex of $ 25.0 million and is eligible to receive (i) success payments of up to $ 22.0 million for each product candidate (up to a maximum of $ 66.0 million) that achieves the applicable development criteria, (ii) up to an aggregate of $ 175.0 million in development milestones and (iii) up to an aggregate of $ 165.0 million in commercial milestone payments. The Company is also eligible to receive tiered single-digit royalties on net sales, with the rate dependent upon the type of product and subject to specified reductions. Such royalty payments will terminate on a country-by-country and product-by-product basis upon the later to occur of (i) the expiration of the last to expire valid claim under the patent rights covering such product in such country, (ii) the period of regulatory exclusivity associated with such product in such country or (iii) ten years after the first commercial sale of such product in such country. Prior to the first patient dosing in the first Phase 1 clinical trial for the first product candidate developed under the Vertex Agreement, the Company also has the right to opt-in to a profit share arrangement pursuant to which Vertex and the Company would share the costs and net profits for all product candidates emerging from the collaboration. If the Company exercises its opt-in right, in lieu of milestones and royalties, it will be obligated to pay for a specified percentage of the development and commercialization costs, and it will have the right to receive a specified percentage of the profits from any sales of any product candidates advanced under the collaboration. At the time the Company exercises the option, it may elect a profit/cost share of up to 40 % (with Vertex retaining a minimum of 60 %). In order to exercise its opt-in right, the Company is required to pay a fee ranging from $ 25.0 million to $ 70.0 million, depending on the profit/cost percentage elected by the Company and the Company’s licensed technology included in the most advanced product candidate at the time it exercises its opt-in right. Under all profit share scenarios, Vertex will control the worldwide development and commercialization of any product candidates resulting from the collaboration. The Vertex Agreement includes customary representations and warranties, covenants and indemnification obligations for a transaction of this nature. The Company and Vertex each have the right to terminate the agreement for material breach by, or insolvency of, the other party following notice, and if applicable, a cure period. Vertex may also terminate the Vertex Agreement in its entirety for convenience upon 90 days’ notice. Accounting Analysis The Company assessed the promised goods and services under the Vertex Agreement, in accordance with ASC Topic 606, "Revenue from Contracts with Customers" ("ASC 606"). At inception, the Vertex Agreement included the following performance obligations: (i) the research services obligation which relates to the research and development services to be provided under the Vertex Research Plan through June 30, 2023 (the “Initial Vertex Research Services”) and (ii) three licensed agent material rights related to the options to obtain licenses to exploit a licensed agent, at a discount. The Company identified $ 20.0 million of fixed transaction price consisting of the $ 25.0 million upfront fee offset by a discount of $ 5.0 million related to the 1,519,756 shares sold to Vertex under the Vertex Stock Purchase Agreement when measured at fair value on the date of issuance. The Company is also entitled to reimbursement of costs incurred associated with the delivery of the Initial Vertex Research Services. The Company utilized the most likely amount approach and estimated the expected cost reimbursement to be $ 5.8 million at inception. The Company concluded that these amounts do not require a constraint and are included in the transaction price at inception. The Company considers this estimate at each reporting date and updates the estimate based on information available. Additional consideration to be paid to the Company upon reaching certain milestones are excluded from the transaction price as that consideration may only be earned subsequent to an option exercise. The Company has concluded that the variable consideration related to the cost reimbursement of the Initial Vertex Research Services obligation will be allocated entirely to that obligation as the cost reimbursement relates specifically to the services being performed under the Vertex Research Plan. The reimbursement of the Initial Vertex Research Services is considered to be at a market rate and therefore depicts the estimated amount it would expect to receive for this obligation. As a result, the Company allocated the fixed consideration of $ 20.0 million to the three licensed agent material rights based on their relative standalone selling prices. The estimated standalone selling price for each material right was based on an adjusted market assessment approach. The Company concluded that the market would be willing to pay an equal amount for each licensed agent license on a standalone basis before being adjusted for the probability of the option becoming exercisable upon the successful completion of research activities to identify the licensed agents. The Company reached this conclusion after considering (i) the downstream economics including success fees, milestones and royalties related to each licensed agent being identical and (ii) all licensed agents are targeting the same gene. As such, based on the relative standalone selling price for each of the three material rights, the allocation of the transaction price to the separate performance obligations, at inception, is as follows: Performance obligation Amount (in thousands) Research services obligation $ 5,845 First licensed agent material right 6,667 Second licensed agent material right 6,667 Third licensed agent material right 6,666 Total $ 25,845 The amount allocated to the Initial Vertex Research Services obligation will be recognized on a proportional performance basis over the period of service using input-based measurements of total cost of research incurred to estimate the proportion performed and remeasured at the end of each reporting period. The amount allocated to the licensed agent material rights was recorded as deferred revenue and will commence recognition upon exercise of each option or, if an option is never exercised, it will be recognized in full upon expiry of the Vertex Research Term. The reimbursement related to the Initial Vertex Research Services was $ 5.4 million , based on the services rendered upon completion of the Initial Vertex Research Services as of June 30, 2023. Upon completion of the Initial Vertex Research Services, the parties agreed upon and estimated additional services to be rendered through December 31, 2024. The Company utilized the most likely amount approach and estimated the expected cost reimbursement to be $ 16.9 million which is being recognized on a proportional performance basis over the period of service using an input-based measurement. During the three and nine months ended September 30, 2023, the Company recognized $ 2.4 million and $ 5.9 million of revenue, respectively, associated with the Vertex Agreement related to research services performed during the period. As of September 30, 2023, the Company has recorded $ 20.0 million as non-current deferred revenue related to the unexercised material rights. During the three and nine months ended September 30, 2022 , the Company recognized $ 0.9 million of revenue associated with the Vertex Agreement related to research services performed during the period. Costs incurred relating to the Company’s collaboration programs under the Vertex Agreement consist of internal and external research costs, which primarily include: salaries and benefits, and preclinical research studies. These costs are included in research and development expenses in the Company’s condensed consolidated statements of operations. Lilly Agreement Summary of Agreement In June 2023, the Company entered into a Research and Collaboration Agreement (the “Lilly Agreement”) with Lilly for an exclusive, five-year worldwide research collaboration initially focused on advancing the Company’s discovery-stage in vivo gene editing lipoprotein(a) program. On July 26, 2023, following expiration of the applicable waiting period under the Hart-Scott-Rodino Antitrust Improvements Act of 1976, as amended, the Lilly Agreement became effective. Additionally, in June 2023, in connection with the execution of the Lilly Agreement, the Company entered into a stock purchase agreement with Lilly (the “Lilly Stock Purchase Agreement”), pursuant to which the Company sold 1,552,795 shares of the Company's common stock to Lilly at a price of $ 19.32 per share for an aggregate purchase price of $ 30.0 million (the “Private Placement”). The Private Placement closed on July 31, 2023. Pursuant to the Lilly Agreement, the Company will be responsible for all research activities and Phase 1 clinical development of the initial target of interest— LPA . The Company’s research and development activities will be focused on (i) identifying and engineering specific gene editing systems and in vivo delivery technologies directed to the relevant target; (ii) evaluating and optimizing development candidates to achieve criteria specified in the Lilly Agreement; and (iii) Phase 1 clinical development ("Lilly Research Services"). Lilly will reimburse the Company’s research expenses and Phase 1 clinical development expenses consistent with an agreed-upon budget (“Lilly Research and Development Plan”). The research term for the initial target is five years and may be extended by Lilly for up to one additional year (“Lilly Research Term”). The Lilly Research and Development Plan is overseen by a Joint Steering Committee (“Lilly JSC”) as detailed in the Lilly Agreement. Any material amendments to the Lilly Research and Development Plan are required to be mutually agreed to by the Lilly JSC. A licensed product under the Lilly Agreement is an in vivo gene editing product that includes a candidate developed from the Lilly Research and Development