Beam Therapeutics (BEAM) 10-Q 5 Nov 24 2024 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2024	Oct. 29, 2024
Cover [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2024
Document Fiscal Year Focus	2024
Document Fiscal Period Focus	Q3
Trading Symbol	BEAM
Entity Registrant Name	Beam Therapeutics Inc.
Entity Central Index Key	0001745999
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Emerging Growth Company	false
Entity Small Business	false
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Shell Company	false
Title of 12(b) Security	Common Stock, par value $0.01 per share
Security Exchange Name	NASDAQ
Entity File Number	001-39208
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	81-5238376
Entity Address, Address Line One	238 Main Street
Entity Address, City or Town	Cambridge
Entity Address, State or Province	MA
Entity Address, Postal Zip Code	02142
City Area Code	857
Local Phone Number	327-8775
Document Quarterly Report	true
Document Transition Report	false
Entity Common Stock, Shares Outstanding		82,805,627

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Current assets:
Cash and cash equivalents	$ 230,203	$ 435,895
Marketable securities	695,554	753,981
Prepaid expenses and other current assets	19,777	21,167
Total current assets	945,534	1,211,043
Property and equipment, net	113,502	124,960
Restricted cash	6,549	8,719
Operating lease right-of-use assets	104,704	112,846
Other assets	1,078	2,146
Total assets	1,171,367	1,459,714
Current liabilities:
Accounts payable	3,812	1,617
Accrued expenses and other current liabilities	51,769	111,664
Current portion of derivative liabilities	8,400	10,800
Current portion of deferred revenue	89,327	68,706
Current portion of lease liability	12,936	12,778
Total current liabilities	166,244	205,565
Long-term lease liability	149,129	159,911
Contingent consideration liabilities	1,104	2,723
Long-term portion of deferred revenue	57,816	109,888
Long-term portion of derivative liabilities	5,276
Other liabilities	481	298
Total liabilities	380,050	478,385
Commitments and contingencies (See Note 7, License agreements and Note 8, Collaboration and license agreements)
Stockholders’ equity:
Preferred stock, $0.01 par value; 25,000,000 shares authorized, and no shares issued or outstanding at September 30, 2024 and December 31, 2023, respectively
Common stock, $0.01 par value; 250,000,000 shares authorized, 82,558,883 and 81,632,496 issued and outstanding at September 30, 2024 and December 31, 2023, respectively	826	816
Additional paid-in capital	2,265,009	2,169,798
Accumulated other comprehensive (loss) income	1,759	604
Accumulated deficit	(1,476,277)	(1,189,889)
Total stockholders' equity	791,317	981,329
Total liabilities and stockholders' equity	$ 1,171,367	$ 1,459,714

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Parenthetical) (Unaudited) - $ / shares	Sep. 30, 2024	Dec. 31, 2023
Statement of Financial Position [Abstract]
Preferred stock, par or stated value per share	$ 0.01	$ 0.01
Preferred stock, shares authorized	25,000,000	25,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par or stated value per share	$ 0.01	$ 0.01
Common stock, shares authorized	250,000,000	250,000,000
Common stock, shares issued	82,558,883	81,632,496
Common stock, shares outstanding	82,558,883	81,632,496

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations and Other Comprehensive Loss (Unaudited) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Income Statement [Abstract]
License and collaboration revenue	$ 14,269,000	$ 17,193,000	$ 33,451,000	$ 61,517,000
Revenue, Product and Service [Extensible List]	us-gaap:LicenseMember	us-gaap:LicenseMember	us-gaap:LicenseMember	us-gaap:LicenseMember
Operating expenses:
Research and development	$ 94,258,000	$ 100,050,000	$ 266,117,000	$ 297,304,000
General and administrative	26,515,000	25,410,000	82,865,000	73,556,000
Total operating expenses	120,773,000	125,460,000	348,982,000	370,860,000
Loss from operations	(106,504,000)	(108,267,000)	(315,531,000)	(309,343,000)
Other income (expense):
Change in fair value of derivative liabilities	(200,000)	4,700,000	2,400,000	9,400,000
Change in fair value of non-controlling equity investments	(2,064,000)	(11,221,000)	(13,003,000)	(17,870,000)
Change in fair value of contingent consideration liabilities	(27,000)	6,002,000	1,619,000	7,877,000
Interest and other income (expense), net	12,127,000	12,698,000	38,166,000	34,612,000
Total other income (expense)	9,836,000	12,179,000	29,182,000	34,019,000
Net loss before income taxes	(96,668,000)	(96,088,000)	(286,349,000)	(275,324,000)
Provision for income taxes			(39,000)	0
Net loss	(96,668,000)	(96,088,000)	(286,388,000)	(275,324,000)
Unrealized gain (loss) on marketable securities	2,869,000	(9,000)	1,155,000	406,000
Comprehensive loss	$ (93,799,000)	$ (96,097,000)	$ (285,233,000)	$ (274,918,000)
Net loss per common share, basic	$ (1.17)	$ (1.22)	$ (3.49)	$ (3.63)
Net loss per common share, diluted	$ (1.17)	$ (1.22)	$ (3.49)	$ (3.63)
Weighted - average common shares outstanding, basic	82,410,095	79,024,647	82,141,383	75,902,612
Weighted - average common shares outstanding, diluted	82,410,095	79,024,647	82,141,383	75,902,612

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Stockholders' Equity (Unaudited) - USD ($) $ in Thousands	Total	ATM Offering	Common Stock	Common Stock ATM Offering	Additional Paid-in Capital	Additional Paid-in Capital ATM Offering	Accumulated Other Comprehensive Income (Loss)	Accumulated Deficit
Beginning Balance at Dec. 31, 2022	$ 733,474		$ 712		$ 1,792,554		$ (2,430)	$ (1,057,362)
Beginning Balance, Shares at Dec. 31, 2022			71,277,339
Purchase of common stock under ESPP	1,708		$ 1		1,707
Purchase of common stock under ESPP, Shares			65,620
Issuance of common stock from At-the-Market offering, net of issuance costs		$ 93,810		$ 24		$ 93,786
Issuance of common stock from At-the-Market offering, net of issuance costs, Shares				2,431,770
Vesting of restricted common stock			$ 3		(3)
Vesting of restricted common stock, Shares			284,858
Stock-based compensation	23,917				23,917
Exercise of common stock options	3,392		$ 4		3,388
Exercise of common stock options, Shares			375,805
Other comprehensive income (loss)	1,665						1,665
Net loss	(96,460)							(96,460)
Ending Balance at Mar. 31, 2023	761,506		$ 744		1,915,349		(765)	(1,153,822)
Ending Balance, Shares at Mar. 31, 2023			74,435,392
Beginning Balance at Dec. 31, 2022	733,474		$ 712		1,792,554		(2,430)	(1,057,362)
Beginning Balance, Shares at Dec. 31, 2022			71,277,339
Net loss	(275,324)
Ending Balance at Sep. 30, 2023	778,941		$ 794		2,112,857		(2,024)	(1,332,686)
Ending Balance, Shares at Sep. 30, 2023			79,382,032
Beginning Balance at Mar. 31, 2023	761,506		$ 744		1,915,349		(765)	(1,153,822)
Beginning Balance, Shares at Mar. 31, 2023			74,435,392
Issuance of common stock from At-the-Market offering, net of issuance costs		107,183		$ 34		107,149
Issuance of common stock from At-the-Market offering, net of issuance costs, Shares				3,387,358
Vesting of restricted common stock			$ 1		(1)
Vesting of restricted common stock, Shares			63,154
Stock-based compensation	26,278				26,278
Exercise of common stock options	702		$ 1		701
Exercise of common stock options, Shares			67,598
Other comprehensive income (loss)	(1,250)						(1,250)
Net loss	(82,776)							(82,776)
Ending Balance at Jun. 30, 2023	811,643		$ 780		2,049,476		(2,015)	(1,236,598)
Ending Balance, Shares at Jun. 30, 2023			77,953,502
Purchase of common stock under ESPP	1,324		$ 1		1,323
Purchase of common stock under ESPP, Shares			64,783
Issuance of common stock from At-the-Market offering, net of issuance costs		$ 34,944		$ 10		$ 34,934
Issuance of common stock from At-the-Market offering, net of issuance costs, Shares				1,133,575
Vesting of restricted common stock			$ 1		(1)
Vesting of restricted common stock, Shares			68,869
Stock-based compensation	25,835				25,835
Exercise of common stock options	1,292		$ 2		1,290
Exercise of common stock options, Shares			161,303
Other comprehensive income (loss)	(9)						(9)
Net loss	(96,088)							(96,088)
Ending Balance at Sep. 30, 2023	778,941		$ 794		2,112,857		(2,024)	(1,332,686)
Ending Balance, Shares at Sep. 30, 2023			79,382,032
Beginning Balance at Dec. 31, 2023	981,329		$ 816		2,169,798		604	(1,189,889)
Beginning Balance, Shares at Dec. 31, 2023			81,632,496
Purchase of common stock under ESPP	1,398		$ 1		1,397
Purchase of common stock under ESPP, Shares			76,461
Vesting of restricted common stock			$ 4		(4)
Vesting of restricted common stock, Shares			420,579
Stock-based compensation	29,281				29,281
Exercise of common stock options	1,676		$ 2		1,674
Exercise of common stock options, Shares			151,291
Other comprehensive income (loss)	(1,525)						(1,525)
Net loss	(98,669)							(98,669)
Ending Balance at Mar. 31, 2024	913,490		$ 823		2,202,146		(921)	(1,288,558)
Ending Balance, Shares at Mar. 31, 2024			82,280,827
Beginning Balance at Dec. 31, 2023	$ 981,329		$ 816		2,169,798		604	(1,189,889)
Beginning Balance, Shares at Dec. 31, 2023			81,632,496
Exercise of common stock options, Shares	215,842
Net loss	$ (286,388)
Ending Balance at Sep. 30, 2024	791,317		$ 826		2,265,009		1,759	(1,476,277)
Ending Balance, Shares at Sep. 30, 2024			82,558,883
Beginning Balance at Mar. 31, 2024	913,490		$ 823		2,202,146		(921)	(1,288,558)
Beginning Balance, Shares at Mar. 31, 2024			82,280,827
Vesting of restricted common stock			$ 1		(1)
Vesting of restricted common stock, Shares			72,040
Stock-based compensation	31,604				31,604
Exercise of common stock options	240				240
Exercise of common stock options, Shares			33,343
Other comprehensive income (loss)	(189)						(189)
Net loss	(91,051)							(91,051)
Ending Balance at Jun. 30, 2024	854,094		$ 824		2,233,989		(1,110)	(1,379,609)
Ending Balance, Shares at Jun. 30, 2024			82,386,210
Purchase of common stock under ESPP	1,224		$ 1		1,223
Purchase of common stock under ESPP, Shares			58,726
Vesting of restricted common stock			$ 1		(1)
Vesting of restricted common stock, Shares			82,739
Stock-based compensation	29,559				29,559
Exercise of common stock options	239				239
Exercise of common stock options, Shares			31,208
Other comprehensive income (loss)	2,869						2,869
Net loss	(96,668)							(96,668)
Ending Balance at Sep. 30, 2024	$ 791,317		$ 826		$ 2,265,009		$ 1,759	$ (1,476,277)
Ending Balance, Shares at Sep. 30, 2024			82,558,883

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Stockholders' Equity (Unaudited) (Parenthetical) - USD ($) $ in Millions	3 Months Ended
	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023
ATM Offering
Stock issuance costs	$ 0.8	$ 5.1	$ 0.2

Condensed Consolidated Statem_4

Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023
Operating activities
Net loss	$ (286,388)	$ (275,324)
Adjustments to reconcile net loss to net cash provided by (used in) operating activities:
Depreciation and amortization	16,482	14,650
Amortization of investment discount (premiums)	(18,125)	(22,389)
Stock-based compensation expense	90,444	76,030
Change in operating lease right-of-use assets	7,193	7,117
Change in fair value of derivative liabilities	(2,400)	(9,400)
Change in fair value of contingent consideration liabilities	(1,619)	(7,877)
Change in fair value of non-controlling equity investments	13,003	17,870
Changes in operating assets and liabilities:
Prepaid expenses and other current assets	2,458	(10,043)
Accounts payable	2,357	(5,810)
Accrued expenses and other liabilities	(53,610)	(2,738)
Operating lease liabilities	(9,676)	(7,161)
Deferred revenue	(31,451)	(60,016)
Other long-term liabilities	451	823
Net cash provided by (used in) operating activities	(270,881)	(284,268)
Investing activities
Purchases of property and equipment	(5,976)	(30,143)
Purchases of marketable securities	(486,439)	(931,066)
Maturities of marketable securities	551,142	934,950
Net cash provided by (used in) investing activities	58,727	(26,259)
Financing activities
Proceeds from issuance of common shares, net of commissions		236,568
Proceeds from issuances of stock under ESPP	2,622	3,032
Payment of equity offering costs		(631)
Repayment of equipment financings	(485)	(1,620)
Proceeds from exercise of stock options	2,155	5,386
Net cash provided by (used in) financing activities	4,292	242,735
Net change in cash, cash equivalents and restricted cash	(207,862)	(67,792)
Cash, cash equivalents and restricted cash—beginning of period	444,614	245,521
Cash, cash equivalents and restricted cash—end of period	236,752	177,729
Supplemental disclosure of cash flow information:
Cash paid for interest	32	140
Supplemental disclosure of non-cash investing and financing activities:
Property and equipment additions in accounts payable and accrued expenses	451	2,192
Operating lease liabilities arising from obtaining right-of-use assets	$ (1,010)	$ 744

Pay vs Performance Disclosure

Pay vs Performance Disclosure - USD ($) $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2024	Jun. 30, 2024	Mar. 31, 2024	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Sep. 30, 2024	Sep. 30, 2023
Pay vs Performance Disclosure
Net Income (Loss)	$ (96,668)	$ (91,051)	$ (98,669)	$ (96,088)	$ (82,776)	$ (96,460)	$ (286,388)	$ (275,324)

