Beam Therapeutics (BEAM) 10-K 27 Feb 24 2023 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Feb. 20, 2024	Jun. 30, 2023
Cover [Abstract]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2023
Document Fiscal Year Focus	2023
Document Fiscal Period Focus	FY
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 Common Stock, Shares Outstanding		81,657,714
Entity Public Float			$ 2,110
Entity Emerging Growth Company	false
ICFR Auditor Attestation Flag	true
Document Financial Statement Error Correction [Flag]	false
Entity Small Business	false
Entity Well-known Seasoned Issuer	Yes
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
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 Annual Report	true
Document Transition Report	false
Documents Incorporated by Reference	Registrant incorporates by reference into Part III (Items 10, 11, 12, 13 and 14) of this Annual Report on Form 10-K portions of the Registrant’s definitive Proxy Statement for the 2024 Annual Meeting of Stockholders to be filed with the Securities and Exchange Commission pursuant to Regulation 14A.
Auditor Name	Deloitte & Touche LLP
Auditor Firm ID	34
Auditor Location	Boston, Massachusetts

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Current assets:
Cash and cash equivalents	$ 435,895	$ 232,767
Marketable securities	753,981	845,367
Prepaid expenses and other current assets	21,167	14,762
Total current assets	1,211,043	1,092,896
Property and equipment, net	124,960	115,620
Restricted cash	8,719	12,754
Operating lease right-of-use assets	112,846	118,513
Other assets	2,146	1,931
Total assets	1,459,714	1,341,714
Current liabilities:
Accounts payable	1,617	9,029
Accrued expenses and other current liabilities	111,664	49,912
Derivative liabilities	10,800	18,300
Current portion of deferred revenue	68,706	135,974
Current portion of lease liability	12,778	10,380
Total current liabilities	205,565	223,595
Long-term lease liability	159,911	168,625
Contingent consideration liabilities	2,723	12,463
Long-term portion of deferred revenue	109,888	202,179
Other liabilities	298	1,378
Total liabilities	478,385	608,240
Commitments and contingencies (See Note 10, License agreements and Note 11, Collaboration and license agreements)
Stockholders' equity:
Preferred stock, $0.01 par value; 25,000,000 shares authorized, and no shares issued or outstanding at December 31, 2023 and December 31, 2022, respectively
Common stock, $0.01 par value; 250,000,000 shares authorized, 81,632,496 and 71,277,339 issued and outstanding at December 31, 2023 and December 31, 2022, respectively	816	712
Additional paid-in capital	2,169,798	1,792,554
Accumulated other comprehensive (loss) income	604	(2,430)
Accumulated deficit	(1,189,889)	(1,057,362)
Total stockholders' equity	981,329	733,474
Total liabilities and stockholders' equity	$ 1,459,714	$ 1,341,714

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - $ / shares	Dec. 31, 2023	Dec. 31, 2022
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	81,632,496	71,277,339
Common stock, shares outstanding	81,632,496	71,277,339

Consolidated Statements of Oper

Consolidated Statements of Operations and Other Comprehensive Loss - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Income Statement [Abstract]
License and collaboration revenue	$ 377,709	$ 60,920	$ 51,844
Revenue, Product and Service [Extensible List]	us-gaap:LicenseMember	us-gaap:LicenseMember	us-gaap:LicenseMember
Operating expenses:
Research and development	$ 437,381	$ 311,594	$ 387,087
General and administrative	116,813	87,805	57,222
Total operating expenses	554,194	399,399	444,309
Loss from operations	(176,485)	(338,479)	(392,465)
Other income (expense):
Change in fair value of derivative liabilities	7,500	23,900	(1,000)
Change in fair value of non-controlling equity investments	(18,592)	20,200	17,690
Change in fair value of contingent consideration liabilities	9,740	18,904	5,146
Interest and other income (expense), net	46,676	15,297	(9)
Total other income (expense)	45,324	78,301	21,827
Net loss before income taxes	(131,161)	(260,178)	(370,638)
Provision for income taxes	(1,366)	(3,410)
Loss from equity method investment		(25,500)
Net loss	(132,527)	(289,088)	(370,638)
Unrealized gain (loss) on marketable securities	3,034	(2,380)	(41)
Comprehensive loss	$ (129,493)	$ (291,468)	$ (370,679)
Net loss per common share, basic	$ (1.72)	$ (4.13)	$ (5.77)
Net loss per common share, diluted	$ (1.72)	$ (4.13)	$ (5.77)
Weighted - average common shares outstanding, basic	77,151,771	70,015,305	64,227,676
Weighted - average common shares outstanding, diluted	77,151,771	70,015,305	64,227,676

Consolidated Statements of Rede

Consolidated Statements of Redeemable Convertible Preferred Stock and Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Income (Loss)	Accumulated Deficit	Private Placement	Private Placement Common Stock	Private Placement Additional Paid-in Capital	ATM Offering	ATM Offering Common Stock	ATM Offering Additional Paid-in Capital
Beginning Balance at Dec. 31, 2020	$ 245,561	$ 573	$ 642,633	$ (9)	$ (397,636)
Beginning Balance, Shares at Dec. 31, 2020		57,254,178
Issuance of common stock from initial public offering/private placement/At-the-Market offering, net of issuance costs						$ 252,005	$ 28	$ 251,977	$ 496,623	$ 49	$ 496,574
Issuance of common stock from initial public offering/private placement/At-the-Market offering, net of issuance costs, Shares							2,795,700			4,907,195
Issuance of common stock for success payment liability	30,000	$ 4	29,996
Issuance of common stock for success payment liability, Shares		349,650
Issuance of common stock to acquire Guide	120,032	$ 10	120,022
Issuance of common stock to acquire Guide, Shares		1,087,153
Vesting of restricted common stock		$ 10	(10)
Vesting of restricted common stock, Shares		1,020,887
Stock-based compensation	43,570		43,570
Exercise of common stock options	9,626	$ 10	9,616
Exercise of common stock options, Shares		974,662
Other comprehensive income (loss)	(41)			(41)
Net Income (Loss)	(370,638)				(370,638)
Ending Balance at Dec. 31, 2021	826,738	$ 684	1,594,378	(50)	(768,274)
Ending Balance, Shares at Dec. 31, 2021		68,389,425
Purchase of common stock under ESPP	3,075		3,075
Purchase of common stock under ESPP, Shares		70,073
Issuance of common stock from initial public offering/private placement/At-the-Market offering, net of issuance costs									108,076	$ 19	108,057
Issuance of common stock from initial public offering/private placement/At-the-Market offering, net of issuance costs, Shares										1,909,103
Vesting of restricted common stock		$ 4	(4)
Vesting of restricted common stock, Shares		424,303
Stock-based compensation	84,321		84,321
Exercise of common stock options	2,732	$ 5	2,727
Exercise of common stock options, Shares		484,435
Other comprehensive income (loss)	(2,380)			(2,380)
Net Income (Loss)	(289,088)				(289,088)
Ending Balance at Dec. 31, 2022	733,474	$ 712	1,792,554	(2,430)	(1,057,362)
Ending Balance, Shares at Dec. 31, 2022		71,277,339
Purchase of common stock under ESPP	3,032	$ 1	3,031
Purchase of common stock under ESPP, Shares		130,403
Issuance of common stock from initial public offering/private placement/At-the-Market offering, net of issuance costs									$ 235,938	$ 70	$ 235,868
Issuance of common stock from initial public offering/private placement/At-the-Market offering, net of issuance costs, Shares										6,952,703
Issuance of unregistered common shares in connection with license agreement	33,600	$ 20	33,580
Issuance of unregistered common shares in connection with license agreement, shares		2,004,811
Vesting of restricted common stock		$ 5	(5)
Vesting of restricted common stock, Shares		469,531
Stock-based compensation	98,647		98,647
Exercise of common stock options	$ 6,131	$ 8	6,123
Exercise of common stock options, Shares	797,709	797,709
Other comprehensive income (loss)	$ 3,034			3,034
Net Income (Loss)	(132,527)				(132,527)
Ending Balance at Dec. 31, 2023	$ 981,329	$ 816	$ 2,169,798	$ 604	$ (1,189,889)
Ending Balance, Shares at Dec. 31, 2023		81,632,496

Consolidated Statements of Re_2

Consolidated Statements of Redeemable Convertible Preferred Stock and Stockholders' Equity (Parenthetical) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Private Placement
Stock issuance costs			$ 8
ATM Offering
Stock issuance costs	$ 6.1	$ 2.7	$ 14.6

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Operating activities
Net loss	$ (132,527)	$ (289,088)	$ (370,638)
Adjustments to reconcile net loss to net cash provided by (used in) operating activities:
Loss from equity method investment		25,500
Depreciation and amortization	20,012	14,147	7,451
Amortization of investment (discount) premiums	(29,743)	(9,410)	(75)
In-process research and development charge			154,953
Stock-based compensation expense	98,647	84,321	43,570
Change in operating lease right-of-use assets	9,519	8,430	8,990
Change in fair value of derivative liabilities	(7,500)	(23,900)	1,000
Change in fair value of contingent consideration liabilities	(9,740)	(18,904)	(5,146)
Change in fair value of non-controlling equity investments	18,592	(20,200)	(17,690)
Other		3	63
Changes in operating assets and liabilities:
Prepaid expenses and other current assets	(6,473)	(7,753)	746
Other long-term assets			(197)
Accounts payable	(7,578)	2,373	818
Accrued expenses and other liabilities	67,663	(16,933)	43,914
Operating lease liabilities	(10,168)	12,430	16,028
Collaboration receivable	(146)	300,000	(300,000)
Deferred revenue	(159,559)	(35,920)	348,156
Other long-term liabilities	(194)	(2,569)	1,789
Net cash provided by (used in) operating activities	(149,195)	22,527	(66,268)
Investing activities
Purchases of property and equipment	(33,732)	(48,951)	(46,811)
Purchases of marketable securities	(984,338)	(1,616,999)	(777,223)
Maturities of marketable securities	1,089,910	1,204,614	529,270
Net cash acquired from Guide			620
Net cash provided by (used in) investing activities	71,840	(461,336)	(294,144)
Financing activities
Proceeds from issuance of common shares, net of commissions	236,568	108,258	757,449
Proceeds from issuances of stock under ESPP	3,032	3,075
Payment of equity offering costs	(631)	(188)	(8,816)
Equipment financings, net	(2,252)	(2,287)	(2,118)
Proceeds from exercise of stock options	6,131	2,732	9,626
Proceeds from private stock issuance	33,600
Net cash provided by (used in) financing activities	276,448	111,590	756,141
Net change in cash, cash equivalents and restricted cash	199,093	(327,219)	395,729
Cash, cash equivalents and restricted cash—beginning of period	245,521	572,740	177,011
Cash, cash equivalents and restricted cash—end of period	444,614	245,521	572,740
Supplemental disclosure of cash flow information:
Cash paid for interest	160	376	567
Supplemental disclosure of non-cash investing and financing activities:
Property and equipment additions in accounts payable and accrued expenses	1,403	5,783	9,264
Operating lease liabilities arising from obtaining right-of-use assets	$ 3,852	41,050	25,925
Equity issuance costs in accounts payable and accrued expenses			5
Fair value of common stock issued to settle success payment liability			30,000
Contingent consideration liabilities assumed in asset acquisition			36,513
Fair value of equity instruments issued in connection with asset acquisition			$ 120,032
Non-cash contribution of intellectual property to Orbital Therapeutics Inc.		$ 25,500

Pay vs Performance Disclosure

Pay vs Performance Disclosure - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Pay vs Performance Disclosure
Net Income (Loss)	$ (132,527)	$ (289,088)	$ (370,638)

Insider Trading Arrangements

Insider Trading Arrangements	3 Months Ended
	Dec. 31, 2023 shares
Trading Arrangements, by Individual
Material Terms of Trading Arrangement	Director and Officer Trading Arrangements The following table describes for the quarterly period ended December 31, 2023 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 ( December 20, 2023 ) Rule 10b5-1 trading arrangement Sale Until June 30, 2024 , or such earlier date upon which all transactions are completed or expire without execution. Up to 147,603 shares Terry-Ann Burrell ( Chief Financial Officer ) Adoption ( December 8, 2023 ) Rule 10b5-1 trading arrangement Sale Until December 31, 2024 , or such earlier date upon which all transactions are completed or expire without execution. Up to 100,000 shares Christine Bellon ( Chief Legal Officer ) Adoption ( December 12, 2023 ) Rule 10b5-1 trading arrangement Sale Until November 10, 2024 , or such earlier date upon which all transactions are completed or expire without execution. Up to 20,000 shares
Giuseppe Ciaramella
Trading Arrangements, by Individual
Name	Giuseppe Ciaramella
Title	President
Rule 10b5-1 Arrangement Adopted	true
Adoption Date	December 20, 2023
Arrangement Duration	194 days
Aggregate Available	147,603
Trd Arr Expiration Date	June 30, 2024
Terry-Ann Burrell
Trading Arrangements, by Individual
Name	Terry-Ann Burrell
Title	Chief Financial Officer
Rule 10b5-1 Arrangement Adopted	true
Adoption Date	December 8, 2023
Arrangement Duration	390 days
Aggregate Available	100,000
Trd Arr Expiration Date	December 31, 2024
Christine Bellon
Trading Arrangements, by Individual
Name	Christine Bellon
Title	Chief Legal Officer
Rule 10b5-1 Arrangement Adopted	true
Adoption Date	December 12, 2023
Arrangement Duration	390 days
Aggregate Available	20,000
Trd Arr Expiration Date	November 10, 2024