Plan. A candidate is agreed upon when reviewed by the Lilly JSC against the candidate success criteria described in the Lilly Agreement. Upon approval of a candidate, Lilly will receive a license to exploit the licensed product, and the licensed product will continue to be developed under the Lilly Research and Development Plan through completion of the Phase 1 clinical trial for the applicable licensed product. Following completion of Phase 1 clinical trials with respect to any licensed product candidate under the Lilly Agreement, Lilly will be solely responsible for subsequent development, manufacturing and commercialization of each such product candidate resulting from the Company’s research efforts. Under the Lilly Agreement, the Company received an upfront payment from Lilly of $ 30.0 million in August 2023. The Company is also eligible to receive (i) up to an aggregate of $ 190.0 million in research and development milestone payments and (ii) up to an aggregate of $ 275.0 million in commercial milestone payments. The Company is also eligible to receive tiered and incremental high single and low-double digit royalties on global net sales, subject to specified reductions. Such royalty payments will terminate on a country-by-country and product-by-product basis upon the latest to occur of (i) the expiration of the last-to-expire valid claim under the patent rights covering such product in such country, (ii) expiration of the period of regulatory and market exclusivity associated with such product in such country or (iii) 10 years after the first commercial sale of such product in such country. Following completion of Phase 1 clinical development, the Company has the right to opt-in to a cost and margin share arrangement pursuant to which Lilly and the Company would share the costs and net margins for all product candidates emerging from the collaboration. If the Company exercises its opt-in right, the Company will be obligated to pay an opt-in fee in addition to funding 40 % of the development and commercialization costs, and it will have the right to receive, in lieu of the milestones and royalties described above, 40 % of the gross margin less eligible expenses from any sales of any product candidates advanced under the collaboration, with Lilly retaining 60 % of the cost and margin share. Notwithstanding this opt-in right, Lilly will control the worldwide development and commercialization of any product candidates resulting from the collaboration. Beyond the initial target of interest, upon the achievement of certain criteria and payment of additional upfront consideration, Lilly has the right to elect one additional, pre-determined target to the collaboration. The research, clinical development and commercialization of such additional target would be subject to the same terms under the Lilly Agreement as the initial target, including the Company’s right to receive up to an additional $ 465.0 million in research, development and commercial milestone payments, the Company’s right to receive tiered and incremental high single and low-double digit royalties on global net sales and the Company’s right to opt-in to a cost and margin share arrangement. During the Lilly Research Term, Lilly can make the determination subject to the terms of the Lilly Agreement, to replace the initial target or additional target with a different specified option target. Such replacement target will be the subject of a new licensed program under the research and development program. All rights granted with respect to the replaced target will cease upon Lilly’s election to select a different specified option target. The Lilly Agreement includes customary representations and warranties, covenants and indemnification obligations for a transaction of this nature. The Company and Lilly each have the right to terminate the agreement for material breach by the other party following notice, and if applicable, a cure period. Lilly may also terminate the Lilly Agreement in its entirety for convenience upon 180 days’ notice or in part, on a research plan, licensed target or product basis, for convenience upon 90 days’ notice. The Company may terminate the Lilly Agreement, in part with respect to its licensed patents, if Lilly directly or indirectly challenges the enforceability, validity or scope of such patent rights, or on a licensed product-by-licensed product basis, if such licensed product ceases to be developed for a period of time. Concurrently with the Lilly Agreement, the Company and Lilly entered into a Sublicense Option Agreement, pursuant to which the Company granted Lilly an option to obtain a non-exclusive sublicense under patent rights licensed to the Company under the Harvard/Broad License Agreement (“Lilly Option”). In consideration for the Lilly Option, Lilly paid the Company an upfront fee of $ 0.3 million . For accounting purposes, the upfront payments for the Lilly Agreement and the Sublicense Option Agreement will be combined. If Lilly exercises the Lilly Option, Lilly will be required to pay a sublicense fee to the Company and Lilly will reimburse the Company for royalties and milestones incurred related to the sublicensed product under the Harvard/Broad License Agreement. Accounting Analysis The Company assessed the promised goods and services under the Lilly Agreement, in accordance with ASC 606. At inception, the Lilly Agreement included the following performance obligations: (i) the Lilly Research Services obligation which relates to the research and development services to be provided under the Lilly Research and Development Plan and (ii) two licensed product material rights related to the right to obtain licenses to exploit a licensed product associated with the initial target upon achievement of certain development criteria. The Company identified $ 28.5 million of fixed transaction price consisting of (i) the $ 30.0 million upfront fee in the Lilly Agreement, (ii) the $ 0.3 million upfront fee in the Lilly Option, which is combined for accounting purposes, (iii) offset by a discount of $ 1.7 million related to the 1,552,795 shares sold to Lilly under the Lilly Stock Purchase Agreement when measured at fair value on the date of issuance. The Company is also entitled to reimbursement of costs incurred associated with the delivery of the Lilly Research Services. The Company utilized the most likely amount approach and estimated the expected cost reimbursement to be $ 16.4 million at inception, which represents the budget for the first year of the Lilly Research Services. The remainder of the Lilly Research and Development Plan budget is subject to annual review by Lilly and the Company. The Company concluded that these amounts do not require a constraint and are included in the transaction price at inception. The Company considers this estimate at each reporting date and updates the estimate based on information available. Additional consideration to be paid to the Company upon reaching certain milestones are excluded from the transaction price at contract inception as they are not probable at this time. The probability will be re-evaluated each reporting period, and the transaction price will be updated accordingly. The Company has concluded that the variable consideration related to the cost reimbursement of the Lilly Research Services obligation will be allocated entirely to that obligation as the cost reimbursement relates specifically to the services being performed under the Research and Development Plan. The reimbursement of the Research and Development Services is considered to be at a market rate and therefore depicts the estimated amount it would expect to receive for this obligation. As a result, the Company allocated the fixed consideration of $ 28.5 million to the two licensed product material rights based on their relative standalone selling prices. The estimated standalone selling price for each material right was based on an adjusted market assessment approach. The Company concluded that the market would be willing to pay an equal amount for each license on a standalone basis before being adjusted for the probability of the option becoming exercisable upon the successful completion of research and development activities to identify the licensed products. The Company reached this conclusion after considering (i) the downstream economics including success fees, milestones and royalties related to each licensed product being identical and (ii) both licensed products are targeting the same gene. As such, based on the relative standalone selling price for each of the material rights, the allocation of the transaction price to the separate performance obligations, at inception, is as follows: Performance obligation Amount (in thousands) Research services obligation $ 16,398 First licensed product material right 14,270 Second licensed product material right 14,270 Total $ 44,938 The amount allocated to the Lilly Research Services obligation will be recognized on a proportional performance basis over the period of service using input-based measurements of total cost of research incurred to estimate the proportion performed and remeasured at the end of each reporting period. The amount allocated to the licensed product material rights was recorded as deferred revenue and will commence recognition upon the achievement of the candidate selection criteria or, if never achieved, it will be recognized in full upon expiry of the Lilly Research Term. During three and nine months ended September 30, 2023, the Company recognized $ 0.7 million of revenue associated with the Lilly Agreement related to the Lilly Research Services performed during the period. As of September 30, 2023, the Company has recorded $ 28.5 million as non-current deferred revenue related to the unexercised material rights. Costs incurred relating to the Company’s collaboration programs under the Lilly Agreement consist of internal and external research costs, which primarily include: salaries and benefits, and preclinical research studies. These costs are included in research and development expenses in the Company’s condensed consolidated statements of operations during the three and nine months ended September 30, 2023 .