Insider Trading Arrangements

Insider Trading Arrangements	3 Months Ended
	Sep. 30, 2024 shares
Trading Arrangements, by Individual
Material Terms of Trading Arrangement	Director and Officer Trading Arrangements The following table describes for the quarterly period covered by this report each trading arrangement for the sale or purchase of Company securities adopted or terminated by our directors and officers that is either (1) a contract, instruction or written plan intended to satisfy the affirmative defense conditions of Rule 10b5-1(c), or a “Rule 10b5-1 trading arrangement,” or (2) a “non-Rule 10b5-1 trading arrangement” (as defined in Item 408(c) of Regulation S-K): Name (Title) Action Taken (Date of Action) Type of Trading Arrangement Nature of Trading Arrangement Duration of Trading Arrangement Aggregate Number of Securities Giuseppe Ciaramella ( President ) Adoption ( September 26, 2024 ) Rule 10b5-1 trading arrangement Sale Until September 26, 2025 , or such earlier date upon which all transactions are completed or expire without execution . Up to 35,000 shares (1) Christine Bellon ( Chief Legal Officer ) Adoption ( September 20, 2024 ) Rule 10b5-1 trading arrangement Until September 20, 2025 , or such earlier date upon which all transactions are completed or expire without execution . Up to 20,000 shares (2) Bethany Cavanagh ( Senior Vice President, Finance ) Adoption ( September 18, 2024 ) Rule 10b5-1 trading arrangement Until September 18, 2025 , or such earlier date upon which all transactions are completed or expire without execution . Up to 14,595 shares Bethany Cavanagh ( Senior Vice President, Finance ) Adoption ( August 9, 2024 ) Durable Rule 10b5-1 trading arrangement for sell-to-cover transactions relating to all RSU equity awards that have been or may be granted Sale Until final settlement of any covered RSU Indeterminable (3) (1) Consists of 35,000 shares issuable upon exercise of options to purchase the Company’s common stock pursuant to the Rule 10b-5-1 trading arrangement (2) Includes up to 10,000 shares issuable upon exercise of options to purchase the Company’s common stock pursuant to the Rule 10b5-1 trading arrangement. (3) The number of shares subject to covered restricted stock units ("RSUs") that will be sold to satisfy applicable tax withholding obligations upon vesting is unknown as the number will vary based on the extent to which vesting conditions are satisfied, the market price of the Company’s common stock at the time of settlement and the potential future grant of additional RSUs subject to this arrangement. This trading arrangement, which applies to RSUs whether vesting is based on the passage of time and/or the achievement of performance goals, provides for the automatic sale of shares that would otherwise be issuable on each settlement date of a covered RSU in an amount sufficient to satisfy the applicable withholding obligation, with the proceeds of the sale delivered to the Company in satisfaction of the applicable withholding obligation.
Giuseppe Ciaramella
Trading Arrangements, by Individual
Name	Giuseppe Ciaramella
Title	President
Rule 10b5-1 Arrangement Adopted	true
Adoption Date	September 26, 2024
Expiration Date	September 26, 2025
Arrangement Duration	366 days
Aggregate Available	35,000
Christine Bellon
Trading Arrangements, by Individual
Name	Christine Bellon
Title	Chief Legal Officer
Rule 10b5-1 Arrangement Adopted	true
Adoption Date	September 20, 2024
Expiration Date	September 20, 2025
Arrangement Duration	366 days
Aggregate Available	20,000
Rule 10b5-1 Trading Plan | Bethany Cavanagh
Trading Arrangements, by Individual
Name	Bethany Cavanagh
Title	Senior Vice President, Finance
Rule 10b5-1 Arrangement Adopted	true
Adoption Date	September 18, 2024
Expiration Date	September 18, 2025
Arrangement Duration	366 days
Aggregate Available	14,595
Durable Rule 10b5-1 Trading Plan | Bethany Cavanagh
Trading Arrangements, by Individual
Name	Bethany Cavanagh
Title	Senior Vice President, Finance
Rule 10b5-1 Arrangement Adopted	true
Adoption Date	August 9, 2024

Nature of the Business and Basi

Nature of the Business and Basis of Presentation	9 Months Ended
	Sep. 30, 2024
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 Beam Therapeutics Inc., which we refer to herein as the “Company” or “Beam,” is a biotechnology company committed to establishing the leading, fully integrated platform for precision genetic medicines. Beam’s vision is to provide life-long cures to patients suffering from genetic diseases. The Company was incorporated on January 25, 2017 as a Delaware corporation and began operations in July 2017. Its principal offices are in Cambridge, Massachusetts. Liquidity and capital resources Since its inception, the Company has devoted substantially all of its resources to building its base editing platform and advancing development of its portfolio of programs, establishing and protecting its intellectual property, conducting research and development activities, making arrangements to conduct manufacturing activities with contract manufacturing organizations, organizing and staffing the Company, establishing and maintaining internal manufacturing capabilities, conducting clinical trials, maintaining its facilities and new facility build-outs, business planning, raising capital and providing general and administrative support for these operations. 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. Even if the Company’s product development efforts are successful, it is uncertain when, if ever, the Company will realize significant revenue from product sales. In April 2021, the Company entered into an at the market, or ATM, sales agreement, or the Sales Agreement, with Jefferies LLC, or Jefferies, pursuant to which the Company was entitled to offer and sell, from time to time at prevailing market prices, shares of the Company’s common stock having aggregate gross proceeds of up to $ 300.0 million. 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. Between April 2021 and July 2021, the Company sold 2,908,009 shares of its common stock under the Sales Agreement at an average price of $ 103.16 per share for aggregate gross proceeds of $ 300.0 million, before deducting commissions and offering expenses payable by the Company. In July 2021 and May 2023, the Company and Jefferies entered into amendments to the Sales Agreement to provide for increases in the aggregate offering amount under the Sales Agreement, such that as of May 10, 2023, the Company may offer and sell shares of common stock having an aggregate offering price of up to an additional $ 800.0 million. As of September 30, 2024, the Company has sold 10,860,992 additional shares of its common stock under the amended Sales Agreement at an average price of $ 51.93 per share for aggregate gross proceeds of $ 564.0 million, before deducting commissions and offering expenses payable by the Company. Since its inception, the Company has incurred substantial losses and had an accumulated deficit of $ 1.5 billion as of September 30, 2024. The Company expects to generate operating losses and negative operating cash flows for the foreseeable future. The Company expects that its cash, cash equivalents, and marketable securities as of September 30, 2024 of $ 925.8 million will be sufficient to fund its operations for at least 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 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 would 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.

Summary of Significant Accounti

Summary of Significant Accounting Policies	9 Months Ended
	Sep. 30, 2024
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	2. S ummary of significant accounting policies The Company’s significant accounting policies are disclosed in the audited consolidated financial statements for the year ended December 31, 2023, and notes thereto, which are included in the Company’s Annual Report on Form 10-K that was filed with the Securities and Exchange Commission, or the SEC, on February 27, 2024, or the 2023 Form 10-K. Since the date of those financial statements, there have been no material changes to the Company's significant accounting policies. Basis of presentation The accompanying condensed consolidated financial statements have been prepared in accordance with United States generally accepted accounting principles, or GAAP. Any reference in these notes to applicable guidance is meant to refer to the authoritative GAAP as found in the Accounting Standards Codification, or ASC, and Accounting Standards Update, or ASU, of the Financial Accounting Standards Board, or FASB. Principles of consolidation The accompanying condensed consolidated financial statements include the results of operations of the Company and its wholly-owned subsidiaries. All intercompany transactions and balances have been eliminated in consolidation. Use of estimates The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets, liabilities, revenues and expenses, and the disclosure of contingent assets and liabilities as of and during the reporting period. The Company bases its estimates and assumptions on historical experience when available and on various factors that it believes to be reasonable under the circumstances. Significant estimates and assumptions reflected in these condensed consolidated financial statements include, but are not limited to, incremental borrowing rate used in the calculation of lease liabilities, research and development expenses, stock-based compensation, contingent consideration liabilities, success payments, settlement payments and certain judgments regarding revenue recognition. Actual results could differ from these estimates. Recently announced accounting pronouncements In November 2023, the FASB issued ASU 2023-07 , Segment Reporting (Topic 280). The amendments in this update expand segment disclosure requirements, including new segment disclosure requirements for entities with a single reportable segment among other disclosure requirements. This update is effective for fiscal years beginning after December 15, 2023, and interim periods within fiscal years beginning after December 15, 2024. The adoption of this standard is not expected to have a material impact on the Company’s consolidated financial statements. In December 2023, the FASB issued ASU 2023-09, Income Taxes (Topic 740). The amendments in this update expand income tax disclosure requirements, including additional information pertaining to the rate reconciliation, income taxes paid, and other disclosures. This update is effective for annual periods beginning after December 15, 2024. The adoption of this standard is not expected to have a material impact on the Company’s consolidated financial statements. Cash, cash equivalents, and restricted cash Cash and cash equivalents consist of standard checking accounts, money market accounts, and all highly liquid investments with a remaining maturity of three months or less at the date of purchase. Restricted cash represents collateral provided for letters of credit issued as security deposits in connection with the Company’s leases of its corporate facilities. The following table reconciles cash, cash equivalents, and restricted cash reported within the Company’s condensed consolidated balance sheets to the total of the amounts shown in the condensed consolidated statements of cash flows (in thousands): September 30, September 30, Cash and cash equivalents $ 230,203 $ 169,049 Restricted cash 6,549 8,680 Total cash, cash equivalents, and restricted cash $ 236,752 $ 177,729

Property and Equipment, Net

Property and Equipment, Net	9 Months Ended
	Sep. 30, 2024
Property, Plant and Equipment [Abstract]
Property and Equipment, Net	3. P roperty and equipment, net Property and equipment consist of the following (in thousands): September 30, December 31, Leasehold improvements $ 100,921 $ 100,186 Lab equipment 69,109 61,674 Furniture and fixtures 4,836 4,836 Computer equipment 3,170 3,163 Construction in process 2,130 5,283 Total property and equipment 180,166 175,142 Less accumulated depreciation ( 66,664 ) ( 50,182 ) Property and equipment, net $ 113,502 $ 124,960 The following table summarizes depreciation expense incurred (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2024 2023 2024 2023 Depreciation expense $ 5,475 $ 5,187 $ 16,482 $ 14,650

