Beam Therapeutics (BEAM) 10-Q 10 May 23 2023 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2023	May 03, 2023
Cover [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Mar. 31, 2023
Document Fiscal Year Focus	2023
Document Fiscal Period Focus	Q1
Trading Symbol	BEAM
Entity Registrant Name	Beam Therapeutics Inc.
Entity Central Index Key	0001745999
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Emerging Growth Company	false
Entity Small Business	false
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Shell Company	false
Title of 12(b) Security	Common Stock, par value $0.01 per share
Security Exchange Name	NASDAQ
Entity File Number	001-39208
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	81-5238376
Entity Address, Address Line One	238 Main Street
Entity Address, City or Town	Cambridge
Entity Address, State or Province	MA
Entity Address, Postal Zip Code	02142
City Area Code	857
Local Phone Number	327-8775
Document Quarterly Report	true
Document Transition Report	false
Entity Common Stock, Shares Outstanding		76,217,463

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Current assets:
Cash and cash equivalents	$ 249,771	$ 232,767
Marketable securities	809,700	845,367
Prepaid expenses and other current assets	23,560	14,762
Total current assets	1,083,031	1,092,896
Property and equipment, net	121,822	115,620
Restricted cash	9,802	12,754
Operating lease right-of-use assets	116,159	118,513
Other assets	1,538	1,931
Total assets	1,332,352	1,341,714
Current liabilities:
Accounts payable	14,063	9,029
Accrued expenses and other current liabilities	37,847	48,059
Derivative liabilities	12,700	18,300
Current portion of deferred revenue	142,737	135,974
Current portion of lease liability	11,157	10,380
Current portion of equipment financing liability	1,421	1,853
Total current liabilities	219,925	223,595
Long-term lease liability	165,298	168,625
Long-term equipment financing liability	983	1,154
Contingent consideration liabilities	12,759	12,463
Long-term portion of deferred revenue	171,708	202,179
Other liabilities	173	224
Total liabilities	570,846	608,240
Commitments and contingencies (See Note 7, License agreements and Note 8, Collaboration and license agreements)
Stockholders’ equity:
Preferred stock, $0.01 par value; 25,000,000 shares authorized, and no shares issued or outstanding at March 31, 2023 and December 31, 2022 , respectively
Common stock, $0.01 par value; 250,000,000 shares authorized, 74,435,392 and 71,277,339 issued and outstanding at March 31,2023 and December 31, 2022 respectively	744	712
Additional paid-in capital	1,915,349	1,792,554
Accumulated other comprehensive (loss) income	(765)	(2,430)
Accumulated deficit	(1,153,822)	(1,057,362)
Total stockholders' equity	761,506	733,474
Total liabilities and stockholders' equity	$ 1,332,352	$ 1,341,714

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Parenthetical) (Unaudited) - $ / shares	Mar. 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	74,435,392	71,277,339
Common stock, shares outstanding	74,435,392	71,277,339

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations and Other Comprehensive Loss (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Income Statement [Abstract]
License and collaboration revenue	$ 24,208	$ 8,432
Revenue, Product and Service [Extensible List]	us-gaap:LicenseMember	us-gaap:LicenseMember
Operating expenses:
Research and development	$ 99,646	$ 65,410
General and administrative	23,490	19,247
Total operating expenses	123,136	84,657
Loss from operations	(98,928)	(76,225)
Other income (expense):
Change in fair value of derivative liabilities	5,600	13,600
Change in fair value of non-controlling equity investments	(12,797)	(7,685)
Change in fair value of contingent consideration liabilities	(296)	452
Interest and other income (expense), net	9,961	644
Total other income (expense)	2,468	7,011
Net loss	(96,460)	(69,214)
Unrealized gain (loss) on marketable securities	1,665	(2,659)
Comprehensive loss	$ (94,795)	$ (71,873)
Net loss per common share, basic	$ (1.33)	$ (1.01)
Net loss per common share, diluted	$ (1.33)	$ (1.01)
Weighted - average common shares outstanding, basic	72,273,829	68,703,864
Weighted - average common shares outstanding, diluted	72,273,829	68,703,864

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Stockholders' Equity (Unaudited) - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Income (Loss)	Accumulated Deficit
Beginning Balance at Dec. 31, 2021	$ 826,738	$ 684	$ 1,594,378	$ (50)	$ (768,274)
Beginning Balance, Shares at Dec. 31, 2021		68,389,425
Purchase of common stock under ESPP	1,412		1,412
Purchase of common stock under ESPP, Shares		28,990
Issuance of common stock from At-the-Market offering, net of issuance costs	53,936	$ 9	53,927
Issuance of common stock from At-the-Market offering, net of issuance costs, Shares		874,770
Vesting of restricted common stock		$ 3	(3)
Vesting of restricted common stock, Shares		283,186
Stock-based compensation	18,035		18,035
Exercise of common stock options	820	$ 2	818
Exercise of common stock options, Shares		176,652
Other comprehensive income (loss)	(2,659)			(2,659)
Net loss	(69,214)				(69,214)
Ending Balance at Mar. 31, 2022	829,068	$ 698	1,668,567	(2,709)	(837,488)
Ending Balance, Shares at Mar. 31, 2022		69,753,023
Beginning Balance at Dec. 31, 2022	733,474	$ 712	1,792,554	(2,430)	(1,057,362)
Beginning Balance, Shares at Dec. 31, 2022		71,277,339
Purchase of common stock under ESPP	1,708	$ 1	1,707
Purchase of common stock under ESPP, Shares		65,620
Issuance of common stock from At-the-Market offering, net of issuance costs	93,810	$ 24	93,786
Issuance of common stock from At-the-Market offering, net of issuance costs, Shares		2,431,770
Vesting of restricted common stock		$ 3	(3)
Vesting of restricted common stock, Shares		284,858
Stock-based compensation	23,917		23,917
Exercise of common stock options	$ 3,392	$ 4	3,388
Exercise of common stock options, Shares	375,805	375,805
Other comprehensive income (loss)	$ 1,665			1,665
Net loss	(96,460)				(96,460)
Ending Balance at Mar. 31, 2023	$ 761,506	$ 744	$ 1,915,349	$ (765)	$ (1,153,822)
Ending Balance, Shares at Mar. 31, 2023		74,435,392