Common stock

Common stock	9 Months Ended
	Sep. 30, 2023
Preferred Stock [Abstract]
Preferred and Common Stock	10. C ommon stock In July 2022, in connection with the execution of the Vertex Agreement, the Company and Vertex also entered into the Vertex Stock Purchase Agreement, pursuant to which the Company sold 1,519,756 shares of common stock to Vertex at a price of $ 23.03 per share, for an aggregate purchase price of $ 35.0 million. In July 2022, the Company completed a follow-on public offering of common stock, pursuant to which the Company issued and sold 9,583,334 shares of its common stock, including 1,250,000 shares of its common stock sold pursuant to the full exercise of the underwriters’ option to purchase additional shares, at a public offering price of $ 27.00 per share. The Company received net proceeds of approximately $ 242.9 million after deducting underwriting discounts and offering expenses of approximately $ 15.9 million. In July 2022, the Company entered into an Open Market Sales Agreement (the “Sales Agreement”) with Jefferies LLC (“Jefferies”) as the agent pursuant to which the Company is entitled to offer and sell, from time to time at prevailing market prices, shares of its common stock. The Company agreed to pay Jefferies a commission of up to 3.0 % of the aggregate gross sale proceeds of any shares sold by Jefferies under the Sales Agreement. During the three months ended September 30, 2023 , the Company did no t make sales under the Sales Agreement. During the nine months ended September 30, 2023, the Company sold 103,184 shares of common stock under the Sales Agreement for aggregate net proceeds of $ 2.0 million , after deducting commissions and offering expenses payable by the Company. As of September 30, 2023, the Company sold 1,383,352 shares of common stock under the Sales Agreement for aggregate net proceeds of $ 44.9 million , after deducting commissions and offering expenses payable by the Company. In July 2023, in connection with the execution of the Lilly Agreement, the Company and Lilly also entered into the Lilly Stock Purchase Agreement, pursuant to which the Company sold 1,552,795 shares of common stock to Lilly at a price of $ 19.32 per share, for an aggregate purchase price of $ 30.0 million .

Stock-based compensation

Stock-based compensation	9 Months Ended
	Sep. 30, 2023
Share-Based Payment Arrangement [Abstract]
Stock-based compensation	11. Stock-based compensation The 2018 Equity Incentive Plan (the "2018 Plan"), adopted by the board of directors in August 2018, provided for the grant of qualified incentive stock options, non-statutory stock options, stock appreciation rights, restricted stock and restricted stock units to the Company’s employees, officers, directors, advisors, and outside consultants for the issuance or purchase of shares of the Company’s common stock. The maximum number of shares of common stock that were authorized for issuance under the 2018 Plan was 6,885,653 . In June 2021, the Company's board of directors adopted, and the Company's stockholders approved, the 2021 Stock Incentive Plan (the "2021 Plan"), which became effective on June 16, 2021. The 2021 Plan provides for the grant of incentive stock options, nonstatutory stock options, stock appreciation rights, restricted and unrestricted stock and stock units, performance awards, and other share-based awards to the Company's employees, directors, advisors and outside consultants. The shares reserved for issuance pursuant to the 2021 Plan are subject to an annual increase through January 1, 2031. On January 1, 2023, 3,086,541 shares of the Company's common stock were added to the amount reserved for issuance under the 2021 Plan. As of September 30, 2023, the Company had reserved 10,144,170 shares of the Company's common stock for issuance of stock options, restricted stock, and restricted stock units, of which 3,278,933 shares remained available for future grant under the 2021 Plan. Upon effectiveness of the 2021 Plan, the Company ceased granting additional awards under the 2018 Plan. Stock-based compensation expense recorded in the Company's condensed consolidated statements of operations and comprehensive loss is as follows: Three months ended September 30, Nine months ended September 30, (in thousands) 2023 2022 2023 2022 Research and development $ 4,895 $ 3,216 $ 14,232 $ 8,637 General and administrative 3,930 2,704 11,630 7,136 Total stock-based compensation expense $ 8,825 $ 5,920 $ 25,862 $ 15,773 Stock options The following table provides a summary of stock option activity during the nine months ended September 30, 2023: Number of Weighted Weighted Aggregate (2) Outstanding at December 31, 2022 7,612,826 $ 16.10 Granted 2,959,242 20.35 Exercised ( 171,037 ) 5.12 Forfeited ( 458,818 ) 26.98 Outstanding at September 30, 2023 9,942,213 $ 17.05 8.1 $ 34,298 Exercisable at September 30, 2023 4,206,762 $ 11.91 7.1 $ 26,495 Expected to vest after September 30, 2023 (1) 5,735,451 $ 20.83 8.7 $ 7,803 (1) This represents the number of unvested options outstanding as of September 30, 2023 that are expected to vest in the future. (2) The aggregate intrinsic value is calculated as the difference between the exercise price of the underlying options and the fair value of the common stock for the options that were in the money as of September 30, 2023 . As of September 30, 2023, there was $ 76.8 million of unrecognized stock-based compensation expense related to unvested stock options, which is expected to be recognized over a weighted-average period of approximately 2.6 years. Restricted stock units During the nine months ended September 30, 2023, the Company granted 436,340 restricted stock units under the 2021 Plan. These restricted stock units vest annually over a four-year period. A summary of the status of and change in unvested restricted stock units as of September 30, 2023 was as follows: Shares Weighted- Unvested restricted stock units as of December 31, 2022 677,825 $ 23.10 Restricted stock units granted 436,340 $ 19.53 Restricted stock units vested ( 127,123 ) $ 20.95 Restricted stock units forfeited ( 103,349 ) $ 24.05 Unvested restricted stock units as of September 30, 2023 883,693 $ 21.54 As of September 30, 2023, there was $ 16.3 million of unrecognized stock-based compensation expense related to restricted stock units that are expected to vest. These costs are expected to be recognized over a weighted-average remaining vesting period of approximately 3.1 years. 2021 Amended and Restated Employee Stock Purchase Plan In June 2021, the board of directors adopted, and the Company's stockholders approved, the 2021 Employee Stock Purchase Plan, or the ESPP, as amended and restated, which became effective on June 16, 2021. The shares reserved for issuance pursuant to the ESPP are subject to an annual increase through January 1, 2031. On January 1, 2023, 617,308 shares of common stock were added to th e amount reserved for sale under the ESPP. As of September 30, 2023, 1,349,500 shares remained available for issuance under the ESPP. The most recent offering period ended on May 31, 2023, for which the Company issued 52,134 shares of its common stock. The current offering period commenced on June 1, 2023 and will end on November 30, 2023.