Fair Value of Financial Instrum

Fair Value of Financial Instruments	9 Months Ended
	Sep. 30, 2024
Fair Value Disclosures [Abstract]
Fair Value of Financial Instruments	4. f air value of financial instruments The Company’s financial instruments that are measured at fair value on a recurring basis consist of cash equivalents, marketable securities, corporate equity securities of Verve Therapeutics, Inc., or Verve, and Prime Medicine, Inc., or Prime, contingent consideration liabilities related to the Agreement and Plan of Merger, dated February 23, 2021, between Guide Therapeutics, Inc., or Guide, and the Company, or the Guide Merger Agreement, success payment derivative liabilities pursuant to the license agreement, or the Harvard License Agreement, between President and Fellows of Harvard University, or Harvard, and the Company, the license agreement, or the Broad License Agreement, between The Broad Institute, Inc., or Broad Institute, and the Company, and settlement payment derivative liabilities associated with a settlement agreement, between the Company and a research institution. The following tables set forth the fair value of the Company’s financial assets and liabilities by level within the fair value hierarchy at September 30, 2024 (in thousands): Carrying Fair Level 1 Level 2 Level 3 Assets Cash equivalents: Money market funds $ 178,597 $ 178,597 $ 178,597 $ — $ — Commercial paper 51,443 51,443 — 51,443 — Marketable securities: Commercial paper 217,714 217,714 — 217,714 — Corporate notes 115,568 115,568 — 115,568 — U.S. Treasury securities 227,457 227,457 — 227,457 — U.S. Government securities 125,943 125,943 — 125,943 — Corporate equity securities 8,872 8,872 8,872 — — Total assets $ 925,594 $ 925,594 $ 187,469 $ 738,125 $ — Liabilities Success payment liability – Harvard $ 4,000 $ 4,000 $ — $ — $ 4,000 Success payment liability – Broad Institute 4,400 4,400 — — 4,400 Derivative settlement liability 5,276 5,276 — — 5,276 Contingent consideration liability – Technology 484 484 — — 484 Contingent consideration liability – Product 620 620 — — 620 Total liabilities $ 14,780 $ 14,780 $ — $ — $ 14,780 The following tables set forth the fair value of the Company’s financial assets and liabilities by level within the fair value hierarchy at December 31, 2023 (in thousands): Carrying Fair Level 1 Level 2 Level 3 Assets Cash equivalents: Money market funds $ 435,689 435,689 $ 435,689 $ — $ — Marketable securities: Commercial paper 285,289 285,289 — 285,289 — Corporate notes 23,525 23,525 — 23,525 — U.S. Treasury securities 152,147 152,147 — 152,147 — U.S. Government securities 271,145 271,145 — 271,145 — Corporate equity securities 21,875 21,875 21,875 — — Total assets $ 1,189,670 $ 1,189,670 $ 457,564 $ 732,106 $ — Liabilities Success payment liability – Harvard $ 5,200 $ 5,200 $ — $ — $ 5,200 Success payment liability – Broad Institute 5,600 5,600 — — 5,600 Contingent consideration liability – Technology 1,371 1,371 — — 1,371 Contingent consideration liability – Product 1,352 1,352 — — 1,352 Total liabilities $ 13,523 $ 13,523 $ — $ — $ 13,523 Cash equivalents – Money market funds included within cash equivalents are classified within Level 1 of the fair value hierarchy because they are valued using quoted market prices in active markets. Commercial paper and corporate notes 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. Marketable securities – Marketable securities, excluding corporate equity securities (held in Verve and Prime), 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 using models or other valuation methodologies. The Company holds an investment in Verve consisting of shares of Verve’s common stock. As of September 30, 2024, the Company owned 546,970 shares of Verve's common stock valued at $ 2.7 million, which is included in marketable securities in the condensed consolidated balance sheet. The Company also holds an investment in Prime consisting of 1,608,337 shares of Prime's common stock. As of September 30, 2024, the Company's investment in Prime's common stock was valued at $ 6.2 million, which is included in marketable securities in the condensed consolidated balance sheet. Pursuant to ASC 825, Financial instruments , the Company records changes in the fair value of its investments in equity securities to other income (expense), in the Company’s condensed consolidated statements of operations. The following table summarizes other income (expense) recorded due to changes in the fair value of corporate equity securities held (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2024 2023 2024 2023 Other income (expense) $ ( 2,064 ) $ ( 11,221 ) $ ( 13,003 ) $ ( 17,870 ) Success payment liabilities – As discussed further in Note 7, License agreements , the Company is required to make payments to Harvard and Broad Institute based upon the achievement of specified multiples of the market value of the Company's common stock, at specified valuation dates. The Company’s liability for the share-based success payments under the Harvard License Agreement and the Broad License Agreement is carried at fair value. To determine the estimated fair value of the success payment liability, the Company uses a Monte Carlo simulation methodology, which models the future movement of stock prices based on several key variables. The following variables were incorporated in the calculation of the estimated fair value of the Harvard and Broad Institute success payment liabilities: Harvard Broad Institute September 30, December 31, September 30, December 31, Fair value of common stock (per share) $ 24.50 $ 27.22 $ 24.50 $ 27.22 Expected volatility 79 % 80 % 80 % 79 % Expected term (years) 0.04 - 4.74 0.06 - 5.49 0.04 - 5.61 0.06 - 6.36 The computation of expected volatility was estimated using available information about the historical volatility of stocks of similar publicly traded companies in addition to the Company's own data for a period matching the expected term assumption. In addition, the Company incorporated the estimated number, timing, and probability of valuation measurement dates in the calculation of the success payment liability. The following table reconciles the change in the fair value of success payment liabilities based on Level 3 inputs (in thousands): Nine Months Ended September 30, 2024 Harvard Broad Institute Total Balance at December 31, 2023 $ 5,200 $ 5,600 $ 10,800 Change in fair value ( 1,200 ) ( 1,200 ) ( 2,400 ) Balance at September 30, 2024 $ 4,000 $ 4,400 $ 8,400 Derivative settlement liability – On July 19, 2024, the Company entered into a settlement agreement with a research institution pursuant to which, in exchange for a release of claims in its favor, the Company agreed, among other things, to pay the research institution an upfront payment of $ 15.0 million and to make additional payments contingent upon the development and commercialization of BEAM-102 and BEAM-302. These contingent payments consist of certain development, regulatory, and sales-bas ed milestone payments, as well as 1 % royalty through 2038. Any amounts due must be settled in cash. The maximum amount of development and regulatory milestone payments under the settlement agreement is $ 15.0 million, and the maximum amount of sales milestone payments is $ 35 million, per program. The Co mpany paid the $ 15.0 million upfront payment during the three months ended September 30, 2024. There was no material charge related to this settlement in the three or nine months ended September 30, 2024 as the settlement value was substantially accrued in prior periods. The contingent settlement payments are accounted for as a derivative under Accounting Standards Codification 815, Derivatives and Hedging, as the potential payments meet the definition of a derivative and are not subject to any scope exceptions. The derivative liability is recorded at fair value on the Company's balance sheet with changes in value recognized in interest and other income (expense) in the consolidated statement of operations and other comprehensive loss. To determine the estimated fair value of the liability, the Company applied a probability-based model, which utilized inputs based on the potential achievement and related timing of certain development, regulatory and sales-based milestones that were unobservable in the market. This derivative liability is classified within Level 3 of the fair value hierarchy above. The following assumptions were incorporated in the calculation of the fair value of the derivative liability: Milestones September 30, Discount rate 10.00 % Probability of achievement of settlement payments 3 %- 44 % Projected Year of achievement of settlement payments 2027 - 2038 The following table reconciles the change in fair value of the derivative liability based on level 3 inputs (in thousands): Nine Months Ended September 30, 2024 Total Balance at December 31, 2023 $ — Initial recognition of derivative liability 5,276 Balance at September 30, 2024 $ 5,276 Contingent consideration liabilities – Under the Guide Merger Agreement, Guide’s former stockholders and optionholders are eligible to receive up to an additional $ 100.0 million in technology milestone payments and $ 220.0 million in product milestone payments, payable in the Company’s common stock valued using the volume-weighted average price of the Company’s stock over the ten-day trading period ending two trading days prior to the date on which the applicable milestone is achieved. As these milestones are payable with a variable number of shares of the Company’s common stock, the milestone payments result in liability classification under ASC 480, Distinguishing Liabilities from Equity . These contingent consideration liabilities are carried at fair value which was estimated by applying a probability-based model, which utilized inputs based on timing of achievement that were unobservable in the market. These contingent consideration liabilities are classified within Level 3 of the fair value hierarchy. The following variables were incorporated in the calculation of the estimated fair value of the contingent consideration liabilities: Technology Milestones Product Milestones September 30, December 31, September 30, December 31, Discount Rate 10.00 % 10.00 % 10.00 % 10.00 % Probability of Achievement 2 % 2 - 5 % 1 - 2 % 1 - 2 % Projected Year of Achievement 2026 2025 2028 - 2034 2025 - 2031 The following table reconciles the change in fair value of the contingent consideration liabilities based on level 3 inputs (in thousands): Nine Months Ended September 30, 2024 Technology Milestones Product Milestones Total Balance at December 31, 2023 $ 1,371 $ 1,352 $ 2,723 Change in fair value ( 887 ) ( 732 ) ( 1,619 ) Balance at September 30, 2024 $ 484 $ 620 $ 1,104

Marketable Securities

Marketable Securities	9 Months Ended
	Sep. 30, 2024
Investments, Debt and Equity Securities [Abstract]
Marketable Securities	5. Marketable securities The following table summarizes the Company’s marketable securities held at September 30, 2024 (in thousands): Amortized Cost Gross Gross Fair Value Commercial paper $ 217,213 $ 501 $ — $ 217,714 Corporate notes 115,320 259 ( 11 ) 115,568 U.S. Treasury securities 226,850 607 — 227,457 U.S. Government securities 125,540 405 ( 2 ) 125,943 Corporate equity securities 8,872 — — 8,872 Total $ 693,795 $ 1,772 $ ( 13 ) $ 695,554 The following table summarizes the Company’s marketable securities held at December 31, 2023 (in thousands): Amortized Cost Gross Gross Fair Value Commercial paper $ 285,054 $ 250 $ ( 15 ) $ 285,289 Corporate notes 23,462 63 — 23,525 U.S. Treasury securities 151,805 436 ( 94 ) 152,147 U.S. Government securities 271,181 328 ( 364 ) 271,145 Corporate equity securities 21,875 — — 21,875 Total $ 753,377 $ 1,077 $ ( 473 ) $ 753,981 The amortized cost of marketable securities is adjusted for amortization of premiums and accretion of discounts to maturity. At September 30, 2024 , the balance in accumulated other comprehensive (loss) income was related to marketable securities. There were no realized gains or losses recognized on the sale or maturity of marketable securities for the nine months ended September 30, 2024 and 2023 and, as a result, the Company did not reclassify any amounts out of accumulated other comprehensive (loss) income for the same periods. The Company holds debt securities of companies with high credit quality and has determined that there was no material change in the credit risk of any of its debt securities.

Accrued Expenses and Other Curr

Accrued Expenses and Other Current Liabilities	9 Months Ended
	Sep. 30, 2024
Payables and Accruals [Abstract]
Accrued Expenses and Other Current Liabilities	6. Accrued expenses and other current liabilities Accrued expenses and other current liabilities consist of the following (in thousands): September 30, December 31, Accrued contingent obligation, refer to Note 7 20,652 43,280 Employee compensation and related benefits 13,712 21,774 Research costs 8,206 9,804 Professional fees 3,551 3,468 Process development and manufacturing costs 3,073 4,697 Other 2,575 28,641 Total $ 51,769 $ 111,664

License Agreements

License Agreements	9 Months Ended
	Sep. 30, 2024
Organization, Consolidation and Presentation of Financial Statements [Abstract]
License Agreements	7. License agreements The Company has various license agreements related to technology used in its research and development activities. The license agreements may include up-front payments, option fees, ongoing maintenance fees, sublicense fees, royalty-based payments, milestone payments, success-based payments, and other payments. Option fees, when applicable, are recognized when exercised, maintenance fees, sublicense fees, and other payments are recorded as incurred based on the estimated amounts due or that will ultimately be paid. Contingent payments that are not required to be accounted for as a derivative are recognized as incurred. As the success-based payments due under the Company’s license arrangements are derivatives, the change in the fair value of the success-based payments are recognized in a separate line item in the statement of operations and comprehensive loss, as discussed further below. The value attributable to sublicenses and the related sublicense fees due under the Company’s license agreements may require estimates and other judgments related to contractual requirements, which creates uncertainty over the ultimate amount that would be paid under these arrangements. Contractual amounts due are accrued and if a contingency exists related to the interpretation of the amounts due under the license agreement, the Company recognizes a liability for the amount that is probable and estimable. When no amount within the range of potential payments is a better estimate than any other amount, however, the minimum amount in the range is accrued. If some amount within a range of loss appears to be a better estimate than any other amount within the range, that amount is accrued. The Company’s accrued liabilities for license fees includes estimates, including approximately $ 20.7 million of contingent obligations that are expected to be due associated with payments received under the Lilly Agreement. As of September 30, 2024, management believes that it is remote that an adjustment to its estimated accrual would result in a material charge in excess of the amount accrued. The ultimate amount paid may differ materially from the estimated amounts. Harvard license agreement Under the Harvard License Agreement, Harvard is entitled to receive success payments, in cash or shares of Company stock, determined based upon the achievement of specified multiples of the initial weighted average value of the Company’s Series A Preferred at specified valuation dates. The success payments range from $ 5.0 million to a maximum of $ 105.0 million and have valuation multiples that range from 5 times to 40 times the initial weighted average value of the Series A Preferred. Subsequent to the Company’s February 2020 IPO, the amount of success payments is based on the market value of the Company's common stock. The Company is required to make success payments to Harvard during a period of time, or the Harvard Success Payment Period, which has been determined to be the later of (1) the ninth anniversary of the Harvard License Agreement or (2) the earlier of (a) the twelfth anniversary of the Harvard License Agreement and (b) the third anniversary of the first date on which a licensed product receives regulatory approval in the United States. During the Harvard Success Payment Period, the Company will perform a calculation of any amounts owed to Harvard on each rolling 90-day period, commencing one year after the Company’s IPO. In May 2021, the first success payment measurement occurred and amounts due to Harvard were calculated to be $ 15.0 million. The Company elected to make the payment in shares of the Company’s common stock and issued 174,825 shares of the Company’s common stock to settle this liability on June 10, 2021. The Company may owe Harvard success payments of up to an additional $ 90.0 million. As of September 30, 2024 , no success payments were due to Harvard. The following table summarizes the Company’s success payment liability for Harvard (in thousands): September 30, December 31, Harvard success payment liability $ 4,000 $ 5,200 The following table summarizes the expense (income) resulting from the change in the fair value of the success payment liability for Harvard (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2024 2023 2024 2023 Change in fair value of Harvard success payment liability $ 100 $ ( 2,400 ) $ ( 1,200 ) $ ( 4,700 ) Broad license agreement Under the Broad License Agreement, Broad Institute is entitled to receive success payments, in cash or shares of Company common stock, determined based upon the achievement of specified multiples of the initial weighted average value of the Series A Preferred at specified valuation dates. The success payments range from $ 5.0 million to a maximum of $ 105.0 million and have valuation multiples that range from 5 times to 40 times the initial weighted average value of the Series A Preferred. Subsequent to the February 2020 IPO, the amount of success payments is based on the market value of the Company’s common stock. The Company is required to make success payments to Broad Institute during a period of time, or the Broad Success Payment Period, which has been determined to be the earliest of (1) the twelfth anniversary of the Broad License Agreement or (2) the third anniversary of the first date on which a licensed product receives regulatory approval in the United States. During the Broad Success Payment Period, the Company will perform a calculation of any amounts owed to Broad Institute on each rolling 90-day period, commencing one year after the Company’s IPO. In May 2021, the first success payment measurement occurred and amounts due to Broad Institute were calculated to be $ 15.0 million. The Company elected to make the payment in shares of the Company’s common stock and issued 174,825 shares of the Company’s common stock to settle this liability on June 10, 2021. The Company may owe Broad Institute success payments of up to an additional $ 90.0 million. As of September 30, 2024 , no success payments were due to Broad Institute. The following table summarizes the Company’s success payment liability for Broad Institute (in thousands): September 30, December 31, Broad Institute success payment liability $ 4,400 $ 5,600 The following table summarizes the expense (income) resulting from the change in the fair value of the success payment liability for Broad Institute (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2024 2023 2024 2023 Change in fair value of Broad Institute success payment liability $ 100 $ ( 2,300 ) $ ( 1,200 ) $ ( 4,700 ) Editas license agreement In May 2018, the Company entered into a license agreement, or the Editas License Agreement, with Editas Medicine, Inc., or Editas. Pursuant to the Editas License Agreement, Editas granted to the Company licenses and options to acquire licenses to certain intellectual property rights owned or controlled by Editas, for specified uses. The annual maintenance fees under the Editas License Agreement are recorded as research and development expense. Annual patent costs are expensed as incurred. In addition, the Company is required to make certain development, regulatory and commercial milestone payments to Editas upon the achievement of specified milestones.