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Stockholders' Equity (Unaudited) (Parenthetical) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
ATM Offering
Stock issuance costs	$ 0.2	$ 1.3

Condensed Consolidated Statem_4

Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Operating activities
Net loss	$ (96,460)	$ (69,214)
Adjustments to reconcile net loss to net cash provided by (used in) operating activities:
Depreciation and amortization	4,647	3,312
Amortization of investment discount (premiums)	(6,932)	(390)
Stock-based compensation expense	23,917	18,035
Change in operating lease right-of-use assets	2,354	1,997
Change in fair value of derivative liabilities	(5,600)	(13,600)
Change in fair value of contingent consideration liabilities	296	(452)
Change in fair value of non-controlling equity investments	12,797	7,685
Other		3
Changes in operating assets and liabilities:
Prepaid expenses and other current assets	(8,405)	(9,185)
Accounts payable	(231)	(1,252)
Accrued expenses and other liabilities	(9,888)	(16,533)
Operating lease liabilities	(2,550)	(1,780)
Collaboration receivable		300,000
Deferred revenue	(23,708)	(8,432)
Other long-term liabilities	(52)	8,296
Net cash provided by (used in) operating activities	(109,815)	218,490
Investing activities
Purchases of property and equipment	(6,017)	(7,259)
Purchases of marketable securities	(266,532)	(690,390)
Maturities of marketable securities	298,000	160,310
Net cash provided by (used in) investing activities	25,451	(537,339)
Financing activities
Proceeds from issuance of common shares, net of commissions	93,981	54,003
Proceeds from issuances of stock under ESPP	1,708	1,412
Payment of equity offering costs	(62)	(6)
Repayment of equipment financings	(603)	(553)
Proceeds from exercise of stock options	3,392	820
Net cash provided by (used in) financing activities	98,416	55,676
Net change in cash, cash equivalents and restricted cash	14,052	(263,173)
Cash, cash equivalents and restricted cash—beginning of period	245,521	572,740
Cash, cash equivalents and restricted cash—end of period	259,573	309,567
Supplemental disclosure of cash flow information:
Cash paid for interest	62	113
Supplemental disclosure of non-cash investing and financing activities:
Property and equipment additions in accounts payable and accrued expenses	10,675	15,306
Operating lease liabilities arising from obtaining right-of-use assets		4,822
Equity issuance costs in accounts payable and accrued expenses	$ 109	$ 67

Nature of the Business and Basi

Nature of the Business and Basis of Presentation	3 Months Ended
	Mar. 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 is also in the process of developing 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 an at the market, or ATM, sales agreement, or the Sales Agreement, with Jefferies LLC, or Jefferies, pursuant to which the Company was entitled to offer and sell, from time to time at prevailing market prices, shares of the Company’s common stock having aggregate gross proceeds of up to $ 300.0 million. The Company agreed to pay Jefferies a commission of up to 3.0 % of the aggregate gross sale proceeds of any shares sold by Jefferies under the Sales Agreement. Between April and July 2021, the Company sold 2,908,009 shares of its common stock under the Sales Agreement at an average price of $ 103.16 per share for aggregate gross proceeds of $ 300.0 million, before deducting commissions and offering expenses payable by the Company. In July 2021, the Company and Jefferies entered into an amendment to the Sales Agreement to provide for an increase in the aggregate offering amount under the Sales Agr eement, such that as of July 7, 2021, the Company may offer and sell shares of common stock having an aggregate offering price of an additional $ 500.0 million. As of March 31, 2023, the Company has sold 6,340,059 additional shares of its common stock under the amended Sales Agreement at an average price of $ 65.95 per share for aggregate gross proceeds of $ 418.1 million, before deducting commissions and offering expenses payable by the Company. Since its inception, the Company has incurred substantial losses and had an accumulated deficit of $ 1.2 billion as of March 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 March 31, 2023 of $ 1.1 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. COVID-19-related significant risks and uncertainties While the COVID-19 pandemic did not significantly impact the Company’s business or results of operations during the three months ended March 31, 2023 , the extent to which the COVID-19 pandemic or any other public health emergency impacts the Company’s business, its corporate development objectives, results of operations and financial condition in future periods will depend on developments that are uncertain. Disruptions to the global economy and supply chain, disruption of global healthcare systems, and other significant impacts of the COVID-19 pandemic or other health emergencies could have a material adverse effect on the Company’s business, financial condition, results of operations and growth prospects.