Net Loss Per Share Attributable

Net Loss Per Share Attributable to Common Stockholders	9 Months Ended
	Sep. 30, 2023
Earnings Per Share [Abstract]
Net Loss Per Share Attributable to Common Stockholders	12. Net loss per share The Company’s potential dilutive securities, which include unvested restricted stock units and common stock options, have been excluded from the computation of diluted net loss per share as the effects would be anti-dilutive. Therefore, the weighted average number of common shares outstanding used to calculate both basic and diluted net loss per share is the same. The Company excluded the following potential common shares, presented based on amounts outstanding at period end, from the computation of diluted net loss per share for the period indicated because including them would have had an anti-dilutive effect: As of September 30, 2023 2022 Unvested restricted stock units 883,693 609,400 Outstanding options to purchase common stock 9,942,213 7,555,094 Total 10,825,906 8,164,494

Income Taxes

Income Taxes	9 Months Ended
	Sep. 30, 2023
Income Tax Disclosure [Abstract]
Income Taxes	13. Income taxes The Company’s effective income tax rate was de minimis for the three and nine months ended September 30, 2023 and 0.0 % for the three and nine months ended September 30, 2022, respectively. The income tax provision was $ 0.1 million and $ 0.2 million for both the three and nine months ended September 30, 2023 , respectively. There was no income tax provision recorded for the three and nine months ended September 30, 2022. The increase in the provision for income taxes primarily relates to an increase in state income taxes based on gross interest income. The effective income tax rate for the three and nine months ended September 30, 2023 and 2022 differed from the 21 % federal statutory rate primarily due to the valuation allowance maintained against the Company’s net deferred tax assets.

Related Party Transactions

Related Party Transactions	9 Months Ended
	Sep. 30, 2023
Related Party Transactions [Abstract]
Related Party Transactions	14. Related party transactions An executive officer of Beam was a board member of the Company until August 2022. In December 2021, the Company entered into a sublease agreement with Beam for laboratory and office space in Cambridge, Massachusetts, which sublease terminated in December 2022. Total rent payments under this sublease were $ 0.5 million and $ 1.4 million for the three and nine months ended September 30, 2022, respectively. An executive of Broad was a board member of the Company until May 2021. In March 2019, the Company entered into the Harvard/Broad License Agreement for certain base editing technologies pursuant to which the Company received exclusive, worldwide, sublicensable, royalty-bearing licenses under specified patent rights to develop and commercialize licensed products and nonexclusive, worldwide, sublicensable, royalty-bearing licenses under certain patent rights to research and develop licensed products. Additional consideration under the Harvard/Broad License Agreement included antidilution rights and includes success payments. See Note 8, "License agreements," to the audited consolidated financial statements for the year ended December 31, 2022 included in the Company’s Annual Report on Form 10-K filed with the SEC on March 2, 2023.

Subsequent Events

Subsequent Events	9 Months Ended
	Sep. 30, 2023
Subsequent Events [Abstract]
Subsequent Events	15. Subsequent events Transfer of product rights under Beam license agreement On October 27, 2023, pursuant to the TDA between Lilly and Beam, Lilly acquired certain rights previously held by Beam under the Amended Beam Agreement, including the right to opt-in to the Company’s PCSK9 and ANGPTL3 programs to share 33% of worldwide development expenses and to jointly commercialize and share profits and expenses related to commercialization in the United States on a 50/50 basis. The Company holds all product rights for the PCSK9 and ANGPTL3 programs outside the United States. Additionally, for a third undisclosed cardiovascular disease target, Lilly acquired Beam’s right to opt-in to share 35% of worldwide expenses of the development of such licensed product, as well as jointly commercialize and share 35% of the profits and expenses of commercializing such licensed product worldwide . Under the Amended Beam Agreement, the Company retains control of the development and commercialization of all collaboration products. Lilly also acquired Beam’s right to receive the same future milestone or royalty payments that were payable to Beam under the Amended Beam Agreement with respect to certain development or commercial activities outside the United States or in the event Lilly does not exercise a program opt-in right.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2023
Accounting Policies [Abstract]
Cash, Cash Equivalents and Restricted Cash	Cash, cash equivalents and restricted cash Restricted cash represents collateral provided for letters of credit issued as security deposits in connection with the Company’s leases of its corporate facilities. A reconciliation of the cash, cash equivalents, and restricted cash reported within the condensed consolidated balance sheet that sum to the total of the same amounts shown in the condensed consolidated statements of cash flows is as follows: September 30, September 30, (in thousands) 2023 2022 Cash and cash equivalents $ 78,370 $ 277,019 Restricted cash 4,774 4,824 Total cash, cash equivalents and restricted cash $ 83,144 $ 281,843
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. The standard requires that credit losses be reported using an expected losses model rather than the incurred losses model that was previously used, and establishes additional disclosures related to credit risks. For available-for-sale debt securities with unrealized losses, this standard requires allowances to be recorded instead of reducing the amortized cost of the investment. The Company adopted the new standard on January 1, 2023. Based upon the Company's analysis, the adoption of this new standard did not have a material impact on the Company's financial statements.