Collaboration and License Agree

Collaboration and License Agreements	9 Months Ended
	Sep. 30, 2024
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Collaboration and License Agreements	8. Collaboration and license agreements Eli Lilly and Company In October 2023, the Company entered into a Transfer and Delegation Agreement, or the Lilly Agreement, with Eli Lilly and Company, or Lilly, pursuant to which Lilly acquired certain assets and other rights under the Company’s amended collaboration and license agreement with Verve, or the Verve Agreement, including the Company’s opt-in rights to co-develop and co-commercialize Verve’s base editing programs for cardiovascular disease (see discussion below related to the Verve Agreement). The Company granted Lilly an exclusive sublicense to the Verve technology originally licensed to the Company under the Verve Agreement. Lilly also acquired from the Company the right to receive any future milestone or royalty payments payable by Verve under the Verve Agreement and the rights and obligations to designate representatives and participate on the joint steering committee with Verve. The Company received a $ 200.0 million nonrefundable upfront payment and is eligible to receive up to $ 350.0 million in potential future development-stage payments upon the completion of certain clinical, regulatory and alliance events. If Lilly does not opt-in to co-develop and co-commercialize a licensed product, Lilly is obligated to pay the Company a percentage of any royalties received from Verve for sales of such product, subject to certain caps on a licensed product-by-licensed product basis. For a period of six years from the effective date of the Lilly Agreement, Lilly has the right to request the Company to perform any critical research and development services, if Lilly reasonably determines that the Company is uniquely able to provide such services and other conditions are met, including that no other third parties can provide such services. The parties will negotiate an agreement governing the Company’s performance of such activity, if any, and the Company will be compensated for any services at approximately cost plus a margin. The Company has not been requested to perform any services and believes it is remote that the Company would be requested to provide any services. In connection with the Lilly Agreement, the Company and Lilly entered into a Stock Purchase Agreement providing for the sale and issuance of 2,004,811 shares of the Company’s common stock to Lilly for an aggregate purchase price of $ 50.0 million. The Company received the consideration under the Stock Purchase Agreement of $ 50.0 million in October 2023 and the upfront payment of $ 200.0 million in November 2023. The Lilly Agreement and Stock Purchase Agreement were negotiated at the same time as a package and have been accounted for as one combined contract. The Company accounts for the component of the arrangement to transfer common stock to Lilly under ASC 505, Equity , or ASC 505, and the revenue component under ASC 606, Revenue from Contracts with Customers , or ASC 606, as it includes a customer-vendor relationship as defined under ASC 606 and meets the criteria to be considered a contract. The Company first applied the guidance in ASC 505 to measure the fair value of the common stock issued and allocated the remaining consideration to the ASC 606 component of the arrangement. The overall ASC 606 transaction price as of the inception of the contract was determined to be $ 216.4 million, which is comprised of the upfront payment of $ 200.0 million and the residual value of the proceeds received in excess of the fair value of the common stock sold to Lilly of $ 16.4 million. The fair value of the common stock issued to Lilly was $ 33.6 million, as determined by management with the assistance of a third-party valuation specialist. There is no variable consideration included in the transaction price at inception. The Company will re-evaluate the transaction price at each reporting period. The Company concluded that the collaboration rights and licenses to intellectual property have the same pattern and timing of transfer and are transferred as of the effective date of the Lilly Agreement. Lilly’s right to request research and development services represents an optional purchase in the agreement that does not constitute a material right. All other items promised to Lilly are immaterial in the context of the agreement. The Company recognized revenue for the performance obligation at a point-in-time in October 2023 as all requirements related to the performance obligation have been completed. Any consideration received related to Lilly’s optional purchase of the Company’s research and development services will be accounted for as a separate contract if and when the option is exercised in accordance with ASC 606. During the year ended December 31, 2023, the Company recognized the full $ 216.4 million of revenue related to the Lilly Agreement. As of September 30, 2024 , there was no deferred revenue related to the Lilly Agreement and there has been no revenue recognized subsequent to the up-front payment. Orbital In September 2022, the Company entered into a License and Research Collaboration Agreement, or the Orbital Agreement, with Orbital Therapeutics, Inc., or Orbital . Under the terms of the Orbital Agreement, the Company will collaborate with Orbital to advance nonviral delivery and ribonucleic acid, or RNA, technology by providing Orbital with certain proprietary materials, a non-exclusive research license to certain RNA technology and nonviral delivery technology controlled by the Company, and by performing research and development support services as outlined in a research plan. The Company also granted Orbital an exploitation license to certain RNA technology and nonviral delivery technology controlled by the Company. The exploitation license is exclusive in the fields of vaccines and certain protein therapeutics and nonexclusive in all other fields other than gene editing and conditioning. The collaboration is managed on an overall basis by a Joint Steering Committee, or JSC, comprised of an equal number of representatives from the Company and Orbital. In exchange for the licenses and services provided by the Company under the Orbital Agreement, the Company received a non-exclusive research license to certain RNA technology and nonviral delivery technology controlled by Orbital, and research and development support services as outlined in a research plan. Orbital also granted the Company an exploitation license to certain RNA technology and nonviral delivery technology controlled by Orbital. The exploitation license is exclusive in the fields of gene editing and conditioning and nonexclusive in all other fields other than vaccines and certain protein therapeutics. The Company also received 75 million shares of Orbital’s common stock at closing. The Company accounts for its investment in Orbital under the equity method of accounting. The research plan has a term of three years and can be extended for unspecified periods upon mutual agreement between the Company and Orbital. The exploitation licenses are exclusive for an initial research term of three years , which may be extended for up to two successive one-year periods by mutual agreement between the Company and Orbital. Either party may terminate the licenses granted to it under the Orbital Agreement for convenience on a product-by-product basis at any time by providing 90 days’ prior written notice. The Company accounts for the Orbital Agreement under ASC 606, as it includes a customer-vendor relationship as defined under ASC 606 and meets the criteria to be considered a contract. The overall transaction price as of the inception of the contract was determined to be $ 25.5 million, which represents the fair value of the Company’s equity interest in Orbital’s common stock at inception. There is no variable consideration included in the transaction price at inception. The Company concluded that the research and exploitation licenses are not distinct from the other promises in the Orbital Agreement, and as such the Company has determined that the licenses combined with the research and development services, know-how transfers, committee participation and materials transfer represent a combined performance obligation. The Company recognizes revenue associated with the Orbital performance obligation over time as it is satisfied during the term of the Orbital Agreement, which is three years . During each of the three and nine months ended September 30, 2024 and 2023, the Company recognized $ 2.1 and $ 6.4 million of revenue, respectively, related to the Orbital agreement. As of September 30, 2024 , there was $ 8.5 million of current deferred revenue related to the Orbital Agreement. Pfizer In December 2021, the Company entered into a research collaboration agreement, or the Pfizer Agreement, with Pfizer Inc., or Pfizer, focused on the use of certain of the Company’s base editing technology to develop in vivo therapies for rare genetic diseases of the liver, muscle, and central nervous system. Under the terms of the Pfizer Agreement, the Company will conduct all research activities through development candidate selection for three base editing programs that target specific genes corresponding to specific diseases that are the subject of such programs. Pfizer will have exclusive rights to license each of the three programs at no additional cost, each an Opt-In Right, and will assume responsibility for subsequent development and commercialization. At the end of the Phase 1/2 clinical trials, the Company may elect to enter into a global co-development and co-commercialization agreement with Pfizer with respect to one program licensed under the collaboration for an option exercise fee equal to a percentage of the applicable development costs incurred by Pfizer, or the Participation Election. In the event the Company elects to exercise its Participation Election, upon the payment of its option exercise fee, Pfizer and the Company would share net profits as well as development and commercialization costs in a 65 %/ 35 % (Pfizer/Company) split for such program. The research collaboration is managed on an overall basis by a Joint Research Committee, or JRC, formed by an equal number of representatives from the Company and Pfizer. At the inception of the Pfizer Agreement, the Company was entitled to receive a nonrefundable upfront payment of $ 300.0 million in consideration for the rights granted to Pfizer under the collaboration. Should Pfizer exercise its Opt-In Right for any of the three programs, the Company would be eligible to receive development, regulatory, and commercial milestones of up to $ 350.0 million per program, for potential total consideration of up to $ 1.35 billion, plus royalty payments on global net sales for each licensed program, if any. If Pfizer does not exercise its Opt-In Right for a program, the Company’s rights in such program revert to the Company and the Company will be required to pay Pfizer earn-out payments equal to a low single digit percentage of net sales earned on such program for a ten-year period, if any. During the collaboration term, Pfizer has a one-time option to substitute a disease that is the subject of a specific program with one pre-defined substitute disease. The collaboration has an initial term of four years and may be extended for an additional year on a program-by-program basis. Pfizer may terminate the Pfizer Agreement for convenience on any or all of the programs by providing 90 days’ prior written notice. The Company accounts for the Pfizer Agreement under ASC 606, as it includes a customer-vendor relationship as defined under ASC 606 and meets the criteria to be considered a contract. The overall transaction price as of the inception of the contract was determined to be $ 300.0 million, which is comprised entirely of the nonrefundable upfront payment. There is no variable consideration included in the transaction price at inception as the future milestone payments are fully constrained and the Company is not required to estimate variable consideration for the royalty payments at contract inception. The Company re-evaluates the transaction price in each reporting period. The Company has concluded that the licenses to its base editing technology, including the exclusive development and commercialization rights, are not capable of being distinct from the other performance obligations, and as such the Company has determined that the licenses combined with the other research and development services represent performance obligations and no up-front revenue was recognized for the licenses. The selling price of each performance obligation was determined based on the Company’s estimated standalone selling price, or the ESSP. The Company developed the ESSP for all of the performance obligations included in the Pfizer Agreement by determining the total estimated costs to fulfill each performance obligation identified with the objective of determining the price at which it would sell such an item if it were to be sold regularly on a standalone basis. The Company allocated the stand-alone selling price to the performance obligations based on the relative standalone selling price method. The Company recognizes revenue for each performance obligation as it is satisfied during the term of the agreement using an input method. The Company allocated the transaction price of $ 300.0 million to each of the three performance obligations, which includes each of the three base editing programs combined with the research and development services, licenses, and exclusive development and commercialization rights. Revenue is recognized using an input method based on the actual costs incurred as a percentage of total estimated costs towards satisfying the performance obligation as this method provides the most faithful depiction of the entity’s performance in transferring control of the goods and services promised to Pfizer and represents the Company’s best estimate of the period of the obligation. During the three and nine months ended September 30, 2024 , the Company recognized $ 2.7 million and $ 8.4 million of revenue related to the Pfizer Agreement, respectively. The Company recognized $ 10.0 million and $ 36.4 million of revenue related to the Pfizer Agreement during the three and nine months ended September 30, 2023, respectively. As of September 30, 2024 , there was $ 66.9 million and $ 42.2 million of current and long-term deferred revenue, respectively, related to the Pfizer Agreement. Apellis Pharmaceuticals In June 2021, the Company entered into a research collaboration agreement, or the Apellis Agreement, with Apellis Pharmaceuticals, Inc., or Apellis, focused on the use of certain of the Company’s base editing technology to discover new treatments for complement system-driven diseases. Under the terms of the Apellis Agreement, the Company will conduct preclinical research on six base editing programs that target specific genes within the complement system in various organs, including the eye, liver, and brain. Apellis has an exclusive option to license any or all of the six programs, or in each case, an Opt-In Right, and will assume responsibility for subsequent development. The Company may elect to enter into a 50-50 U.S. co-development and co-commercialization agreement with Apellis with respect to one program instead of a license. The collaboration is managed on an overall basis by an alliance steering committee formed by an equal number of representatives from the Company and Apellis. As part of the collaboration, the Company received a total of $ 75.0 million in upfront and near-term milestones from Apellis, which was comprised of $ 50.0 million received upon signing and an additional $ 25.0 million payment on June 30, 2022, the one-year anniversary of the effective date of the Apellis Agreement, or the First Anniversary Payment. Following any exercise of an Opt-In Right for any of the six programs, the Company will be eligible to receive development, regulatory, and sales milestones from Apellis, as well as royalty payments on sales. The collaboration has an initial term of five years and may be extended up to two years on a per year and program-by-program basis. During the collaboration term, Apellis may, subject to certain limitations, substitute a specific complement gene and/or organ for any of the initial base editing programs. Apellis may terminate the Apellis Agreement for convenience on any or all of the programs by providing prior written notice. The Company accounts for the Apellis Agreement under ASC 606 as it includes a customer-vendor relationship as defined under ASC 606 and meets the criteria to be considered a contract. The overall transaction price as of the inception of the contract was determined to be $ 75.0 million, which is composed of the upfront payment of $ 50.0 million and the First Anniversary Payment of $ 25.0 million. The Company re-evaluates the transaction price in each reporting period. The Company concluded that each of the six base editing programs combined with the research and development service, licenses, substitution rights and governance participation were material promises that were both capable of being distinct and were distinct within the context of the Apellis Agreement and represented separate performance obligations. The Company further concluded that the Opt-In Rights and option to extend the collaboration term did not grant Apellis a material right. The Company determined that the term of the contract is five years , as this is the period during which both parties have enforceable rights. The selling price of each performance obligation was determined based on the Company’s ESSP. The Company developed the ESSP for all of the performance obligations included in the Apellis Agreement by determining the total estimated costs to fulfill each performance obligation identified with the objective of determining the price at which it would sell such an item if it were to be sold regularly on a standalone basis. The Company allocated the stand-alone selling price to the performance obligations based on the relative standalone selling price method. The Company recognizes revenue for each performance obligation as it is satisfied over the five-year term using an input method. The Company allocated the transaction price of $ 75.0 million to each of the six performance obligations, which includes each of the six base editing programs combined with the research and development service, licenses, substitution rights and governance participation, and is being recognized using an input method based on the actual costs incurred as a percentage of total estimated costs towards satisfying the performance obligation as this method provides the most faithful depiction of the entity’s performance in transferring control of the goods and services promised to Apellis and represents the Company’s best estimate of the period of the obligation. For the three and nine months ended September 30, 2024 , the Company recognized $ 8.5 million and $ 16.7 million of revenue related to the Apellis Agreement, respectively. For the three and nine months ended September 30, 2023, the Company recognized $ 5.0 million and $ 17.3 million of revenue related to the Apellis Agreement, respectively. As of September 30, 2024 , there was $ 13.9 million and $ 15.6 million of current and long-term deferred revenue, respectively, related to the Apellis Agreement. Verve In April 2019, the Company entered into the Verve Agreement to investigate gene editing strategies to modify genes associated with an increased risk of coronary diseases and in July 2022, the Company and Verve amended the Verve Agreement. Under the terms of the Verve Agreement, as amended, the Company granted Verve an exclusive license to certain base editor technology and improvements and Verve granted the Company a non-exclusive license under certain know-how and patents controlled by Verve, an interest in joint collaboration technology and a non-exclusive license under certain delivery technology. The Company retained the option, after the dosing of the final patient in a Phase 1 clinical trial of a licensed product, to participate in future development and commercialization, and share 35 % of worldwide profits and losses, for any licensed product directed against one of the Verve program targets, and share 50 % of U.S. profits and losses for any licensed product directed against the other two targets. In October 2023, the Company entered into the Lilly Agreement, pursuant to which Lilly acquired certain assets and other rights under the Verve Agreement, including the Company’s opt-in rights to co-develop and co-commercialize Verve’s base editing programs for cardiovascular disease, which consist of programs targeting PCSK9, ANGPTL3 and an undisclosed liver-mediated, cardiovascular target. In addition, Lilly acquired the right to receive any future milestone or royalty payments payable to the Company under the Verve Agreement. During the year ended December 31, 2023, the Company recognized all remaining license revenue related to the Verve Agreement and has no related deferred revenue as of September 30, 2024 .