Summary of Significant Accounti

Summary of Significant Accounting Policies	3 Months Ended
	Mar. 31, 2023
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	2. S ummary of significant accounting policies The Company’s significant accounting policies are disclosed in the audited consolidated financial statements for the year ended December 31, 2022, and notes thereto, which are included in the Company’s Annual Report on Form 10-K that was filed with the Securities and Exchange Commission, or the SEC, on February 28, 2023, or the 2022 Form 10-K. Since the date of those financial statements, there have been no material changes to Beam’s significant accounting policies. Basis of presentation The accompanying condensed consolidated financial statements have been prepared in accordance with United States generally accepted accounting principles, or GAAP. Any reference in these notes to applicable guidance is meant to refer to the authoritative GAAP as found in the Accounting Standards Codification, or ASC, and Accounting Standards Update, or ASU, of the Financial Accounting Standards Board. Principles of consolidation The accompanying condensed consolidated financial statements include the results of operations of the Company and its wholly-owned subsidiaries. All intercompany transactions and balances have been eliminated in consolidation. Use of estimates The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets, liabilities, revenues and expenses, and the disclosure of contingent assets and liabilities as of and during the reporting period. The Company bases its estimates and assumptions on historical experience when available and on various factors that it believes to be reasonable under the circumstances. Significant estimates and assumptions reflected in these condensed consolidated financial statements include, but are not limited to, incremental borrowing rate used in the calculation of lease liabilities, research and development expenses, stock-based compensation, contingent consideration liabilities, success payments 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 standard checking accounts, money market accounts, and all highly liquid investments with a remaining maturity of three months or less at the date of purchase. Restricted cash represents collateral provided for letters of credit issued as security deposits in connection with the Company’s leases of its corporate and manufacturing facilities. The following table reconciles cash, cash equivalents, and restricted cash reported within the Company’s condensed consolidated balance sheets to the total of the amounts shown in the condensed consolidated statements of cash flows (in thousands) : March 31, March 31, Cash and cash equivalents $ 249,771 $ 296,821 Restricted cash 9,802 12,746 Total cash, cash equivalents, and restricted cash $ 259,573 $ 309,567

Property and Equipment, Net

Property and Equipment, Net	3 Months Ended
	Mar. 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): March 31, December 31, Leasehold improvements $ 86,680 $ 85,804 Lab equipment 50,614 47,383 Furniture and fixtures 4,450 4,332 Computer equipment 3,073 3,073 Construction in process 11,822 5,198 Total property and equipment 156,639 145,790 Less accumulated depreciation ( 34,817 ) ( 30,170 ) Property and equipment, net $ 121,822 $ 115,620 The following table summarizes depreciation expense incurred (in thousands): Three Months Ended March 31, 2023 2022 Depreciation expense $ 4,647 $ 3,262

Fair Value of Financial Instrum

Fair Value of Financial Instruments	3 Months Ended
	Mar. 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, corporate equity securities of Verve Therapeutics, Inc., or Verve, and Prime Medicine, Inc., or Prime, contingent consideration liabilities related to the agreement and plan of merger pursuant to which the Company acquired Guide, or the Guide Merger Agreement, and success payment derivative liabilities pursuant to the license agreement, or the Harvard License Agreement, between President and Fellows of Harvard University, or Harvard, and the Company, and the license agreement, or the Broad License Agreement, between The Broad Institute, Inc., or Broad Institute, and the Company. The following tables set forth the fair value of the Company’s financial assets and liabilities by level within the fair value hierarchy at March 31, 2023 (in thousands): Carrying Fair Level 1 Level 2 Level 3 Assets Cash equivalents: Money market funds $ 217,038 217,038 $ 217,038 $ — $ — Marketable securities: Commercial paper 588,022 588,022 — 588,022 — U.S. Treasury securities 58,567 58,567 — 58,567 — U.S Government securities 135,441 135,441 — 135,441 — Corporate equity securities 27,670 27,670 27,670 — — Total assets $ 1,026,738 $ 1,026,738 $ 244,708 $ 782,030 $ — Liabilities Success payment liability – Harvard $ 6,200 $ 6,200 $ — $ — $ 6,200 Success payment liability – Broad Institute 6,500 6,500 — — 6,500 Contingent consideration liability – Technology 6,168 6,168 — — 6,168 Contingent consideration liability – Product 6,591 6,591 — — 6,591 Total liabilities $ 25,459 $ 25,459 $ — $ — $ 25,459 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 the use of 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. The Company holds an investment in Verve consisting of shares of Verve’s common stock. As of March 31, 2023, the Company owned 546,970 shares of Verve's common stock valued at $ 7.9 million, which is included in marketable securities in the condensed consolidated balance sheet. The Company also holds an investment in Prime consisting of 1,608,337 shares of Prime's common stock. As of March 31, 2023, the Company's investment in Prime's common stock was valued at $ 19.8 million, which is included in marketable securities in the condensed consolidated balance sheet. Pursuant to ASC 825, Financial instruments , the Company records changes in the fair value of its investments in equity securities to other income (expense), in the Company’s condensed consolidated statements of operations. The following table summarizes other income (expense) recorded due to changes in the fair value of corporate equity securities held (in thousands): Three Months Ended March 31, 2023 2022 Other income (expense) $ ( 12,797 ) $ ( 7,685 ) Success payment liabilities – As discussed further in Note 8, License agreements , the Company is required to make payments to Harvard and Broad Institute based upon the achievement of specified multiples of the market value of the Company's common stock, at specified valuation dates. The Company’s liability for the share-based success payments under the Harvard and Broad License Agreements is carried at fair value. To determine the estimated fair value of the success payment liability, the Company uses a Monte Carlo simulation methodology, which models the future movement of stock prices based on several key variables. The following variables were incorporated in the calculation of the estimated fair value of the Harvard and Broad Institute success payment liabilities: Harvard Broad Institute March 31, December 31, March 31, December 31, Fair value of common stock (per share) $ 30.62 $ 39.11 $ 30.62 $ 39.11 Expected volatility 80 % 82 % 79 % 82 % Expected term (years) 0.08 - 6.25 0.08 - 6.49 0.08 - 7.11 0.08 - 7.36 The computation of expected volatility was estimated using available information about the historical volatility of stocks of similar publicly traded companies in addition to the Company's own data for a period matching the expected term assumption. In addition, the Company incorporated the estimated number, timing, and probability of valuation measurement dates in the calculation of the success payment liability. The following table reconciles the change in the fair value of success payment liabilities based on Level 3 inputs (in thousands): Three Months Ended March 31, 2023 Harvard Broad Institute Total Balance at December 31, 2022 $ 9,000 $ 9,300 $ 18,300 Change in fair value ( 2,800 ) ( 2,800 ) ( 5,600 ) Balance at March 31, 2023 $ 6,200 $ 6,500 $ 12,700 Contingent consideration liabilities – Under the Guide Merger Agreement, Guide’s former stockholders and optionholders are eligible to receive up to an additional $ 100.0 million in technology milestone payments and $ 220.0 million in product milestone payments, payable in the Company’s common stock valued using the volume-weighted average price of the Company’s stock over the ten-day trading period ending two trading days prior to the date on which the applicable milestone is achieved. As these milestones are payable in 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. Changes in fair value are reflected in the Company’s condensed consolidated statements of operations and other comprehensive loss, presented in other income (expense). These contingent consideration liabilities are classified within Level 3 of the fair value hierarchy. The following table reconciles the change in fair value of the contingent consideration liabilities based on level 3 inputs (in thousands): Three Months Ended March 31, 2023 Technology Milestones Product Milestones Total Balance at December 31, 2022 $ 6,025 $ 6,438 $ 12,463 Change in fair value 143 153 296 Balance at March 31, 2023 $ 6,168 $ 6,591 $ 12,759 The following variables were incorporated in the calculation of the estimated fair value of the contingent consideration liabilities: Technology Milestones Product Milestones March 31, December 31, March 31, December 31, Discount Rate 10.00 % 10.00 % 10.00 % 10.00 % Probability of Achievement 5 - 15 % 5 - 15 % 2 - 15 % 2 - 15 % Projected Year of Achievement 2024 - 2025 2024 - 2025 2025 - 2030 2025 - 2030