Nature of the Business and Basi

Nature of the Business and Basis of Presentation	12 Months Ended
	Dec. 31, 2023
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Nature of the Business and Basis of Presentation	1. Nature of the business and basis of presentation Organization 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, research and development costs including preclinical studies and IND-enabling studies, organizing and staffing the Company, maintaining its facilities and new facility build-outs, business planning, raising capital and providing general and administrative support for these operations. The Company has established internal manufacturing capabilities. 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 a 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. As of December 31, 2023 , the Company has 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 an additional $ 800.0 million. As of December 31, 2023, 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, resulting in an aggregate of $ 864.0 million in gross proceeds received under the Sales Agreement, as amended, as of December 31, 2023. 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, or the Verve Agreement, with Verve Therapeutics, Inc., or Verve, including the Company’s opt-in rights to co-develop and co-commercialize Verve’s base editing programs for cardiovascular disease. The Company received a $ 200.0 million 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. 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. Since its inception, the Company has incurred substantial losses and had an accumulated deficit of $ 1.2 billion as of December 31, 2023. 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 December 31, 2023 of $ 1.2 billion 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	12 Months Ended
	Dec. 31, 2023
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	2. S ummary of significant accounting policies Basis of presentation The accompanying 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 the FASB. Principles of consolidation The accompanying 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 consolidated financial statements include, but are not limited to, incremental borrowing rate used in the calculation of lease liabilities, research and development expenses, the fair values of common stock, stock-based compensation, contingent consideration liabilities, success payments, estimated license fees, contingent liabilities, and certain judgments regarding revenue recognition. Actual results could differ from these estimates. Cash, cash equivalents, and restricted cash Cash and cash equivalents consist of 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 facilities. The following table reconciles cash, cash equivalents, and restricted cash reported within the Company’s consolidated balance sheets to the total of the amounts shown in the consolidated statements of cash flows (in thousands): December 31, 2023 2022 2021 Cash and cash equivalents $ 435,895 $ 232,767 $ 559,994 Restricted cash 8,719 12,754 12,746 Total cash, cash equivalents, and restricted cash $ 444,614 $ 245,521 $ 572,740 Marketable securities The Company classifies marketable securities as available-for-sale. Available-for-sale securities consist of commercial paper, high-grade corporate notes, U.S. Treasury securities and government securities. Available-for-sale securities are carried at fair value with the unrealized gains and losses included in accumulated other comprehensive (loss) income as a component of stockholders’ equity until realized. Any premium or discount arising at purchase is amortized and/or accreted to interest income and/or expensed over the life of the instrument. Realized gains and losses are determined using the specific identification method and are included in interest and other income (expense), net. Corporate equity securities The Company classifies investments in equity securities that have a readily determinable fair value as marketable securities in the Company's consolidated balance sheets. The Company’s marketable securities are stated at fair value. Typically, the fair value of these securities is based on a quoted price for an identical equity security. The Company held an investment in privately issued corporate equity securities, which were accounted for as investments in equity securitie s. This investment did not have a readily determinable fair value and the Company valued the investment based on the cost of the equity securities adjusted for observable market transactions or impairments, if any, and records any changes in value through earnings. The Company records changes in the fair value of its equity securities in other income (expense), net in its consolidated statements of operations and other comprehensive loss. Concentrations of credit risk Financial instruments that are potentially subject to significant concentration of credit risk consist primarily of cash, cash equivalents, marketable securities, and restricted cash. The Company attempts to minimize the risk related to marketable securities by working with highly rated financial institutions that invest in a broad and diverse range of financial instruments. The Company has established guidelines relative to credit ratings and maturities intended to safeguard principal balances and maintain liquidity. The Company maintains its funds in accordance with its investment policy, which defines allowable investments, specifies credit quality standards and is designed to limit credit exposure to any single issuer. Guarantees and indemnifications As permitted under Delaware law, the Company indemnifies its officers, directors, consultants, and employees for certain events or occurrences that happen by reason of the relationship with, or position held at, the Company. For the years ended December 31, 2023, 2022 and 2021 , the Company had not experienced any losses related to these indemnification obligations, and no claims were outstanding. The Company does not expect significant claims related to these indemnification obligations and, consequently, concluded that the fair value of these obligations is negligible, and no related reserves were established. Equity issuance costs The Company capitalizes incremental legal, professional, accounting and other third-party fees that were directly associated with its stock offerings as other non-current assets until the offerings are consummated. Upon consummation, these costs are recorded in stockholders’ equity as a reduction of additional paid-in-capital generated as a result of the offerings. As of December 31, 2023 and 2022 , there were no deferred offering costs. Fair value of financial instruments ASC Topic 820, Fair Value Measurement , or ASC 820, establishes a fair value hierarchy for instruments measured at fair value that distinguishes between assumptions based on market data (observable inputs) and the Company’s own assumptions (unobservable inputs). Observable inputs are inputs that market participants would use in pricing the asset or liability based on market data obtained from independent sources. Unobservable inputs are inputs that reflect the Company’s assumptions about the inputs that market participants would use in pricing the assets or liability and are developed based on the best information available in the circumstances. ASC 820 identifies fair value as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. As a basis for considering market participant assumptions in fair value measurements, ASC 820 establishes a three-tiered value hierarchy that distinguishes between the following: Level 1—Quoted market prices in active markets for identical assets or liabilities. Level 2—Inputs other than Level 1 inputs that are either directly or indirectly observable, such as quoted market prices, interest rates and yield curves. Level 3—Unobservable inputs for the asset or liability (i.e., supported by little or no market activity). Level 3 inputs include management’s own assumptions about the assumptions that market participants would use in pricing the asset or liability (including assumptions about risk). To the extent the valuation is based on models or inputs that are less observable or unobservable in the market, the determination of fair values requires more judgment. Accordingly, the degree of judgment exercised by the Company in determining fair value is greatest for instruments categorized as Level 3. A financial instrument’s level within the fair value hierarchy is based on the lowest level of any input that is significant to the fair value measurement. There have been no changes to the valuation methods utilized during the years ended December 31, 2023 and 2022 . The Company evaluates transfers between levels at the end of each reporting period. Property and equipment Property and equipment are stated at cost less accumulated depreciation. Depreciation expense is recognized using the straight-line method over the estimated useful life of each asset as follows: Asset category Estimated useful life Computer equipment and software 3 years Laboratory equipment and office furniture 5 years Leasehold improvements Shorter of useful life or remaining term Upon retirement or sale, the cost of assets disposed of and the related accumulated depreciation are removed from the accounts and any resulting gain or loss is included in interest and other income (expense). Expenditures for repairs and maintenance are charged to expense as incurred. Impairment of long-lived assets The Company evaluates its long-lived assets, which consist primarily of property and equipment and operating lease right-of-use assets, for impairment whenever events or changes in circumstances indicate that the carrying amount of such assets (or asset groups) may not be recoverable. Recoverability of assets to be held and used is measured by a comparison of the carrying amount of an asset to the future undiscounted net cash flows expected to be generated by the asset. If such assets are considered to be impaired, the impairment to be recognized is measured by the amount by which the carrying amount of the asset exceeds the fair value of the asset. There were no impairment losses recognized during the years ended December 31, 2023, 2022 and 2021 . Freestanding financial instruments and derivatives Pursuant to a license agreement between the President and Fellows of Harvard College, or Harvard, and the Company, or the Harvard License Agreement, and a license agreement with The Broad Institute, Inc., or Broad Institute, and the Company, or the Broad License Agreement, (see Note 10), the Company is required to make success payments to Harvard and Broad Institute based the achievement of specified multiples of the initial weighted average value of the Company’s redeemable convertible Series A-1 Preferred Stock and the Company’s redeemable convertible Series A-2 Preferred Stock, or together the Series A Preferred, at specified valuation dates, payable in cash or Company common stock. Subsequent to the IPO, the amount of the success payments is based on the market value of Beam’s common stock. The success payments are accounted for as derivatives under ASC 815, Derivatives and Hedging and were initially recorded at fair value with a corresponding charge to research and development expense. The liabilities are recorded at fair value at each balance sheet date with all changes in value recognized in other income (expense), in the consolidated statement of operations and other comprehensive loss. The Company will continue to adjust the liability for changes in fair value until the earlier of the achievement or expiration of the success payment obligation. To determine the estimated fair value of the success payments, the Company used a Monte Carlo simulation model, which models the value of the liability based on several key variables, including probability of event occurrence, timing of event occurrence, as well as the value of the Series A Preferred, prior to the IPO, and the value of the Company’s common stock, subsequent to the IPO. Leases and rent expense The Company accounts for leases using a right-of-use, or ROU, model, which recognizes that, at the date of commencement, a lessee has a financial obligation to make lease payments to the lessor for the right to use the underlying asset during the lease term. At the inception of an arrangement, the Company determines whether the arrangement is or contains a lease based on the unique facts and circumstances present in the arrangement. Leases with a term greater than one year are recognized on the balance sheet as ROU assets and short-term and long-term lease liabilities, as applicable. ROU assets represent the Company’s right to use an underlying asset for the lease term and lease liabilities represent its obligation to make lease payments arising from the lease. The Company typically only includes an initial lease term in its assessment of the term of the lease arrangement. It also considers termination options and factors those into the determination of lease payments. Options to renew a lease are not included in the lease term unless there is reasonable certainty that the Company will renew. Operating lease liabilities and their corresponding ROU assets are recorded based on the present value of lease payments over the expected remaining lease term. Certain adjustments to the ROU asset may be required for items such as incentives received. The interest rate implicit in lease contracts is typically not readily determinable. As a result, the Company utilizes its incremental borrowing rate, which reflects the fixed rate at which it could borrow on a collateralized basis the amount of the lease payments in the same currency, for a similar term, in a similar economic environment. Lease expense for operating lease payments is recognized on a straight-line basis over the lease term. The Company is required to pay fees for operating expenses in addition to monthly base rent for certain operating leases (non-lease components). The Company has elected the practical expedient which allows non-lease components to be combined with lease components for all asset classes. Variable lease payments are not included within the lease right-of-use asset and lease liability on the consolidated balance sheet, and instead are reflected as expense in the period they are incurred. Leasehold improvements are not unique and are retained by the lessor at the end of the lease. However, in the case of a space designed to be suitable for the Company’s specific real estate needs and if the Company is responsible for cost overruns, the Company is the accounting owner of the leasehold improvements and costs associated are capitalized. The Company’s real estate operating leases provide for scheduled annual rent increases throughout the lease terms. The Company recognizes the effects of the scheduled rent increases on a straight-line basis over the full terms of the lease. Tenant improvement allowances, if any, provided by a landlord are recorded as a reduction of the ROU asset related to that lease at lease commencement. Asset acquisitions The Company measures and recognizes asset acquisitions that are not deemed to be business combinations based on the cost to acquire the assets, which includes transaction costs, and the consideration is allocated to the items acquired based on a relative fair value methodology. Goodwill is not recognized in asset acquisitions. In an asset acquisition, the cost allocated to acquire in-process research and development with no alternative future use is charged to research and development expense at the acquisition date. At the time of acquisition, the Company determines if a transaction should be accounted for as a business combination or acquisition of assets. Contingent consideration liabilities The Company may be required to make milestone payments to the former stockholders and optionholders of Guide Therapeutics, Inc., or Guide, in the form of its common stock based on the achievement of certain product and technology milestones. The payments are accounted for 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 primarily based upon the achievement and related timing of certain product and technology milestones that were unobservable in the market. The estimated fair value of contingent consideration liabilities, initially measured and recorded on the acquisition date, are considered to be a Level 3 measurement and are reviewed quarterly, or whenever events or circumstances occur that indicate a change in fair value. The contingent consideration liabilities are recorded at fair value at the end of each reporting period with changes in estimated fair values recorded in other income (expense) in the consolidated statements of operations and other comprehensive loss. The estimated fair value is determined based on probability adjusted discounted cash flow model that include significant estimates and assumptions pertaining to technology and product development. Significant changes in any of the probabilities of success or in the probabili ties as to the periods in which milestones would be achieved would result in a significantly higher or lower fair value measurement. The Company will continue to adjust the liabilities for changes in fair value until the earlier of the achievement or expiration of the obligations. Revenue recognition At inception, the Company determines whether contracts are within the scope of ASC 606 or other topics. For contracts that are determined to be within the scope of ASC 606, revenue is recognized when a customer obtains control of promised goods or services. The amount of revenue recognized reflects the consideration to which the Company expects to be entitled to receive in exchange for these goods and services. To achieve this core principle, the Company applies the following five steps: (i) identify the contract with the customer; (ii) identify the performance obligations in the contract; (iii) determine the transaction price; (iv) allocate the transaction price to the performance obligations in the contract; and (v) recognize revenue when the performance obligation is satisfied. The Company only applies the five-step model to contracts when it determines that collection of substantially all consideration for goods and services that are transferred is probable based on the customer’s intent and ability to pay the promised consideration. Performance obligations promised in a contract are identified based on the goods and services that will be transferred to the customer that are both capable of being distinct and are distinct in the context of the contract. To the extent a contract includes multiple promised goods and services, the Company applies judgment to determine whether promised goods and services are both capable of being distinct and are distinct in the context of the contract. If these criteria are not met, the promised goods and services are accounted for as a combined performance obligation. The transaction price is determined based on the consideration to which the Company will be entitled in exchange for transferring goods and services to the customer. To the extent the transaction price includes variable consideration, the Company estimates the amount of variable consideration that should be included in the transaction price utilizing either the expected value method or the most likely amount method, depending on the nature of the variable consideration. Variable consideration is included in the transaction price if, in management’s judgment, it is probable that a significant future reversal of cumulative revenue under the contract will not occur. Any estimates, including the effect of the constraint on variable consideration, are evaluated at each reporting period for any changes. Determining the transaction price requires significant judgment and is discussed in further detail for each of the Company’s license and collaboration agreements in Note 11. If the contract contains a single performance obligation, the entire transaction price is allocated to the single performance obligation. Contracts that contain multiple performance obligations require an allocation of the transaction price to each performance obligation on a relative standalone selling price basis unless the transaction price is variable and meets the criteria to be allocated entirely to a performance obligation or to a distinct service that forms part of a single performance obligation. Determining the standalone selling price requires significant judgment and is discussed in further detail for each of the Company’s license and collaboration agreements in Note 11. The Company satisfies performance obligations either over time or at a point in time. Revenue is recognized over time if either (i) the customer simultaneously receives and consumes the benefits provided by the entity’s performance, (ii) the entity’s performance creates or enhances an asset that the customer controls as the asset is created or enhanced, or (iii) the entity’s performance does not create an asset with an alternative use to the entity and the entity has an enforceable right to payment for performance completed to date. If the entity does not satisfy a performance obligation over time, the related performance obligation is satisfied at a point in time by transferring the control of a promised good or service to a customer. Licenses of intellectual property, or IP: If the license to the Company’s IP is determined to be distinct from the other performance obligations identified in the arrangement, the Company recognizes revenues from consideration allocated to the license when the license is transferred to the customer and the customer can use and benefit from the licenses. For licenses that are combined with other promises, the Company utilizes judgment to assess the nature of the combined performance obligation to determine whether the combined performance obligation is satisfied over time or at a point in time and, if over time, the appropriate method of measuring progress for purposes of recognizing revenue. The Company evaluates the measure of progress each reporting period and, if necessary, adjusts the measure of performance and related revenue recognition. The Company generally recognizes revenue using the cost incurred to date as compared to the total estimated cost. The impact on revenue of changes in total estimated costs are recognized on a cumulative basis in the period that the change occurs. If estimates of the total cost change, or if contract amendments change the scope of the performance obligation, the required adjustments to revenue could be material. Determining the revenue recognition of IP licenses requires significant judgment and is discussed in further detail for each of the Company’s license and collaboration agreements in Notes 10 and 11. Milestone payments: At the inception of each arrangement that includes development or regulatory milestone payments, the Company evaluates the probability of reaching the milestones and estimates the amount to be included in the transaction price using the most likely amount method. If it is probable that a significant revenue reversal would not occur in the future, the associated milestone value is included in the transaction price. Milestone payments that are not within the Company’s control or the licensee’s, such as regulatory approvals, are not considered probable of being achieved until those approvals are received and therefore consideration included in the transaction price is constrained. The transaction price is then allocated to each performance obligation on a relative standalone selling price basis, for which the Company recognizes revenue as or when the performance obligations under the contract are satisfied. At the end of each subsequent reporting period, the Company re-evaluates the probability of achievement of such development milestones and any related constraint, and if necessary, adjusts its estimate of the overall transaction price. Any such adjustments are recorded on a cumulative catch-up basis, which would affect revenues and earnings in the period of adjustment. Commercial Milestone Payments and Royalties: For arrangements that include sales-based royalties, including milestone payments based on levels of sales, if the license is deemed to be the predominant item to which the royalties relate, the Company recognizes revenue at the later of (i) when the related sales occur, or (ii) when the performance obligation to which some or all of the royalty has been allocated has been satisfied (or partially satisfied). To date, the Company has not recognized any royalty revenue resulting from any of its agreements. When no remaining performance obligations are required of the Company, or following the completion of the performance obligation period, such amounts are recognized as revenue upon transfer of control of the goods or services to the customer. Generally, all amounts received or due other than sales-based milestones and royalties are classified as license and collaboration revenue. Sales-based milestones and royalties will be recognized as royalty revenue at the later of when the related sales occur or when the performance obligation to which some or all of the royalty has been allocated has been satisfied (or partially satisfied). Deferred revenue expected to be recognized within the next twelve months is classified as a current liability. Contract balances The Company recognizes a contract asset when the Company transfers goods or services to a customer before the customer pays consideration or before payment is due, excluding any amounts presented as an account or other receivable. A contract asset is an entity’s right to consideration in exchange for goods or services that the entity has transferred to a customer. The contract liabilities, or deferred revenue, primarily relate to contracts where the Company has received payment, but it has not yet satisfied or fully satisfied the related performance obligations. Upfront payments and fees are recorded as deferred revenue upon receipt or when due and may require deferral of revenue recognition to a future period until the Company satisfies its obligations under these arrangements. Upfront payment contract liabilities resulting from the Company’s license agreements do not represent a financing component as the payment is not financing the transfer of goods or services, and the technology underlying the licenses granted reflects research and development expenses already incurred by the Company. The changes in the total deferred revenue for the years ended December 31, 2023 and 2022 were as follows (in thousands): December 31, December 31, Beginning balance $ 338,153 $ 348,573 Additions to deferred revenue from license agreements — 50,500 Amounts recognized in revenue ( 159,559 ) ( 60,920 ) Ending balance $ 178,594 $ 338,153 Research and development costs Research and development costs are charged to expense as incurred. Research and development costs consist of costs incurred in performing research and development activities, including salaries and bonuses, stock-based compensation, employee benefits, facilities costs, laboratory supplies, depreciation, manufacturing expenses, preclinical expenses, consulting, and other contracted services. The cost of obtaining licenses for certain technology or IP is recorded to research and development expense when incurred if the licensed technology or IP has not yet reached technological feasibility and has no alternative future use. Costs for certain research and development activities are recognized based on the terms of the individual arrangements, which may differ from the pattern of costs incurred, and are reflected in the financial statements as prepaid or accrued research and development costs. Stock-based compensation The Company’s stock-based compensation program allows for grants of stock options, restricted stock awards and restricted stock units. Grants are awarded to employees and non-employees, including directors. The Company accounts for stock-based compensation in accordance with ASC Topic 718, Compensation-Stock Compensation , or ASC 718. ASC 718 requires all stock-based payments to employees, non-employees and directors to be recognized as expense in the consolidated statements of operations and other comprehensive loss based on their fair values. The Company estimates the fair value of options granted using the Black-Scholes option pricing model, or Black-Scholes, for stock option grants to both employees and non-employees. The fair value of the Company’s common stock is used to determine the fair value of restricted stock awards and restricted stock units. Stock-based compensation awards are subject to either service- or performance-based vesting conditions. Compensation expense related to awards to employees, directors and non-employees with service-based vesting conditions is recognized on a straight-line basis based on the grant date fair value over the associated service period of the award, which is generally the vesting term. Compensation expense related to awards to employees with performance-based vesting conditions is recognized based on grant date fair value over the requisite service period using the accelerated attribution method to the extent achievement of the of performance condition is probable. The Black-Scholes option pricing model requires inputs based on certain subjective assumptions, including (i) the expected stock price volatility, (ii) the expected term of the award, (iii) the risk-free interest rate, and (iv) expected dividends. The Company bases its computation of expected volatility on the historical volatility of a representative group of public companies with similar characteristics to the Company, including stage of product development and life science industry focus, weighted with its own volatility for the period in which its stock has been publicly traded. The historical volatility is calculated based on a period of time commensurate with expected term assumption. The Company uses the simplified method as prescribed by the SEC Staff Accounting Bulletin No. 107, Share-Based Payment , to calculate the expected term for options granted to employees and non-employees, whereby the expected term equals the arithmetic average of the vesting term and the original contractual term of the options due to its lack of sufficient historical data. The risk-free interest rate is based on U.S. Treasury securities with a maturity date commensurate with the expected term of the associated award. The expected dividend yield is assumed to be zero as the Company has never paid dividends and has no current plans to pay any dividends on its common stock. The Company recognizes forfeitures as they occur. Patent costs All patent-related costs incurred in connection with filing and prosecuting patent applications are expensed as incurred. Due to the uncertainty about the recovery of the expenditure, amounts incurred are classified as general and administrative expenses in the accompanying consolidated statements of operations and other comprehensive loss. Variable interest entities The Company reviews each legal entity in which it has a financial interest to determine whether or not the entity is a variable interest entity, or VIE. If the entity is a VIE, the Company assesses whether or not it is the primary beneficiary of that VIE based on a number of factors, including (i) which party has the power to direct the activities that most significantly affect the VIE’s economic performance, (ii) the parties’ contractual rights and responsibilities pursuant to any contractual agreements and (iii) which party has the obligation to absorb losses or the right to receive benefits from the VIE. If the Company determines that it is the primary beneficiary of a VIE, it consolidates the financial statements of the VIE into its consolidated financial statements. If the Company determines that it is no longer the primary beneficiary of a consolidated VIE, or no longer has a variable interest in the VIE, the Company deconsolidates the VIE in the period that the determination is made. Income taxes The Company recognizes deferred tax assets and liabilities for the expected future tax consequences of events that have been included in the Company’s financial statements and tax returns. Deferred tax assets and liabilities are determined based upon the differences between the financial statement carrying amounts and the tax bases of existing assets and liabilities and for loss and credit carryforwards, using enacted tax rates expected to be in effect in the year in which the differences are expected to reverse. Deferred tax assets are reduced by a valuation allowance if it is more likely than not that these assets may not be realized. The Company determines whether it is more likely than not that a ta

Property and Equipment, Net

Property and Equipment, Net	12 Months Ended
	Dec. 31, 2023
Property, Plant and Equipment [Abstract]
Property and Equipment, Net	3. P roperty and equipment, net Property and equipment consist of the following (in thousands): December 31, December 31, Leasehold improvements $ 100,186 $ 85,804 Lab equipment 61,674 47,383 Furniture and fixtures 4,836 4,332 Computer equipment 3,163 3,073 Construction in process 5,283 5,198 Total property and equipment 175,142 145,790 Less accumulated depreciation ( 50,182 ) ( 30,170 ) Property and equipment, net $ 124,960 $ 115,620 The following table summarizes depreciation expense incurred (in thousands): Years Ended December 31, 2023 2022 2021 Depreciation expense $ 20,012 $ 14,097 $ 7,201

Fair Value of Financial Instrum

Fair Value of Financial Instruments	12 Months Ended
	Dec. 31, 2023
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, 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 the Company and Guide, or the Guide Merger Agreement, and success payment derivative liabilities pursuant to the Harvard and Broad License Agreements. 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 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, 2022 (in thousands): Carrying Fair Level 1 Level 2 Level 3 Assets Cash equivalents: Money market funds $ 218,794 $ 218,794 $ 218,794 $ — $ — Commercial paper 10,475 10,475 — 10,475 — Corporate notes 3,498 3,498 — 3,498 — Marketable securities: Commercial paper 577,728 577,728 — 577,728 — Corporate notes 18,996 18,996 — 18,996 — U.S. Treasury securities 145,312 145,312 — 145,312 — U.S. Government securities 62,864 62,864 — 62,864 — Equity securities included in marketable securities: Corporate equity securities 40,467 40,467 40,467 — — Total assets $ 1,078,134 $ 1,078,134 $ 259,261 $ 818,873 $ — Liabilities Success payment liability – Harvard $ 9,000 $ 9,000 $ — $ — $ 9,000 Success payment liability – Broad Institute 9,300 9,300 — — 9,300 Contingent consideration liability – Technology 6,025 6,025 — — 6,025 Contingent consideration liability – Product 6,438 6,438 — — 6,438 Total liabilities $ 30,763 $ 30,763 $ — $ — $ 30,763 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 using models or other valuation methodologies. Marketable securities – Marketable securities, excluding corporate equity securities, are classified within Level 2 of the fair value hierarchy because pricing inputs are other than quoted prices in active markets, which are either directly or indirectly observable as of the reporting date, and fair value is determined using models or other valuation methodologies. During the years ended December 31, 2023 and 2022, the Company held an investment in Verve consisting of shares of Verve’s common stock. As of December 31, 2023, the Company owned 546,970 shares of Verve's common stock, the value of which is included in marketable securities in the consolidated balance sheet. The Company recorded the investment at fair value of $ 7.6 million and $ 10.6 million as of December 31, 2023 and 2022, respectively. The Company recognized $ 3.0 million and $ 9.6 million of other expense during the years ended December 31, 2023 and 2022, respectively, associated with changes in the fair value of Verve's common stock. In October 2022, Prime completed an initial public offering of its common stock. As of December 31, 2023 and 2022 , the Company owned 1,608,337 shares of Prime's common stock valued at $ 14.2 million and $ 29.9 million, respectively. The Company recognized $ 15.6 million of other expense and $ 29.8 million of other income during the years ended December 31, 2023 and 2022, respectively, associated with changes in the fair value of Prime's common stock. The following table summarizes other income (expense) incurred due to changes in the fair value of corporate equity securities held (in thousands): Years Ended December 31, 2023 2022 2021 Other income (expense) $ ( 18,592 ) $ 20,200 $ 17,690 Success Payment Liability – As discussed further in Note 10, the Company is required to make payments to Harvard and Broad Institute based upon the achievement of specified multiples of the initial weighted average value of the Company’s Series A Preferred or, subsequent to the IPO, 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 and Broad License Agreements are 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 December 31, December 31, December 31, December 31, Fair value of common stock (per share) $ 27.22 $ 39.11 $ 27.22 $ 39.11 Expected volatility 80 % 82 % 79 % 82 % Expected term (years) 0.06 - 5.49 0.08 - 6.49 0.06 - 6.36 0.08 - 7.36 The computation of expected volatility was estimated using the Company's historical volatility along with available information about the historical volatility of stocks of similar publicly traded companies 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): Year Ended December 31, 2023 Harvard Broad Institute Total Balance at December 31, 2021 $ 21,000 $ 21,200 $ 42,200 Change in fair value ( 12,000 ) ( 11,900 ) ( 23,900 ) Balance at December 31, 2022 $ 9,000 $ 9,300 $ 18,300 Change in fair value ( 3,800 ) ( 3,700 ) ( 7,500 ) Balance at December 31, 2023 $ 5,200 $ 5,600 $ 10,800 Contingent consideration liabilities – As discussed further in Note 9, 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 December 31, December 31, December 31, December 31, Discount Rate 10.00 % 10.00 % 10.00 % 10.00 % Probability of Achievement 2 - 5 % 5 - 15 % 1 - 2 % 2 - 15 % Projected Year of Achievement 2025 2024 - 2025 2025 - 2031 2025 - 2030 The following table reconciles the change in fair value of the contingent consideration liabilities based on level 3 inputs (in thousands): Technology Milestones Product Milestones Total Balance at December 31, 2021 $ 24,359 $ 7,008 31,367 Change in fair value ( 18,334 ) ( 570 ) ( 18,904 ) Balance at December 31, 2022 $ 6,025 $ 6,438 $ 12,463 Change in fair value ( 4,654 ) ( 5,086 ) ( 9,740 ) Balance at December 31, 2023 $ 1,371 $ 1,352 $ 2,723

Marketable Securities

Marketable Securities	12 Months Ended
	Dec. 31, 2023
Investments, Debt and Equity Securities [Abstract]
Marketable Securities	5. Marketable securities 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 following table summarizes the Company’s marketable securities held at December 31, 2022 (in thousands): Amortized Cost Gross Gross Fair Value Commercial paper $ 578,813 $ 72 $ ( 1,157 ) $ 577,728 Corporate notes 19,033 — ( 37 ) 18,996 U.S. Treasury securities 146,270 — ( 958 ) 145,312 U.S. Government securities 63,214 13 ( 363 ) 62,864 Corporate equity securities 40,467 — — 40,467 Total $ 847,797 $ 85 $ ( 2,515 ) $ 845,367 The amortized cost of marketable securities is adjusted for amortization of premiums and accretion of discounts to maturity. At December 31, 2023 and 2022 , the balance in accumulated other comprehensive (loss) income was comprised solely of activity related to marketable securities. There were no realized gains or losses recognized on the sale or maturity of marketable securities for the years ended December 31, 2023, 2022 and 2021 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. The contractual maturity dates of all the investments are less than one year .

Accrued Expenses and Other Curr

Accrued Expenses and Other Current Liabilities	12 Months Ended
	Dec. 31, 2023
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): December 31, December 31, Accrued contingent obligation, refer to Note 10 $ 43,280 $ — Employee compensation and related benefits 21,774 19,122 Research costs 9,804 4,844 Process development and manufacturing costs 4,697 5,080 Professional fees 3,468 6,751 Equipment financing costs 484 1,853 Other 28,157 12,262 Total $ 111,664 $ 49,912 The Company received correspondence from a research institution regarding a confidentiality agreement between such institution and the Company. The confidentiality agreement related to certain technology that the Company evaluated for development in connection with certain of its programs. The correspondence alleged that the Company breached the terms of the confidentiality agreement, misappropriated trade secrets and other confidential information of such institution, engaged in unfair and deceptive trade practices, and was unjustly enriched in connection with developing its therapeutics, including BEAM-302. The research institution claimed that it is entitled to monetary damages (including damages for the apportioned value of the Company and enhanced damages for an alleged willful violation) and certain ongoing royalty and/or milestone payments related to the technology that is the subject of the alleged breaches of contract, among other possible remedies. No complaint has been filed, and the Company continues to discuss the matter with the research institution. As of December 31, 2023 , no amount of loss is determinable and the Company had a liability accrued of $ 21.3 million included within Other in the table above for the minimum amount in the range of loss based on its settlement offer. The ultimate resolution of this matter could require a cash payment, ongoing royalty and/or milestone payments and result in a material charge in excess of the amount accrued as of December 31, 2023 .