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Tables)	9 Months Ended
	Sep. 30, 2023
Accounting Policies [Abstract]
Reconciliation of Cash, Cash Equivalents and Restricted Cash	A reconciliation of the cash, cash equivalents, and restricted cash reported within the condensed consolidated balance sheet that sum to the total of the same amounts shown in the condensed consolidated statements of cash flows is as follows: September 30, September 30, (in thousands) 2023 2022 Cash and cash equivalents $ 78,370 $ 277,019 Restricted cash 4,774 4,824 Total cash, cash equivalents and restricted cash $ 83,144 $ 281,843

Marketable Securities (Tables)

Marketable Securities (Tables)	9 Months Ended
	Sep. 30, 2023
Investments, Debt and Equity Securities [Abstract]
Schedule of Marketable Securities by Security	Marketable securities by security type consisted of the following: September 30, 2023 (in thousands) Amortized Gross Gross Fair U.S. treasury bills and notes $ 112,735 $ 2 $ ( 84 ) $ 112,653 U.S. agency securities 294,718 21 ( 536 ) 294,203 Total $ 407,453 $ 23 $ ( 620 ) $ 406,856 December 31, 2022 (in thousands) Amortized Gross Gross Fair U.S. treasury bills and notes $ 228,432 $ 13 $ ( 301 ) $ 228,144 U.S. agency securities 211,658 68 ( 474 ) 211,252 Total $ 440,090 $ 81 $ ( 775 ) $ 439,396

Property and equipment, net (Ta

Property and equipment, net (Tables)	9 Months Ended
	Sep. 30, 2023
Property, Plant and Equipment [Abstract]
Schedule of Property and Equipment, net	Property and equipment, net, consisted of the following: (in thousands) September 30, 2023 December 31, 2022 Lab equipment $ 25,649 $ 20,379 Leasehold improvements 746 266 Furniture and fixtures 2,323 2,294 Computer equipment 970 826 Total property and equipment 29,688 23,765 Less accumulated depreciation ( 8,885 ) ( 4,987 ) Property and equipment, net $ 20,803 $ 18,778
Schedule of Depreciation Expense	The following table summarizes depreciation expense incurred: Three months ended September 30, Nine months ended September 30, (in thousands) 2023 2022 2023 2022 Depreciation expense $ 1,474 $ 717 $ 3,938 $ 1,879

Fair Value of Financial Instr_2

Fair Value of Financial Instruments (Tables)	9 Months Ended
	Sep. 30, 2023
Fair Value Disclosures [Abstract]
Schedule of Fair Value of Financial Instruments, Assets and Liabilities	The following tables set forth the fair value of the Company’s financial instruments by level within the fair value hierarchy: As of September 30, 2023 (in thousands) Fair Level 1 Level 2 Level 3 Assets Money market funds $ 57,567 $ 57,567 $ — $ — Marketable securities: U.S. treasury bills and notes 112,653 — 112,653 — U.S. agency securities 294,203 — 294,203 — Total assets $ 464,423 $ 57,567 $ 406,856 $ — Liabilities Success payment liability $ 2,007 $ — $ — $ 2,007 Total liabilities $ 2,007 $ — $ — $ 2,007 As of December 31, 2022 (in thousands) Fair Level 1 Level 2 Level 3 Assets Money market funds $ 105,303 $ 105,303 $ — $ — Marketable securities: U.S. treasury bills and notes 228,144 — 228,144 — U.S. agency securities 211,252 — 211,252 — Total assets $ 544,699 $ 105,303 $ 439,396 $ — Liabilities Success payment liability $ 2,885 $ — $ — $ 2,885 Total liabilities $ 2,885 $ — $ — $ 2,885
Schedule of Fair Value Liabilities Measured on Recurring Basis	The primary inputs used in valuing the success payment liability at September 30, 2023 and December 31, 2022, were as follows: At At Fair value of common stock (per share) $ 13.26 $ 19.35 Equity volatility 84 % 84 %
Schedule of Reconciliation of Changes in Fair Value of Financial Instruments	The reconciliation of change in the fair value of financial instruments based on Level 3 inputs for the nine months ended September 30, 2023 is as follows: (in thousands) Success Balance at December 31, 2022 $ 2,885 Changes in fair value ( 878 ) Balance at September 30, 2023 $ 2,007 The reconciliation of change in the fair value of financial instruments based on Level 3 inputs for the nine months ended September 30, 2022 is as follows: (in thousands) Success Balance at December 31, 2021 $ 4,371 Changes in fair value 691 Balance at September 30, 2022 $ 5,062

Accrued Expenses (Tables)

Accrued Expenses (Tables)	9 Months Ended
	Sep. 30, 2023
Payables and Accruals [Abstract]
Schedule of Accrued Expenses	Accrued expenses consisted of the following: (in thousands) September 30, December 31, Employee compensation and related benefits $ 9,322 $ 9,124 Accrued external research and development expenses 9,995 8,919 Professional fees 2,665 1,193 License and milestone payments 348 310 Other 1,073 1,221 Total $ 23,403 $ 20,767

Leases (Tables)

Leases (Tables)	9 Months Ended
	Sep. 30, 2023
Leases [Abstract]
Components of Operating Lease Cost	The components of operating lease cost were as follows: Three months ended September 30, Nine months ended September 30, (in thousands) 2023 2022 2023 2022 Operating lease costs $ 3,234 $ 1,356 $ 9,702 $ 2,366 Variable lease costs 1,127 428 2,775 885 Total $ 4,361 $ 1,784 $ 12,477 $ 3,251
Supplemental Cash Flow Information Related to Operating Leases	Supplemental cash flow information related to operating leases was as follows: Nine months ended September 30, (in thousands) 2023 2022 Cash paid for amounts included in the measurements of lease liabilities: Operating cash flows related to operating leases $ 9,983 $ 2,898
Schedule of Future Minimum Lease Commitments under Non-Cancellable Leases	Future minimum commitments under non-cancelable leases as of September 30, 2023 were as follows: Years ending December 31, Amount (in thousands) Remainder of 2023 $ 2,567 2024 10,563 2025 10,868 2026 11,183 2027 11,506 Thereafter 62,735 Total lease payments $ 109,422 Less: interest ( 32,615 ) Present value of operating lease liabilities $ 76,807

Collaboration and License Agr_2

Collaboration and License Agreements (Tables)	9 Months Ended
	Sep. 30, 2023
Collaboration and License Agreements [Abstract]
Schedule of transaction price separate performance obligations	Performance obligation Amount (in thousands) Research services obligation $ 5,845 First licensed agent material right 6,667 Second licensed agent material right 6,667 Third licensed agent material right 6,666 Total $ 25,845 Performance obligation Amount (in thousands) Research services obligation $ 16,398 First licensed product material right 14,270 Second licensed product material right 14,270 Total $ 44,938