Marketable Securities

Marketable Securities	3 Months Ended
	Mar. 31, 2023
Investments, Debt and Equity Securities [Abstract]
Marketable Securities	5. Marketable securities The following table summarizes the Company’s marketable securities held at March 31, 2023 (in thousands): Amortized Cost Gross Gross Fair Value Commercial paper $ 588,410 $ 60 $ ( 448 ) $ 588,022 U.S. Treasury securities 58,749 — ( 182 ) 58,567 U.S. Government securities 135,636 77 ( 272 ) 135,441 Corporate equity securities 27,670 — — 27,670 Total $ 810,465 $ 137 $ ( 902 ) $ 809,700 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 March 31, 2023 , the balance in accumulated other comprehensive (loss) income was related to marketable securities. There were no realized gains or losses recognized on the sale or maturity of marketable securities for the three months ended March 31, 2023 and 2022 and, as a result, the Company did not reclassify any amounts out of accumulated other comprehensive (loss) income for the same periods. The Company holds debt securities of companies with high credit quality and has determined that there was no material change in the credit risk of any of its debt securities.

Accrued Expenses and Other Curr

Accrued Expenses and Other Current Liabilities	3 Months Ended
	Mar. 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): March 31, December 31, Research costs $ 7,769 $ 4,844 Professional fees 7,111 6,751 Process development and manufacturing costs 6,246 5,080 Employee compensation and related benefits 5,622 19,122 Other 11,099 12,262 Total $ 37,847 $ 48,059 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 alleges that the Company breached the terms of the confidentiality agreement, misappropriated trade secret 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-102 and BEAM-302. The research institution claims 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. As of March 31, 2023 , the Company has accrued a $ 3.4 million liability equal to an amount the Company offered to resolve the dispute. The settlement proposal was rejected by the research institution. No complaint has been filed, and the Company continues to discuss the matter with the research institution. Although it may do so, the Company has not determined to make a further offer and believes that it is unable at this time to provide any estimate of a reasonably possible loss in excess of the amount offered. The ultimate resolution of this matter could result in an outcome that is materially different from the amount accrued as of March 31, 2023 .