Leases

Leases	12 Months Ended
	Dec. 31, 2023
Leases [Abstract]
Leases	7. Leases Operating leases The Company’s operating leases are as follows: • A February 2018 lease for office and laboratory space, which commenced in March 2018 and terminates in September 2028 . The lease is subject to fixed-rate rent escalations and provided for $ 6.1 million in tenant improvements allowances and a term extension option. • An October 2018 lease for laboratory space as amended, which commenced in April 2019 and terminates in December 2025 . The amended lease is subject to fixed-rate rent escalations and provides an option to extend the lease for two additional two-year periods through December 31, 2029. • An April 2019 lease for office and laboratory space that was built over the course of 2020 and 2021. Pursuant to the terms of the original lease agreement, the first phase of the lease commenced in October 2020 (rent payments for the first phase began in August 2021 ) and the second phase of the lease commenced in January 2021 (rent payments for the second phase began in February 2022 ). The lease is subject to fixed-rate rent escalations and provides for $ 23.4 million in tenant improvements and the option to extend the lease for two terms of five years each . The Company determined that it is the accounting owner of all tenant improvements. In August 2021, the Company executed an amendment to this lease to occupy additional space. The term of this lease runs concurrent with the term of the April 2019 lease through February 2034 . • An August 2020 lease for a 100,000 square foot manufacturing facility in Research Triangle Park, North Carolina. Construction of the manufacturing facility began in 2020 and the Company began making rent payments in the fourth quarter of 2022. The lease will terminate 15 years from the rent commencement date, December 2022 . The lease is subject to fixed-rate rent escalations and provides for $ 20.0 million in tenant improvements and the option to extend the lease for two terms of five years each, which were not reasonably certain of exercise as of December 31, 2022. The following table summarizes operating lease costs as well as sublease income (in thousands): Years Ended December 31, 2023 2022 2021 Operating lease costs $ 22,063 $ 19,536 $ 18,309 Variable lease costs 5,777 4,364 2,065 Short-term lease costs 9,000 307 1,145 Sublease income — ( 1,319 ) ( 110 ) Total $ 36,840 $ 22,888 $ 21,409 The following table summarizes the lease term and discount rate for operating leases: December 31, 2023 2022 Weighted-average remaining lease term (years) 10.3 11.0 Weighted-average discount rate 7.6 % 7.5 % The following table summarizes the lease costs included in the measurement of lease liabilities (in thousands): Years Ended December 31, 2023 2022 2021 Operating cash flows used for operating leases $ 22,603 $ 19,052 $ 11,462 Operating lease liabilities arising from obtaining ROU assets 3,852 41,050 25,925 At December 31, 2023, the future maturity of the Company’s operating leases for each of the next five years and total thereafter were as follows (in thousands): Years ending December 31, Amount 2024 $ 24,985 2025 25,315 2026 22,526 2027 23,157 2028 22,806 Thereafter 132,500 Undiscounted lease payments 251,289 Less: imputed interest ( 78,600 ) Total operating lease liabilities $ 172,689

Strategic Restructuring

Strategic Restructuring	12 Months Ended
	Dec. 31, 2023
Restructuring and Related Activities [Abstract]
Strategic Restructuring	8. Strategic restructuring In October 2023, the Company announced updated portfolio priorities and strategic plans to restructure the Company to streamline its business operations. In connection with this portfolio prioritization and strategic restructuring, the Company reduced its employee headcount by approximately 100 positions, or about 20 % of its workforce. During the year ended December 31, 2023, the Company recognized $ 6.7 million of restructuring charges in the consolidated statement of operations related to these actions. These charges included $ 6.5 million of one-time termination benefits and contractual termination benefits for severance, healthcare, and related benefits and $ 0.2 million of non-cash stock-based compensation expense. The workforce reductions were substantially completed as of December 31, 2023, however the severance and other costs are paid over time. Details of the restructuring liability activity for the Company's workforce reductions for the year ended December 31, 2023 as recorded in accrued expenses and other current liabilities in the consolidated balance sheet are as follows: Amount Accrued restructuring balance at December 31, 2022 $ — Expenses incurred 6,494 Payments ( 1,999 ) Accrued restructuring balance at December 31, 2023 $ 4,495

Guide Acquisition

Guide Acquisition	12 Months Ended
	Dec. 31, 2023
Business Combinations [Abstract]
Guide Acquisition	9. Guide acquisition On February 23, 2021 , the Company entered into the Guide Merger Agreement. Under the Guide Merger Agreement, the Company paid Guide’s former stockholders and optionholders upfront consideration in an aggregate amount of $ 120.0 million, excluding customary purchase price adjustments and closing costs, in shares of the Company’s common stock, based upon the volume-weighted average price of the Company’s stock over the ten trading-day period ending on February 19, 2021. Pursuant to the Guide Merger Agreement, the Company acquired all of the issued and outstanding shares of Guide. The Company issued a total of 1,087,153 shares of its common stock valued at $ 120.0 million in connection with the upfront payment to Guide’s former stockholders and optionholders. The Guide transaction resulted in the acquisition of certain know-how and intellectual property assets related to Guide’s proprietary in vivo LNP screening technology and its library of lipids and lipid nanoparticle formulations identified using the screening technology. Management determined that the acquired assets do not meet the definition of a business pursuant to ASC 805, as substantially all of the fair value of the acquired assets is concentrated into one identifiable asset, the LNP screening technology and associated lipid library. As of the date of closing of the transactions contemplated by the Guide Merger Agreement, or the Guide Merger Agreement Date, the asset acquired had no alternative future use and had not reached a stage of technological feasibility. As a result, all share-based and cash payment obligations have been recorded as research and development expense in the consolidated statements of operations and other comprehensive loss in the amount of $ 155.0 million. The total transaction price was allocated to the assets acquired and liabilities assumed on a relative fair value basis. In addition, 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 common stock over the ten trading-day period ending two trading days prior to the date on which the applicable milestone is achieved. The Company determined that all future technology and product milestone payments are classified as liabilities under ASC 480 and therefore the Company recorded a liability for these milestone payments as of the Guide Merger Agreement Date at fair value of $ 36.5 million. These contingent consideration liabilities are remeasured at fair value each financial reporting period, with the resulting impact reflected in the Company’s consolidated statements of operations and other comprehensive loss, presented within other income (expense). The transaction price was determined and allocated as follows (in thousands): Transaction price Fair value of equity instruments issued $ 120,032 Technology and product contingent consideration liabilities 36,513 Transaction costs 2,531 Total transaction price $ 159,076 Transaction price allocated In-process research and development $ 154,953 Cash acquired 3,151 Prepaid expenses and other assets 264 Property and equipment 1,835 Assembled workforce 300 Other liabilities assumed ( 1,427 ) Total transaction price $ 159,076

License Agreements

License Agreements	12 Months Ended
	Dec. 31, 2023
Organization, Consolidation and Presentation of Financial Statements [Abstract]
License Agreements	10. 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 total contingent obligations and non-royalty sublicense fees included in research and development expenses in the statement of operations and comprehensive loss were $ 43.5 million, $ 2.7 million, and $ 39.9 million for the years ended December 31, 2023, 2022, and 2021, respectively. 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 $ 43.3 million of contingent obligations that may be due associated with payments received under the Lilly Agreement for which discussions are continuing related to the potential applicability to such payments of the terms of license agreements. As of December 31, 2023, 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 In June 2017, the Company entered into the Harvard License Agreement for certain base editing technology pursuant to which the Company received an exclusive, worldwide, sublicensable, royalty-bearing license under specified patent rights to develop and commercialize licensed products and a nonexclusive, worldwide, sublicensable, royalty-bearing license under certain patent rights to research and develop licensed products. The Company agreed to use commercially reasonable efforts to develop licensed products in accordance with the development plan, to introduce any licensed products that gain regulatory approval into the commercial market, to market licensed products that have gained regulatory approval following such introduction into the market, and to make licensed products that have gained regulatory approval reasonably available to the public. The license term extends until the later of the expiration of (i) the last to expire licensed patent covering a licensed product, (ii) the period of exclusivity associated with a licensed product or (iii) a certain period after the first commercial sale of a licensed product, unless terminated earlier by either party under certain provisions. Partial consideration for the rights granted under the Harvard License Agreement include success payments, which are further described below. Success Payments – 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. The following table summarizes the Company’s success payment liability for Harvard (in thousands): December 31, December 31, Harvard success payment liability $ 5,200 $ 9,000 The following table summarizes the expense resulting from the change in the fair value of the success payment liability for Harvard (in thousands): Years Ended December 31, 2023 2022 2021 Change in fair value of Harvard success payment liability $ ( 3,800 ) $ ( 12,000 ) $ 500 Other Payments – The Company agreed to pay Harvard an annual license maintenance fee ranging from low-to-mid five figures to low six figures, depending on the calendar year. The Company is responsible for the payment of certain patent prosecution and maintenance costs incurred by Harvard related to licensed patents. To the extent achieved, the Company is obligated to pay up to an aggregate of $ 75.9 million in product development and regulatory approval milestones, or Harvard Product Milestones. If the Company completes a change of control during the term of the Harvard License Agreement, then certain of the milestone payments would be increased. To the extent there are sales of a licensed product, the Company is required to pay low single digit royalties on net sales. The Company is entitled to certain reductions and offsets on these royalties with respect to a licensed product in a given country. If the Company sublicenses its rights to develop or commercialize a licensed product under the Harvard License Agreement to a third party and the Company receives non-royalty sublicense income, then Harvard is entitled to a percentage of such consideration, ranging from the high single digits to low double digits depending on the date in which such sublicense agreement is executed and the stage of development of the Company’s licensed products at such time. The annual maintenance fees are recorded as an expense on an annual basis based on the stated amount for the applicable year. Annual patent costs are expensed as incurred. Upon determination that a Harvard Product Milestone is probable to occur, the amount due will be recorded as research and development expense. The Company will monitor the Harvard Product Milestone payments for this arrangement on an ongoing basis. To the extent products are commercialized under the Harvard License Agreement, the Company will accrue royalty expense and sublicense nonroyalty payments, as applicable, for the amount it is obligated to pay, with adjustments as sales are made. Broad license agreement In May 2018, the Broad License Agreement was entered into with Broad Institute for certain RNA base editing technology including an RNA editor platform. Under the Broad License Agreement, Broad Institute granted exclusive and non-exclusive worldwide, sublicensable, royalty-bearing licenses under specified patent rights to develop and commercialize licensed product and a nonexclusive, worldwide, sublicensable, royalty-bearing license under certain patent rights to research and develop licensed products. Under the agreement the Company shall use commercially reasonable efforts to develop licensed products in accordance with the development plan, to introduce any licensed products that gain regulatory approval into the commercial market, to market licensed products that have gained regulatory approval following such introduction into the market, and to make licensed products that have gained regulatory approval reasonably available to the public. The license term extends until the later of the expiration of (i) the last to expire licensed patent covering a licensed product, (ii) the period of regulatory exclusivity associated with a licensed product or (iii) a certain period after the first commercial sale of a licensed product unless terminated earlier by either party under certain provisions. Additional consideration under the Broad License Agreement included Success Payments, which are further described below. Success Payments – 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 December 31, 2023, no success payments were due to Broad Institute. The following table summarizes the Company’s success payment liability for Broad Institute (in thousands): December 31, 2023 2022 Broad Institute success payment liability $ 5,600 $ 9,300 The following table summarizes the expense resulting from the change in the fair value of the success payment liability for Broad Institute (in thousands): Years Ended December 31, 2023 2022 2021 Change in fair value of Broad Institute success payment liability $ ( 3,700 ) $ ( 11,900 ) $ 500 Other Payments – The Company agreed to pay Broad Institute an annual license maintenance fee ranging from low-to-mid five figures to low six figures, depending on the particular calendar year. The Company is responsible for the payment of certain patent prosecution and maintenance costs incurred by Broad Institute related to licensed patents. To the extent achieved, the Company is obligated to pay up to an aggregate of $ 75.9 million in product development and regulatory approval milestones, or Broad Product Milestones. If the Company completes a change of control during the term of the Broad License Agreement, then certain of the milestone payments would be increased. To the extent there are commercial sales of a licensed product, the Company is required to pay low single digit royalties on net sales. The Company is entitled to certain reductions and offsets on these royalties with respect to a licensed product in a given country. If the Company sublicenses its rights to develop or commercialize a licensed product under the Broad License Agreement to a third party and the Company receives non-royalty sublicense income, then Broad Institute is entitled to a percentage of such consideration, ranging from the high single digits to low double digits depending on the date in which such sublicense agreement is executed and the stage of development of the Company’s licensed products at such time. The annual maintenance fees are recorded as an expense on an annual basis based on the stated amount for the applicable year. Annual patent costs will be expensed as incurred. Upon determination that a Broad Product Milestone is probable to occur, the amount due will be recorded as research and development expense. The Company monitors the Broad Product Milestone payments for this arrangement on an ongoing basis. To the extent products are commercialized under the Broad License Agreement, the Company will accrue royalty expense and sublicense nonroyalty payments, as applicable, for the amount it is obligated to pay, with adjustments as sales are made. 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. More specifically, Editas granted to the Company a worldwide, exclusive, sublicensable, license (subject to certain exceptions and conditions) under certain intellectual property controlled by Editas for the use of base editing therapies for the treatment of any field of human diseases and conditions, subject to certain exceptions, or the Beam Field, and the licenses granted or to be granted under the Editas License Agreement, or the Editas Development and Commercialization License. Additionally, Editas granted to the Company a royalty-free, non-exclusive license under certain intellectual property owned or controlled by Editas to perform research activities in the Beam Field, or the Editas Research License. Editas provided the Company with an exclusive option to obtain an Editas Development and Commercialization License to three additional groups of intellectual property owned or controlled by Editas, on a group by group basis, during the specified option period, subject to certain exceptions. Pursuant to the Editas License Agreement, the Company will use commercially reasonable efforts to develop a product that includes the rights licensed to the Company within a specified period of time and to commercialize any such products that have received regulatory approval in certain specified countries. Additional consideration will be due to Editas if the Company elects to exercise its option to obtain an Editas Development and Commercialization License to any of the three categories of intellectual property underlying the Editas Research License, for a fee ranging from a mid-teen million dollar amount to a low to mid-eight digit dollar amount per group, depending on the timing of the option exercise. Additionally, the Company is required to reimburse Editas for certain payments Editas may be obligated to make under existing Editas license agreements related to the intellectual property being licensed to the Company, including (i) development, regulatory and commercial milestone payments and certain sublicense income payments due as a result of the Editas License Agreement and (ii) a percentage of the annual maintenance fees and patent fees due to certain of the Editas’ licensors. In addition, to the extent any products are commercialized under an Editas Development and Commercialization License, the Company would be required to make royalty payments equivalent to the royalties that would be due from Editas to any applicable licensors of Editas related to the sales of such licensed products, plus an additional tiered low- to mid-single digit royalty, depending on whether such licensed product is covered by an Editas-owned patent. The license rights and option rights granted by Editas to the Company are subject to the terms and conditions of the underlying license agreements that Editas is a party to and under which Editas licensed rights or option rights to the Company and the termination of such in-licenses, as applicable. Unless earlier terminated by either party pursuant to the terms of the agreement, the Editas License Agreement will continue in full force and effect and will expire on a licensed product-by licensed product and country-by-country basis upon the later of (i) the last-to-expire royalty term under any applicable institutional license to Editas and (ii) the date at which such product is no longer covered by a valid claim of a licensed Editas-owned patent in such country. The Company has the right, at its sole discretion, at any time to terminate the Editas License Agreement in its entirety or on a group-by-group of intellectual property basis, upon ninety days written notice to Editas. Upon termination of the Editas License Agreement, all rights and licenses granted by Editas to the Company (including the rights to exercise options and obtain such licenses) will immediately terminate and patents within a group of patents will no longer be deemed licensed patents. Expiration or termination of the Editas License Agreement for any reason does not release either party of any obligation or liability which had accrued, or which is attributable to a period prior to such expiration or termination. The option exercise fees under the agreement will be recorded as research and development expense, if and when the Company exercises such options. To date, no options have been exercised. The annual maintenance fees are recorded as an expense on an annual basis based on the stated amount for the applicable year. 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. To the extent applicable, sublicense income payments will be accrued for the amount the Company is obligated to pay under each applicable in-license as amounts are due to Editas. Lastly, to the extent products are commercialized under the Editas License agreement, the Company will accrue royalty expense for the amount it is obligated to pay, with adjustments as sales are made.

Collaboration and License Agree

Collaboration and License Agreements	12 Months Ended
	Dec. 31, 2023
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Collaboration and License Agreements	11. 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, or the Verve Agreement, with Verve Therapeutics, Inc., or Verve, 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 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 Beam 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 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 , and the revenue component 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 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 2023 the Company recognized $ 216.4 million of revenue related to the Lilly Agreement. As of December 31, 2023 , there was no deferred revenue related to the Lilly Agreement. 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 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 consideration received under the Orbital Agreement 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 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. 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 determined that the licenses combined with the research and development services, know-how transfers, committee participation and materials transfer represent a performance obligation. The Company recognizes revenue associated with the Orbital performance obligation over time as it is satisfied during the term of the agreement, which is three years . The Company recognized $ 8.5 million and $ 2.1 million of revenue during the years ended December 31, 2023 and 2022, respectively. As of December 31, 2023 , there was $ 8.5 million and $ 6.4 million of current and long-term deferred revenue, respectively, related to the Orbital Agreement. Beam does not have a controlling financial interest in Orbital as Beam does not have the power to direct the activities of Orbital. The Company has significant influence over Orbital through its noncontrolling representation on Orbital’s board of directors and the Company’s equity interest in Orbital. Accordingly, the Company does not consolidate the financial statements of Orbital and accounts for its investment using the equity method of accounting. As of the closing date in September 2022, the fair value of the Company’s investment in Orbital was $ 25.5 million. The fair value of the Orbital common stock was determined by management with the assistance of a third-party valuation specialist. In determining the fair value of the Company’s investment, the valuation specialist used an option pricing model backsolve approach based on Orbital's most recent funding of preferred stock. The valuation requires the input of certain subjective assumptions. The key assumptions used in the option pricing model, which are level 3 inputs, include the anticipated holding period to an exit and liquidity event, the volatility of market participants ( 68 %) and the discount for lack of marketability ( 43 %). At the date of the investment, a basis difference was identified as the carrying value of the Company’s investment in Orbital exceeded the Company’s proportionate share of the underlying net assets in Orbital. The Company concluded that the basis difference was primarily attributable to Orbital’s IPR&D assets. As Orbital did not meet the definition of a business due to substantially all of the estimated fair value of the gross assets being concentrated in the group of similar IPR&D assets, the basis difference attributable to the IPR&D with no alternative future use was immediately expensed as of the date of the investment. The Company’s proportionate share of the basis difference exceeded its carrying value of the equity method investment in Orbital and the equity investment balance was reduced to zero . There is no commitment for the Company to provide financial support to Orbital. The Company did no t recognize a gain or loss from the equity method investment for the year ended December 31, 2023 and recognized a loss of $ 25.5 million in association with the basis difference charge in the Company’s consolidated statements of operations for the year ended December 31, 2022. 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. As the $ 300.0 million upfront fee was not received by the Company as of December 31, 2021, the Company recorded a collaboration receivable for $ 300.0 million with a corresponding deferred revenue liability. The Company received the $ 300.0 million upfront payment in January 2022. 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 will re-evaluate 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 tow ards 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. The impact on revenue of changes in total estimated costs are recognized on a cumulative basis in the period that the change occurs. If estimates of the total cost change, or if contract amendments change the scope of the performance obligation, the required adjustments to revenue could be material. During the year ended December 31, 2023, the Company recognized $ 134.3 million, which includes a cumulative catch-up adjustment to increase revenue due to changes in estimated total costs. In 2022 the Company recognized $ 48.2 million of revenue related to the Pfizer Agreement. There was no revenue recognized related to the Pfizer Agreement during the year ended December 31, 2021. As of December 31, 2023, there was $ 42.9 million and $ 74.6 million of current and long-term deferred revenue, respectively, related to the Pfizer Agreement. Sana Biotechnology In October 2021, the Company entered into an option and license agreement, or the Sana Agreement, with Sana Biotechnology, Inc., or Sana, under which the Company granted Sana a license for non-exclusive rights to its CRISPR Cas12b nuclease system for the development and commercialization of certain engineered cellular therapy programs. In addition to the license, the Company performed an initial technology transfer following the effective date of the Sana Agreement providing Sana with certain know-how, as required under the Sana Agreement. This technology transfer occurred in 2021. Following the license transfer and completion of the initial technology transfer, Sana is responsible, at its sole expense, for the development and commercialization of therapeutic products which must contain either specified CAR antigen targets or pluripotent stem cell, or PSC, product types. As consideration for the license, the Company received an upfront payment of $ 50.0 million from Sana in October 2021. In addition, the Company may be eligible to receive development, regulatory, and commercial milestones of up to $ 65.0 million from Sana on any product candidate or product. The Company will also be entitled to receive royalties equal to a low single digit percentage of net sales on any product. For up to thirty months following the effective date of the Sana Agreement, Sana has the option to select up to a cumulative total of two additional CAR antigen targets or PSC product types for an additional fee of $ 10.0 million per additional CAR antigen target and additional PSC product type, or the Option Rights, for an aggregate potential additional consideration of $ 20.0 million. Further, for up to thirty months following the effective date of the Sana Agreement, Sana has a one-time right to substitute, in the aggregate, either one CAR antigen target or one PSC product type at no additional cost, or the Replacement Right. Sana may also select a specified number of additional or replacement genetic targets for each PSC product type at any time prior to the third anniversary of the effective date at no additional cost, or the Genetic Target Nomination Rights. Sana may terminate the Sana Agreement for convenience prior to the first commercial sale of any licensed product by providing 90 days’ prior written notice or upon 180 days’ prior written notice after first commercial sale. The Company accounts for the Sana 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 $ 50.0 million, which is composed 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 will re-evaluate the transaction price in each reporting period. The Company has identified a single performance obligation, which includes (i) the non-exclusive license granted to Sana under the Company’s patent rights and know-how and (ii) the initial technology transfer following the effective date, which occurred in 2021. The Company further concluded that the Option Rights, Replacement Right, and Genetic Target Nomination Rights did not grant Sana a material right. As the Company only identified one performance obligation, no allocation of the transaction price is required. During the year ended December 31, 2021, the Company recognized $ 50.0 million of revenue associated with the single performance obligation at a point in time upon the transfer of the license to Sana and completion of the initial technology transfer. The Company did not recognize revenue under the Sana Agreement for the year ended December 31, 2022 . The Company recognized $ 1.8 million of revenue under the Sana Agreement during the year ended December 31, 2023. 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 up to 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 is eligible to receive a total of $ 75.0 million in upfront and near-term milestones from Apellis, which is 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 received the $ 50.0 million upfront payment from Apellis in July 2021 and the $ 25.0 million First Anniversary Payment in June 2022. 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 will re-evaluate 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. Therefore, the Company did no t recognize any upfront revenue related to the license. 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 estimated standalone selling price, or the 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 budgeted 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 years ended December 31, 2023, 2022, and 2021, the Company recognized $ 16.4 million, $ 10.6 million and $ 1.8 million of revenue, respectively, related to the Apellis Agreement. As of December 31, 2023, there is $ 17.3 million and $ 28.9 million of current and long-term deferred revenue, respectively, related to the Apellis Agreement. Prime Medicine In September 2019, the Company entered into a collaboration and license agreement with Prime Medicine to research and develop a novel gene editing technology developed by one of the Company’s founders. Under the terms of the agreement, the Company granted Prime Medicine a non-exclusive license to certain of its CRISPR technology (including Cas12b), delivery technology and certain other technology controlled by the Company to develop and commercialize gene editing products for the treatment of human diseases. Prime Medicine granted the Company an exclusive license to develop and commercialize prime gene editing technology for the creation or modification of any single base transition mutations, as well as any edits made for the treatment of sickle cell disease. For any products that use technology licensed from Prime Medicine, the Company is required to make milestone payments to Prime Medicine upon the achievement of certain clinical, regulatory and commercial events. It is also required to use commercially reasonable efforts to develop and seek regulatory approval for two products that use licensed technology from Prime Medicine in certain specified countries and to commercialize any such product(s) for which approval has been obtained in certain specified countries. Prime Medicine has an option to jointly develop and commercialize, and share expenses and revenue for, certain products that use technology licensed from Prime Medicine in the United States. Royalty payments may become due by either party to the other based on the net sales of commercialized products under the agreement. The Company had an obligation to issue $ 5.0 million in shares of its common stock to Prime Medicine, and Prime Medicine had an obligation to issue 5,000,000 shares of its common stock to the Company, should the Company elect to extend the collaboration beyond one year . In September 2020, the Company elected to continue the collaboration and, in October 2020, issued 200,307 shares of the Company’s common stock to Prime Medicine. Additionally, in October 2020, the Company received 5,000,000 shares of Prime Medicine’s common stock. In October 2022, Prime completed an initial public offering of its common stock. In connection with Prime's initial public offering, Prime effected a one-for- 3.1088 reverse stock split. As of December 31, 2023 , the Company owned 1,608,337 shares of Prime's common stock valued at $ 14.2 million. Additionally, the Company provided immaterial interim management and startup services to Prime Medicine through March 2021 but did not provide any such services during 2022 or 2023. As of December 31, 2023, the Company determined that future milestones and royalties under the agreement were not probable of recognition. Verve In April 2019, the Company entered into a collaboration and license agreement with Verve, or 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. In connection with the Verve Agreement, Verve issued the Company 2.6 million shares of its common stock as partial consideration for the licenses granted, having a fair value of $ 0.5 million. The fair value of the Verve common stock was determined by management with the assistance of a third-party valuation specialist. In addition, to the extent certain clinical, regulatory, and commercial milestones were met with respect to licensed products, Verve was required to pay to the Company certain amounts, as defined in the agreement. Lastly, to the extent there were sales of a licensed product, Verve was obligated to pay the Company royalties, as defined in the agreement. The Company also purchased shares of Verve's Series A preferred stock during the year ended December 31, 2020. During June 2021, Verve completed an initial public offering of its common stock. In connection with Verve’s initial public offering, Verve effected a one-for- 9.2592 reverse stock split and also converted all shares of its preferred stock into shares of common stock. As of December 31, 2023, the Company owned 546,970 shares of Verve's common stock valued at $ 7.6 million. Management determined that the performance obligations associated with the Verve Agreement were the combined licenses and improvements related to the licensed technology. All other items promised to Verve were immaterial in the context of the agreement. The fair value of the shares issued by Verve to the Company were considered a fixed upfront payment of $ 0.5 million in the form of non-cash consideration. In October 2023, the Company, Verve, and Lilly entered into a Side Letter Agreement whereby the Company agreed to delegate to Lilly certain rights and obligations existing under the Verve Agreement, including the Company’s rights and obligations to co-develop and co-commercialize opt-in products, the financial rights to milestone and royalty payments, and the right to participate on certain joint decision-making committees. The Company determined that the transfer and delegation of rights represents a modification of the Verve Agreement to be accounted for as if it were part of the existing contract in accordance with ASC 606. Prior to the modification, the Company determined that its performance obligations associated with the Verve Agreement at contract inception and subsequent modifications were not distinct and represented a single performance obligation, and that the obligation would be completed over the performance period of the agreement. Accordingly, the upfront payment was being recognized as revenue using a time-based proportional performance model over the contract term (April 2019 through 2038) of the collaboration,