Common Stock

Common Stock	9 Months Ended
	Sep. 30, 2024
Equity, Attributable to Parent [Abstract]
Common Stock	9. Common stock In April 2021, the Company entered into the Sales Agreement with Jefferies, pursuant to which the Company was entitled to offer and sell, from time to time at prevailing market prices, shares of the Company’s common stock having aggregate gross proceeds of up to $ 300.0 million. 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. Between April 2021 and July 2021, the Company sold 2,908,009 shares of its common stock under the Sales Agreement at an average price of $ 103.16 per share for aggregate gross proceeds of $ 300.0 million, before deducting commissions and offering expenses payable by the Company. In July 2021 and May 2023, the Company and Jefferies entered into amendments to the Sales Agreement to provide for increases in the aggregate offering amount under the Sales Agreement, such that as of May 10, 2023, the Company may offer and sell shares of common stock having an aggregate offering price of up to an additional $ 800.0 million. As of September 30, 2024, the Company has sold 10,860,992 additional shares of its common stock under the amended Sales Agreement at an average price of $ 51.93 per share for aggregate gross proceeds of $ 564.0 million, before deducting commissions and offering expenses payable by the Company.

Stock Option and Grant Plan

Stock Option and Grant Plan	9 Months Ended
	Sep. 30, 2024
Share-Based Payment Arrangement [Abstract]
Stock Option and Grant Plan	10. Stock option and grant plan 2019 equity incentive plan As of September 30, 2024, the Company had 14,850,473 shares reserved including 1,592,485 shares available for future issuance, pursuant to the Beam Therapeutics Inc. 2019 Equity Incentive Plan. Stock-based compensation expense recorded as research and development and general and administrative expenses in the condensed consolidated statements of operations and other comprehensive loss is as follows (in thousands): Three Months Ended Nine Months Ended 2024 2023 2024 2023 Research and development $ 18,371 $ 15,230 $ 54,819 $ 44,973 General and administrative 11,188 10,605 35,625 31,057 Total stock-based compensation expense $ 29,559 $ 25,835 $ 90,444 $ 76,030 Stock options The following table provides a summary of stock option activity under the Company’s equity award plans: Number Weighted Outstanding at December 31, 2023 8,276,033 $ 42.59 Granted 2,436,259 24.74 Exercised ( 215,842 ) 9.99 Forfeited ( 451,828 ) 47.76 Outstanding at September 30, 2024 10,044,622 38.73 Exercisable as of September 30, 2024 6,139,139 $ 39.59 The weighted-average grant date fair value per share of stock options granted in the nine months ended September 30, 2024 was $ 17.05 . As of September 30, 2024, there was $ 97.6 million of unrecognized compensation expense related to unvested stock options, which is expected to be recognized over a weighted-average remaining vesting period of approximately 2.5 years. Restricted stock The Company issues shares of restricted common stock, including both restricted stock units and restricted stock awards. Restricted common stock issued generally vests over a period of two to four years . The following table summarizes the Company’s restricted stock activity: Shares Weighted- Unvested as of December 31, 2023 2,927,152 $ 40.89 Issued 1,132,288 31.61 Vested ( 575,358 ) 53.27 Forfeited ( 270,716 ) 38.74 Unvested as of September 30, 2024 3,213,366 $ 35.59 At September 30, 2024, there was approximately $ 81.5 million of unrecognized stock-based compensation expense related to restricted stock that is expected to vest. These costs are expected to be recognized over a weighted-average remaining vesting period of approximately 2.1 years. 2019 employee stock purchase plan The Company issued 135,187 and 130,403 shares under the Beam Therapeutics Inc. 2019 Employee Stock Purchase Plan, or ESPP, during the nine months ended September 30, 2024 and 2023, respectively. As of September 30, 2024 , the Company had 2,928,706 shares available for issuance under the ESPP. Stock-based compensation recognized under the ESPP for the three and nine months ended September 30, 2024 was $ 0.3 million and $ 1.0 million, respectively. The Company recognized stock-based compensation under the ESPP of $ 0.3 million and $ 1.1 million for the three and nine months ended September 30, 2023 , respectively.

Net Loss per Share

Net Loss per Share	9 Months Ended
	Sep. 30, 2024
Earnings Per Share [Abstract]
Net Loss per Share	11. Net loss per share For periods in which the Company reports a net loss, potentially dilutive securities have been excluded from the computation of diluted net loss per share as their 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 because including them would have had an anti-dilutive effect: As of September 30, 2024 2023 Unvested restricted stock 3,213,366 2,177,818 Outstanding options to purchase common stock 10,044,622 8,727,251 Total 13,257,988 10,905,069 The following table summarizes the computation of basic and diluted net loss per share of the Company (in thousands, except share and per share amounts): Three Months Ended September 30, Nine Months Ended September 30, 2024 2023 2024 2023 Numerator: Net loss $ ( 96,668 ) $ ( 96,088 ) $ ( 286,388 ) $ ( 275,324 ) Denominator: Weighted average common shares outstanding, basic and diluted 82,410,095 79,024,647 82,141,383 75,902,612 Net loss per common share, basic and diluted $ ( 1.17 ) $ ( 1.22 ) $ ( 3.49 ) $ ( 3.63 )

Income Taxes

Income Taxes	9 Months Ended
	Sep. 30, 2024
Income Tax Disclosure [Abstract]
Income Taxes	12. Income taxes Through September 30, 2024 , the Company recorded a full valuation allowance on federal and state deferred tax assets since there is insufficient evidence that the deferred tax assets are more likely than not realizable. The Company recorded a current tax provision of less than $ 0.1 million in the nine months ended September 30, 2024 and did no t record any tax provision or benefit during the nine months ended September 30, 2023 .

Related Party Transactions

Related Party Transactions	9 Months Ended
	Sep. 30, 2024
Related Party Transactions [Abstract]
Related Party Transactions	13. Related party transactions Orbital The Company has significant influence over, but does not control, Orbital through its noncontrolling representation on Orbital's board of directors and the Company’s equity interest in Orbital. The Company and Orbital are also parties to a collaboration and license agreement and have multiple common board members. Founders The Company made payments of $ 0.3 million and $ 0.4 million to its founding shareholders for scientific consulting and other expenses during the nine months ended September 30, 2024 and 2023 , respectively.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2024
Accounting Policies [Abstract]
Basis of Presentation	Basis of presentation The accompanying condensed consolidated financial statements have been prepared in accordance with United States generally accepted accounting principles, or GAAP. Any reference in these notes to applicable guidance is meant to refer to the authoritative GAAP as found in the Accounting Standards Codification, or ASC, and Accounting Standards Update, or ASU, of the Financial Accounting Standards Board, or FASB.
Principles of Consolidation	Principles of consolidation The accompanying condensed consolidated financial statements include the results of operations of the Company and its wholly-owned subsidiaries. All intercompany transactions and balances have been eliminated in consolidation.
Use of Estimates	Use of estimates The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets, liabilities, revenues and expenses, and the disclosure of contingent assets and liabilities as of and during the reporting period. The Company bases its estimates and assumptions on historical experience when available and on various factors that it believes to be reasonable under the circumstances. Significant estimates and assumptions reflected in these condensed consolidated financial statements include, but are not limited to, incremental borrowing rate used in the calculation of lease liabilities, research and development expenses, stock-based compensation, contingent consideration liabilities, success payments, settlement payments and certain judgments regarding revenue recognition. Actual results could differ from these estimates.
Recently Announced Accounting Pronouncements	Recently announced accounting pronouncements In November 2023, the FASB issued ASU 2023-07 , Segment Reporting (Topic 280). The amendments in this update expand segment disclosure requirements, including new segment disclosure requirements for entities with a single reportable segment among other disclosure requirements. This update is effective for fiscal years beginning after December 15, 2023, and interim periods within fiscal years beginning after December 15, 2024. The adoption of this standard is not expected to have a material impact on the Company’s consolidated financial statements. In December 2023, the FASB issued ASU 2023-09, Income Taxes (Topic 740). The amendments in this update expand income tax disclosure requirements, including additional information pertaining to the rate reconciliation, income taxes paid, and other disclosures. This update is effective for annual periods beginning after December 15, 2024. The adoption of this standard is not expected to have a material impact on the Company’s consolidated financial statements.
Cash, Cash Equivalents, and Restricted Cash	Cash, cash equivalents, and restricted cash Cash and cash equivalents consist of standard checking accounts, money market accounts, and all highly liquid investments with a remaining maturity of three months or less at the date of purchase. Restricted cash represents collateral provided for letters of credit issued as security deposits in connection with the Company’s leases of its corporate facilities. The following table reconciles cash, cash equivalents, and restricted cash reported within the Company’s condensed consolidated balance sheets to the total of the amounts shown in the condensed consolidated statements of cash flows (in thousands): September 30, September 30, Cash and cash equivalents $ 230,203 $ 169,049 Restricted cash 6,549 8,680 Total cash, cash equivalents, and restricted cash $ 236,752 $ 177,729

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Tables)	9 Months Ended
	Sep. 30, 2024
Accounting Policies [Abstract]
Reconciliation of Cash, Cash Equivalents and Restricted Cash	The following table reconciles cash, cash equivalents, and restricted cash reported within the Company’s condensed consolidated balance sheets to the total of the amounts shown in the condensed consolidated statements of cash flows (in thousands): September 30, September 30, Cash and cash equivalents $ 230,203 $ 169,049 Restricted cash 6,549 8,680 Total cash, cash equivalents, and restricted cash $ 236,752 $ 177,729
Reconciliation of Restricted Cash, Cash Equivalents	The following table reconciles cash, cash equivalents, and restricted cash reported within the Company’s condensed consolidated balance sheets to the total of the amounts shown in the condensed consolidated statements of cash flows (in thousands): September 30, September 30, Cash and cash equivalents $ 230,203 $ 169,049 Restricted cash 6,549 8,680 Total cash, cash equivalents, and restricted cash $ 236,752 $ 177,729

Property and Equipment, Net (Ta

Property and Equipment, Net (Tables)	9 Months Ended
	Sep. 30, 2024
Property, Plant and Equipment [Abstract]
Schedule of Property and Equipment	Property and equipment consist of the following (in thousands): September 30, December 31, Leasehold improvements $ 100,921 $ 100,186 Lab equipment 69,109 61,674 Furniture and fixtures 4,836 4,836 Computer equipment 3,170 3,163 Construction in process 2,130 5,283 Total property and equipment 180,166 175,142 Less accumulated depreciation ( 66,664 ) ( 50,182 ) Property and equipment, net $ 113,502 $ 124,960
Summary of Depreciation Expense Incurred	The following table summarizes depreciation expense incurred (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2024 2023 2024 2023 Depreciation expense $ 5,475 $ 5,187 $ 16,482 $ 14,650