Stock-based compensation (Table

Stock-based compensation (Tables)	9 Months Ended
	Sep. 30, 2023
Share-Based Payment Arrangement [Abstract]
Summary of Stock Based Compensation Expense	Stock-based compensation expense recorded in the Company's condensed consolidated statements of operations and comprehensive loss is as follows: Three months ended September 30, Nine months ended September 30, (in thousands) 2023 2022 2023 2022 Research and development $ 4,895 $ 3,216 $ 14,232 $ 8,637 General and administrative 3,930 2,704 11,630 7,136 Total stock-based compensation expense $ 8,825 $ 5,920 $ 25,862 $ 15,773
Schedule of Stock Option Activity	The following table provides a summary of stock option activity during the nine months ended September 30, 2023: Number of Weighted Weighted Aggregate (2) Outstanding at December 31, 2022 7,612,826 $ 16.10 Granted 2,959,242 20.35 Exercised ( 171,037 ) 5.12 Forfeited ( 458,818 ) 26.98 Outstanding at September 30, 2023 9,942,213 $ 17.05 8.1 $ 34,298 Exercisable at September 30, 2023 4,206,762 $ 11.91 7.1 $ 26,495 Expected to vest after September 30, 2023 (1) 5,735,451 $ 20.83 8.7 $ 7,803 (1) This represents the number of unvested options outstanding as of September 30, 2023 that are expected to vest in the future. (2) The aggregate intrinsic value is calculated as the difference between the exercise price of the underlying options and the fair value of the common stock for the options that were in the money as of September 30, 2023 .
Schedule of Status and Change in Unvested Restricted Stock	A summary of the status of and change in unvested restricted stock units as of September 30, 2023 was as follows: Shares Weighted- Unvested restricted stock units as of December 31, 2022 677,825 $ 23.10 Restricted stock units granted 436,340 $ 19.53 Restricted stock units vested ( 127,123 ) $ 20.95 Restricted stock units forfeited ( 103,349 ) $ 24.05 Unvested restricted stock units as of September 30, 2023 883,693 $ 21.54

Net Loss Per Share Attributab_2

Net Loss Per Share Attributable to Common Stockholders (Tables)	9 Months Ended
	Sep. 30, 2023
Earnings Per Share [Abstract]
Potential Common Shares, Based on Amounts Outstanding at Period End were Excluded From the Computation of Diluted Net Loss Per Share Attributable to Common Stockholders	The Company excluded the following potential common shares, presented based on amounts outstanding at period end, from the computation of diluted net loss per share for the period indicated because including them would have had an anti-dilutive effect: As of September 30, 2023 2022 Unvested restricted stock units 883,693 609,400 Outstanding options to purchase common stock 9,942,213 7,555,094 Total 10,825,906 8,164,494

Nature of the Business and Ba_2

Nature of the Business and Basis of Presentation - Additional Information (Details) - USD ($) $ in Millions	Jul. 31, 2022	Sep. 30, 2023
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Cash, cash equivalents, and marketable securities		$ 485.2
Commission on aggregate gross sale proceeds	3%

Summary of Significant Accoun_4

Summary of Significant Accounting Policies - Reconciliation of Cash, Cash Equivalents and Restricted Cash (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022	Sep. 30, 2022	Dec. 31, 2021
Accounting Policies [Abstract]
Cash and cash equivalents	$ 78,370	$ 115,412	$ 277,019
Restricted cash	4,774		4,824
Total cash, cash equivalents and restricted cash	$ 83,144	$ 120,236	$ 281,843	$ 69,567

Marketable securities - Schedul

Marketable securities - Schedule of Marketable Securities (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Marketable Securities [Line Items]
Amortized cost	$ 407,453	$ 440,090
Gross unrealized gains	23	81
Gross unrealized losses	(620)	(775)
Fair value	406,856	439,396
U.S. Treasury Bills and Notes [Member]
Marketable Securities [Line Items]
Amortized cost	112,735	228,432
Gross unrealized gains	2	13
Gross unrealized losses	(84)	(301)
Fair value	112,653	228,144
U.S. Agency Securities [Member]
Marketable Securities [Line Items]
Amortized cost	294,718	211,658
Gross unrealized gains	21	68
Gross unrealized losses	(536)	(474)
Fair value	$ 294,203	$ 211,252

Marketable securities - Additio

Marketable securities - Additional Information (Details) - USD ($) $ in Millions	9 Months Ended	12 Months Ended
	Sep. 30, 2023	Dec. 31, 2022
Marketable Securities [Line Items]
Unrealized losses on marketable securities	$ 0.6	$ 0.8
Remaining contractual maturities of marketable securities term	12 months	12 months

Property and Equipment, net - S

Property and Equipment, net - Schedule of Property and Equipment, net (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Property Plant And Equipment [Line Items]
Total property and equipment	$ 29,688	$ 23,765
Less accumulated depreciation	(8,885)	(4,987)
Property and equipment, net	20,803	18,778
Lab equipment
Property Plant And Equipment [Line Items]
Total property and equipment	25,649	20,379
Leasehold Improvements
Property Plant And Equipment [Line Items]
Total property and equipment	746	266
Furniture and Fixtures
Property Plant And Equipment [Line Items]
Total property and equipment	2,323	2,294
Computer Equipment
Property Plant And Equipment [Line Items]
Total property and equipment	$ 970	$ 826

Property and equipment, net -_2

Property and equipment, net - Schedule of Depreciation Expense (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Property, Plant and Equipment [Abstract]
Depreciation expense	$ 1,474	$ 717	$ 3,938	$ 1,879

Fair value of financial instr_3

Fair value of financial instruments - Summary of Assets and Liabilities Measured at Fair Value (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total assets	$ 464,423	$ 544,699
Total liabilities	2,007	2,885
Success Payment Liability
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total liabilities	2,007	2,885
U.S. Treasury Bills and Notes
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total assets	112,653	228,144
U.S. Agency Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total assets	294,203	211,252
Level 1
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total assets	57,567	105,303
Total liabilities	0	0
Level 1 | Success Payment Liability
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total liabilities	0	0
Level 1 | U.S. Treasury Bills and Notes
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total assets	0	0
Level 1 | U.S. Agency Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total assets	0	0
Level 2
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total assets	406,856	439,396
Total liabilities	0	0
Level 2 | Success Payment Liability
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total liabilities	0	0
Level 2 | U.S. Treasury Bills and Notes
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total assets	112,653	228,144
Level 2 | U.S. Agency Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total assets	294,203	211,252
Level 3
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total assets	0	0
Total liabilities	2,007	2,885
Level 3 | Success Payment Liability
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total liabilities	2,007	2,885
Level 3 | U.S. Treasury Bills and Notes
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total assets	0	0
Level 3 | U.S. Agency Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total assets	0	0
Money Market Funds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total assets	57,567	105,303
Money Market Funds | Level 1
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total assets	57,567	105,303
Money Market Funds | Level 2
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total assets	0	0
Money Market Funds | Level 3
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total assets	$ 0	$ 0

Fair value of financial instr_4

Fair value of financial instruments - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash equivalents	$ 57.6		$ 57.6		$ 105.3
Other Income
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Success Payment Liability, Payable	(0.8)	$ 3.3	0.9	$ 0.7
Harvard and Board
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Success payment liability, payable	10,000		10,000
Harvard | Maximum
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Success payment liability, payable	$ 31.3		$ 31.3