Common Stock

Common Stock	12 Months Ended
	Dec. 31, 2023
Equity, Attributable to Parent [Abstract]
Common Stock	12. Common stock In January 2021, the Company issued and sold 2,795,700 shares of its common stock in a private placement at an offering price of $ 93.00 per share for aggregate gross proceeds of $ 260.0 million. The Company received $ 252.0 million in net proceeds after deducting fees to the placement agents and offering expenses payable by the Company. 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 its 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. 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 it. 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 an additional $ 800.0 million. As of December 31, 2023, 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 it. In May 2021, the first success payment measurements under each of the Harvard and Broad License Agreements occurred and success payments to Harvard and Broad Institute were calculated to be $ 15.0 million and $ 15.0 million, respectively. The Company elected to make each payment in shares of the Company’s common stock and issued 174,825 shares of the Company’s common stock to each of Harvard and Broad Institute to settle these liabilities in June 2021. The holders of the Company’s common stock are entitled to one vote for each share of common stock. The holders of the Company’s common stock shall be entitled to receive ratably dividends out of funds legally available. In the event of any voluntary or involuntary liquidation, dissolution, or winding up of the Company, after the payment or provision for payment of all debts and liabilities of the Company, the holders of common stock shall be entitled to share ratably in the remaining assets of the Company available for distribution.

Stock Option and Grant Plan

Stock Option and Grant Plan	12 Months Ended
	Dec. 31, 2023
Share-Based Payment Arrangement [Abstract]
Stock Option and Grant Plan	13. Stock option and grant plan 2017 stock option and grant plan In June 2017, the Company’s board of directors adopted the Beam Therapeutics Inc. 2017 Stock Option and Grant Plan, or the 2017 Plan, which provided for the grant of qualified incentive stock options and nonqualified stock options, restricted stock or other awards to the Company’s employees, officers, directors, advisors, and outside consultants for the issuance or purchase of shares of the Company’s common stock. The 2017 Plan is administered by the board of directors. Stock options awarded under the 2017 Plan expire 10 years after the grant date. Vesting periods for awards under the 2017 Plan are determined at the discretion of the board of directors. Incentive stock options granted to employees and shares of restricted stock granted to officers, founders and consultants of the Company typically vest over four years . Certain options provide for accelerated vesting if there is a change in control, as defined in the 2017 Plan. Non-statutory options granted to employees, officers, members of the board of directors and consultants of the Company typically vest over four years . 2019 incentive plan In October 2019, the Company’s board of directors adopted the Beam Therapeutics Inc. 2019 Equity Incentive Plan, or the 2019 Plan, and, following the IPO, all equity-based awards are granted under the 2019 Plan. The 2019 Plan provides for the grant of qualified and nonqualified stock options, stock appreciation rights, restricted and unrestricted stock and stock units, performance awards, and other share-based awards to the Company’s employees, officers, directors, advisors, and outside consultants. The maximum number of shares of the Company’s common stock that may be issued under the 2019 Plan was initially 3,700,000 shares, or the Share Pool, plus the number of shares of the Company’s common stock underlying awards under the 2017 Plan, not to exceed 5,639,818 shares, that become available again for grant under the 2017 Plan in accordance with its terms. The Share Pool will automatically increase on January 1st of each year from 2021 to 2029 by the lesser of (i) four percent of the number of shares of the Company’s common stock outstanding as of the close of business on the immediately preceding December 31st and (ii) the number of shares determined by the Company’s board of directors on or prior to such date for such year. As of December 31, 2023 , the Company had 12,376,374 shares reserved and 1,173,189 shares available for future issuance under the 2019 Plan. Stock-based compensation expense recorded as research and development and general and administrative expenses in the consolidated statements of operations and other comprehensive loss is as follows (in thousands): Years Ended December 31, 2023 2022 2021 Research and development $ 57,812 $ 52,004 $ 26,644 General and administrative 40,835 32,317 16,926 Total stock-based compensation expense $ 98,647 $ 84,321 $ 43,570 Stock options The assumptions used in the Black-Scholes option-pricing model for stock options granted were: Years Ended December 31, 2023 2022 2021 Expected volatility 76.3 - 78.8 % 74.8 - 77.3 % 71.4 - 76.7 % Weighted-average risk-free interest rate 3.73 % 2.27 % 1.11 % Expected dividend yield 0.00 % 0.00 % 0.00 % Expected term (in years) 6.03 6.08 6.12 The following table provides a summary of option activity under the Company’s equity award plans: Number Weighted Weighted Aggregate Outstanding at December 31, 2022 7,548,392 $ 41.77 7.5 $ 110,990 Granted 2,356,838 39.62 Exercised ( 797,709 ) 7.69 Forfeitures ( 831,488 ) 60.18 Outstanding at December 31, 2023 8,276,033 42.59 7.2 51,653 Exercisable as of December 31, 2023 4,818,116 $ 37.81 6.3 $ 45,895 (1) The aggregate intrinsic value is calculated as the difference between the exercise price of the underlying options and the estimated fair value of the common stock for the options that were in the money as of December 31, 2023 and 2022 . The Company has granted stock options to certain employees to purchase shares of common stock that contain certain performance-based vesting criteria, primarily related to the achievement of certain development milestones related to editing applications, and the closing price of the Company’s common stock following an IPO. Recognition of stock-based compensation expense associated with these performance-based stock options commences when the performance condition is considered probable of achievement, using management’s best estimates, which consider the inherent risk and uncertainty regarding the future outcomes of the milestones. There was no expense related to performance-based stock options for the year ended December 31, 2023. The expense related to performance-based options was immaterial for the years ended December 31, 2022 and 2021. The weighted-average grant date fair value per share of stock options granted during the years ended December 31, 2023, 2022 and 2021, was $ 27.88 , $ 40.86 and $ 58.56 , respectively. The aggregate intrinsic value of stock options exercised during the years ended December 31, 2023, 2022 and 2021 was $ 20.0 million, $ 23.4 million and $ 85.1 million, respectively. The weighted-average exercise price of stock options exercised for the years ended December 31, 2023, 2022 and 2021 was $ 7.69 , $ 5.64 and $ 9.88 , respectively. As of December 31, 2023, there was $ 111.5 million of unrecognized compensation cost related to unvested stock options, which is expected to be recognized over a weighted-average period of approximately 2.3 years. Restricted stock The Company issued shares of restricted common stock during the years ended December 31, 2023, 2022 and 2021, which consisted only of restricted stock units. Restricted common stock issued generally vests over a period of two to four years . Generally, if the holders of restricted stock units cease to have a business relationship with the Company, any unvested restricted stock units will be cancelled. The following summarizes the Company’s restricted stock activity: Shares Weighted- Unvested as of December 31, 2022 1,692,819 $ 65.49 Issued 2,050,025 28.69 Vested ( 469,531 ) 67.77 Forfeited ( 346,161 ) 52.49 Unvested as of December 31, 2023 2,927,152 $ 40.89 The aggregate fair value of restricted shares that vested during the years ended December 31, 2023, 2022 and 2021 was $ 13.8 million, $ 53.1 million and $ 6.4 million, respectively. At December 31, 2023, there was approximately $ 72.8 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 2.2 years. 2019 Employee Stock Purchase Plan In February 2020, the Company’s board of directors adopted the Beam Therapeutics Inc. 2019 Employee Stock Purchase Plan, or ESPP, which was approved by the Company’s stockholders. Pursuant to the ESPP, certain employees of the Company, excluding consultants and non-employee directors, are eligible to purchase common stock of the Company at a reduced rate during offering periods. The ESPP permits participants to purchase common stock using funds contributed through payroll deductions, subject to a calendar year limit of $ 25,000 and at a purchase price of 85 % of the lower of the fair market value of the Company’s common stock on the first trading day of the offering period or on the applicable purchase date, which will be the final trading day of the applicable purchase period. The Company uses the straight-line attribution approach to record the expense over the offering period. Stock-based compensation expense related to the ESPP for the years ended December 31, 2023 , 2022 and 2021 was $ 1.3 million, $ 1.5 million, $ 0.3 million, respectively. The Company issued 130,403 and 70,073 shares under the ESPP during the years ended December 31, 2023 and 2022 , respectively. There were no shares issued under the ESPP during the year ended December 31, 2021. As of December 31, 2023 , the Company had 2,247,569 shares available for issuance under the ESPP.

Net Loss per Share Attributable

Net Loss per Share Attributable to Common Stockholders	12 Months Ended
	Dec. 31, 2023
Earnings Per Share [Abstract]
Net Loss per Share Attributable to Common Stockholders	14. Net loss per share attributable to common stockholders As noted above, for periods in which the Company reports a net loss attributable to common stockholders, 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 attributable to common stockholders 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 attributable to common stockholders because including them would have had an anti-dilutive effect: As of December 31, 2023 2022 2021 Unvested restricted stock 2,927,152 1,692,819 1,126,206 Outstanding options to purchase common stock 8,276,033 7,548,392 6,034,192 ESPP 73,415 45,906 19,379 Total 11,276,600 9,287,117 7,179,777 The following table summarizes the computation of basic and diluted net loss per share attributable to common stockholders of the Company (in thousands, except share and per share amounts): Years Ended December 31, 2023 2022 2021 Numerator: Net loss $ ( 132,527 ) $ ( 289,088 ) $ ( 370,638 ) Denominator: Weighted average common shares outstanding, basic and diluted 77,151,771 70,015,305 64,227,676 Net loss per common share, basic and diluted $ ( 1.72 ) $ ( 4.13 ) $ ( 5.77 )

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2023
Income Tax Disclosure [Abstract]
Income Taxes	15. Income taxes A reconciliation of the income tax expense computed using the federal statutory income tax rate to the Company’s effective income tax rate is as follows: Years Ended December 31, 2023 2022 2021 Federal statutory rate 21.0 % 21.0 % 21.0 % State income taxes, net of federal benefit 13.3 7.4 5.1 Research and development tax credits 18.0 4.2 2.6 Nondeductible/ nontaxable permanent items ( 2.5 ) ( 1.8 ) 0.7 IPR&D Guide Acquisition — — ( 8.8 ) Change in valuation allowance ( 50.9 ) ( 32.0 ) ( 20.6 ) Total - 1.1 % - 1.2 % 0.0 % The components of the Company’s deferred taxes are as follows (in thousands): December 31, 2023 2022 Deferred tax assets: Net operating loss carryforwards $ 3,959 $ 25,740 Research and development tax credits 56,759 27,801 Accrued expenses and other 17,386 12,472 Deferred revenue 48,792 84,622 Derivative liabilities 2,951 4,920 Stock options 20,587 9,714 Amortization 30,917 19,893 Capitalized Research 137,721 63,816 Lease liability 47,179 48,122 Total deferred tax assets 366,251 297,100 ROU asset ( 30,830 ) ( 31,860 ) Property and equipment ( 649 ) ( 508 ) Other ( 5,415 ) ( 10,325 ) Less: valuation allowance ( 329,357 ) ( 254,407 ) Deferred tax assets, net $ — $ — For the years ended December 31, 2023 and 2022, the Company recorded a current tax provision of $ 1.4 million and $ 3.4 million of income tax expense, respectively, which reflects that Company generated taxable income that was not fully offset by the use of net operating loss carryforwards and tax credits. Management has evaluated the positive and negative evidence bearing upon the realizability of the Company’s deferred tax assets and has determined that it is more likely than not that the Company will not recognize the benefits of the deferred tax assets. As a result, the Company has recorded a full valuation allowance at December 31, 2023 and 2022. The valuation allowance increased by $ 75.0 million in 2023 due to the increase in deferred tax assets, primarily due to increased capitalization of research and development expenditures in 2023. The valuation allowance increased by $ 82.3 million in 2022. Additionally, Sections 382 and 383 of the Internal Revenue Code of 1986, as amended, limit a corporation’s ability to utilize tax attributes to the extent the corporation experiences an “ownership change,” generally defined as a greater than 50 percentage point change in ownership, measured by value, among 5% or greater shareholders over a rolling three-year testing period. To the extent a corporation experiences an ownership change, utilization of pre-ownership change tax attributes (e.g., net operating losses and general business tax credits) to offset post-ownership change taxable income or taxes, is subject to an annual limitation, generally calculated as the pre-ownership change equity value of the corporation, subject to certain prescribed adjustments, multiplied by the long-term tax exempt rate published monthly by the Internal Revenue Service. The Company completed a Section 382 study as of December 31, 2023, and determined that historical ownership changes occurred in June 2017, December 2018, and December 2021. In addition, the Company may experience ownership changes in the future as a result of shifts in stock ownership. As of December 31, 2023 and 2022, the Company had $ 16.6 million and $ 120.3 million, respectively, of federal net operating loss carryforwards that do not expire. Additionally, as of December 31, 2023, the Company had $ 41.3 million of federal and $ 19.5 million of Massachusetts tax credits that expire starting in 2042 and 2037 . As of December 31, 2023, and 2022, the Company had no uncertain tax positions. The Company recognizes both interest and penalties associated with unrecognized tax benefits as a component of income tax expense. The Company has no t recorded any interest or penalties for unrecognized tax benefits since its inception. The Company filed income tax returns in the United States and the Commonwealth of Massachusetts in all tax years since inception. Tax years beginning in 2020 remain open to examination in these jurisdictions, as carryforward attributes generated in past years may be adjusted in a future period. The IRS has not made any assessments as of December 31, 2023.

Related Party Transactions

Related Party Transactions	12 Months Ended
	Dec. 31, 2023
Related Party Transactions [Abstract]
Related Party Transactions	16. Related party transactions Orbital As described in Note 11, 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 For the years ended December 31, 2023, 2022 and 2021 , the Company made payments of $ 0.4 million, $ 0.4 million and $ 0.5 million, respectively, to its three founder shareholders for scientific consulting and other expenses. Verve The Company and Verve are parties to a collaboration and license agreement and had a common board member through the first half of 2022. As of December 31, 2023, the Company owned 546,970 shares of Verve's common stock, the value of which is included in marketable securities in the consolidated balance sheet. See discussion of the collaboration and license agreement in Note 11 and the Company's investment in Verve's common stock in Note 5. The Company purchased an immaterial amount of certain materials from Verve, which is recorded as research and development expenses within the accompanying consolidated statements of operations and other comprehensive loss for the years ended December 31, 2022, and 2021 respectively. The Company did not purchase any materials from Verve during the year ended December 31, 2023. In October 2021, the Company entered into an agreement pursuant to which Verve subleased 12,000 square feet of the Company’s existing office and laboratory space for a term of one year which began in December 2021 . The Company recorded $ 1.3 million and $ 0.1 million of sublease income related to this sublease within the accompanying consolidated statements of operations and other comprehensive loss for the years ended December 31, 2022 and 2021, respectively, as well as its proportionate costs for the landlord’s operating expense, insurance, property taxes, and utilities. As of December 31, 2022, the Verve sublease agreement had expired and as such no sublease income was recognized during the year ended December 31, 2023. Prime Medicine The Company and Prime Medicine are parties to a collaboration and license agreement and have a common founder and had a common board member into the third quarter of 2022. As of December 31, 2023, the Company owned 1,608,337 shares of Prime's common stoc k, the value of which is included in marketable securities in the consolidated balance sheet. See discussion of the collaboration and license agreement in Note 11 and the Company's investment in Prime's common stock in Note 5.