Fair Value of Financial Instr_2

Fair Value of Financial Instruments (Tables)	9 Months Ended
	Sep. 30, 2024
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Schedule of Fair Value of Financial Assets and Liabilities	The following tables set forth the fair value of the Company’s financial assets and liabilities by level within the fair value hierarchy at September 30, 2024 (in thousands): Carrying Fair Level 1 Level 2 Level 3 Assets Cash equivalents: Money market funds $ 178,597 $ 178,597 $ 178,597 $ — $ — Commercial paper 51,443 51,443 — 51,443 — Marketable securities: Commercial paper 217,714 217,714 — 217,714 — Corporate notes 115,568 115,568 — 115,568 — U.S. Treasury securities 227,457 227,457 — 227,457 — U.S. Government securities 125,943 125,943 — 125,943 — Corporate equity securities 8,872 8,872 8,872 — — Total assets $ 925,594 $ 925,594 $ 187,469 $ 738,125 $ — Liabilities Success payment liability – Harvard $ 4,000 $ 4,000 $ — $ — $ 4,000 Success payment liability – Broad Institute 4,400 4,400 — — 4,400 Derivative settlement liability 5,276 5,276 — — 5,276 Contingent consideration liability – Technology 484 484 — — 484 Contingent consideration liability – Product 620 620 — — 620 Total liabilities $ 14,780 $ 14,780 $ — $ — $ 14,780 The following tables set forth the fair value of the Company’s financial assets and liabilities by level within the fair value hierarchy at December 31, 2023 (in thousands): Carrying Fair Level 1 Level 2 Level 3 Assets Cash equivalents: Money market funds $ 435,689 435,689 $ 435,689 $ — $ — Marketable securities: Commercial paper 285,289 285,289 — 285,289 — Corporate notes 23,525 23,525 — 23,525 — U.S. Treasury securities 152,147 152,147 — 152,147 — U.S. Government securities 271,145 271,145 — 271,145 — Corporate equity securities 21,875 21,875 21,875 — — Total assets $ 1,189,670 $ 1,189,670 $ 457,564 $ 732,106 $ — Liabilities Success payment liability – Harvard $ 5,200 $ 5,200 $ — $ — $ 5,200 Success payment liability – Broad Institute 5,600 5,600 — — 5,600 Contingent consideration liability – Technology 1,371 1,371 — — 1,371 Contingent consideration liability – Product 1,352 1,352 — — 1,352 Total liabilities $ 13,523 $ 13,523 $ — $ — $ 13,523
Summary Of Other Income (Expense) Recorded Due To Changes In Fair Value Of Corporate Equity Securities Held	The following table summarizes other income (expense) recorded due to changes in the fair value of corporate equity securities held (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2024 2023 2024 2023 Other income (expense) $ ( 2,064 ) $ ( 11,221 ) $ ( 13,003 ) $ ( 17,870 )
Success Payment Liabilities
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Schedule of Variables Included in Calculation of Estimated Fair Value	The following variables were incorporated in the calculation of the estimated fair value of the Harvard and Broad Institute success payment liabilities: Harvard Broad Institute September 30, December 31, September 30, December 31, Fair value of common stock (per share) $ 24.50 $ 27.22 $ 24.50 $ 27.22 Expected volatility 79 % 80 % 80 % 79 % Expected term (years) 0.04 - 4.74 0.06 - 5.49 0.04 - 5.61 0.06 - 6.36
Schedule of change in Fair Value of Liabilities based on Level 3 inputs	The following table reconciles the change in the fair value of success payment liabilities based on Level 3 inputs (in thousands): Nine Months Ended September 30, 2024 Harvard Broad Institute Total Balance at December 31, 2023 $ 5,200 $ 5,600 $ 10,800 Change in fair value ( 1,200 ) ( 1,200 ) ( 2,400 ) Balance at September 30, 2024 $ 4,000 $ 4,400 $ 8,400
Derivative Liability
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Schedule of Variables Included in Calculation of Estimated Fair Value	The following assumptions were incorporated in the calculation of the fair value of the derivative liability: Milestones September 30, Discount rate 10.00 % Probability of achievement of settlement payments 3 %- 44 % Projected Year of achievement of settlement payments 2027 - 2038
Schedule of change in Fair Value of Liabilities based on Level 3 inputs	The following table reconciles the change in fair value of the derivative liability based on level 3 inputs (in thousands): Nine Months Ended September 30, 2024 Total Balance at December 31, 2023 $ — Initial recognition of derivative liability 5,276 Balance at September 30, 2024 $ 5,276
Contingent Consideration Liabilities
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Schedule of Variables Included in Calculation of Estimated Fair Value	The following variables were incorporated in the calculation of the estimated fair value of the contingent consideration liabilities: Technology Milestones Product Milestones September 30, December 31, September 30, December 31, Discount Rate 10.00 % 10.00 % 10.00 % 10.00 % Probability of Achievement 2 % 2 - 5 % 1 - 2 % 1 - 2 % Projected Year of Achievement 2026 2025 2028 - 2034 2025 - 2031
Schedule of change in Fair Value of Liabilities based on Level 3 inputs	The following table reconciles the change in fair value of the contingent consideration liabilities based on level 3 inputs (in thousands): Nine Months Ended September 30, 2024 Technology Milestones Product Milestones Total Balance at December 31, 2023 $ 1,371 $ 1,352 $ 2,723 Change in fair value ( 887 ) ( 732 ) ( 1,619 ) Balance at September 30, 2024 $ 484 $ 620 $ 1,104

Marketable Securities (Tables)

Marketable Securities (Tables)	9 Months Ended
	Sep. 30, 2024
Investments, Debt and Equity Securities [Abstract]
Summary of Marketable Securities Held	The following table summarizes the Company’s marketable securities held at September 30, 2024 (in thousands): Amortized Cost Gross Gross Fair Value Commercial paper $ 217,213 $ 501 $ — $ 217,714 Corporate notes 115,320 259 ( 11 ) 115,568 U.S. Treasury securities 226,850 607 — 227,457 U.S. Government securities 125,540 405 ( 2 ) 125,943 Corporate equity securities 8,872 — — 8,872 Total $ 693,795 $ 1,772 $ ( 13 ) $ 695,554 The following table summarizes the Company’s marketable securities held at December 31, 2023 (in thousands): Amortized Cost Gross Gross Fair Value Commercial paper $ 285,054 $ 250 $ ( 15 ) $ 285,289 Corporate notes 23,462 63 — 23,525 U.S. Treasury securities 151,805 436 ( 94 ) 152,147 U.S. Government securities 271,181 328 ( 364 ) 271,145 Corporate equity securities 21,875 — — 21,875 Total $ 753,377 $ 1,077 $ ( 473 ) $ 753,981

Accrued Expenses and Other Cu_2

Accrued Expenses and Other Current Liabilities (Tables)	9 Months Ended
	Sep. 30, 2024
Payables and Accruals [Abstract]
Schedule of Accrued Expenses and Other Current Liabilities	Accrued expenses and other current liabilities consist of the following (in thousands): September 30, December 31, Accrued contingent obligation, refer to Note 7 20,652 43,280 Employee compensation and related benefits 13,712 21,774 Research costs 8,206 9,804 Professional fees 3,551 3,468 Process development and manufacturing costs 3,073 4,697 Other 2,575 28,641 Total $ 51,769 $ 111,664

License Agreements (Tables)

License Agreements (Tables)	9 Months Ended
	Sep. 30, 2024
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Schedule of Success Payment Liability	The following table summarizes the Company’s success payment liability for Harvard (in thousands): September 30, December 31, Harvard success payment liability $ 4,000 $ 5,200 The following table summarizes the Company’s success payment liability for Broad Institute (in thousands): September 30, December 31, Broad Institute success payment liability $ 4,400 $ 5,600
Schedule of Change in Fair Value of Success Payment Liability	The following table summarizes the expense (income) resulting from the change in the fair value of the success payment liability for Harvard (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2024 2023 2024 2023 Change in fair value of Harvard success payment liability $ 100 $ ( 2,400 ) $ ( 1,200 ) $ ( 4,700 ) The following table summarizes the expense (income) resulting from the change in the fair value of the success payment liability for Broad Institute (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2024 2023 2024 2023 Change in fair value of Broad Institute success payment liability $ 100 $ ( 2,300 ) $ ( 1,200 ) $ ( 4,700 )

Stock Option and Grant Plan (Ta

Stock Option and Grant Plan (Tables)	9 Months Ended
	Sep. 30, 2024
Share-Based Payment Arrangement [Abstract]
Summary of Stock-based Compensation Expense	Stock-based compensation expense recorded as research and development and general and administrative expenses in the condensed consolidated statements of operations and other comprehensive loss is as follows (in thousands): Three Months Ended Nine Months Ended 2024 2023 2024 2023 Research and development $ 18,371 $ 15,230 $ 54,819 $ 44,973 General and administrative 11,188 10,605 35,625 31,057 Total stock-based compensation expense $ 29,559 $ 25,835 $ 90,444 $ 76,030
Summary of Stock Option Activity Under Equity Award Plans	The following table provides a summary of stock option activity under the Company’s equity award plans: Number Weighted Outstanding at December 31, 2023 8,276,033 $ 42.59 Granted 2,436,259 24.74 Exercised ( 215,842 ) 9.99 Forfeited ( 451,828 ) 47.76 Outstanding at September 30, 2024 10,044,622 38.73 Exercisable as of September 30, 2024 6,139,139 $ 39.59
Summary of Restricted Stock Activity	The following table summarizes the Company’s restricted stock activity: Shares Weighted- Unvested as of December 31, 2023 2,927,152 $ 40.89 Issued 1,132,288 31.61 Vested ( 575,358 ) 53.27 Forfeited ( 270,716 ) 38.74 Unvested as of September 30, 2024 3,213,366 $ 35.59

Net Loss per Share (Tables)

Net Loss per Share (Tables)	9 Months Ended
	Sep. 30, 2024
Earnings Per Share [Abstract]
Schedule of Potential Common Shares Excluded from Computation of Diluted Net Loss per Share	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 because including them would have had an anti-dilutive effect: As of September 30, 2024 2023 Unvested restricted stock 3,213,366 2,177,818 Outstanding options to purchase common stock 10,044,622 8,727,251 Total 13,257,988 10,905,069
Summary of Computation of Basic and Diluted Net Loss per Share	The following table summarizes the computation of basic and diluted net loss per share of the Company (in thousands, except share and per share amounts): Three Months Ended September 30, Nine Months Ended September 30, 2024 2023 2024 2023 Numerator: Net loss $ ( 96,668 ) $ ( 96,088 ) $ ( 286,388 ) $ ( 275,324 ) Denominator: Weighted average common shares outstanding, basic and diluted 82,410,095 79,024,647 82,141,383 75,902,612 Net loss per common share, basic and diluted $ ( 1.17 ) $ ( 1.22 ) $ ( 3.49 ) $ ( 3.63 )

Nature of the Business and Ba_2

Nature of the Business and Basis of Presentation - Additional Information (Details) - USD ($)	1 Months Ended	4 Months Ended	39 Months Ended
	Apr. 30, 2021	Jul. 31, 2021	Sep. 30, 2024	Dec. 31, 2023	May 10, 2023
Nature Of Business And Basis Of Presentation [Line Items]
Accumulated deficit			$ 1,476,277,000	$ 1,189,889,000
Cash, cash equivalents, and marketable securities			925,800,000
Jeffries LLC Amended Sales Agreement
Nature Of Business And Basis Of Presentation [Line Items]
Gross proceeds from issuance of common stock			$ 564,000,000
Jeffries LLC Amended Sales Agreement | Common Stock
Nature Of Business And Basis Of Presentation [Line Items]
Stock sold during period shares, new issues			10,860,992
Price per share of shares issued			$ 51.93
Jeffries LLC Amended Sales Agreement | Maximum | ATM Offering
Nature Of Business And Basis Of Presentation [Line Items]
Aggregate gross proceeds of shares authorized under ATM sales agreement					$ 800,000,000
Jeffries LLC Sales Agreement
Nature Of Business And Basis Of Presentation [Line Items]
Stock sold during period shares, new issues		2,908,009
Gross proceeds from issuance of common stock		$ 300,000,000
Jeffries LLC Sales Agreement | Common Stock
Nature Of Business And Basis Of Presentation [Line Items]
Price per share of shares issued		$ 103.16
Jeffries LLC Sales Agreement | Maximum | ATM Offering
Nature Of Business And Basis Of Presentation [Line Items]
Commission rate	3%
Aggregate gross proceeds of shares authorized under ATM sales agreement	$ 300,000,000

Summary of Significant Accoun_4

Summary of Significant Accounting Policies - Reconciliation of Cash, Cash Equivalents, and Restricted Cash (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023	Sep. 30, 2023	Dec. 31, 2022
Accounting Policies [Abstract]
Cash and cash equivalents	$ 230,203	$ 435,895	$ 169,049
Restricted cash	6,549	8,719	8,680
Total cash, cash equivalents, and restricted cash	$ 236,752	$ 444,614	$ 177,729	$ 245,521

Property and Equipment, Net - S

Property and Equipment, Net - Schedule of Property and Equipment (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Property Plant And Equipment [Line Items]
Total property and equipment	$ 180,166	$ 175,142
Less accumulated depreciation	(66,664)	(50,182)
Property and equipment, net	113,502	124,960
Leasehold Improvements
Property Plant And Equipment [Line Items]
Total property and equipment	100,921	100,186
Lab Equipment
Property Plant And Equipment [Line Items]
Total property and equipment	69,109	61,674
Furniture and Fixtures
Property Plant And Equipment [Line Items]
Total property and equipment	4,836	4,836
Computer Equipment
Property Plant And Equipment [Line Items]
Total property and equipment	3,170	3,163
Construction in Process
Property Plant And Equipment [Line Items]
Total property and equipment	$ 2,130	$ 5,283

Property and Equipment, Net -_2

Property and Equipment, Net - Summary of Depreciation Expense Incurred (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Property, Plant and Equipment [Abstract]
Depreciation expense	$ 5,475	$ 5,187	$ 16,482	$ 14,650

Fair Value of Financial Instr_3

Fair Value of Financial Instruments - Schedule of Fair Value of Financial Assets and Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Commercial Paper
Assets
Marketable securities	$ 217,714	$ 285,289
Harvard
Liabilities
Success payment liability	4,000	5,200
Broad Institute
Liabilities
Success payment liability	4,400	5,600
Recurring | Carrying Amount
Assets
Total assets	925,594	1,189,670
Liabilities
Derivative settlement liability	5,276
Total liabilities	14,780	13,523
Recurring | Carrying Amount | Money Market Funds
Assets
Cash equivalents	178,597	435,689
Recurring | Carrying Amount | Commercial Paper
Assets
Cash equivalents	51,443
Marketable securities	217,714	285,289
Recurring | Carrying Amount | Corporate Notes
Assets
Marketable securities	115,568	23,525
Recurring | Carrying Amount | U.S. Treasury Securities
Assets
Marketable securities	227,457	152,147
Recurring | Carrying Amount | U.S Government Securities
Assets
Marketable securities	125,943	271,145
Recurring | Carrying Amount | Corporate Equity Securities
Assets
Equity securities included in marketable securities	8,872	21,875
Recurring | Carrying Amount | Consideration of Technology Liabilities
Liabilities
Contingent consideration liability	484	1,371
Recurring | Carrying Amount | Contingent Consideration of Product Liabilities
Liabilities
Contingent consideration liability	620	1,352
Recurring | Fair Value
Assets
Total assets	925,594	1,189,670
Liabilities
Derivative settlement liability	5,276
Total liabilities	14,780	13,523
Recurring | Fair Value | Money Market Funds
Assets
Cash equivalents	178,597	435,689
Recurring | Fair Value | Commercial Paper
Assets
Cash equivalents	51,443
Marketable securities	217,714	285,289
Recurring | Fair Value | Corporate Notes
Assets
Marketable securities	115,568	23,525
Recurring | Fair Value | U.S. Treasury Securities
Assets
Marketable securities	227,457	152,147
Recurring | Fair Value | U.S Government Securities
Assets
Marketable securities	125,943	271,145
Recurring | Fair Value | Corporate Equity Securities
Assets
Equity securities included in marketable securities	8,872	21,875
Recurring | Fair Value | Consideration of Technology Liabilities
Liabilities
Contingent consideration liability	484	1,371
Recurring | Fair Value | Contingent Consideration of Product Liabilities
Liabilities
Contingent consideration liability	620	1,352
Recurring | Fair Value | Level 1
Assets
Total assets	187,469	457,564
Recurring | Fair Value | Level 1 | Money Market Funds
Assets
Cash equivalents	178,597	435,689
Recurring | Fair Value | Level 1 | Corporate Equity Securities
Assets
Equity securities included in marketable securities	8,872	21,875
Recurring | Fair Value | Level 2
Assets
Total assets	738,125	732,106
Recurring | Fair Value | Level 2 | Commercial Paper
Assets
Cash equivalents	51,443
Marketable securities	217,714	285,289
Recurring | Fair Value | Level 2 | Corporate Notes
Assets
Marketable securities	115,568	23,525
Recurring | Fair Value | Level 2 | U.S. Treasury Securities
Assets
Marketable securities	227,457	152,147
Recurring | Fair Value | Level 2 | U.S Government Securities
Assets
Marketable securities	125,943	271,145
Recurring | Fair Value | Level 3
Liabilities
Derivative settlement liability	5,276
Total liabilities	14,780	13,523
Recurring | Fair Value | Level 3 | Consideration of Technology Liabilities
Liabilities
Contingent consideration liability	484	1,371
Recurring | Fair Value | Level 3 | Contingent Consideration of Product Liabilities
Liabilities
Contingent consideration liability	620	1,352
Recurring | Harvard | Carrying Amount
Liabilities
Success payment liability	4,000	5,200
Recurring | Harvard | Fair Value
Liabilities
Success payment liability	4,000	5,200
Recurring | Harvard | Fair Value | Level 3
Liabilities
Success payment liability	4,000	5,200
Recurring | Broad Institute | Carrying Amount
Liabilities
Success payment liability	4,400	5,600
Recurring | Broad Institute | Fair Value
Liabilities
Success payment liability	4,400	5,600
Recurring | Broad Institute | Fair Value | Level 3
Liabilities
Success payment liability	$ 4,400	$ 5,600