Fair value of financial instr_5

Fair value of financial instruments - Schedule of Fair Value Liabilities Measured on Recurring Basis (Details) - $ / shares	9 Months Ended	12 Months Ended
	Sep. 30, 2023	Dec. 31, 2022
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of common stock (per share)	$ 13.26	$ 19.35
Equity Volatility
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Equity volatility	84%	84%

Fair value of financial instr_6

Fair value of financial instruments - Schedule of Reconciliation of Changes in Fair Value of Financial Instruments (Details) - Success Payment Liability - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022
Fair Value Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Beginning balance	$ 2,885	$ 4,371
Changes in fair value	(878)	(691)
Ending balance	$ 2,007	$ 5,062

Accrued expenses - Schedule of

Accrued expenses - Schedule of Accrued Expenses (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Payables and Accruals [Abstract]
Employee compensation and related benefits	$ 9,322	$ 9,124
Accrued external research and development expenses	9,995	8,919
Professional fees	2,665	1,193
License and milestone payments	348	310
Other	1,073	1,221
Total	$ 23,403	$ 20,767

Leases - Additional Information

Leases - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Lessee, Lease, Description [Line Items]
Operating lease incremental borrowing rate	7.89%		7.89%
Weighted average remaining lease term	9 years 3 months 18 days		9 years 3 months 18 days
ASC 842
Lessee, Lease, Description [Line Items]
Short-Term Lease, Cost	$ 0.4	$ 0.2	$ 0.9	$ 0.6

Leases - Summary of Components

Leases - Summary of Components of Operating Lease Cost (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Lease, Cost [Abstract]
Operating lease costs	$ 3,234	$ 1,356	$ 9,702	$ 2,366
Variable lease costs	1,127	428	2,775	885
Total	$ 4,361	$ 1,784	$ 12,477	$ 3,251

Leases - Summary of Supplementa

Leases - Summary of Supplemental Cash Flow Information Related to Operating Leases (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022
Cash paid for amounts included in the measurements of lease liabilities [Abstract]
Operating cash flows related to operating leases	$ 9,983	$ 2,898

Leases - Summary of Future Mini

Leases - Summary of Future Minimum Commitments under Non-Cancellable Operating Leases (Details) $ in Thousands	Sep. 30, 2023 USD ($)
Lessee, Operating Lease, Liability, to be Paid, Fiscal Year Maturity [Abstract]
Remainder of 2023	$ 2,567
2024	10,563
2025	10,868
2026	11,183
2027	11,506
Thereafter	62,735
Total lease payments	109,422
Less: interest	(32,615)
Present value of operating lease liabilities	$ 76,807

License Agreements - Additional

License Agreements - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Research And Development Arrangement Contract To Perform For Others [Line Items]
Research and development expenses	$ 43,765	$ 35,197	$ 138,135	$ 92,811
Harvard and Board
Research And Development Arrangement Contract To Perform For Others [Line Items]
Success payment liability	300		300
Payment of milestone development			23,100
Payment of sales based milestone			54,000
Beam License Agreement
Research And Development Arrangement Contract To Perform For Others [Line Items]
Research and development expenses	$ 0	$ 0	0	$ 0
Novartis license agreement
Research And Development Arrangement Contract To Perform For Others [Line Items]
Payment of sales based milestone			35,000
Clinical And Regulatory Milestone			10,000
Milestone related expenses			$ 0

Collaboration and License Agr_3

Collaboration and License Agreements - Additional Information (Details) - USD ($) $ / shares in Units, $ in Millions					3 Months Ended		9 Months Ended
	Aug. 31, 2023	Jun. 30, 2023	Jul. 31, 2022	Jul. 18, 2022	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Payments to Acquire Commercial Real Estate			$ 165
Vertex Stock Purchase Agreement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Stock Issued During Period, Shares, New Issues			1,519,756
Price per share			$ 23.03
Aggregate purchase price			$ 35
Non-refundable upfront payment			25
Success payments for each product			22
Payments to Acquire Commercial Real Estate			175
Fixed consideration amount							$ 20
Revenue recognized					$ 2.4	$ 0.9	5.9	$ 0.9
Non-current deferred revenue					20		20
Vertex Stock Purchase Agreement | Maximum
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Success payments for each product			$ 66
Percentage of profit/cost share				40%
Required fee payments				$ 70
Vertex Stock Purchase Agreement | Minimum
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Percentage of profit/cost share				60%
Required fee payments				$ 25
Vertex Stock Purchase Agreement | Stock Purchase Agreement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Fixed transaction price				20
Fixed transaction price consisting upfront fee				25
Upfront fee discount				$ 5
Shares issued and sold				1,519,756
Cost Reimbursement at Inception							5.8
Estimated expected cost reimbursement		$ 16.9
Reimbursement related to Initial Research Services		$ 5.4
Lilly Agreement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Stock Issued During Period, Shares, New Issues		1,552,795
Price per share		$ 19.32
Aggregate purchase price		$ 30
Non-refundable upfront payment	$ 30
Percentage of profit/cost share	60%
Fixed consideration amount							28.5
Revenue recognized					0.7		0.7
Non-current deferred revenue					$ 28.5		28.5
Commercial Milestone Payments							275
Development milestone payments under collaboration agreement							190
Lilly Agreement | Maximum
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Percentage of profit/cost share	40%
Lilly Agreement | Minimum
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Percentage of profit/cost share	40%
Lilly Agreement | Stock Purchase Agreement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Non-refundable upfront payment	$ 0.3
Required fee payments	465
Fixed transaction price	28.5
Fixed transaction price consisting upfront fee	30
Upfront fee discount	$ 1.7
Shares issued and sold	1,552,795
Cost Reimbursement at Inception							$ 16.4
Lilly Option | Stock Purchase Agreement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Fixed transaction price consisting upfront fee	$ 0.3

Collaboration and License Agr_4

Collaboration and License Agreements - Schedule of transaction price separate performance obligations (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Jun. 30, 2023
Performance obligation	$ 44,938	$ 25,845
Research services obligation [Member]
Performance obligation	16,398	5,845
First licensed agent material right [Member]
Performance obligation	14,270	6,667
Second licensed agent material right [Member]
Performance obligation	$ 14,270	6,667
Third licensed agent material right [Member]
Performance obligation		$ 6,666