Employee Benefits

Employee Benefits	12 Months Ended
	Dec. 31, 2023
Retirement Benefits [Abstract]
Employee Benefits	17. Employee benefits In 2018, the Company established a defined-contribution plan under Section 401(k) of the Internal Revenue Code, or the 401(k) Plan. The 401(k) Plan covers all employees who meet defined minimum age and service requirements and allows participants to defer a portion of their annual compensation on a pre-tax basis. Beginning January 1, 2020, the Company made matching contributions equal to 50 % of the employee’s contributions, subject to a maximum of 6 % of eligible compensation. The Company made matching contributions of $ 2.5 million, $ 2.0 million, and $ 1.1 million for the years ended December 31, 2023, 2022, and 2021 respectively.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2023
Accounting Policies [Abstract]
Basis of Presentation	Basis of presentation The accompanying 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 the FASB.
Principles of Consolidation	Principles of consolidation The accompanying 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 consolidated financial statements include, but are not limited to, incremental borrowing rate used in the calculation of lease liabilities, research and development expenses, the fair values of common stock, stock-based compensation, contingent consideration liabilities, success payments, estimated license fees, contingent liabilities, and certain judgments regarding revenue recognition. Actual results could differ from these estimates.
Cash, Cash Equivalents, and Restricted Cash	Cash, cash equivalents, and restricted cash Cash and cash equivalents consist of 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 facilities. The following table reconciles cash, cash equivalents, and restricted cash reported within the Company’s consolidated balance sheets to the total of the amounts shown in the consolidated statements of cash flows (in thousands): December 31, 2023 2022 2021 Cash and cash equivalents $ 435,895 $ 232,767 $ 559,994 Restricted cash 8,719 12,754 12,746 Total cash, cash equivalents, and restricted cash $ 444,614 $ 245,521 $ 572,740
Marketable Securities	Marketable securities The Company classifies marketable securities as available-for-sale. Available-for-sale securities consist of commercial paper, high-grade corporate notes, U.S. Treasury securities and government securities. Available-for-sale securities are carried at fair value with the unrealized gains and losses included in accumulated other comprehensive (loss) income as a component of stockholders’ equity until realized. Any premium or discount arising at purchase is amortized and/or accreted to interest income and/or expensed over the life of the instrument. Realized gains and losses are determined using the specific identification method and are included in interest and other income (expense), net.
Corporate Equity Securities	Corporate equity securities The Company classifies investments in equity securities that have a readily determinable fair value as marketable securities in the Company's consolidated balance sheets. The Company’s marketable securities are stated at fair value. Typically, the fair value of these securities is based on a quoted price for an identical equity security. The Company held an investment in privately issued corporate equity securities, which were accounted for as investments in equity securitie s. This investment did not have a readily determinable fair value and the Company valued the investment based on the cost of the equity securities adjusted for observable market transactions or impairments, if any, and records any changes in value through earnings. The Company records changes in the fair value of its equity securities in other income (expense), net in its consolidated statements of operations and other comprehensive loss. Equity method of accounting In circumstances where the Company has the ability to exercise significant influence, but not control, over the operating and financial policies of an entity in which the Company has an investment in common stock or in-substance common stock, the Company utilizes the equity method of accounting for recording related investment activity. In assessing whether the Company exercises significant influence, the Company considers the nature and magnitude of the investment, participating rights the Company holds, and relevant factors such as the presence of a collaborative or other business relationship. Under the equity method of accounting, the Company’s investments are initially recorded at cost on the consolidated balance sheets. Upon recording an equity method investment, the Company evaluates whether there are basis differences between the carrying value and fair value of the Company’s proportionate share of the investee’s underlying net assets. Typically, the Company amortizes basis differences identified on a straight-line basis over the underlying asset’s or liability's estimated useful lives when calculating the attributable earnings or losses, excluding the basis differences attributable to in-process research and development, or IPR&D, that has no alternative future use. To the extent a basis difference relates to IPR&D and the investee is not a business as defined in ASC 805, Business Combinations, or ASC 805, the Company immediately expenses such basis difference related to IPR&D. If the Company is unable to attribute all of the basis difference to specific assets or liabilities of the investee, the residual excess of the cost of the investment over the proportional fair value of the investee’s assets and liabilities is considered to be Equity Method Goodwill and is recognized within the equity investment balance, which is tracked separately within the Company’s memo accounts. The Company subsequently records in the consolidated statements of operations and comprehensive loss its share of income or loss of the other entity within the loss from equity method investment line item. If the share of losses exceeds the carrying value of the Company’s investment, the Company will suspend recognizing additional losses and will continue to do so unless it commits to providing additional funding or commits to guarantee investee liabilities. The Company evaluates its equity method investments for impairment whenever events or changes in circumstances indicate that the carrying amounts of such investments may be impaired and considers qualitative and quantitative factors including the investee’s financial metrics, product and commercial outlook and cash usage. If a decline in the value of an equity method investment is determined to be other than temporary, a loss is recorded in earnings in the current period and the investment is written down to fair value. At December 31, 2023 , the Company accounted for its investment in Orbital under the equity method of accounting. The Company has no carrying value related to this investment as of December 31, 2023 and 2022. Refer to Note 11 for further details.
Concentrations of Credit Risk	Concentrations of credit risk Financial instruments that are potentially subject to significant concentration of credit risk consist primarily of cash, cash equivalents, marketable securities, and restricted cash. The Company attempts to minimize the risk related to marketable securities by working with highly rated financial institutions that invest in a broad and diverse range of financial instruments. The Company has established guidelines relative to credit ratings and maturities intended to safeguard principal balances and maintain liquidity. The Company maintains its funds in accordance with its investment policy, which defines allowable investments, specifies credit quality standards and is designed to limit credit exposure to any single issuer.
Guarantees and Indemnifications	Guarantees and indemnifications As permitted under Delaware law, the Company indemnifies its officers, directors, consultants, and employees for certain events or occurrences that happen by reason of the relationship with, or position held at, the Company. For the years ended December 31, 2023, 2022 and 2021 , the Company had not experienced any losses related to these indemnification obligations, and no claims were outstanding. The Company does not expect significant claims related to these indemnification obligations and, consequently, concluded that the fair value of these obligations is negligible, and no related reserves were established.
Equity Issuance Costs	Equity issuance costs The Company capitalizes incremental legal, professional, accounting and other third-party fees that were directly associated with its stock offerings as other non-current assets until the offerings are consummated. Upon consummation, these costs are recorded in stockholders’ equity as a reduction of additional paid-in-capital generated as a result of the offerings. As of December 31, 2023 and 2022 , there were no deferred offering costs.
Fair Value of Financial Instruments	Fair value of financial instruments ASC Topic 820, Fair Value Measurement , or ASC 820, establishes a fair value hierarchy for instruments measured at fair value that distinguishes between assumptions based on market data (observable inputs) and the Company’s own assumptions (unobservable inputs). Observable inputs are inputs that market participants would use in pricing the asset or liability based on market data obtained from independent sources. Unobservable inputs are inputs that reflect the Company’s assumptions about the inputs that market participants would use in pricing the assets or liability and are developed based on the best information available in the circumstances. ASC 820 identifies fair value as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. As a basis for considering market participant assumptions in fair value measurements, ASC 820 establishes a three-tiered value hierarchy that distinguishes between the following: Level 1—Quoted market prices in active markets for identical assets or liabilities. Level 2—Inputs other than Level 1 inputs that are either directly or indirectly observable, such as quoted market prices, interest rates and yield curves. Level 3—Unobservable inputs for the asset or liability (i.e., supported by little or no market activity). Level 3 inputs include management’s own assumptions about the assumptions that market participants would use in pricing the asset or liability (including assumptions about risk). To the extent the valuation is based on models or inputs that are less observable or unobservable in the market, the determination of fair values requires more judgment. Accordingly, the degree of judgment exercised by the Company in determining fair value is greatest for instruments categorized as Level 3. A financial instrument’s level within the fair value hierarchy is based on the lowest level of any input that is significant to the fair value measurement. There have been no changes to the valuation methods utilized during the years ended December 31, 2023 and 2022 . The Company evaluates transfers between levels at the end of each reporting period.
Property and Equipment	Property and equipment Property and equipment are stated at cost less accumulated depreciation. Depreciation expense is recognized using the straight-line method over the estimated useful life of each asset as follows: Asset category Estimated useful life Computer equipment and software 3 years Laboratory equipment and office furniture 5 years Leasehold improvements Shorter of useful life or remaining term Upon retirement or sale, the cost of assets disposed of and the related accumulated depreciation are removed from the accounts and any resulting gain or loss is included in interest and other income (expense). Expenditures for repairs and maintenance are charged to expense as incurred.
Impairment of Long-Lived Assets	Impairment of long-lived assets The Company evaluates its long-lived assets, which consist primarily of property and equipment and operating lease right-of-use assets, for impairment whenever events or changes in circumstances indicate that the carrying amount of such assets (or asset groups) may not be recoverable. Recoverability of assets to be held and used is measured by a comparison of the carrying amount of an asset to the future undiscounted net cash flows expected to be generated by the asset. If such assets are considered to be impaired, the impairment to be recognized is measured by the amount by which the carrying amount of the asset exceeds the fair value of the asset. There were no impairment losses recognized during the years ended December 31, 2023, 2022 and 2021 .
Freestanding Financial Instruments and Derivatives	Freestanding financial instruments and derivatives Pursuant to a license agreement between the President and Fellows of Harvard College, or Harvard, and the Company, or the Harvard License Agreement, and a license agreement with The Broad Institute, Inc., or Broad Institute, and the Company, or the Broad License Agreement, (see Note 10), the Company is required to make success payments to Harvard and Broad Institute based the achievement of specified multiples of the initial weighted average value of the Company’s redeemable convertible Series A-1 Preferred Stock and the Company’s redeemable convertible Series A-2 Preferred Stock, or together the Series A Preferred, at specified valuation dates, payable in cash or Company common stock. Subsequent to the IPO, the amount of the success payments is based on the market value of Beam’s common stock. The success payments are accounted for as derivatives under ASC 815, Derivatives and Hedging and were initially recorded at fair value with a corresponding charge to research and development expense. The liabilities are recorded at fair value at each balance sheet date with all changes in value recognized in other income (expense), in the consolidated statement of operations and other comprehensive loss. The Company will continue to adjust the liability for changes in fair value until the earlier of the achievement or expiration of the success payment obligation. To determine the estimated fair value of the success payments, the Company used a Monte Carlo simulation model, which models the value of the liability based on several key variables, including probability of event occurrence, timing of event occurrence, as well as the value of the Series A Preferred, prior to the IPO, and the value of the Company’s common stock, subsequent to the IPO.
Leases and Rent Expense	Leases and rent expense The Company accounts for leases using a right-of-use, or ROU, model, which recognizes that, at the date of commencement, a lessee has a financial obligation to make lease payments to the lessor for the right to use the underlying asset during the lease term. At the inception of an arrangement, the Company determines whether the arrangement is or contains a lease based on the unique facts and circumstances present in the arrangement. Leases with a term greater than one year are recognized on the balance sheet as ROU assets and short-term and long-term lease liabilities, as applicable. ROU assets represent the Company’s right to use an underlying asset for the lease term and lease liabilities represent its obligation to make lease payments arising from the lease. The Company typically only includes an initial lease term in its assessment of the term of the lease arrangement. It also considers termination options and factors those into the determination of lease payments. Options to renew a lease are not included in the lease term unless there is reasonable certainty that the Company will renew. Operating lease liabilities and their corresponding ROU assets are recorded based on the present value of lease payments over the expected remaining lease term. Certain adjustments to the ROU asset may be required for items such as incentives received. The interest rate implicit in lease contracts is typically not readily determinable. As a result, the Company utilizes its incremental borrowing rate, which reflects the fixed rate at which it could borrow on a collateralized basis the amount of the lease payments in the same currency, for a similar term, in a similar economic environment. Lease expense for operating lease payments is recognized on a straight-line basis over the lease term. The Company is required to pay fees for operating expenses in addition to monthly base rent for certain operating leases (non-lease components). The Company has elected the practical expedient which allows non-lease components to be combined with lease components for all asset classes. Variable lease payments are not included within the lease right-of-use asset and lease liability on the consolidated balance sheet, and instead are reflected as expense in the period they are incurred. Leasehold improvements are not unique and are retained by the lessor at the end of the lease. However, in the case of a space designed to be suitable for the Company’s specific real estate needs and if the Company is responsible for cost overruns, the Company is the accounting owner of the leasehold improvements and costs associated are capitalized. The Company’s real estate operating leases provide for scheduled annual rent increases throughout the lease terms. The Company recognizes the effects of the scheduled rent increases on a straight-line basis over the full terms of the lease. Tenant improvement allowances, if any, provided by a landlord are recorded as a reduction of the ROU asset related to that lease at lease commencement.
Asset Acquisitions	Asset acquisitions The Company measures and recognizes asset acquisitions that are not deemed to be business combinations based on the cost to acquire the assets, which includes transaction costs, and the consideration is allocated to the items acquired based on a relative fair value methodology. Goodwill is not recognized in asset acquisitions. In an asset acquisition, the cost allocated to acquire in-process research and development with no alternative future use is charged to research and development expense at the acquisition date. At the time of acquisition, the Company determines if a transaction should be accounted for as a business combination or acquisition of assets.
Contingent Consideration Liabilities	Contingent consideration liabilities The Company may be required to make milestone payments to the former stockholders and optionholders of Guide Therapeutics, Inc., or Guide, in the form of its common stock based on the achievement of certain product and technology milestones. The payments are accounted for 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 primarily based upon the achievement and related timing of certain product and technology milestones that were unobservable in the market. The estimated fair value of contingent consideration liabilities, initially measured and recorded on the acquisition date, are considered to be a Level 3 measurement and are reviewed quarterly, or whenever events or circumstances occur that indicate a change in fair value. The contingent consideration liabilities are recorded at fair value at the end of each reporting period with changes in estimated fair values recorded in other income (expense) in the consolidated statements of operations and other comprehensive loss. The estimated fair value is determined based on probability adjusted discounted cash flow model that include significant estimates and assumptions pertaining to technology and product development. Significant changes in any of the probabilities of success or in the probabili ties as to the periods in which milestones would be achieved would result in a significantly higher or lower fair value measurement. The Company will continue to adjust the liabilities for changes in fair value until the earlier of the achievement or expiration of the obligations.
Revenue Recognition	Revenue recognition At inception, the Company determines whether contracts are within the scope of ASC 606 or other topics. For contracts that are determined to be within the scope of ASC 606, revenue is recognized when a customer obtains control of promised goods or services. The amount of revenue recognized reflects the consideration to which the Company expects to be entitled to receive in exchange for these goods and services. To achieve this core principle, the Company applies the following five steps: (i) identify the contract with the customer; (ii) identify the performance obligations in the contract; (iii) determine the transaction price; (iv) allocate the transaction price to the performance obligations in the contract; and (v) recognize revenue when the performance obligation is satisfied. The Company only applies the five-step model to contracts when it determines that collection of substantially all consideration for goods and services that are transferred is probable based on the customer’s intent and ability to pay the promised consideration. Performance obligations promised in a contract are identified based on the goods and services that will be transferred to the customer that are both capable of being distinct and are distinct in the context of the contract. To the extent a contract includes multiple promised goods and services, the Company applies judgment to determine whether promised goods and services are both capable of being distinct and are distinct in the context of the contract. If these criteria are not met, the promised goods and services are accounted for as a combined performance obligation. The transaction price is determined based on the consideration to which the Company will be entitled in exchange for transferring goods and services to the customer. To the extent the transaction price includes variable consideration, the Company estimates the amount of variable consideration that should be included in the transaction price utilizing either the expected value method or the most likely amount method, depending on the nature of the variable consideration. Variable consideration is included in the transaction price if, in management’s judgment, it is probable that a significant future reversal of cumulative revenue under the contract will not occur. Any estimates, including the effect of the constraint on variable consideration, are evaluated at each reporting period for any changes. Determining the transaction price requires significant judgment and is discussed in further detail for each of the Company’s license and collaboration agreements in Note 11. If the contract contains a single performance obligation, the entire transaction price is allocated to the single performance obligation. Contracts that contain multiple performance obligations require an allocation of the transaction price to each performance obligation on a relative standalone selling price basis unless the transaction price is variable and meets the criteria to be allocated entirely to a performance obligation or to a distinct service that forms part of a single performance obligation. Determining the standalone selling price requires significant judgment and is discussed in further detail for each of the Company’s license and collaboration agreements in Note 11. The Company satisfies performance obligations either over time or at a point in time. Revenue is recognized over time if either (i) the customer simultaneously receives and consumes the benefits provided by the entity’s performance, (ii) the entity’s performance creates or enhances an asset that the customer controls as the asset is created or enhanced, or (iii) the entity’s performance does not create an asset with an alternative use to the entity and the entity has an enforceable right to payment for performance completed to date. If the entity does not satisfy a performance obligation over time, the related performance obligation is satisfied at a point in time by transferring the control of a promised good or service to a customer. Licenses of intellectual property, or IP: If the license to the Company’s IP is determined to be distinct from the other performance obligations identified in the arrangement, the Company recognizes revenues from consideration allocated to the license when the license is transferred to the customer and the customer can use and benefit from the licenses. For licenses that are combined with other promises, the Company utilizes judgment to assess the nature of the combined performance obligation to determine whether the combined performance obligation is satisfied over time or at a point in time and, if over time, the appropriate method of measuring progress for purposes of recognizing revenue. The Company evaluates the measure of progress each reporting period and, if necessary, adjusts the measure of performance and related revenue recognition. The Company generally recognizes revenue using the cost incurred to date as compared to the total estimated cost. The impact on revenue of changes in total estimated costs are recognized on a cumulative basis in the period that the change occurs. If estimates of the total cost change, or if contract amendments change the scope of the performance obligation, the required adjustments to revenue could be material. Determining the revenue recognition of IP licenses requires significant judgment and is discussed in further detail for each of the Company’s license and collaboration agreements in Notes 10 and 11. Milestone payments: At the inception of each arrangement that includes development or regulatory milestone payments, the Company evaluates the probability of reaching the milestones and estimates the amount to be included in the transaction price using the most likely amount method. If it is probable that a significant revenue reversal would not occur in the future, the associated milestone value is included in the transaction price. Milestone payments that are not within the Company’s control or the licensee’s, such as regulatory approvals, are not considered probable of being achieved until those approvals are received and therefore consideration included in the transaction price is constrained. The transaction price is then allocated to each performance obligation on a relative standalone selling price basis, for which the Company recognizes revenue as or when the performance obligations under the contract are satisfied. At the end of each subsequent reporting period, the Company re-evaluates the probability of achievement of such development milestones and any related constraint, and if necessary, adjusts its estimate of the overall transaction price. Any such adjustments are recorded on a cumulative catch-up basis, which would affect revenues and earnings in the period of adjustment. Commercial Milestone Payments and Royalties: For arrangements that include sales-based royalties, including milestone payments based on levels of sales, if the license is deemed to be the predominant item to which the royalties relate, the Company recognizes revenue at the later of (i) when the related sales occur, or (ii) when the performance obligation to which some or all of the royalty has been allocated has been satisfied (or partially satisfied). To date, the Company has not recognized any royalty revenue resulting from any of its agreements. When no remaining performance obligations are required of the Company, or following the completion of the performance obligation period, such amounts are recognized as revenue upon transfer of control of the goods or services to the customer. Generally, all amounts received or due other than sales-based milestones and royalties are classified as license and collaboration revenue. Sales-based milestones and royalties will be recognized as royalty revenue at the later of when the related sales occur or when the performance obligation to which some or all of the royalty has been allocated has been satisfied (or partially satisfied). Deferred revenue expected to be recognized within the next twelve months is classified as a current liability.
Contract Balances	Contract balances The Company recognizes a contract asset when the Company transfers goods or services to a customer before the customer pays consideration or before payment is due, excluding any amounts presented as an account or other receivable. A contract asset is an entity’s right to consideration in exchange for goods or services that the entity has transferred to a customer. The contract liabilities, or deferred revenue, primarily relate to contracts where the Company has received payment, but it has not yet satisfied or fully satisfied the related performance obligations. Upfront payments and fees are recorded as deferred revenue upon receipt or when due and may require deferral of revenue recognition to a future period until the Company satisfies its obligations under these arrangements. Upfront payment contract liabilities resulting from the Company’s license agreements do not represent a financing component as the payment is not financing the transfer of goods or services, and the technology underlying the licenses granted reflects research and development expenses already incurred by the Company. The changes in the total deferred revenue for the years ended December 31, 2023 and 2022 were as follows (in thousands): December 31, December 31, Beginning balance $ 338,153 $ 348,573 Additions to deferred revenue from license agreements — 50,500 Amounts recognized in revenue ( 159,559 ) ( 60,920 ) Ending balance $ 178,594 $ 338,153
Research and Development Costs	Research and development costs Research and development costs are charged to expense as incurred. Research and development costs consist of costs incurred in performing research and development activities, including salaries and bonuses, stock-based compensation, employee benefits, facilities costs, laboratory supplies, depreciation, manufacturing expenses, preclinical expenses, consulting, and other contracted services. The cost of obtaining licenses for certain technology or IP is recorded to research and development expense when incurred if the licensed technology or IP has not yet reached technological feasibility and has no alternative future use. Costs for certain research and development activities are recognized based on the terms of the individual arrangements, which may differ from the pattern of costs incurred, and are reflected in the financial statements as prepaid or accrued research and development costs.
Stock-Based Compensation	Stock-based compensation The Company’s stock-based compensation program allows for grants of stock options, restricted stock awards and restricted stock units. Grants are awarded to employees and non-employees, including directors. The Company accounts for stock-based compensation in accordance with ASC Topic 718, Compensation-Stock Compensation , or ASC 718. ASC 718 requires all stock-based payments to employees, non-employees and directors to be recognized as expense in the consolidated statements of operations and other comprehensive loss based on their fair values. The Company estimates the fair value of options granted using the Black-Scholes option pricing model, or Black-Scholes, for stock option grants to both employees and non-employees. The fair value of the Company’s common stock is used to determine the fair value of restricted stock awards and restricted stock units. Stock-based compensation awards are subject to either service- or performance-based vesting conditions. Compensation expense related to awards to employees, directors and non-employees with service-based vesting conditions is recognized on a straight-line basis based on the grant date fair value over the associated service period of the award, which is generally the vesting term. Compensation expense related to awards to employees with performance-based vesting conditions is recognized based on grant date fair value over the requisite service period using the accelerated attribution method to the extent achievement of the of performance condition is probable. The Black-Scholes option pricing model requires inputs based on certain subjective assumptions, including (i) the expected stock price volatility, (ii) the expected term of the award, (iii) the risk-free interest rate, and (iv) expected dividends. The Company bases its computation of expected volatility on the historical volatility of a representative group of public companies with similar characteristics to the Company, including stage of product development and life science industry focus, weighted with its own volatility for the period in which its stock has been publicly traded. The historical volatility is calculated based on a period of time commensurate with expected term assumption. The Company uses the simplified method as prescribed by the SEC Staff Accounting Bulletin No. 107, Share-Based Payment , to calculate the expected term for options granted to employees and non-employees, whereby the expected term equals the arithmetic average of the vesting term and the original contractual term of the options due to its lack of sufficient historical data. The risk-free interest rate is based on U.S. Treasury securities with a maturity date commensurate with the expected term of the associated award. The expected dividend yield is assumed to be zero as the Company has never paid dividends and has no current plans to pay any dividends on its common stock. The Company recognizes forfeitures as they occur.
Patent Costs	Patent costs All patent-related costs incurred in connection with filing and prosecuting patent applications are expensed as incurred. Due to the uncertainty about the recovery of the expenditure, amounts incurred are classified as general and administrative expenses in the accompanying consolidated statements of operations and other comprehensive loss.
Variable Interest Entities	Variable interest entities The Company reviews each legal entity in which it has a financial interest to determine whether or not the entity is a variable interest entity, or VIE. If the entity is a VIE, the Company assesses whether or not it is the primary beneficiary of that VIE based on a number of factors, including (i) which party has the power to direct the activities that most significantly affect the VIE’s economic performance, (ii) the parties’ contractual rights and responsibilities pursuant to any contractual agreements and (iii) which party has the obligation to absorb losses or the right to receive benefits from the VIE. If the Company determines that it is the primary beneficiary of a VIE, it consolidates the financial statements of the VIE into its consolidated financial statements. If the Company determines that it is no longer the primary beneficiary of a consolidated VIE, or no longer has a variable interest in the VIE, the Company deconsolidates the VIE in the period that the determination is made.
Income Taxes	Income taxes The Company recognizes deferred tax assets and liabilities for the expected future tax consequences of events that have been included in the Company’s financial statements and tax returns. Deferred tax assets and liabilities are determined based upon the differences between the financial statement carrying amounts and the tax bases of existing assets and liabilities and for loss and credit carryforwards, using enacted tax rates expected to be in effect in the year in which the differences are expected to reverse. Deferred tax assets are reduced by a valuation allowance if it is more likely than not that these assets may not be realized. The Company determines whether it is more likely than not that a tax position will be sustained upon examination. If it is not more likely than not that a position will be sustained, none of the benefit attributable to the position is recognized. The tax benefit to be recognized for any tax position that meets the more-likely-than-not recognition threshold is calculated as the largest amount that is more than 50% likely of being realized upon resolution of the contingency. The Company accounts for interest and penalties related to uncertain tax positions as part of its provision for income taxes.
Comprehensive Loss	Comprehensive loss Comprehensive loss is defined as the change in stockholders’ equity of a business enterprise during a period from transactions and other events and circumstances from non-owner sources. Comprehensive loss includes net loss as well as other changes in equity that are excluded from net loss. The Company’s only element of other comprehensive loss is unrealized gains and losses on marketable securities.
Net Loss Per Share	Net loss per share The Company follows the two-class method when computing net loss per share, as the Company has issued shares that meet the definition of participating securities. The two-class method determines net loss per share for each class of common and participating securities according to dividends declared or accumulated and participation rights in undistributed earnings. The two-class method requires income available to common stockholders for the period to be allocated between common and participating securities based upon their respective rights to receive dividends as if all income for the period had been distributed. Basic net loss per share attributable to common stockholders is computed by dividing the net loss attributable to common stockholders by the weighted average number of common shares outstanding for the period. Diluted net loss attributable to common stockholders is computed by adjusting net loss attributable to common stockholders to reallocate undistributed earnings based on the potential impact of dilutive securities. Diluted net loss per share attributable to common stockholders is computed by dividing the diluted net loss attributable to common stockholders by the weighted average number of common shares outstanding for the period, including potential dilutive common shares assuming the dilutive effect of common stock equivalents. For purposes of the dilutive net loss per share calculation, stock options and stock units for which the performance and market vesting conditions have been deemed probable, potential dilutive securities, unvested restricted stock, and common stock options are considered to be common stock equivalents, while stock options and stock units with performance- or market-based vesting conditions that were not deemed probable of meeting the applicable vesting conditions are not considered to be common stock equivalents. Accordingly, in periods in which the Company reported a net loss, such losses were not allocated to such participating securities. In periods in which the Company reported a net loss attributable to common stockholders, diluted net loss per share attributable to common stockholders was the same as basic net loss per share attributable to common stockholders, since dilutive common shares were not assumed to have been issued if their effect is anti-dilutive. The Company reported a net loss attributable to common stockholders for the years ended December 31, 2023, 2022 and 2021 .
Segment and Geographic Information	Segment and geographic information Operating segments are defined as components of an entity about which separate discrete information is available for evaluation by the chief operating decision maker, or CODM, or decision-making group, in deciding how to allocate resources and in assessing performance. The CODM is the Company’s Chief Executive Officer. The Company views its operations as and manages its business in one operating segment operating exclusively in the United States. 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.
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.