License Agreements

License Agreements	3 Months Ended
	Mar. 31, 2023
Organization, Consolidation and Presentation of Financial Statements [Abstract]
License Agreements	7. License agreements Harvard license agreement Under the Harvard License Agreement, Harvard is entitled to receive success payments, in cash or shares of Company stock, determined based upon the achievement of specified multiples of the initial weighted average value of the Company’s Series A Preferred at specified valuation dates. The success payments range from $ 5.0 million to a maximum of $ 105.0 million and have valuation multiples that range from 5 times to 40 times the initial weighted average value of the Series A Preferred. Subsequent to the Company’s February 2020 IPO, the amount of success payments is based on the market value of the Company's common stock. The Company is required to make success payments to Harvard during a period of time, or the Harvard Success Payment Period, which has been determined to be the later of (1) the ninth anniversary of the Harvard License Agreement or (2) the earlier of (a) the twelfth anniversary of the Harvard License Agreement and (b) the third anniversary of the first date on which a licensed product receives regulatory approval in the United States. During the Harvard Success Payment Period and beginning one year after the Company’s IPO, the Company will perform a calculation of any amounts owed to Harvard on each rolling 90-day period. In May 2021, the first success payment measurement occurred and amounts due to Harvard were calculated to be $ 15.0 million. The Company elected to make the payment in shares of the Company’s common stock and issued 174,825 shares of the Company’s common stock to settle this liability on June 10, 2021. The Company may owe Harvard success payments of up to an additional $ 90.0 million. As of March 31, 2023 , no success payments were due to Harvard. The following table summarizes the Company’s success payment liability for Harvard (in thousands): March 31, December 31, Harvard success payment liability $ 6,200 $ 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): Three Months Ended March 31, 2023 2022 Change in fair value of Harvard success payment liability $ ( 2,800 ) $ ( 6,800 ) As of each of March 31, 2023 and 2022 , the Company determined that product development and regulatory approval milestones under the Harvard License Agreement were not probable and, as such, no amounts were recognized for the three months ended March 31, 2023 or 2022. During the three months ended March 31, 2023 , the Company did no t incur expense related to non-royalty sublicense fees owed to Harvard. The Company incurred $ 0.5 million of expense related to non-royalty sublicense fees owed to Harvard during the three months ended March 31, 2022. Broad license agreement Under the Broad License Agreement, Broad Institute is entitled to receive success payments, in cash or shares of Company common stock, determined based upon the achievement of specified multiples of the initial weighted average value of the Series A Preferred at specified valuation dates. The success payments range from $ 5.0 million to a maximum of $ 105.0 million and have valuation multiples that range from 5 times to 40 times the initial weighted average value of the Series A Preferred. Subsequent to the February 2020 IPO, the amount of success payments is based on the market value of the Company’s common stock. The Company is required to make success payments to Broad Institute during a period of time, or the Broad Success Payment Period, which has been determined to be the earliest of (1) the twelfth anniversary of the Broad License Agreement or (2) the third anniversary of the first date on which a licensed product receives regulatory approval in the United States. During the Broad Success Payment Period, the Company will perform a calculation of any amounts owed to Broad Institute on each rolling 90-day period, commencing one year after the Company’s IPO. In May 2021, the first success payment measurement occurred and amounts due to Broad Institute were calculated to be $ 15.0 million. The Company elected to make the payment in shares of the Company’s common stock and issued 174,825 shares of the Company’s common stock to settle this liability on June 10, 2021. The Company may owe Broad Institute success payments of up to an additional $ 90.0 million. As of March 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): March 31, December 31, Broad Institute success payment liability $ 6,500 $ 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): Three Months Ended March 31, 2023 2022 Change in fair value of Broad Institute success payment liability $ ( 2,800 ) $ ( 6,800 ) As of March 31, 2023, the Company determined that product development and regulatory approval milestones and royalties under the Broad License Agreement were not probable and, as such, no amounts were recognized for the three months ended March 31, 2023 or 2022. The Company recorded less than $ 0.1 million of expense related to non-royalty sublicense fees owed to the Broad Institute during the three months ended March 31, 2023 , which is included in accrued expenses and other current liabilities in the accompanying consolidated balance sheet. The Company recorded no expense related to non-royalty sublicense fees owed to the Broad Institute during the three months ended March 31, 2022. The Company paid $ 6.1 million of non-royalty sublicense fees to Broad Institute during the three months ended March 31, 2022 related to non-royalty sublicense fee expense incurred during the second half of 2021. Editas license agreement In May 2018, the Company entered into a license agreement, or the Editas License Agreement, with Editas Medicine, Inc., or Editas. Pursuant to the Editas License Agreement, Editas granted to the Company licenses and options to acquire licenses to certain intellectual property rights owned or controlled by Editas, for specified uses. The annual maintenance fees under the Editas License Agreement are recorded as research and development expense. Annual patent costs are expensed as incurred. In addition, the Company is required to make certain development, regulatory and commercial milestone payments to Editas upon the achievement of specified milestones.