Fair Value of Financial Instr_4

Fair Value of Financial Instruments - Additional Information (Details) - USD ($) $ in Millions		3 Months Ended
	Jul. 19, 2024	Sep. 30, 2024	Feb. 23, 2021
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Settlement agreement upfront payment	$ 15
Percentage of royalty payment	1%
Settlement agreement upfront payment paid		$ 15
Verve Therapeutics, Inc.
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Equity securities		$ 2.7
Verve Therapeutics, Inc. | Common Stock
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Equity shares held		546,970
Prime Medicine Inc
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Equity securities		$ 6.2
Prime Medicine Inc | Common Stock
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Equity shares held		1,608,337
Technology Milestones | Guide Therapeutics, Inc. | Maximum | Merger Agreement | Former Stockholders and Optionholders
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Potential milestone payable in form of common stock			$ 100
Product Milestones | Guide Therapeutics, Inc. | Maximum | Merger Agreement | Former Stockholders and Optionholders
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Potential milestone payable in form of common stock			$ 220
Development and Regulatory Milestones | Maximum
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Potential milestone payments due under settlement agreement	$ 15
Sales Milestone | Maximum
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Potential milestone payments due under settlement agreement	$ 35

Fair Value of Financial Instr_5

Fair Value of Financial Instruments - Summarizes Other Income ( Expense) Recorded Due To Changes In Fair Value Of Corporate Equity Securities Held (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Fair Value Disclosures [Abstract]
Other income (expense)	$ (2,064)	$ (11,221)	$ (13,003)	$ (17,870)

Fair Value of Financial Instr_6

Fair Value of Financial Instruments - Schedule of Calculation of Estimated Fair Value of Success Payment Liabilities (Details) - Success Payment Liabilities	9 Months Ended	12 Months Ended
	Sep. 30, 2024	Dec. 31, 2023
Fair Value of Common Stock | Harvard
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Success payment liability measurement input	24.5	27.22
Fair Value of Common Stock | Broad Institute
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Success payment liability measurement input	24.5	27.22
Expected Volatility | Harvard
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Success payment liability measurement input	0.79	0.80
Expected Volatility | Broad Institute
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Success payment liability measurement input	0.80	0.79
Expected Term (years) | Minimum | Harvard
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Success payment liability, term	14 days	21 days
Expected Term (years) | Minimum | Broad Institute
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Success payment liability, term	14 days	21 days
Expected Term (years) | Maximum | Harvard
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Success payment liability, term	4 years 8 months 26 days	5 years 5 months 26 days
Expected Term (years) | Maximum | Broad Institute
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Success payment liability, term	5 years 7 months 9 days	6 years 4 months 9 days

Fair Value of Financial Instr_7

Fair Value of Financial Instruments - Schedule of Change in Fair Value of Success Payment Liabilities Based on Level 3 Inputs (Details) - Success Payment Liabilities $ in Thousands	9 Months Ended
	Sep. 30, 2024 USD ($)
Fair Value Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Beginning Balance	$ 10,800
Change in fair value	(2,400)
Ending Balance	8,400
Harvard
Fair Value Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Beginning Balance	5,200
Change in fair value	(1,200)
Ending Balance	4,000
Broad Institute
Fair Value Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Beginning Balance	5,600
Change in fair value	(1,200)
Ending Balance	$ 4,400

Fair Value of Financial Instr_8

Fair Value of Financial Instruments - Schedule of Calculation of Fair Value of Derivative Liability (Details) - Derivative Liability	9 Months Ended
	Sep. 30, 2024
Minimum
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Settlement payments expected achievement year	2027
Maximum
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Settlement payments expected achievement year	2038
Discount Rate
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Derivative liability measurement input	0.10
Probability of Achievement | Minimum
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Derivative liability measurement input	0.03
Probability of Achievement | Maximum
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Derivative liability measurement input	0.44

Fair Value of Financial Instr_9

Fair Value of Financial Instruments - Schedule of Change in Fair Value of the Derivative Liability (Details) - Derivative Liability $ in Thousands	9 Months Ended
	Sep. 30, 2024 USD ($)
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Initial recognition of derivative liability	$ 5,276
Ending Balance	$ 5,276

Fair Value of Financial Inst_10

Fair Value of Financial Instruments - Schedule of Calculation of Estimated Fair Value of Contingent Consideration Liabilities (Details) - Contingent Consideration Liabilities	9 Months Ended	12 Months Ended
	Sep. 30, 2024	Dec. 31, 2023
Technology Milestones
Derivative Liability [Abstract]
Milestone liabilities projected year of achievement	2026	2025
Product Milestones | Minimum
Derivative Liability [Abstract]
Milestone liabilities projected year of achievement	2028	2025
Product Milestones | Maximum
Derivative Liability [Abstract]
Milestone liabilities projected year of achievement	2034	2031
Discount Rate | Technology Milestones
Derivative Liability [Abstract]
Contingent consideration liability measurement input	0.10	0.10
Discount Rate | Product Milestones
Derivative Liability [Abstract]
Contingent consideration liability measurement input	0.10	0.10
Probability of Achievement | Technology Milestones
Derivative Liability [Abstract]
Contingent consideration liability measurement input	0.02
Probability of Achievement | Technology Milestones | Minimum
Derivative Liability [Abstract]
Contingent consideration liability measurement input		0.02
Probability of Achievement | Technology Milestones | Maximum
Derivative Liability [Abstract]
Contingent consideration liability measurement input		0.05
Probability of Achievement | Product Milestones | Minimum
Derivative Liability [Abstract]
Contingent consideration liability measurement input	0.01	0.01
Probability of Achievement | Product Milestones | Maximum
Derivative Liability [Abstract]
Contingent consideration liability measurement input	0.02	0.02

Fair Value of Financial Inst_11

Fair Value of Financial Instruments - Schedule of Change in Fair Value of Contingent Consideration Liabilities Based on Level 3 Inputs (Details) - Contingent Consideration Liabilities $ in Thousands	9 Months Ended
	Sep. 30, 2024 USD ($)
Fair Value Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Beginning Balance	$ 2,723
Change in fair value	(1,619)
Ending Balance	1,104
Technology Milestones
Fair Value Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Beginning Balance	1,371
Change in fair value	(887)
Ending Balance	484
Product Milestones
Fair Value Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Beginning Balance	1,352
Change in fair value	(732)
Ending Balance	$ 620

Marketable Securities - Summary

Marketable Securities - Summary of Marketable Securities (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Debt Securities, Available-for-Sale [Line Items]
Marketable securities held, Amortized Cost	$ 693,795	$ 753,377
Marketable securities held, Gross Unrealized Gains	1,772	1,077
Marketable securities held, Gross Unrealized Losses	(13)	(473)
Marketable securities held, Fair Value	695,554	753,981
Commercial Paper
Debt Securities, Available-for-Sale [Line Items]
Available-for-sale, Amortized Cost	217,213	285,054
Available-for-sale, Gross Unrealized Gains	501	250
Available-for-sale, Gross Unrealized Losses		(15)
Available-for-sale, Fair Value	217,714	285,289
Corporate Notes
Debt Securities, Available-for-Sale [Line Items]
Available-for-sale, Amortized Cost	115,320	23,462
Available-for-sale, Gross Unrealized Gains	259	63
Available-for-sale, Gross Unrealized Losses	(11)
Available-for-sale, Fair Value	115,568	23,525
U.S. Treasury Securities
Debt Securities, Available-for-Sale [Line Items]
Available-for-sale, Amortized Cost	226,850	151,805
Available-for-sale, Gross Unrealized Gains	607	436
Available-for-sale, Gross Unrealized Losses		(94)
Available-for-sale, Fair Value	227,457	152,147
Corporate Equity Securities
Debt Securities, Available-for-Sale [Line Items]
Equity securities, Amortized Cost	8,872	21,875
Equity securities, Fair Value	8,872	21,875
U.S Government Securities
Debt Securities, Available-for-Sale [Line Items]
Available-for-sale, Amortized Cost	125,540	271,181
Available-for-sale, Gross Unrealized Gains	405	328
Available-for-sale, Gross Unrealized Losses	(2)	(364)
Available-for-sale, Fair Value	$ 125,943	$ 271,145

Marketable Securities - Additio

Marketable Securities - Additional Information (Details) - USD ($)	9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023
Investments, Debt and Equity Securities [Abstract]
Realized gains or losses recognized on sale or maturity of marketable securities	$ 0	$ 0

Accrued Expenses and Other Cu_3

Accrued Expenses and Other Current Liabilities - Schedule of Accrued Expenses and Other Current Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Payables and Accruals [Abstract]
Accrued contingent obligation, refer to Note 7	$ 20,652	$ 43,280
Employee compensation and related benefits	13,712	21,774
Research costs	8,206	9,804
Professional fees	3,551	3,468
Process development and manufacturing costs	3,073	4,697
Other	2,575	28,641
Total	$ 51,769	$ 111,664

License agreements - Additional

License agreements - Additional Information (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Accrued liabilities for license fees	$ 20,652	$ 43,280
Lilly Agreement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Accrued liabilities for license fees	$ 20,700

License Agreements - Harvard Li

License Agreements - Harvard License Agreement - Additional Information (Details)		1 Months Ended	9 Months Ended
	Jun. 10, 2021 shares	Oct. 31, 2023	Sep. 30, 2024 USD ($)	May 31, 2021 USD ($)
Lilly Agreement
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Agreement description		In October 2023, the Company entered into a Transfer and Delegation Agreement, or the Lilly Agreement, with Eli Lilly and Company, or Lilly, pursuant to which Lilly acquired certain assets and other rights under the Company’s amended collaboration and license agreement with Verve, or the Verve Agreement, including the Company’s opt-in rights to co-develop and co-commercialize Verve’s base editing programs for cardiovascular disease (see discussion below related to the Verve Agreement). The Company granted Lilly an exclusive sublicense to the Verve technology originally licensed to the Company under the Verve Agreement. Lilly also acquired from the Company the right to receive any future milestone or royalty payments payable by Verve under the Verve Agreement and the rights and obligations to designate representatives and participate on the joint steering committee with Verve. The Company received a $200.0 million nonrefundable upfront payment and is eligible to receive up to $350.0 million in potential future development-stage payments upon the completion of certain clinical, regulatory and alliance events.
Harvard
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Success payment amount due			$ 0	$ 15,000,000
Harvard | Common Stock
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Issuance of common stock for success payment liability, Shares | shares	174,825
Harvard | Minimum
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Success payments			$ 5,000,000
Harvard | Minimum | Series A Preferred Stock
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Success Payments, valuation multiples			5
Harvard | Maximum
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Additional success payment amount due				$ 90,000,000
Success payments			$ 105,000,000
Harvard | Maximum | Series A Preferred Stock
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Success Payments, valuation multiples			40
Success Payments | Harvard
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Agreement description			The Company is required to make success payments to Harvard during a period of time, or the Harvard Success Payment Period, which has been determined to be the later of (1) the ninth anniversary of the Harvard License Agreement or (2) the earlier of (a) the twelfth anniversary of the Harvard License Agreement and (b) the third anniversary of the first date on which a licensed product receives regulatory approval in the United States. During the Harvard Success Payment Period, the Company will perform a calculation of any amounts owed to Harvard on each rolling 90-day period, commencing one year after the Company’s IPO.