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2023
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 consolidated balance sheets to the total of the amounts shown in the consolidated statements of cash flows (in thousands): December 31, 2023 2022 2021 Cash and cash equivalents $ 435,895 $ 232,767 $ 559,994 Restricted cash 8,719 12,754 12,746 Total cash, cash equivalents, and restricted cash $ 444,614 $ 245,521 $ 572,740
Estimated Useful Life of Property and Equipment	Property and equipment are stated at cost less accumulated depreciation. Depreciation expense is recognized using the straight-line method over the estimated useful life of each asset as follows: Asset category Estimated useful life Computer equipment and software 3 years Laboratory equipment and office furniture 5 years Leasehold improvements Shorter of useful life or remaining term
Summary of Changes in Total Deferred Revenue	The changes in the total deferred revenue for the years ended December 31, 2023 and 2022 were as follows (in thousands): December 31, December 31, Beginning balance $ 338,153 $ 348,573 Additions to deferred revenue from license agreements — 50,500 Amounts recognized in revenue ( 159,559 ) ( 60,920 ) Ending balance $ 178,594 $ 338,153

Property and Equipment, Net (Ta

Property and Equipment, Net (Tables)	12 Months Ended
	Dec. 31, 2023
Property, Plant and Equipment [Abstract]
Schedule of Property and Equipment	Property and equipment consist of the following (in thousands): December 31, December 31, Leasehold improvements $ 100,186 $ 85,804 Lab equipment 61,674 47,383 Furniture and fixtures 4,836 4,332 Computer equipment 3,163 3,073 Construction in process 5,283 5,198 Total property and equipment 175,142 145,790 Less accumulated depreciation ( 50,182 ) ( 30,170 ) Property and equipment, net $ 124,960 $ 115,620
Summary of Depreciation Expense Incurred	The following table summarizes depreciation expense incurred (in thousands): Years Ended December 31, 2023 2022 2021 Depreciation expense $ 20,012 $ 14,097 $ 7,201

Fair Value of Financial Instr_2

Fair Value of Financial Instruments (Tables)	12 Months Ended
	Dec. 31, 2023
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 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 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, 2022 (in thousands): Carrying Fair Level 1 Level 2 Level 3 Assets Cash equivalents: Money market funds $ 218,794 $ 218,794 $ 218,794 $ — $ — Commercial paper 10,475 10,475 — 10,475 — Corporate notes 3,498 3,498 — 3,498 — Marketable securities: Commercial paper 577,728 577,728 — 577,728 — Corporate notes 18,996 18,996 — 18,996 — U.S. Treasury securities 145,312 145,312 — 145,312 — U.S. Government securities 62,864 62,864 — 62,864 — Equity securities included in marketable securities: Corporate equity securities 40,467 40,467 40,467 — — Total assets $ 1,078,134 $ 1,078,134 $ 259,261 $ 818,873 $ — Liabilities Success payment liability – Harvard $ 9,000 $ 9,000 $ — $ — $ 9,000 Success payment liability – Broad Institute 9,300 9,300 — — 9,300 Contingent consideration liability – Technology 6,025 6,025 — — 6,025 Contingent consideration liability – Product 6,438 6,438 — — 6,438 Total liabilities $ 30,763 $ 30,763 $ — $ — $ 30,763
Summary Of Other Income (Expense) Incurred Due To Changes In Fair Value Of Corporate Equity Securities Held	The following table summarizes other income (expense) incurred due to changes in the fair value of corporate equity securities held (in thousands): Years Ended December 31, 2023 2022 2021 Other income (expense) $ ( 18,592 ) $ 20,200 $ 17,690
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 December 31, December 31, December 31, December 31, Fair value of common stock (per share) $ 27.22 $ 39.11 $ 27.22 $ 39.11 Expected volatility 80 % 82 % 79 % 82 % Expected term (years) 0.06 - 5.49 0.08 - 6.49 0.06 - 6.36 0.08 - 7.36
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): Year Ended December 31, 2023 Harvard Broad Institute Total Balance at December 31, 2021 $ 21,000 $ 21,200 $ 42,200 Change in fair value ( 12,000 ) ( 11,900 ) ( 23,900 ) Balance at December 31, 2022 $ 9,000 $ 9,300 $ 18,300 Change in fair value ( 3,800 ) ( 3,700 ) ( 7,500 ) Balance at December 31, 2023 $ 5,200 $ 5,600 $ 10,800
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 December 31, December 31, December 31, December 31, Discount Rate 10.00 % 10.00 % 10.00 % 10.00 % Probability of Achievement 2 - 5 % 5 - 15 % 1 - 2 % 2 - 15 % Projected Year of Achievement 2025 2024 - 2025 2025 - 2031 2025 - 2030
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): Technology Milestones Product Milestones Total Balance at December 31, 2021 $ 24,359 $ 7,008 31,367 Change in fair value ( 18,334 ) ( 570 ) ( 18,904 ) Balance at December 31, 2022 $ 6,025 $ 6,438 $ 12,463 Change in fair value ( 4,654 ) ( 5,086 ) ( 9,740 ) Balance at December 31, 2023 $ 1,371 $ 1,352 $ 2,723

Marketable Securities (Tables)

Marketable Securities (Tables)	12 Months Ended
	Dec. 31, 2023
Investments, Debt and Equity Securities [Abstract]
Summary of Marketable Securities Held	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 following table summarizes the Company’s marketable securities held at December 31, 2022 (in thousands): Amortized Cost Gross Gross Fair Value Commercial paper $ 578,813 $ 72 $ ( 1,157 ) $ 577,728 Corporate notes 19,033 — ( 37 ) 18,996 U.S. Treasury securities 146,270 — ( 958 ) 145,312 U.S. Government securities 63,214 13 ( 363 ) 62,864 Corporate equity securities 40,467 — — 40,467 Total $ 847,797 $ 85 $ ( 2,515 ) $ 845,367

Accrued Expenses and Other Cu_2

Accrued Expenses and Other Current Liabilities (Tables)	12 Months Ended
	Dec. 31, 2023
Payables and Accruals [Abstract]
Schedule of Accrued Expenses and Other Current Liabilities	Accrued expenses and other current liabilities consist of the following (in thousands): December 31, December 31, Accrued contingent obligation, refer to Note 10 $ 43,280 $ — Employee compensation and related benefits 21,774 19,122 Research costs 9,804 4,844 Process development and manufacturing costs 4,697 5,080 Professional fees 3,468 6,751 Equipment financing costs 484 1,853 Other 28,157 12,262 Total $ 111,664 $ 49,912

Leases (Tables)

Leases (Tables)	12 Months Ended
	Dec. 31, 2023
Summary of Operating Lease Costs	The following table summarizes operating lease costs as well as sublease income (in thousands): Years Ended December 31, 2023 2022 2021 Operating lease costs $ 22,063 $ 19,536 $ 18,309 Variable lease costs 5,777 4,364 2,065 Short-term lease costs 9,000 307 1,145 Sublease income — ( 1,319 ) ( 110 ) Total $ 36,840 $ 22,888 $ 21,409
Summary of Lease Term and Discount Rate	The following table summarizes the lease term and discount rate for operating leases: December 31, 2023 2022 Weighted-average remaining lease term (years) 10.3 11.0 Weighted-average discount rate 7.6 % 7.5 %
Summary of Lease Costs Included in Measurement of Lease Liabilities	The following table summarizes the lease costs included in the measurement of lease liabilities (in thousands): Years Ended December 31, 2023 2022 2021 Operating cash flows used for operating leases $ 22,603 $ 19,052 $ 11,462 Operating lease liabilities arising from obtaining ROU assets 3,852 41,050 25,925
Summary of Future Maturity of Operating Leases	At December 31, 2023, the future maturity of the Company’s operating leases for each of the next five years and total thereafter were as follows (in thousands): Years ending December 31, Amount 2024 $ 24,985 2025 25,315 2026 22,526 2027 23,157 2028 22,806 Thereafter 132,500 Undiscounted lease payments 251,289 Less: imputed interest ( 78,600 ) Total operating lease liabilities $ 172,689

Strategic Restructuring (Tables

Strategic Restructuring (Tables)	12 Months Ended
	Dec. 31, 2023
Restructuring and Related Activities [Abstract]
Schedule of Restructuring Liability Activity for Company's Workforce Reductions	Details of the restructuring liability activity for the Company's workforce reductions for the year ended December 31, 2023 as recorded in accrued expenses and other current liabilities in the consolidated balance sheet are as follows: Amount Accrued restructuring balance at December 31, 2022 $ — Expenses incurred 6,494 Payments ( 1,999 ) Accrued restructuring balance at December 31, 2023 $ 4,495

Guide Acquisition (Tables)

Guide Acquisition (Tables)	12 Months Ended
	Dec. 31, 2023
Business Combinations [Abstract]
Summary of Transaction Price Determined and Allocated	The transaction price was determined and allocated as follows (in thousands): Transaction price Fair value of equity instruments issued $ 120,032 Technology and product contingent consideration liabilities 36,513 Transaction costs 2,531 Total transaction price $ 159,076 Transaction price allocated In-process research and development $ 154,953 Cash acquired 3,151 Prepaid expenses and other assets 264 Property and equipment 1,835 Assembled workforce 300 Other liabilities assumed ( 1,427 ) Total transaction price $ 159,076

License Agreements (Tables)

License Agreements (Tables)	12 Months Ended
	Dec. 31, 2023
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): December 31, December 31, Harvard success payment liability $ 5,200 $ 9,000 The following table summarizes the Company’s success payment liability for Broad Institute (in thousands): December 31, 2023 2022 Broad Institute success payment liability $ 5,600 $ 9,300
Schedule of Change in Fair Value of Success Payment Liability	The following table summarizes the expense resulting from the change in the fair value of the success payment liability for Harvard (in thousands): Years Ended December 31, 2023 2022 2021 Change in fair value of Harvard success payment liability $ ( 3,800 ) $ ( 12,000 ) $ 500 The following table summarizes the expense resulting from the change in the fair value of the success payment liability for Broad Institute (in thousands): Years Ended December 31, 2023 2022 2021 Change in fair value of Broad Institute success payment liability $ ( 3,700 ) $ ( 11,900 ) $ 500

Stock Option and Grant Plan (Ta

Stock Option and Grant Plan (Tables)	12 Months Ended
	Dec. 31, 2023
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 consolidated statements of operations and other comprehensive loss is as follows (in thousands): Years Ended December 31, 2023 2022 2021 Research and development $ 57,812 $ 52,004 $ 26,644 General and administrative 40,835 32,317 16,926 Total stock-based compensation expense $ 98,647 $ 84,321 $ 43,570
Schedule of Assumptions Used in Black-Scholes Option-Pricing Model for Stock Options Granted	The assumptions used in the Black-Scholes option-pricing model for stock options granted were: Years Ended December 31, 2023 2022 2021 Expected volatility 76.3 - 78.8 % 74.8 - 77.3 % 71.4 - 76.7 % Weighted-average risk-free interest rate 3.73 % 2.27 % 1.11 % Expected dividend yield 0.00 % 0.00 % 0.00 % Expected term (in years) 6.03 6.08 6.12
Summary of Option Activity Under Equity Award Plans	The following table provides a summary of option activity under the Company’s equity award plans: Number Weighted Weighted Aggregate Outstanding at December 31, 2022 7,548,392 $ 41.77 7.5 $ 110,990 Granted 2,356,838 39.62 Exercised ( 797,709 ) 7.69 Forfeitures ( 831,488 ) 60.18 Outstanding at December 31, 2023 8,276,033 42.59 7.2 51,653 Exercisable as of December 31, 2023 4,818,116 $ 37.81 6.3 $ 45,895 (1) The aggregate intrinsic value is calculated as the difference between the exercise price of the underlying options and the estimated fair value of the common stock for the options that were in the money as of December 31, 2023 and 2022 .
Summary of Restricted Stock Activity	The following summarizes the Company’s restricted stock activity: Shares Weighted- Unvested as of December 31, 2022 1,692,819 $ 65.49 Issued 2,050,025 28.69 Vested ( 469,531 ) 67.77 Forfeited ( 346,161 ) 52.49 Unvested as of December 31, 2023 2,927,152 $ 40.89

Net Loss per Share Attributab_2

Net Loss per Share Attributable to Common Stockholders (Tables)	12 Months Ended
	Dec. 31, 2023
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 attributable to common stockholders because including them would have had an anti-dilutive effect: As of December 31, 2023 2022 2021 Unvested restricted stock 2,927,152 1,692,819 1,126,206 Outstanding options to purchase common stock 8,276,033 7,548,392 6,034,192 ESPP 73,415 45,906 19,379 Total 11,276,600 9,287,117 7,179,777
Summary of Computation of Basic and Diluted Net Loss per Share Attributable to Common Stockholders	The following table summarizes the computation of basic and diluted net loss per share attributable to common stockholders of the Company (in thousands, except share and per share amounts): Years Ended December 31, 2023 2022 2021 Numerator: Net loss $ ( 132,527 ) $ ( 289,088 ) $ ( 370,638 ) Denominator: Weighted average common shares outstanding, basic and diluted 77,151,771 70,015,305 64,227,676 Net loss per common share, basic and diluted $ ( 1.72 ) $ ( 4.13 ) $ ( 5.77 )

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2023
Income Tax Disclosure [Abstract]
Schedule of Reconciliation of Income Tax Expense	A reconciliation of the income tax expense computed using the federal statutory income tax rate to the Company’s effective income tax rate is as follows: Years Ended December 31, 2023 2022 2021 Federal statutory rate 21.0 % 21.0 % 21.0 % State income taxes, net of federal benefit 13.3 7.4 5.1 Research and development tax credits 18.0 4.2 2.6 Nondeductible/ nontaxable permanent items ( 2.5 ) ( 1.8 ) 0.7 IPR&D Guide Acquisition — — ( 8.8 ) Change in valuation allowance ( 50.9 ) ( 32.0 ) ( 20.6 ) Total - 1.1 % - 1.2 % 0.0 %
Schedule of Components of Deferred Taxes	The components of the Company’s deferred taxes are as follows (in thousands): December 31, 2023 2022 Deferred tax assets: Net operating loss carryforwards $ 3,959 $ 25,740 Research and development tax credits 56,759 27,801 Accrued expenses and other 17,386 12,472 Deferred revenue 48,792 84,622 Derivative liabilities 2,951 4,920 Stock options 20,587 9,714 Amortization 30,917 19,893 Capitalized Research 137,721 63,816 Lease liability 47,179 48,122 Total deferred tax assets 366,251 297,100 ROU asset ( 30,830 ) ( 31,860 ) Property and equipment ( 649 ) ( 508 ) Other ( 5,415 ) ( 10,325 ) Less: valuation allowance ( 329,357 ) ( 254,407 ) Deferred tax assets, net $ — $ —

Nature of the Business and Ba_2

Nature of the Business and Basis of Presentation - Additional Information (Details) - USD ($)	1 Months Ended			12 Months Ended	30 Months Ended	33 Months Ended
	Nov. 30, 2023	Oct. 31, 2023	Apr. 30, 2021	Dec. 31, 2023	Dec. 31, 2023	Dec. 31, 2023	May 10, 2023	Dec. 31, 2022
Nature Of Business And Basis Of Presentation [Line Items]
Accumulated deficit				$ 1,189,889,000	$ 1,189,889,000	$ 1,189,889,000		$ 1,057,362,000
Cash, cash equivalents, and marketable securities				1,200,000,000	1,200,000,000	$ 1,200,000,000
Jeffries LLC Amended Sales Agreement
Nature Of Business And Basis Of Presentation [Line Items]
Gross proceeds from issuance of common stock				$ 564,000,000	$ 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
Public offering price per share				$ 51.93	$ 51.93	$ 51.93
Jeffries LLC Amended Sales Agreement | 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	2,908,009
Public offering price per share				$ 103.16	$ 103.16	$ 103.16
Gross proceeds from issuance of common stock			$ 300,000,000	$ 300,000,000
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
Jeffries LLC Sales Agreement and Amended Sales Agreement
Nature Of Business And Basis Of Presentation [Line Items]
Gross proceeds from issuance of common stock						$ 864,000,000
Lilly Agreement
Nature Of Business And Basis Of Presentation [Line Items]
Stock purchase agreement amount received		$ 50,000,000
Proceeds from potential future development-stage upfront payments		$ 200,000,000
Collaboration agreement upfront payment received	$ 200,000,000
Sale and issuance of common stock		2,004,811
Aggregated purchase price		$ 50,000,000
Lilly Agreement | Maximum
Nature Of Business And Basis Of Presentation [Line Items]
Additional proceeds from potential future development-stage payments		$ 350,000,000

Summary of Significant Accoun_4

Summary of Significant Accounting Policies - Reconciliation of Cash, Cash Equivalents, and Restricted Cash (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Accounting Policies [Abstract]
Cash and cash equivalents	$ 435,895	$ 232,767	$ 559,994
Restricted cash	8,719	12,754	12,746
Total cash, cash equivalents, and restricted cash	$ 444,614	$ 245,521	$ 572,740	$ 177,011

Summary of Significant Accoun_5

Summary of Significant Accounting Policies - Additional Information (Details)	12 Months Ended
	Dec. 31, 2023 USD ($) Segment	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)
Summary Of Significant Accounting Policies [Line Items]
Claims outstanding	$ 0	$ 0	$ 0
Impairment of long-lived assets	$ 0	$ 0	$ 0
Expected dividend yield	0%	0%	0%
Carrying value of equity method investment	$ 0	$ 0
Number of operating segment | Segment	1
Other Assets
Summary Of Significant Accounting Policies [Line Items]
Equity issuance costs	$ 0	$ 0

Summary of Significant Accoun_6

Summary of Significant Accounting Policies - Estimated Useful Life of Property and Equipment (Details)	Dec. 31, 2023
Computer Equipment and Software
Property Plant And Equipment [Line Items]
Property and equipment, estimated useful life	3 years
Laboratory Equipment and Office Furniture
Property Plant And Equipment [Line Items]
Property and equipment, estimated useful life	5 years
Leasehold Improvements
Property Plant And Equipment [Line Items]
Property and equipment, estimated useful life	us-gaap:UsefulLifeShorterOfTermOfLeaseOrAssetUtilityMember

Summary of Significant Accoun_7

Summary of Significant Accounting Policies - Summary of Changes in Total Deferred Revenue (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Accounting Policies [Abstract]
Beginning balance	$ 338,153	$ 348,573
Additions to deferred revenue from license agreements		50,500
Amounts recognized in revenue	(159,559)	(60,920)
Ending balance	$ 178,594	$ 338,153

Property and Equipment, Net - S

Property and Equipment, Net - Schedule of Property and Equipment (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Property Plant And Equipment [Line Items]
Total property and equipment	$ 175,142	$ 145,790
Less accumulated depreciation	(50,182)	(30,170)
Property and equipment, net	124,960	115,620
Leasehold Improvements
Property Plant And Equipment [Line Items]
Total property and equipment	100,186	85,804
Lab Equipment
Property Plant And Equipment [Line Items]
Total property and equipment	61,674	47,383
Furniture and Fixtures
Property Plant And Equipment [Line Items]
Total property and equipment	4,836	4,332
Computer Equipment
Property Plant And Equipment [Line Items]
Total property and equipment	3,163	3,073
Construction in Process
Property Plant And Equipment [Line Items]
Total property and equipment	$ 5,283	$ 5,198