Common stock - Additional Infor

Common stock - Additional Information (Details) - USD ($) $ / shares in Units, $ in Millions			3 Months Ended	9 Months Ended
	Jul. 31, 2023	Jul. 31, 2022	Sep. 30, 2023	Sep. 30, 2023	Dec. 31, 2022
Subsidiary Sale Of Stock [Line Items]
Common stock shares issued			63,737,089	63,737,089	61,730,816
Common stock, par value			$ 0.001	$ 0.001	$ 0.001
Underwriting discounts and offering expenses		$ 15.9
Sales Agreement
Subsidiary Sale Of Stock [Line Items]
Common stock, par value	$ 19.32	$ 23.03
Shares issued and sold				1,383,352
Net proceeds from sale of common stock				$ 44.9
Stock Purchase Agreement
Subsidiary Sale Of Stock [Line Items]
Agreegate purchase price	$ 30	$ 35
Public offering
Subsidiary Sale Of Stock [Line Items]
Common stock shares issued		1,250,000
Shares issued and sold		9,583,334
Common Stock Offering Price Per Share		$ 27
Net proceeds from sale of common stock		$ 242.9
Vertex Stock Purchase Agreement
Subsidiary Sale Of Stock [Line Items]
Common stock shares issued		1,519,756
Lilly Agreement
Subsidiary Sale Of Stock [Line Items]
Common stock shares issued	1,552,795
Common Stock | Sales Agreement
Subsidiary Sale Of Stock [Line Items]
Shares issued and sold			0	103,184
Net proceeds from sale of common stock				$ 2

Stock-based compensation - Addi

Stock-based compensation - Additional Information (Details) - USD ($) $ / shares in Units, $ in Millions	9 Months Ended
	Sep. 30, 2023	May 31, 2023	Jan. 01, 2023
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares of common stock reserved for future issuance	10,144,170
Employee Stock Option
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unrecognized stock-based compensation cost	$ 76.8
Weighted average period over which unrecognized compensation is expected to be recognized	2 years 7 months 6 days
Restricted Stock
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unrecognized stock-based compensation cost	$ 16.3
Weighted average period over which unrecognized compensation is expected to be recognized	3 years 1 month 6 days
Twent Eighteen | Common Stock
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares of common stock reserved for future issuance	6,885,653
2021 Stock Incentive Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares of common stock reserved for future issuance			3,086,541
Stock available for issuance under ESPP	1,349,500
Company Issued Common Stock Shares		$ 52,134
Shares available for future grant	3,278,933
Increase in common stock capital shares, reserved for future issuance			617,308
2021 Stock Incentive Plan | Restricted Stock
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares available for future grant	436,340
Vesting period	4 years

Stock-based compensation - Summ

Stock-based compensation - Summary of Stock Based Compensation Expense (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total stock-based compensation expense	$ 8,825	$ 5,920	$ 25,862	$ 15,773
Research and Development
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total stock-based compensation expense	4,895	3,216	14,232	8,637
General and Administrative
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total stock-based compensation expense	$ 3,930	$ 2,704	$ 11,630	$ 7,136

Stock-based compensation - Sche

Stock-based compensation - Schedule of Stock Option Activity (Details) - USD ($) $ / shares in Units, $ in Thousands		9 Months Ended
		Sep. 30, 2023
Share-Based Payment Arrangement [Abstract]
Number of options, Outstanding, Beginning balance		7,612,826
Number of options, Granted		2,959,242
Number of options, Exercised		(171,037)
Number of options, Forfeited		(458,818)
Number of options, Outstanding, Ending balance		9,942,213
Number of options, Exercisable		4,206,762
Number of options, Expected to vest	[1]	5,735,451
Weighted average exercise price, Beginning balance		$ 16.1
Weighted average exercise price, Granted		20.35
Weighted average exercise price, Exercised		5.12
Weighted average exercise price, Forfeited		26.98
Weighted average exercise price, Ending balance		17.05
Weighted average exercise price, Exercisable		11.91
Weighted average exercise price, Expected to vest	[1]	$ 20.83
Weighted average remaining contractual life (in years), Outstanding		8 years 1 month 6 days
Weighted average remaining contractual life (in years), Exercisable		7 years 1 month 6 days
Weighted average remaining contractual life (in years), Expected to vest	[1]	8 years 8 months 12 days
Aggregate intrinsic value, Outstanding	[2]	$ 34,298
Aggregate intrinsic value, Exercisable	[2]	26,495
Aggregate intrinsic value, Expected to vest	[1],[2]	$ 7,803
[1] This represents the number of unvested options outstanding as of September 30, 2023 that are expected to vest in the future. The aggregate intrinsic value is calculated as the difference between the exercise price of the underlying options and the fair value of the common stock for the options that were in the money as of September 30, 2023 .

Stock-based compensation - Su_2

Stock-based compensation - Summary of the Restricted Stock Units (Details) - 2021 Stock Incentive Plan	9 Months Ended
	Sep. 30, 2023 $ / shares shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unvested RSUs, beginning balance, Unvested | shares	677,825
Restricted stock units granted | shares	436,340
Restricted stock units forfeited | shares	(103,349)
Unvested RSUs, Vested | shares	(127,123)
Unvested RSUs, ending balance, unvested | shares	883,693
Weighted-Average Grant Date Fair Value Per Share, beginning balance, Unvested | $ / shares	$ 23.1
Weighted-Average Grant-Date Fair Value, Granted | $ / shares	19.53
Weighted-Average Grant-Date Fair Value, forfeited | $ / shares	24.05
Weighted-Average Grant Date Fair Value Per Share, Vested | $ / shares	20.95
Weighted-Average Grant Date Fair Value Per Share, ending balance, Unvested | $ / shares	$ 21.54

Net Loss Per Share Attributab_3

Net Loss Per Share Attributable to Common Stockholders - Potential Common Shares, Based on Amounts Outstanding at Period End were Excluded From the Computation of Diluted Net Loss Per Share Attributable to Common Stockholders (Details) - shares	9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive securities	10,825,906	8,164,494
Unvested restricted stock units
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive securities	883,693	609,400
Outstanding Options To Purchase Common Stock
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive securities	9,942,213	7,555,094

Income taxes (Additional Inform

Income taxes (Additional Information) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Income Tax Disclosure [Abstract]
Effectice Income Tax Rate	0%		0%
Provision for income taxes	$ 67	$ 0	$ 243	$ 0
Effective income tax rate, Change in enacted tax rate, Percent	21%	21%	21%	21%

Related Party Transactions - Ad

Related Party Transactions - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2022	Sep. 30, 2022
Related Party Transaction [Line Items]
Lease Rent Payment	$ 0.5	$ 1.4

Subsequent Events - Additional

Subsequent Events - Additional Information (Details)	Oct. 27, 2023
Subsequent Event
Subsequent Event [Line Items]
Description of opt-in fees payment	On October 27, 2023, pursuant to the TDA between Lilly and Beam, Lilly acquired certain rights previously held by Beam under the Amended Beam Agreement, including the right to opt-in to the Company’s PCSK9 and ANGPTL3 programs to share 33% of worldwide development expenses and to jointly commercialize and share profits and expenses related to commercialization in the United States on a 50/50 basis. The Company holds all product rights for the PCSK9 and ANGPTL3 programs outside the United States. Additionally, for a third undisclosed cardiovascular disease target, Lilly acquired Beam’s right to opt-in to share 35% of worldwide expenses of the development of such licensed product, as well as jointly commercialize and share 35% of the profits and expenses of commercializing such licensed product worldwide