License Agreements - Harvard _2

License Agreements - Harvard License Agreement - Success Payment Liability (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Harvard
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Success payment liability	$ 4,000	$ 5,200

License Agreements - Harvard _3

License Agreements - Harvard License Agreement - Change in Fair Value of Success Payment Liability (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Change in fair value of derivative liabilities	$ 200	$ (4,700)	$ (2,400)	$ (9,400)
Harvard
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Change in fair value of derivative liabilities	$ 100	$ (2,400)	$ (1,200)	$ (4,700)

License Agreements - Broad Lice

License Agreements - Broad License Agreement - Additional Information (Details) - Broad Institute		9 Months Ended
	Jun. 10, 2021 shares	Sep. 30, 2024 USD ($)	May 31, 2021 USD ($)
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Success payment amount due		$ 0	$ 15,000,000
Common Stock
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Issuance of common stock for success payment liability, Shares | shares	174,825
Success Payments
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Agreement description		The Company is required to make success payments to Broad Institute during a period of time, or the Broad Success Payment Period, which has been determined to be the earliest of (1) the twelfth anniversary of the Broad License Agreement or (2) the third anniversary of the first date on which a licensed product receives regulatory approval in the United States. During the Broad Success Payment Period, the Company will perform a calculation of any amounts owed to Broad Institute on each rolling 90-day period, commencing one year after the Company’s IPO.
Minimum
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Success payments		$ 5,000,000
Minimum | Series A Preferred Stock
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Success Payments, valuation multiples		5
Maximum
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Success payments		$ 105,000,000
Additional success payment amount due			$ 90,000,000
Maximum | Series A Preferred Stock
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Success Payments, valuation multiples		40

License Agreements - Broad Li_2

License Agreements - Broad License Agreement - Success Payment Liability (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Broad Institute
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Success payment liability	$ 4,400	$ 5,600

License Agreements - Broad Li_3

License Agreements - Broad License Agreement - Change in Fair Value of Success Payment Liability (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Change in fair value of derivative liabilities	$ 200	$ (4,700)	$ (2,400)	$ (9,400)
Broad Institute
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Change in fair value of derivative liabilities	$ 100	$ (2,300)	$ (1,200)	$ (4,700)

Collaboration and License Agr_2

Collaboration and License Agreements - Additional Information (Details) - USD ($) $ in Thousands	1 Months Ended						3 Months Ended		9 Months Ended		12 Months Ended
	Nov. 30, 2023	Oct. 31, 2023	Sep. 30, 2022	Dec. 31, 2021	Jun. 30, 2021	Apr. 30, 2019	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Current portion of deferred revenue							$ 89,327		$ 89,327		$ 68,706
Long-term portion of deferred revenue							57,816		57,816		109,888
Lilly Agreement
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Sale and issuance of common stock		2,004,811
Aggregated purchase price		$ 50,000
Stock purchase agreement amount received		$ 50,000
Agreement description		In October 2023, the Company entered into a Transfer and Delegation Agreement, or the Lilly Agreement, with Eli Lilly and Company, or Lilly, pursuant to which Lilly acquired certain assets and other rights under the Company’s amended collaboration and license agreement with Verve, or the Verve Agreement, including the Company’s opt-in rights to co-develop and co-commercialize Verve’s base editing programs for cardiovascular disease (see discussion below related to the Verve Agreement). The Company granted Lilly an exclusive sublicense to the Verve technology originally licensed to the Company under the Verve Agreement. Lilly also acquired from the Company the right to receive any future milestone or royalty payments payable by Verve under the Verve Agreement and the rights and obligations to designate representatives and participate on the joint steering committee with Verve. The Company received a $200.0 million nonrefundable upfront payment and is eligible to receive up to $350.0 million in potential future development-stage payments upon the completion of certain clinical, regulatory and alliance events.
Collaboration agreement aggregate transaction price		$ 216,400
Collaboration agreement upfront payment received	$ 200,000
Collaboration agreement performance obligation revenue recognized									0		$ 216,400
Collaboration agreement term of contract		6 years
Deferred revenue liability							0		0
Lilly Agreement | Common Stock
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Fair value of common stock sold		$ 16,400
Collaboration license agreement fair value of shares issued		33,600
Lilly Agreement | Maximum
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Additional proceeds from potential future development-stage payments		$ 350,000
Pfizer
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Agreement description				In December 2021, the Company entered into a research collaboration agreement, or the Pfizer Agreement, with Pfizer Inc., or Pfizer, focused on the use of certain of the Company’s base editing technology to develop in vivo therapies for rare genetic diseases of the liver, muscle, and central nervous system. Under the terms of the Pfizer Agreement, the Company will conduct all research activities through development candidate selection for three base editing programs that target specific genes corresponding to specific diseases that are the subject of such programs. Pfizer will have exclusive rights to license each of the three programs at no additional cost, each an Opt-In Right, and will assume responsibility for subsequent development and commercialization. At the end of the Phase 1/2 clinical trials, the Company may elect to enter into a global co-development and co-commercialization agreement with Pfizer with respect to one program licensed under the collaboration for an option exercise fee equal to a percentage of the applicable development costs incurred by Pfizer, or the Participation Election. In the event the Company elects to exercise its Participation Election, upon the payment of its option exercise fee, Pfizer and the Company would share net profits as well as development and commercialization costs in a 65%/35% (Pfizer/Company) split for such program. The research collaboration is managed on an overall basis by a Joint Research Committee, or JRC, formed by an equal number of representatives from the Company and Pfizer.
Collaboration arrangement, initial term				4 years
Collaboration arrangement extension term description				extended for an additional year on a program-by-program basis.
Potential total consideration				$ 1,350,000
Collaboration agreement aggregate transaction price				300,000
Nonrefundable upfront payment receivable				$ 300,000
Collaboration agreement performance obligation revenue recognized							2,700	$ 10,000	8,400	$ 36,400
Earn-out payment period				10 years
Current portion of deferred revenue							66,900		66,900
Long-term portion of deferred revenue							42,200		42,200
Pfizer | Assigned to Company | Upon Participation Election
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Net profits as well as development and commercialization costs percentage				35%
Pfizer | Assigned to Pfizer | Upon Participation Election
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Net profits as well as development and commercialization costs percentage				65%
Pfizer | Maximum | Per Program
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Development regulatory and commercial milestones receivable				$ 350,000
Apellis Pharmaceuticals, Inc
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Agreement description					In June 2021, the Company entered into a research collaboration agreement, or the Apellis Agreement, with Apellis Pharmaceuticals, Inc., or Apellis, focused on the use of certain of the Company’s base editing technology to discover new treatments for complement system-driven diseases. Under the terms of the Apellis Agreement, the Company will conduct preclinical research on six base editing programs that target specific genes within the complement system in various organs, including the eye, liver, and brain. Apellis has an exclusive option to license any or all of the six programs, or in each case, an Opt-In Right, and will assume responsibility for subsequent development. The Company may elect to enter into a 50-50 U.S. co-development and co-commercialization agreement with Apellis with respect to one program instead of a license. The collaboration is managed on an overall basis by an alliance steering committee formed by an equal number of representatives from the Company and Apellis.
Collaboration arrangement, initial term					5 years
Collaboration agreement aggregate transaction price					$ 75,000
Collaboration agreement performance obligation revenue recognized							8,500	5,000	16,700	17,300
Upfront fee receivable upon signing contract					50,000
Collaboration agreement first anniversary amount receivable					$ 25,000
Current portion of deferred revenue							13,900		13,900
Long-term portion of deferred revenue							15,600		15,600
Apellis Pharmaceuticals, Inc | Maximum
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Collaboration arrangement extension term					2 years
Verve
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Agreement description						In April 2019, the Company entered into the Verve Agreement to investigate gene editing strategies to modify genes associated with an increased risk of coronary diseases and in July 2022, the Company and Verve amended the Verve Agreement. Under the terms of the Verve Agreement, as amended, the Company granted Verve an exclusive license to certain base editor technology and improvements and Verve granted the Company a non-exclusive license under certain know-how and patents controlled by Verve, an interest in joint collaboration technology and a non-exclusive license under certain delivery technology.
Deferred revenue liability							0		0
Verve | One Target
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Profit on future development and commercialization percentage						35%
Verve | US | Two Target
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Profit on future development and commercialization percentage						50%
Orbital
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Common stock shares received at closing			75,000,000
Agreement description			. Under the terms of the Orbital Agreement, the Company will collaborate with Orbital to advance nonviral delivery and ribonucleic acid, or RNA, technology by providing Orbital with certain proprietary materials, a non-exclusive research license to certain RNA technology and nonviral delivery technology controlled by the Company, and by performing research and development support services as outlined in a research plan. The Company also granted Orbital an exploitation license to certain RNA technology and nonviral delivery technology controlled by the Company. The exploitation license is exclusive in the fields of vaccines and certain protein therapeutics and nonexclusive in all other fields other than gene editing and conditioning. The collaboration is managed on an overall basis by a Joint Steering Committee, or JSC, comprised of an equal number of representatives from the Company and Orbital.
Collaboration agreement performance obligation revenue period for recognition			3 years
Collaboration agreement aggregate transaction price			$ 25,500
Collaboration agreement performance obligation revenue recognized							2,100	$ 2,100	6,400	$ 6,400
Current portion of deferred revenue							$ 8,500		$ 8,500
Orbital | Exploitation Licenses
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Collaboration arrangement, initial term			3 years
Collaboration arrangement extension term description			which may be extended for up to two successive one-year periods
Orbital | Research Plan
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Collaboration arrangement, initial term			3 years

Common Stock - Additional Infor

Common Stock - Additional Information (Details) - USD ($)	1 Months Ended	4 Months Ended	39 Months Ended
	Apr. 30, 2021	Jul. 31, 2021	Sep. 30, 2024	May 10, 2023
Jeffries LLC Sales Agreement
Class Of Stock [Line Items]
Shares issued and sold		2,908,009
Gross proceeds from issuance of common stock		$ 300,000,000
Jeffries LLC Sales Agreement | Common Stock
Class Of Stock [Line Items]
Price per share of shares issued		$ 103.16
Jeffries LLC Amended Sales Agreement
Class Of Stock [Line Items]
Gross proceeds from issuance of common stock			$ 564,000,000
Jeffries LLC Amended Sales Agreement | Common Stock
Class Of Stock [Line Items]
Shares issued and sold			10,860,992
Price per share of shares issued			$ 51.93
At-The-Market | Jeffries LLC Sales Agreement | Maximum
Class Of Stock [Line Items]
Aggregate gross proceeds of shares authorized under ATM sales agreement	$ 300,000,000
Commission rate	3%
At-The-Market | Jeffries LLC Amended Sales Agreement | Maximum
Class Of Stock [Line Items]
Aggregate gross proceeds of shares authorized under ATM sales agreement				$ 800,000,000

Stock Option and Grant Plan - A

Stock Option and Grant Plan - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation expense	$ 29,559	$ 25,835	$ 90,444	$ 76,030
Weighted-average grant date fair value per share of stock options granted			$ 17.05
Employee Stock Option
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unrecognized compensation expense related to unvested stock options	97,600		$ 97,600
Unrecognized compensation cost, cost to recognize over a weighted-average remaining vesting period			2 years 6 months
Restricted Stock
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unrecognized compensation cost, cost to recognize over a weighted-average remaining vesting period			2 years 1 month 6 days
Unrecognized stock-based compensation expense, expected to vest	$ 81,500		$ 81,500
Restricted Stock | Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vesting period			4 years
Restricted Stock | Minimum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vesting period			2 years
2019 Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares reserved for future issuance	14,850,473		14,850,473
Number of shares available for future issuance	1,592,485		1,592,485
2019 Employee Stock Purchase Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares available for future issuance	2,928,706		2,928,706
Number of shares issued			135,187	130,403
Stock-based compensation expense	$ 300	$ 300	$ 1,000	$ 1,100

Stock Option and Grant Plan - S

Stock Option and Grant Plan - Summary of Stock-based Compensation Expense (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock-based compensation expense	$ 29,559	$ 25,835	$ 90,444	$ 76,030
Research and Development
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock-based compensation expense	18,371	15,230	54,819	44,973
General and Administrative
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock-based compensation expense	$ 11,188	$ 10,605	$ 35,625	$ 31,057

Stock Option and Grant Plan -_2

Stock Option and Grant Plan - Summary of Stock Option Activity Under Equity Award Plans (Details) - $ / shares	9 Months Ended
	Sep. 30, 2024
Number of options
Outstanding at December 31, 2023	8,276,033
Granted	2,436,259
Exercised	(215,842)
Forfeited	(451,828)
Outstanding at September 30, 2024	10,044,622
Exercisable as of September 30, 2024	6,139,139
Weighted average exercise price
Outstanding at December 31, 2023	$ 42.59
Granted	24.74
Exercised	9.99
Forfeited	47.76
Outstanding at September 30, 2024	38.73
Exercisable as of September 30, 2024	$ 39.59

Stock Option and Grant Plan -_3

Stock Option and Grant Plan - Summary of Restricted Stock Activity (Details) - Restricted Stock	9 Months Ended
	Sep. 30, 2024 $ / shares shares
Shares
Unvested as of December 31, 2023 | shares	2,927,152
Issued | shares	1,132,288
Vested | shares	(575,358)
Forfeited | shares	(270,716)
Unvested as of September 30, 2024 | shares	3,213,366
Weighted-average grant date fair value
Unvested as of December 31, 2023 | $ / shares	$ 40.89
Issued | $ / shares	31.61
Vested | $ / shares	53.27
Cancelled | $ / shares	38.74
Unvested as of September 30, 2024 | $ / shares	$ 35.59

Net Loss per Share - Schedule o

Net Loss per Share - Schedule of Potential Common Shares Excluded from Computation of Diluted Net Loss per Share (Details) - shares	9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive shares excluded from computation of diluted net loss per share	13,257,988	10,905,069
Unvested Restricted Stock
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive shares excluded from computation of diluted net loss per share	3,213,366	2,177,818
Outstanding Options to Purchase Common Stock
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive shares excluded from computation of diluted net loss per share	10,044,622	8,727,251

Net Loss per Share - Summary of

Net Loss per Share - Summary of Computation of Basic and Diluted Net Loss per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Numerator:
Net loss	$ (96,668)	$ (96,088)	$ (286,388)	$ (275,324)
Denominator:
Weighted - average common shares outstanding, basic	82,410,095	79,024,647	82,141,383	75,902,612
Weighted - average common shares outstanding, diluted	82,410,095	79,024,647	82,141,383	75,902,612
Net loss per common share, basic	$ (1.17)	$ (1.22)	$ (3.49)	$ (3.63)
Net loss per common share, diluted	$ (1.17)	$ (1.22)	$ (3.49)	$ (3.63)

Income Taxes - Additional Infor

Income Taxes - Additional Information (Details) - USD ($)	9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023
Operating Loss Carryforwards [Line Items]
Provision (Benefit) for income tax	$ 39,000	$ 0
Maximum
Operating Loss Carryforwards [Line Items]
Provision (Benefit) for income tax	$ 100,000

Related Party Transactions - Ad

Related Party Transactions - Additional Information (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023
Founder Shareholders | Scientific Consulting and Other Expenses
Related Party Transaction [Line Items]
Payments received from (made to) related parties	$ 0.3	$ 0.4