Property and Equipment, Net -_2

Property and Equipment, Net - Summary of Depreciation Expense Incurred (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Property, Plant and Equipment [Abstract]
Depreciation expense	$ 20,012	$ 14,097	$ 7,201

Fair Value of Financial Instr_3

Fair Value of Financial Instruments - Schedule of Fair Value of Financial Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Commercial Paper
Assets
Marketable securities	$ 285,289	$ 577,728
Harvard
Liabilities
Success payment liability	5,200	9,000
Broad Institute
Liabilities
Success payment liability	5,600	9,300
Recurring | Carrying Amount
Assets
Total assets	1,189,670	1,078,134
Liabilities
Total liabilities	13,523	30,763
Recurring | Carrying Amount | Money Market Funds
Assets
Cash equivalents	435,689	218,794
Recurring | Carrying Amount | Commercial Paper
Assets
Cash equivalents		10,475
Marketable securities	285,289	577,728
Recurring | Carrying Amount | Corporate Notes
Assets
Cash equivalents		3,498
Marketable securities	23,525	18,996
Recurring | Carrying Amount | U.S. Treasury Securities
Assets
Marketable securities	152,147	145,312
Recurring | Carrying Amount | U.S Government Securities
Assets
Marketable securities	271,145	62,864
Recurring | Carrying Amount | Corporate Equity Securities
Assets
Equity securities included in marketable securities	21,875	40,467
Recurring | Carrying Amount | Consideration of Technology Liabilities
Liabilities
Contingent consideration liability	1,371	6,025
Recurring | Carrying Amount | Contingent Consideration of Product Liabilities
Liabilities
Contingent consideration liability	1,352	6,438
Recurring | Fair Value
Assets
Total assets	1,189,670	1,078,134
Liabilities
Total liabilities	13,523	30,763
Recurring | Fair Value | Money Market Funds
Assets
Cash equivalents	435,689	218,794
Recurring | Fair Value | Commercial Paper
Assets
Cash equivalents		10,475
Marketable securities	285,289	577,728
Recurring | Fair Value | Corporate Notes
Assets
Cash equivalents		3,498
Marketable securities	23,525	18,996
Recurring | Fair Value | U.S. Treasury Securities
Assets
Marketable securities	152,147	145,312
Recurring | Fair Value | U.S Government Securities
Assets
Marketable securities	271,145	62,864
Recurring | Fair Value | Corporate Equity Securities
Assets
Equity securities included in marketable securities	21,875	40,467
Recurring | Fair Value | Consideration of Technology Liabilities
Liabilities
Contingent consideration liability	1,371	6,025
Recurring | Fair Value | Contingent Consideration of Product Liabilities
Liabilities
Contingent consideration liability	1,352	6,438
Recurring | Fair Value | Level 1
Assets
Total assets	457,564	259,261
Recurring | Fair Value | Level 1 | Money Market Funds
Assets
Cash equivalents	435,689	218,794
Recurring | Fair Value | Level 1 | Corporate Equity Securities
Assets
Equity securities included in marketable securities	21,875	40,467
Recurring | Fair Value | Level 2
Assets
Total assets	732,106	818,873
Recurring | Fair Value | Level 2 | Commercial Paper
Assets
Cash equivalents		10,475
Marketable securities	285,289	577,728
Recurring | Fair Value | Level 2 | Corporate Notes
Assets
Cash equivalents		3,498
Marketable securities	23,525	18,996
Recurring | Fair Value | Level 2 | U.S. Treasury Securities
Assets
Marketable securities	152,147	145,312
Recurring | Fair Value | Level 2 | U.S Government Securities
Assets
Marketable securities	271,145	62,864
Recurring | Fair Value | Level 3
Liabilities
Total liabilities	13,523	30,763
Recurring | Fair Value | Level 3 | Consideration of Technology Liabilities
Liabilities
Contingent consideration liability	1,371	6,025
Recurring | Fair Value | Level 3 | Contingent Consideration of Product Liabilities
Liabilities
Contingent consideration liability	1,352	6,438
Recurring | Harvard | Carrying Amount
Liabilities
Success payment liability	5,200	9,000
Recurring | Harvard | Fair Value
Liabilities
Success payment liability	5,200	9,000
Recurring | Harvard | Fair Value | Level 3
Liabilities
Success payment liability	5,200	9,000
Recurring | Broad Institute | Carrying Amount
Liabilities
Success payment liability	5,600	9,300
Recurring | Broad Institute | Fair Value
Liabilities
Success payment liability	5,600	9,300
Recurring | Broad Institute | Fair Value | Level 3
Liabilities
Success payment liability	$ 5,600	$ 9,300

Fair Value of Financial Instr_4

Fair Value of Financial Instruments - Additional Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Feb. 23, 2021
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Equity securities recognition amount	$ (18,592)	$ 20,200	$ 17,690
Verve Therapeutics, Inc.
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Equity securities recognition amount	(3,000)	(9,600)
Equity securities	$ 7,600	10,600
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 recognition amount	$ (15,600)	29,800
Equity securities	$ 14,200	$ 29,900
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				$ 100,000
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				$ 220,000

Fair Value of Financial Instr_5

Fair Value of Financial Instruments - Summarizes Other Income (Expense) Incurred Due To Changes In Fair Value Of Corporate Equity Securities Held (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Fair Value Disclosures [Abstract]
Other income (expense)	$ (18,592)	$ 20,200	$ 17,690

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	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Fair Value of Common Stock | Harvard
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Success payment liability measurement input	27.22	39.11
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	27.22	39.11
Expected Volatility | Harvard
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Success payment liability measurement input	0.80	0.82
Expected Volatility | Broad Institute
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Success payment liability measurement input	0.79	0.82
Expected Term (years) | Minimum | Harvard
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Success payment liability, term	21 days	29 days
Expected Term (years) | Minimum | Broad Institute
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Success payment liability, term	21 days	29 days
Expected Term (years) | Maximum | Harvard
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Success payment liability, term	5 years 5 months 26 days	6 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	6 years 4 months 9 days	7 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 - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Fair Value Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Beginning Balance	$ 18,300	$ 42,200
Change in fair value	(7,500)	(23,900)
Ending Balance	10,800	18,300
Harvard
Fair Value Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Beginning Balance	9,000	21,000
Change in fair value	(3,800)	(12,000)
Ending Balance	5,200	9,000
Broad Institute
Fair Value Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Beginning Balance	9,300	21,200
Change in fair value	(3,700)	(11,900)
Ending Balance	$ 5,600	$ 9,300

Fair Value of Financial Instr_8

Fair Value of Financial Instruments - Schedule of Change in Fair Value of Contingent Consideration Liabilities Based on Level 3 Inputs (Details) - Contingent Consideration Liabilities - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning Balance	$ 12,463	$ 31,367
Change in fair value	(9,740)	(18,904)
Ending Balance	2,723	12,463
Technology Milestones
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning Balance	6,025	24,359
Change in fair value	(4,654)	(18,334)
Ending Balance	1,371	6,025
Product Milestones
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning Balance	6,438	7,008
Change in fair value	(5,086)	(570)
Ending Balance	$ 1,352	$ 6,438

Fair Value of Financial Instr_9

Fair Value of Financial Instruments - Schedule of Calculation of Estimated Fair Value of Contingent Consideration Liabilities (Details) - Contingent Consideration Liabilities	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Technology Milestones
Derivative Liability [Abstract]
Milestone liabilities projected year of achievement	2025
Technology Milestones | Minimum
Derivative Liability [Abstract]
Milestone liabilities projected year of achievement		2024
Technology Milestones | Maximum
Derivative Liability [Abstract]
Milestone liabilities projected year of achievement		2025
Product Milestones | Minimum
Derivative Liability [Abstract]
Milestone liabilities projected year of achievement	2025	2025
Product Milestones | Maximum
Derivative Liability [Abstract]
Milestone liabilities projected year of achievement	2031	2030
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 | Minimum
Derivative Liability [Abstract]
Contingent consideration liability measurement input	0.02	0.05
Probability of Achievement | Technology Milestones | Maximum
Derivative Liability [Abstract]
Contingent consideration liability measurement input	0.05	0.15
Probability of Achievement | Product Milestones | Minimum
Derivative Liability [Abstract]
Contingent consideration liability measurement input	0.01	0.02
Probability of Achievement | Product Milestones | Maximum
Derivative Liability [Abstract]
Contingent consideration liability measurement input	0.02	0.15

Marketable Securities - Summary

Marketable Securities - Summary of Marketable Securities (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Debt Securities, Available-for-Sale [Line Items]
Marketable securities held, Amortized Cost	$ 753,377	$ 847,797
Marketable securities held, Gross Unrealized Gains	1,077	85
Marketable securities held, Gross Unrealized Losses	(473)	(2,515)
Marketable securities held, Fair Value	753,981	845,367
Commercial Paper
Debt Securities, Available-for-Sale [Line Items]
Available-for-sale, Amortized Cost	285,054	578,813
Available-for-sale, Gross Unrealized Gains	250	72
Available-for-sale, Gross Unrealized Losses	(15)	(1,157)
Available-for-sale, Fair Value	285,289	577,728
Corporate Notes
Debt Securities, Available-for-Sale [Line Items]
Available-for-sale, Amortized Cost	23,462	19,033
Available-for-sale, Gross Unrealized Gains	63
Available-for-sale, Gross Unrealized Losses		(37)
Available-for-sale, Fair Value	23,525	18,996
U.S. Treasury Securities
Debt Securities, Available-for-Sale [Line Items]
Available-for-sale, Amortized Cost	151,805	146,270
Available-for-sale, Gross Unrealized Gains	436
Available-for-sale, Gross Unrealized Losses	(94)	(958)
Available-for-sale, Fair Value	152,147	145,312
Corporate Equity Securities
Debt Securities, Available-for-Sale [Line Items]
Equity securities, Amortized Cost	21,875	40,467
Equity securities, Fair Value	21,875	40,467
U.S Government Securities
Debt Securities, Available-for-Sale [Line Items]
Available-for-sale, Amortized Cost	271,181	63,214
Available-for-sale, Gross Unrealized Gains	328	13
Available-for-sale, Gross Unrealized Losses	(364)	(363)
Available-for-sale, Fair Value	$ 271,145	$ 62,864

Marketable Securities - Additio

Marketable Securities - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Investments, Debt and Equity Securities [Abstract]
Realized gains or losses recognized on sale or maturity of marketable securities	$ 0	$ 0	$ 0
Contractual maturity dates of investments	less than one year

Accrued Expenses and Other Cu_3

Accrued Expenses and Other Current Liabilities - Schedule of Accrued Expenses and Other Current Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Payables and Accruals [Abstract]
Accrued contingent obligation, refer to Note 10	$ 43,280
Employee compensation and related benefits	21,774	$ 19,122
Research costs	9,804	4,844
Process development and manufacturing costs	4,697	5,080
Professional fees	3,468	6,751
Equipment financing costs	484	1,853
Other	28,157	12,262
Total	$ 111,664	$ 49,912

Accrued Expenses and Other Cu_4

Accrued Expenses and Other Current Liabilities (Additional Information) (Details) $ in Millions	Dec. 31, 2023 USD ($)
Payables and Accruals [Abstract]
Liability accrued for loss based on settlement offer	$ 21.3

Leases - Additional Information

Leases - Additional Information (Details) $ in Thousands	1 Months Ended
	Aug. 31, 2021	Aug. 31, 2020 USD ($) ft² Option	Apr. 30, 2019 USD ($) Option	Oct. 31, 2018 Option	Feb. 28, 2018 USD ($)	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)
Lessee Lease Description [Line Items]
Operating lease right-of-use assets						$ 112,846	$ 118,513
Lease liability						$ 172,689
Office and Laboratory Space
Lessee Lease Description [Line Items]
Operating lease, commencement month and year					2018-03
Operating lease, termination month and year	2034-02				2028-09
Operating lease, option to extend			option to extend the lease for two terms of five years each		a term extension option.
Operating lease, existence of option to extend			true		true
Operating lease, number of renewal options | Option			2
Operating lease, option to extend term			5 years
Leasehold improvements landlord allowance			$ 23,400		$ 6,100
Office and Laboratory Space | First Phase of Lease in October 2020
Lessee Lease Description [Line Items]
Operating lease, commencement month and year			2020-10
Rent payments beginning month and year			2021-08
Office and Laboratory Space | Second Phase of Lease in January 2021
Lessee Lease Description [Line Items]
Operating lease, commencement month and year			2021-01
Rent payments beginning month and year			2022-02
Laboratory Space
Lessee Lease Description [Line Items]
Operating lease, commencement month and year				2019-04
Operating lease, termination month and year				2025-12
Operating lease, option to extend				The amended lease is subject to fixed-rate rent escalations and provides an option to extend the lease for two additional two-year periods through December 31, 2029.
Operating lease, existence of option to extend				true
Operating lease, number of renewal options | Option				2
Operating lease, option to extend term				2 years
Manufacturing Facility
Lessee Lease Description [Line Items]
Operating lease, commencement month and year		2022-12
Operating lease, existence of option to extend		true
Operating lease, number of renewal options | Option		2
Operating lease, option to extend term		5 years
Leasehold improvements landlord allowance		$ 20,000
Manufacturing facility, number of square feet | ft²		100,000
Operating lease term		15 years
Lessee operating lease, description		The lease will terminate 15 years from the rent commencement date, December 2022. The lease is subject to fixed-rate rent escalations and provides for $20.0 million in tenant improvements and the option to extend the lease for two terms of five years each, which were not reasonably certain of exercise as of December 31, 2022.

Leases - Summary of Operating L

Leases - Summary of Operating Lease Costs (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Leases [Abstract]
Operating lease costs	$ 22,063	$ 19,536	$ 18,309
Variable lease costs	5,777	4,364	2,065
Short-term lease costs	9,000	307	1,145
Sublease income		(1,319)	(110)
Total	$ 36,840	$ 22,888	$ 21,409

Leases - Summary of Lease Term

Leases - Summary of Lease Term and Discount Rate (Details)	Dec. 31, 2023	Dec. 31, 2022
Leases [Abstract]
Weighted-average remaining lease term (years)	10 years 3 months 18 days	11 years
Weighted-average discount rate	7.60%	7.50%

Leases - Summary of Lease Costs

Leases - Summary of Lease Costs Included in Measurement of Lease Liabilities (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Leases [Abstract]
Operating cash flows used for operating leases	$ 22,603	$ 19,052	$ 11,462
Operating lease liabilities arising from obtaining ROU assets	$ 3,852	$ 41,050	$ 25,925

Leases - Summary of Future Matu

Leases - Summary of Future Maturity of Operating Leases (Details) $ in Thousands	Dec. 31, 2023 USD ($)
Lessee, Operating Lease, Liability, to be Paid, Fiscal Year Maturity [Abstract]
2024	$ 24,985
2025	25,315
2026	22,526
2027	23,157
2028	22,806
Thereafter	132,500
Undiscounted lease payments	251,289
Less: imputed interest	(78,600)
Total operating lease liabilities	$ 172,689

Equity Method Investment - Addi

Equity Method Investment - Additional Information (Details)	12 Months Ended
	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)	Sep. 30, 2022 USD ($)
Schedule of Equity Method Investments [Line Items]
Carrying value of equity method investment	$ 0	$ 0
Loss from equity method investment		25,500,000
Orbital
Schedule of Equity Method Investments [Line Items]
Collaboration agreement aggregate transaction price			$ 25,500,000
Carrying value of equity method investment			$ 0
Loss from equity method investment	$ 0	$ 25,500,000
Orbital | Option Pricing Model | Volatility of Market Participants | Level 3
Schedule of Equity Method Investments [Line Items]
Alternate investment, measurement input			0.68
Orbital | Option Pricing Model | Discount for Lack of Marketability | Level 3
Schedule of Equity Method Investments [Line Items]
Alternate investment, measurement input			0.43

Strategic restructuring - Addit

Strategic restructuring - Additional Information (Details) $ in Thousands	1 Months Ended	12 Months Ended
	Oct. 31, 2023 Positions	Dec. 31, 2023 USD ($)
Restructuring Cost and Reserve [Line Items]
Reduction in employee headcount, positions | Positions	100
Reduction in employee headcount, percentage	20%
Restructuring charges		$ 6,494
Workforce Reduction
Restructuring Cost and Reserve [Line Items]
Restructuring charges		6,700
Workforce Reduction | One-time Termination Benefits
Restructuring Cost and Reserve [Line Items]
Restructuring charges		6,500
Workforce Reduction | Non-cash Stock Based Compensation Expense
Restructuring Cost and Reserve [Line Items]
Restructuring charges		$ 200

Strategic restructuring - Sched

Strategic restructuring - Schedule of Restructuring Liability Activity for Company's Workforce Reductions (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2023 USD ($)
Restructuring Reserve Disclosures [Abstract]
Expenses incurred	$ 6,494
Payments	(1,999)
Accrued restructuring, Ending balance	$ 4,495

Guide Acquisition - Additional

Guide Acquisition - Additional Information (Details) - USD ($) $ in Thousands		12 Months Ended
	Feb. 23, 2021	Dec. 31, 2021	Dec. 31, 2023	Dec. 31, 2022
Business Acquisition [Line Items]
Value of shares issued for upfront payment of acquisition		$ 120,032
Research and development expense		154,953
Contingent consideration liabilities			$ 2,723	$ 12,463
Common Stock
Business Acquisition [Line Items]
Value of shares issued for upfront payment of acquisition		$ 10
Guide Therapeutics, Inc. | Merger Agreement
Business Acquisition [Line Items]
Business Acquisition, merger agreement date	Feb. 23, 2021
Business combination upfront consideration paid in common stock	$ 120,000
Value of shares issued for upfront payment of acquisition	120,000
Research and development expense	155,000
Contingent consideration liabilities	$ 36,500
Guide Therapeutics, Inc. | Merger Agreement | Common Stock
Business Acquisition [Line Items]
Number of shares issued for upfront payment of acquisition	1,087,153
Guide Therapeutics, Inc. | Merger Agreement | Technology Milestones | Maximum | Former Stockholders and Optionholders
Business Acquisition [Line Items]
Potential milestone payable in form of common stock	$ 100,000
Guide Therapeutics, Inc. | Merger Agreement | Product Milestones | Maximum | Former Stockholders and Optionholders
Business Acquisition [Line Items]
Potential milestone payable in form of common stock	$ 220,000

Guide Acquisition - Summary of

Guide Acquisition - Summary of Transaction Price Determined and Allocated (Details) - Guide Therapeutics, Inc. - Merger Agreement $ in Thousands	Feb. 23, 2021 USD ($)
Transaction price
Fair value of equity instruments issued	$ 120,032
Technology and product contingent consideration liabilities	36,513
Transaction costs	2,531
Total transaction price	159,076
Transaction price allocated
Cash acquired	3,151
Prepaid expenses and other assets	264
Property and equipment	1,835
Other liabilities assumed	(1,427)
Total transaction price	159,076
In-Process Research and Development
Transaction price allocated
Intangible assets	154,953
Assembled Workforce
Transaction price allocated
Intangible assets	$ 300

License Agreements - Additional

License Agreements - Additional Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Lilly Agreement | License Fees
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Accrued liabilities for license fees	$ 43.3
Research and Development
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Contingent obligations and non-royalty sublicense fees	$ 43.5	$ 2.7	$ 39.9

License Agreements - Harvard Li

License Agreements - Harvard License Agreement - Additional Information (Details) - Harvard		12 Months Ended
	Jun. 10, 2021 shares	Dec. 31, 2023 USD ($)	May 31, 2021 USD ($)
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Success payment amount due			$ 15,000,000
Issuance of common stock for success payment liability, Shares | shares	174,825
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]
Additional success payment amount due			$ 90,000,000
Success payments		$ 105,000,000
Maximum | Series A Preferred Stock
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Success Payments, valuation multiples		40
Success Payments
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.
Other Payments
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Agreement description		The Company agreed to pay Harvard an annual license maintenance fee ranging from low-to-mid five figures to low six figures, depending on the calendar year. The Company is responsible for the payment of certain patent prosecution and maintenance costs incurred by Harvard related to licensed patents. To the extent achieved, the Company is obligated to pay up to an aggregate of $75.9 million in product development and regulatory approval milestones, or Harvard Product Milestones. If the Company completes a change of control during the term of the Harvard License Agreement, then certain of the milestone payments would be increased. To the extent there are sales of a licensed product, the Company is required to pay low single digit royalties on net sales. The Company is entitled to certain reductions and offsets on these royalties with respect to a licensed product in a given country. If the Company sublicenses its rights to develop or commercialize a licensed product under the Harvard License Agreement to a third party and the Company receives non-royalty sublicense income, then Harvard is entitled to a percentage of such consideration, ranging from the high single digits to low double digits depending on the date in which such sublicense agreement is executed and the stage of development of the Company’s licensed products at such time.
Product Development and Regulatory Approval | Maximum
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Aggregate milestone amount		$ 75,900,000

License Agreements - Harvard _2

License Agreements - Harvard License Agreement - Success Payment Liability (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Harvard
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Success payment liability	$ 5,200	$ 9,000

License Agreements - Harvard _3

License Agreements - Harvard License Agreement - Change in Fair Value of Success Payment Liability (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Change in fair value of derivative liabilities	$ (7,500)	$ (23,900)	$ 1,000
Harvard
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Change in fair value of derivative liabilities	$ (3,800)	$ (12,000)	$ 500

License Agreements - Broad Lice

License Agreements - Broad License Agreement - Additional Information (Details) - Broad Institute		12 Months Ended
	Jun. 10, 2021 shares	Dec. 31, 2023 USD ($)	May 31, 2021 USD ($)
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Success payment amount due		$ 0	$ 15,000,000
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.
Other Payments
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Agreement description		The Company agreed to pay Broad Institute an annual license maintenance fee ranging from low-to-mid five figures to low six figures, depending on the particular calendar year. The Company is responsible for the payment of certain patent prosecution and maintenance costs incurred by Broad Institute related to licensed patents. To the extent achieved, the Company is obligated to pay up to an aggregate of $75.9 million in product development and regulatory approval milestones, or Broad Product Milestones. If the Company completes a change of control during the term of the Broad License Agreement, then certain of the milestone payments would be increased. To the extent there are commercial sales of a licensed product, the Company is required to pay low single digit royalties on net sales. The Company is entitled to certain reductions and offsets on these royalties with respect to a licensed product in a given country. If the Company sublicenses its rights to develop or commercialize a licensed product under the Broad License Agreement to a third party and the Company receives non-royalty sublicense income, then Broad Institute is entitled to a percentage of such consideration, ranging from the high single digits to low double digits depending on the date in which such sublicense agreement is executed and the stage of development of the Company’s licensed products at such time.
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
Maximum | Product Development and Regulatory Approval
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Aggregate milestone amount		$ 75,900,000

License Agreements - Broad Li_2

License Agreements - Broad License Agreement - Success Payment Liability (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Broad Institute
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Success payment liability	$ 5,600	$ 9,300

License Agreements - Broad Li_3

License Agreements - Broad License Agreement - Change in Fair Value of Success Payment Liability (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Change in fair value of derivative liabilities	$ (7,500)	$ (23,900)	$ 1,000
Broad Institute
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Change in fair value of derivative liabilities	$ (3,700)	$ (11,900)	$ 500

License Agreements - Editas Lic

License Agreements - Editas License Agreement - Additional Information (Details)	12 Months Ended
	Dec. 31, 2023
Editas License Agreement
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Agreement description	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. More specifically, Editas granted to the Company a worldwide, exclusive, sublicensable, license (subject to certain exceptions and conditions) under certain intellectual property controlled by Editas for the use of base editing therapies for the treatment of any field of human diseases and conditions, subject to certain exceptions, or the Beam Field, and the licenses granted or to be granted under the Editas License Agreement, or the Editas Development and Commercialization License. Additionally, Editas granted to the Company a royalty-free, non-exclusive license under certain intellectual property owned or controlled by Editas to perform research activities in the Beam Field, or the Editas Research License. Editas provided the Company with an exclusive option to obtain an Editas Development and Commercialization License to three additional groups of intellectual property owned or controlled by Editas, on a group by group basis, during the specified option period, subject to certain exceptions. Pursuant to the Editas License Agreement, the Company will use commercially reasonable efforts to develop a product that includes the rights licensed to the Company within a specified period of time and to commercialize any such products that have received regulatory approval in certain specified countries.Additional consideration will be due to Editas if the Company elects to exercise its option to obtain an Editas Development and Commercialization License to any of the three categories of intellectual property underlying the Editas Research License, for a fee ranging from a mid-teen million dollar amount to a low to mid-eight digit dollar amount per group, depending on the timing of the option exercise. Additionally, the Company is required to reimburse Editas for certain payments Editas may be obligated to make under existing Editas license agreements related to the intellectual property being licensed to the Company, including (i) development, regulatory and commercial milestone payments and certain sublicense income payments due as a result of the Editas License Agreement and (ii) a percentage of the annual maintenance fees and patent fees due to certain of the Editas’ licensors. In addition, to the extent any products are commercialized under an Editas Development and Commercialization License, the Company would be required to make royalty payments equivalent to the royalties that would be due from Editas to any applicable licensors of Editas related to the sales of such licensed products, plus an additional tiered low- to mid-single digit royalty, depending on whether such licensed product is covered by an Editas-owned patent.