Collaboration and License Agree

Collaboration and License Agreements	3 Months Ended
	Mar. 31, 2023
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Collaboration and License Agreements	8. Collaboration and license agreements 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 Beam 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, which represented a 31.5 % fully diluted equity interest in Orbital as of the closing. The Company accounts for its investment in Orbital under the equity method of accounting. The research plan has a term of three years and can be extended for unspecified periods upon mutual agreement between the Company and Orbital. The exploitation licenses are exclusive for an initial research term of three years , which may be extended for up to two successive one-year periods by mutual agreement between the Company and Orbital. Either party may terminate the licenses granted to it under the Orbital Agreement for convenience on a product-by-product basis at any time by providing 90 days’ prior written notice. The Company accounts for the Orbital Agreement under ASC 606, 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 at inception. The Company concluded that the research and exploitation licenses are not distinct from the other promises in the Orbital Agreement, and as such the Company has determined that the licenses combined with the research and development services, know-how transfers, committee participation and materials transfer represent a 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 $ 2.1 million of revenue during the three months ended March 31, 2023. As of March 31, 2023 , there was $ 8.5 million and $ 12.8 million of current and long-term deferred revenue, respectively, related to the Orbital Agreement. Pfizer In December 2021, the Company entered into a research collaboration agreement, or the Pfizer Agreement, with Pfizer Inc., or Pfizer, focused on the use of certain of the Company’s base editing technology to develop in vivo therapies for rare genetic diseases of the liver, muscle, and central nervous system. Under the terms of the Pfizer Agreement, the Company will conduct all research activities through development candidate selection for three base editing programs that target specific genes corresponding to specific diseases that are the subject of such programs. Pfizer will have exclusive rights to license each of the three programs at no additional cost, each an Opt-In Right, and will assume responsibility for subsequent development and commercialization. At the end of the Phase 1/2 clinical trials, the Company may elect to enter into a global co-development and co-commercialization agreement with Pfizer with respect to one program licensed under the collaboration for an option exercise fee equal to a percentage of the applicable development costs incurred by Pfizer, or the Participation Election. In the event the Company elects to exercise its Participation Election, upon the payment of its option exercise fee, Pfizer and the Company would share net profits as well as development and commercialization costs in a 65 %/ 35 % (Pfizer/Company) split for such program. The research collaboration is managed on an overall basis by a Joint Research Committee, or JRC, formed by an equal number of representatives from the Company and Pfizer. At the inception of the Pfizer Agreement, the Company was entitled to receive a nonrefundable upfront payment of $ 300.0 million in consideration for the rights granted to Pfizer under the collaboration. Should Pfizer exercise its Opt-In Right for any of the three programs, the Company would be eligible to receive development, regulatory, and commercial milestones of up to $ 350.0 million per program, for potential total consideration of up to $ 1.35 billion, plus royalty payments on global net sales for each licensed program, if any. If Pfizer does not exercise its Opt-In Right for a program, the Company’s rights in such program revert to the Company and the Company will be required to pay Pfizer earn-out payments equal to a low single digit percentage of net sales earned on such program for a ten-year period, if any. 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 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 Pfizer and represents the Company’s best estimate of the period of the obligation. For the three months ended March 31, 2023 and 2022, the Company recognized $ 16.2 million and $ 6.3 million of revenue related to the Pfizer Agreement, respectively. As of March 31, 2023 , there was $ 102.7 million and $ 132.9 million of current and long-term deferred revenue, respectively, related to the Pfizer Agreement. Apellis Pharmaceuticals In June 2021, the Company entered into a research collaboration agreement, or the Apellis Agreement, with Apellis Pharmaceuticals, Inc., or Apellis, focused on the use of certain of the Company’s base editing technology to discover new treatments for complement system-driven diseases. Under the terms of the Apellis Agreement, the Company will conduct preclinical research on six base editing programs that target specific genes within the complement system in various organs, including the eye, liver, and brain. Apellis has an exclusive option to license any or all of the six programs, or in each case, an Opt-In Right, and will assume responsibility for subsequent development. The Company may elect to enter into a 50-50 U.S. co-development and co-commercialization agreement with Apellis with respect to one program instead of a license. The collaboration is managed on an overall basis by an alliance steering committee formed by an equal number of representatives from the Company and Apellis. As part of the collaboration, the Company was eligible to receive a total of $ 75.0 million in upfront and near-term milestones from Apellis, which was comprised of $ 50.0 million received upon signing and an additional $ 25.0 million payment on June 30, 2022, the one-year anniversary of the effective date of the Apellis Agreement, or the First Anniversary Payment. Following any exercise of an Opt-In Right for any of the six programs, the Company will be eligible to receive development, regulatory, and sales milestones from Apellis, as well as royalty payments on sales. The collaboration has an initial term of five years and may be extended up to two years on a per year and program-by-program basis. During the collaboration term, Apellis may, subject to certain limitations, substitute a specific complement gene and/or organ for any of the initial base editing programs. Apellis may terminate the Apellis Agreement for convenience on any or all of the programs by providing prior written notice. The Company 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. The Company further concluded that the Opt-In Rights and option to extend the collaboration term did not grant Apellis a material right. The Company determined that the term of the contract is five years , as this is the period during which both parties have enforceable rights. The selling price of each performance obligation was determined based on the Company’s ESSP. The Company developed the ESSP for all of the performance obligations included in the Apellis Agreement by determining the total estimated costs to fulfill each performance obligation identified with the objective of determining the price at which it would sell such an item if it were to be sold regularly on a standalone basis. The Company allocated the stand-alone selling price to the performance obligations based on the relative standalone selling price method. The Company recognizes revenue for each performance obligation as it is satisfied over the five-year term using an input method. The Company allocated the transaction price of $ 75.0 million to each of the six performance obligations, which includes each of the six base editing programs combined with the research and development service, licenses, substitution rights and governance participation, and is being recognized using an input method based on the actual costs incurred as a percentage of total 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 three months ended March 31, 2023 and March 31, 2022 , the Company recognized $ 5.4 million and $ 2.1 million of revenue related to the Apellis Agreement, respectively. As of March 31, 2023 , there is $ 31.6 million and $ 25.7 million of current and long-term deferred revenue, respectively, related to the Apellis Agreement. 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 Beam 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. As of March 31, 2023 , the Company determined that milestones and royalties under the Verve Agreement were not probable of recognition.

Common Stock

Common Stock	3 Months Ended
	Mar. 31, 2023
Stockholders' Equity Attributable to Parent [Abstract]
Common Stock	9. Common stock In April 2021, the Company entered into the Sales Agreement with Jefferies, pursuant to which the Company was entitled to offer and sell, from time to time at prevailing market prices, shares of the Company’s common stock having aggregate gross proceeds of up to $ 300.0 million. The Company agreed to pay Jefferies a commission of up to 3.0 % of the aggregate gross sale proceeds of any shares sold by Jefferies under the Sales Agreement. Between April and July 2021, 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, the Company and Jefferies entered into an amendment to the Sales Agreement to provide for an increase in the aggregate offering amount under the Sales Agreement, such that as of July 7, 2021, the Company may offer and sell shares of common stock having an aggregate offering price of an additional $ 500.0 million. As of March 31, 2023, the Company has sold 6,340,059 additional shares of its common stock under the amended Sales Agreement at an average price of $ 65.95 per share for aggregate gross proceeds of $ 418.1 million, before deducting commissions and offering expenses payable by the Company. The holders of the Company’s common stock are entitled to one vote for each share of common stock. Subject to the payment in full of all preferential dividends to which the holders of the Company’s preferred stock are entitled, 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 and all preferential amounts to which the holders of Company’s preferred stock are entitled with respect to the distribution of assets in liquidation, 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	3 Months Ended
	Mar. 31, 2023
Share-Based Payment Arrangement [Abstract]
Stock Option and Grant Plan	10. Stock option and grant plan 2019 equity incentive plan As of March 31, 2023, the Company had 12,984,890 shares reserved including 1,925,296 shares available for future issuance pursuant to the Beam Therapeutics Inc. 2019 Equity Incentive Plan. Stock-based compensation expense recorded as research and development and general and administrative expenses in the condensed consolidated statements of operations and other comprehensive loss is as follows (in thousands): Three Months Ended 2023 2022 Research and development $ 14,222 $ 11,294 General and administrative 9,695 6,741 Total stock-based compensation expense $ 23,917 $ 18,035 Stock options The following table provides a summary of option activity under the Company’s equity award plans: Number Weighted Outstanding at December 31, 2022 7,548,392 $ 41.77 Granted 1,770,350 43.07 Exercised ( 375,805 ) 9.02 Forfeitures ( 129,457 ) 63.25 Outstanding at March 31, 2023 8,813,480 43.11 Exercisable as of March 31, 2023 3,912,166 31.31 The weighted-average grant date fair value per share of options granted in the three months ended March 31, 2023 was $ 30.20 . As of March 31, 2023, there was $ 169.4 million of unrecognized compensation expense related to unvested stock options, which is expected to be recognized over a weighted-average remaining vesting period of approximately 2.7 years. Restricted stock The Company issues shares of restricted common stock, including both restricted stock units and restricted stock awards. Restricted common stock issued generally vests over a period of two to four years . The following table summarizes the Company’s restricted stock activity: Shares Weighted- Unvested as of December 31, 2022 1,692,819 $ 65.49 Issued 874,025 30.62 Vested ( 284,858 ) 66.43 Forfeited ( 35,872 ) 64.97 Unvested as of March 31, 2023 2,246,114 $ 51.82 At March 31, 2023, there was approximately $ 109.3 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 3.3 years. 2019 employee stock purchase plan The Company issued 65,620 and 28,990 shares under the Beam Therapeutics Inc. 2019 Employee Stock Purchase Plan, or ESPP, during the three months ended March 31, 2023 and 2022, respectively. As of March 31, 2023 , the Company had 2,312,352 shares available for issuance under the ESPP. Stock-based compensation recognized under the ESPP for the three months ended March 31, 2023 and 2022 was $ 0.4 million and $ 0.3 million, respectively.

Net Loss per Share

Net Loss per Share	3 Months Ended
	Mar. 31, 2023
Earnings Per Share [Abstract]
Net Loss per Share	11. Net loss per share For periods in which the Company reports a net loss, potentially dilutive securities have been excluded from the computation of diluted net loss per share as their effects would be anti-dilutive. Therefore, the weighted average number of common shares outstanding used to calculate both basic and diluted net loss per share is the same. The Company excluded the following potential common shares, presented based on amounts outstanding at period end, from the computation of diluted net loss per share because including them would have had an anti-dilutive effect: As of March 31, 2023 2022 Unvested restricted stock 2,246,114 1,542,526 Outstanding options to purchase common stock 8,813,480 7,264,403 Total 11,059,594 8,806,929 The following table summarizes the computation of basic and diluted net loss per share of the Company (in thousands, except share and per share amounts): Three Months Ended March 31, 2023 2022 Numerator: Net loss $ ( 96,460 ) $ ( 69,214 ) Denominator: Weighted average common shares outstanding, basic and diluted 72,273,829 68,703,864 Net loss per common share, basic and diluted $ ( 1.33 ) $ ( 1.01 )

Income Taxes

Income Taxes	3 Months Ended
	Mar. 31, 2023
Income Tax Disclosure [Abstract]
Income Taxes	12. Income taxes During the three months ended March 31, 2023 and 2022 , the Company recorded a full valuation allowance on federal and state deferred tax assets since there is insufficient evidence that the deferred tax assets are more likely than not realizable. The Company did no t have any tax provision or benefit in the three months ended March 31, 2023 and 2022 .