Collaboration and License Agr_2

Collaboration and License Agreements - Additional Information (Details)

1 Months Ended

12 Months Ended

Nov. 30, 2023 USD ($)

Oct. 31, 2023 USD ($) shares

Oct. 31, 2022

Sep. 30, 2022 USD ($) shares

Jun. 30, 2022 USD ($)

Jan. 31, 2022 USD ($)

Dec. 31, 2021 USD ($)

Oct. 31, 2021 USD ($)

Jul. 31, 2021 USD ($)

Jun. 30, 2021 USD ($)

Oct. 31, 2020 shares

Sep. 30, 2019 USD ($) shares

Apr. 30, 2019 USD ($) shares

Dec. 31, 2023 USD ($) shares

Dec. 31, 2022 USD ($)

Dec. 31, 2021 USD ($)

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Current portion of deferred revenue

$ 68,706,000

$ 135,974,000

Long-term portion of deferred revenue

109,888,000

202,179,000

Deferred revenue liability

$ 348,573,000

178,594,000

338,153,000

$ 348,573,000

Research and development expense

437,381,000

311,594,000

387,087,000

Gain (loss) from equity method investment

(25,500,000)

License revenue

377,709,000

60,920,000

51,844,000

Carrying value of equity method investment

$ 0

0

Verve Therapeutics, Inc. | Common Stock

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Equity shares held | shares

546,970

Lilly Agreement

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Proceeds from potential future development-stage upfront payments

$ 200,000,000

Sale and issuance of common stock | shares

2,004,811

Aggregated purchase price

$ 50,000,000

Stock purchase agreement amount received

50,000,000

Fair value of common stock sold

16,400,000

Collaboration agreement upfront payment received

$ 200,000,000

Collaboration agreement performance obligation revenue recognized

$ 216,400,000

License agreement upfront payment received

200,000,000

Collaboration agreement aggregate transaction price

$ 216,400,000

Collaboration agreement term of contract

6 years

Deferred revenue liability

0

Collaboration license agreement fair value of shares issued

$ 33,600,000

Lilly Agreement | Maximum

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Additional proceeds from potential future development-stage payments

350,000,000

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

$ 1,350,000,000

1,350,000,000

Nonrefundable upfront payment receivable

300,000,000

300,000,000

Collaboration agreement upfront payment received

$ 300,000,000

Collaboration agreement performance obligation revenue recognized

134,300,000

48,200,000

0

Collaboration agreement aggregate transaction price

$ 300,000,000

300,000,000

Current portion of deferred revenue

42,900,000

Long-term portion of deferred revenue

74,600,000

Earn-out payment period

10 years

Deferred revenue liability

$ 300,000,000

$ 300,000,000

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%

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%

65%

Pfizer | Maximum | Per Program

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Development regulatory and commercial milestones receivable

$ 350,000,000

$ 350,000,000

Sana Biotechnology

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Collaboration agreement performance obligation revenue recognized

1,800,000

50,000,000

License agreement upfront payment received

$ 50,000,000

Collaboration agreement aggregate transaction price

50,000,000

Additional fee per additional option right

10,000,000

Option rights aggregate potential additional consideration

20,000,000

Sana Biotechnology | Maximum

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Development regulatory and commercial milestones receivable

$ 65,000,000

Sana Biotechnology | License Agreement Terms

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Agreement description

For up to thirty months following the effective date of the Sana Agreement, Sana has the option to select up to a cumulative total of two additional CAR antigen targets or PSC product types for an additional fee of $10.0 million per additional CAR antigen target and additional PSC product type, or the Option Rights, for an aggregate potential additional consideration of $20.0 million. Further, for up to thirty months following the effective date of the Sana Agreement, Sana has a one-time right to substitute, in the aggregate, either one CAR antigen target or one PSC product type at no additional cost, or the Replacement Right. Sana may also select a specified number of additional or replacement genetic targets for each PSC product type at any time prior to the third anniversary of the effective date at no additional cost, or the Genetic Target Nomination Rights. Sana may terminate the Sana Agreement for convenience prior to the first commercial sale of any licensed product by providing 90 days’ prior written notice or upon 180 days’ prior written notice after first commercial sale.

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 up to 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

Upfront revenue recognized

$ 0

Collaboration agreement performance obligation revenue recognized

16,400,000

10,600,000

1,800,000

Collaboration agreement aggregate transaction price

75,000,000

Upfront fee receivable upon signing contract

50,000,000

Collaboration agreement first anniversary amount receivable

$ 25,000,000

$ 25,000,000

Upfront payment received under term of agreement

$ 50,000,000

Collaboration agreement first anniversary payment received

$ 25,000,000

Current portion of deferred revenue

17,300,000

Long-term portion of deferred revenue

$ 28,900,000

Apellis Pharmaceuticals, Inc | Maximum

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Collaboration arrangement extension term

2 years

Prime Medicine Inc

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Collaborative arrangement rights and obligations, description

The Company had an obligation to issue $5.0 million in shares of its common stock to Prime Medicine, and Prime Medicine had an obligation to issue 5,000,000 shares of its common stock to the Company, should the Company elect to extend the collaboration beyond one year

Obligation to issue common stock value

$ 5,000,000

Obligation to issue common stock shares | shares

5,000,000

Reverse stock split ratio

3.1088

Reverse stock split

one-for-3.1088

Equity shares held | shares

1,608,337

Prime Medicine Inc | Common Stock

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Shares issued and sold | shares

200,307

Number of common stock received | shares

5,000,000

Equity shares held | shares

1,608,337

Equity shares value held

$ 14,200,000

Verve

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Remaining unrecognized revenue recognized

$ 300,000

Deferred revenue liability

0

Upfront payment fair value shares received

$ 500,000

License revenue

400,000

24,000

$ 24,000

Reverse stock split ratio

9.2592

Reverse stock split

one-for-9.2592

Equity shares value held

7,600,000

Verve | Common Stock

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Collaboration license agreement fair value of shares received

$ 500,000

Number of common stock received | shares

2,600,000

Orbital

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Common stock shares received at closing | shares

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

$ 25,500,000

Collaboration agreement performance obligation revenue recognized

8,500,000

2,100,000

Collaboration agreement aggregate transaction price

25,500,000

Current portion of deferred revenue

8,500,000

Long-term portion of deferred revenue

6,400,000

Gain (loss) from equity method investment

$ 0

$ (25,500,000)

Carrying value of equity method investment

$ 0

Orbital | Research Plan

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Collaboration arrangement, initial term

3 years

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 | Option Pricing Model | Level 3 | Volatility of Market Participants

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Alternate investment, measurement input

0.68

Orbital | Option Pricing Model | Level 3 | Discount for Lack of Marketability

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Alternate investment, measurement input

0.43

Common Stock - Additional Infor

Common Stock - Additional Information (Details) - USD ($)	1 Months Ended			12 Months Ended			30 Months Ended	33 Months Ended
	Jun. 30, 2021	Apr. 30, 2021	Jan. 31, 2021	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2023	Dec. 31, 2023	May 10, 2023	May 10, 2021
Class Of Stock [Line Items]
Preferred stock, shares authorized				25,000,000	25,000,000		25,000,000	25,000,000
Preferred stock, par or stated value per share				$ 0.01	$ 0.01		$ 0.01	$ 0.01
Common stock, shares authorized				250,000,000	250,000,000		250,000,000	250,000,000
Common stock, par or stated value per share				$ 0.01	$ 0.01		$ 0.01	$ 0.01
Common stock, voting rights				The holders of the Company’s common stock are entitled to one vote for each share of common stock.
Common Stock
Class Of Stock [Line Items]
Issuance of common stock for success payment liability, Shares						349,650
Harvard Institute
Class Of Stock [Line Items]
Success payments liability										$ 15,000,000
Issuance of common stock for success payment liability, Shares	174,825
Broad Institute
Class Of Stock [Line Items]
Success payments liability										$ 15,000,000
Issuance of common stock for success payment liability, Shares	174,825
Sales Agreement, with Jefferies
Class Of Stock [Line Items]
Price per share of stock sold				$ 103.16			$ 103.16	103.16
Price per share of shares issued		$ 103.16
Gross proceeds from issuance of common stock		$ 300,000,000		$ 300,000,000
Shares issued and sold		2,908,009		2,908,009
Jeffries LLC Amended Sales Agreement
Class Of Stock [Line Items]
Gross proceeds from issuance of common stock				$ 564,000,000			$ 564,000,000
Jeffries LLC Amended Sales Agreement | Common Stock
Class Of Stock [Line Items]
Price per share of stock sold				$ 51.93			$ 51.93	$ 51.93
Shares issued and sold				10,860,992
Jeffries LLC Sales Agreement and Amended Sales Agreement
Class Of Stock [Line Items]
Gross proceeds from issuance of common stock								$ 864,000,000
Private Placement
Class Of Stock [Line Items]
Gross proceeds from issuance of common stock			$ 260,000,000
Private Placement | Common Stock
Class Of Stock [Line Items]
Shares issued and sold			2,795,700			2,795,700
Price per share of stock sold			$ 93
Net proceeds from sale of common stock			$ 252,000,000
At-The-Market | Common Stock
Class Of Stock [Line Items]
Shares issued and sold				6,952,703	1,909,103	4,907,195
At-The-Market | Sales Agreement, with Jefferies | 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
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 ($)	1 Months Ended		12 Months Ended
	Feb. 29, 2020	May 31, 2019	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Oct. 31, 2019
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation expense			$ 98,647,000	$ 84,321,000	$ 43,570,000
Weighted-average grant date fair value per share of stock options granted			$ 27.88	$ 40.86	$ 58.56
Aggregate intrinsic value of stock options exercised			$ 20,000,000	$ 23,400,000	$ 85,100,000
Weighted-average exercise price of stock options			$ 7.69	$ 5.64	$ 9.88
Employee Stock Option
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unrecognized compensation cost related to unvested stock options			$ 111,500,000
Unrecognized compensation cost, cost to recognize over a weighted-average period			2 years 3 months 18 days
Performance-based Stock Options
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation expense			$ 0
Restricted Stock
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unrecognized compensation cost, cost to recognize over a weighted-average period			2 years 2 months 12 days
Aggregate fair value of restricted shares vested			$ 13,800,000	$ 53,100,000	$ 6,400,000
Unrecognized stock-based compensation expense, expected to vest			$ 72,800,000
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
2017 Plan | Stock Options and Restricted Stock | Employees, Officers, Founders and Consultants
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vesting period		4 years
2017 Plan | Employee Stock Option
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expiration period		10 years
2017 Plan | Non-Statutory Options | Employees, Officers, Board of Directors and Consultants
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vesting period		4 years
2019 Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Maximum number of shares for future issuance						3,700,000
Number of shares reserved for future issuance			12,376,374
Number of shares available for future issuance			1,173,189
2019 Plan | Common Stock | Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Annual percentage increase in shares authorized			4%
2019 Plan | From 2017 Plan Shares | Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Maximum number of shares for future issuance						5,639,818
2019 Employee Stock Purchase Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares available for future issuance			2,247,569
Number of shares issued			130,403	70,073	0
Stock-based compensation expense			$ 1,300,000	$ 1,500,000	$ 300,000
Common stock, shares description	In February 2020, the Company’s board of directors adopted the Beam Therapeutics Inc. 2019 Employee Stock Purchase Plan, or ESPP, which was approved by the Company’s stockholders. Pursuant to the ESPP, certain employees of the Company, excluding consultants and non-employee directors, are eligible to purchase common stock of the Company at a reduced rate during offering periods. The ESPP permits participants to purchase common stock using funds contributed through payroll deductions, subject to a calendar year limit of $25,000 and at a purchase price of 85% of the lower of the fair market value of the Company’s common stock on the first trading day of the offering period or on the applicable purchase date, which will be the final trading day of the applicable purchase period.
Maximum amount allowed to purchase common stock using payroll deduction	$ 25,000
Percentage of common stock purchase price lower of the fair market value	85%

Stock Option and Grant Plan - S

Stock Option and Grant Plan - Summary of Stock-based Compensation Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock-based compensation expense	$ 98,647	$ 84,321	$ 43,570
Research and Development
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock-based compensation expense	57,812	52,004	26,644
General and Administrative
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock-based compensation expense	$ 40,835	$ 32,317	$ 16,926

Stock Option and Grant Plan -_2

Stock Option and Grant Plan - Schedule of Assumptions Used in Black-Scholes Option-Pricing Model for Stock Options Granted (Details)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected volatility	76.30%	74.80%	71.40%
Expected volatility	78.80%	77.30%	76.70%
Weighted-average risk-free interest rate	3.73%	2.27%	1.11%
Expected dividend yield	0%	0%	0%
Expected term (in years)	6 years 10 days	6 years 29 days	6 years 1 month 13 days

Stock Option and Grant Plan -_3

Stock Option and Grant Plan - Summary of Option Activity Under Equity Award Plans (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Number of options
Outstanding as of December 31, 2022	7,548,392
Granted	2,356,838
Exercised	(797,709)
Forfeitures	(831,488)
Outstanding as of December 31, 2023	8,276,033	7,548,392
Exercisable as of December 31, 2023	4,818,116
Weighted average exercise price
Outstanding as of December 31, 2022	$ 41.77
Granted	39.62
Exercised	7.69	$ 5.64	$ 9.88
Forfeitures	60.18
Outstanding as of December 31, 2023	42.59	$ 41.77
Exercisable as of December 31, 2023	$ 37.81
Weighted average remaining contractual life (years)
Outstanding	7 years 2 months 12 days	7 years 6 months
Exercisable as of December 31, 2023	6 years 3 months 18 days
Aggregate intrinsic value
Outstanding	$ 51,653	$ 110,990
Exercisable as of December 31, 2023	$ 45,895

Stock Option and Grant Plan -_4

Stock Option and Grant Plan - Summary of Restricted Stock Activity (Details) - Restricted Stock	12 Months Ended
	Dec. 31, 2023 $ / shares shares
Shares
Unvested as of December 31, 2022 | shares	1,692,819
Issued | shares	2,050,025
Vested | shares	(469,531)
Forfeited | shares	(346,161)
Unvested as of December 31, 2023 | shares	2,927,152
Weighted-average grant date fair value
Unvested as of December 31, 2022 | $ / shares	$ 65.49
Issued | $ / shares	28.69
Vested | $ / shares	67.77
Forfeited | $ / shares	52.49
Unvested as of December 31, 2023 | $ / shares	$ 40.89

Net Loss per Share Attributab_3

Net Loss per Share Attributable to Common Stockholders - Schedule of Potential Common Shares Excluded from Computation of Diluted Net Loss per Share (Details) - shares	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive shares excluded from computation of diluted net loss per share	11,276,600	9,287,117	7,179,777
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	2,927,152	1,692,819	1,126,206
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	8,276,033	7,548,392	6,034,192
ESPP
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive shares excluded from computation of diluted net loss per share	73,415	45,906	19,379

Net Loss per Share Attributab_4

Net Loss per Share Attributable to Common Stockholders - Summary of Computation of Basic and Diluted Net Loss per Share Attributable to Common Stockholders (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Numerator:
Net loss	$ (132,527)	$ (289,088)	$ (370,638)
Denominator:
Weighted - average common shares outstanding, basic	77,151,771	70,015,305	64,227,676
Weighted - average common shares outstanding, diluted	77,151,771	70,015,305	64,227,676
Net loss per common share, basic	$ (1.72)	$ (4.13)	$ (5.77)
Net loss per common share, diluted	$ (1.72)	$ (4.13)	$ (5.77)

Income Taxes - Schedule of Reco

Income Taxes - Schedule of Reconciliation of Income Tax Expense (Details)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Income Tax Disclosure [Abstract]
Federal statutory rate	21%	21%	21%
State income taxes, net of federal benefit	13.30%	7.40%	5.10%
Research and development tax credits	18%	4.20%	2.60%
Nondeductible/ nontaxable permanent items	(2.50%)	(1.80%)	0.70%
IPR&D Guide Acquisition			(8.80%)
Change in valuation allowance	(50.90%)	(32.00%)	(20.60%)
Total	(1.10%)	(1.20%)	0%

Income Taxes - Schedule of Comp

Income Taxes - Schedule of Components of Deferred Taxes (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Deferred tax assets:
Net operating loss carryforwards	$ 3,959	$ 25,740
Research and development tax credits	56,759	27,801
Accrued expenses and other	17,386	12,472
Deferred revenue	48,792	84,622
Derivative liabilities	2,951	4,920
Stock options	20,587	9,714
Amortization	30,917	19,893
Capitalized Research	137,721	63,816
Lease liability	47,179	48,122
Total deferred tax assets	366,251	297,100
ROU asset	(30,830)	(31,860)
Property and equipment	(649)	(508)
Other	(5,415)	(10,325)
Less: valuation allowance	(329,357)	(254,407)
Deferred tax assets, net

Income Taxes - Additional Infor

Income Taxes - Additional Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Operating Loss Carryforwards [Line Items]
Increase in valuation allowance	$ 75,000	$ 82,300
Current tax provision	1,400	3,400
Income tax expense	1,366	3,410
Uncertain tax positions	0	0
Interest or penalties for unrecognized tax benefits since inception	$ 0
Earliest Tax Year
Operating Loss Carryforwards [Line Items]
Open tax year	2020
Massachusetts
Operating Loss Carryforwards [Line Items]
Tax credits	$ 19,500
Tax credits expiration starting year	2037
Federal
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards	$ 16,600	$ 120,300
Tax credits	$ 41,300
Tax credits expiration starting year	2042

Related Party Transactions - Ad

Related Party Transactions - Additional Information (Details)	1 Months Ended		12 Months Ended
	Oct. 31, 2021 ft²	Oct. 31, 2020 shares	Dec. 31, 2023 USD ($) Founder shares	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)
Related Party Transaction [Line Items]
Number of founder shareholders | Founder			3
Sublease income | $				$ (1,319,000)	$ (110,000)
Research and development expense | $			$ 437,381,000	311,594,000	387,087,000
Common stock, value | $			$ 816,000	712,000
Prime Medicine Inc
Related Party Transaction [Line Items]
Equity shares held | shares			1,608,337
Prime Medicine Inc | Common Stock
Related Party Transaction [Line Items]
Equity shares held | shares			1,608,337
Number of common stock issued | shares		200,307
Number of common stock received | shares		5,000,000
Founder Shareholders | Scientific Consulting and Other Expenses
Related Party Transaction [Line Items]
Payments received from (made to) related parties | $			$ 400,000	400,000	500,000
Verve Therapeutics, Inc. | Office and Laboratory Space
Related Party Transaction [Line Items]
Sublease area of rented space | ft²	12,000
Operating lease term	1 year
Sublease, commencement month and year	2021-12
Sublease income | $			$ 0	$ (1,300,000)	$ (100,000)
Verve Therapeutics, Inc. | Common Stock
Related Party Transaction [Line Items]
Equity shares held | shares			546,970

Employee Benefits - Additional

Employee Benefits - Additional Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Retirement Benefits [Abstract]
Defined contribution plan name	401(k)
Employer matching contribution to 401(k) Plan as a percentage of employee's contribution	50%
Employer matching contribution to 401(k) Plan as a percentage of employee's eligible earnings	6%
Employer matching contribution to 401(k)	$ 2.5	$ 2	$ 1.1