Related Party Transactions

Related Party Transactions	3 Months Ended
	Mar. 31, 2023
Related Party Transactions [Abstract]
Related Party Transactions	13. Related party transactions Orbital The Company has significant influence over, but does not control, Orbital through its noncontrolling representation on Orbital's board of directors and the Company’s equity interest in Orbital. The Company and Orbital are also parties to a collaboration and license agreement and have multiple common board members. Founders The Company made payments of $ 0.1 million and $ 0.1 million to its three founder shareholders for scientific consulting and other expenses for each of the three months ended March 31, 2023 and 2022. Verve The Company and Verve are parties to a collaboration and license agreement and had a common board member from August 2018 to August 2022. As of March 31, 2023 , the Company owns 546,970 shares of Verve's common stock, the value of which is included in marketable securities in the condensed consolidated balance sheet. The Company recorded the investment at fair value as of March 31, 2023, which resulted in a recognition of other expense of $ 2.7 million for the three months ended March 31, 2023. The Company recorded other expense of $ 7.7 million for the three months ended March 31, 2022 related to the changes in fair value of Verve's stock. The value of this investment as of March 31, 2023 is $ 7.9 million. 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 $ 0.3 million of sublease income related to this sublease within the accompanying consolidated statements of operations and other comprehensive loss for the three months ended March 31, 2022 , 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 related to this sublease was recorded during the three months ended March 31, 2023. Prime Medicine The Company and Prime are parties to a collaboration and license agreement and had a common founder and had a common board member from September 2019 to September 2022. As of March 31, 2023 the Company owns 1,608,337 shares of Prime's common stock, the value of which is included in marketable securities in the condensed consolidated balance sheet. The Company recorded the investment at fair value as of March 31, 2023, which resulted in a recognition of other expense of $ 10.1 million during the three months ended March 31, 2023 . The Company did no t record any other income or expense related to the changes in fair value of Prime's common stock for the three months ended March 31, 2022. The value of this investment as of March 31, 2023 is $ 19.8 million.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	3 Months Ended
	Mar. 31, 2023
Accounting Policies [Abstract]
Basis of Presentation	Basis of presentation The accompanying condensed consolidated financial statements have been prepared in accordance with United States generally accepted accounting principles, or GAAP. Any reference in these notes to applicable guidance is meant to refer to the authoritative GAAP as found in the Accounting Standards Codification, or ASC, and Accounting Standards Update, or ASU, of the Financial Accounting Standards Board.
Principles of Consolidation	Principles of consolidation The accompanying condensed consolidated financial statements include the results of operations of the Company and its wholly-owned subsidiaries. All intercompany transactions and balances have been eliminated in consolidation.
Use of Estimates	Use of estimates The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets, liabilities, revenues and expenses, and the disclosure of contingent assets and liabilities as of and during the reporting period. The Company bases its estimates and assumptions on historical experience when available and on various factors that it believes to be reasonable under the circumstances. Significant estimates and assumptions reflected in these condensed consolidated financial statements include, but are not limited to, incremental borrowing rate used in the calculation of lease liabilities, research and development expenses, stock-based compensation, contingent consideration liabilities, success payments 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 standard checking accounts, money market accounts, and all highly liquid investments with a remaining maturity of three months or less at the date of purchase. Restricted cash represents collateral provided for letters of credit issued as security deposits in connection with the Company’s leases of its corporate and manufacturing facilities. The following table reconciles cash, cash equivalents, and restricted cash reported within the Company’s condensed consolidated balance sheets to the total of the amounts shown in the condensed consolidated statements of cash flows (in thousands) : March 31, March 31, Cash and cash equivalents $ 249,771 $ 296,821 Restricted cash 9,802 12,746 Total cash, cash equivalents, and restricted cash $ 259,573 $ 309,567

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Tables)	3 Months Ended
	Mar. 31, 2023
Accounting Policies [Abstract]
Reconciliation of Cash, Cash Equivalents	The following table reconciles cash, cash equivalents, and restricted cash reported within the Company’s condensed consolidated balance sheets to the total of the amounts shown in the condensed consolidated statements of cash flows (in thousands) March 31, March 31, Cash and cash equivalents $ 249,771 $ 296,821 Restricted cash 9,802 12,746 Total cash, cash equivalents, and restricted cash $ 259,573 $ 309,567
Reconciliation of Restricted Cash, Cash Equivalents	The following table reconciles cash, cash equivalents, and restricted cash reported within the Company’s condensed consolidated balance sheets to the total of the amounts shown in the condensed consolidated statements of cash flows (in thousands) : March 31, March 31, Cash and cash equivalents $ 249,771 $ 296,821 Restricted cash 9,802 12,746 Total cash, cash equivalents, and restricted cash $ 259,573 $ 309,567

Property and Equipment, Net (Ta

Property and Equipment, Net (Tables)	3 Months Ended
	Mar. 31, 2023
Property, Plant and Equipment [Abstract]
Schedule of Property and Equipment	Property and equipment consist of the following (in thousands): March 31, December 31, Leasehold improvements $ 86,680 $ 85,804 Lab equipment 50,614 47,383 Furniture and fixtures 4,450 4,332 Computer equipment 3,073 3,073 Construction in process 11,822 5,198 Total property and equipment 156,639 145,790 Less accumulated depreciation ( 34,817 ) ( 30,170 ) Property and equipment, net $ 121,822 $ 115,620
Summary of Depreciation Expense Incurred	The following table summarizes depreciation expense incurred (in thousands): Three Months Ended March 31, 2023 2022 Depreciation expense $ 4,647 $ 3,262

Fair Value of Financial Instr_2

Fair Value of Financial Instruments (Tables)	3 Months Ended
	Mar. 31, 2023
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 March 31, 2023 (in thousands): Carrying Fair Level 1 Level 2 Level 3 Assets Cash equivalents: Money market funds $ 217,038 217,038 $ 217,038 $ — $ — Marketable securities: Commercial paper 588,022 588,022 — 588,022 — U.S. Treasury securities 58,567 58,567 — 58,567 — U.S Government securities 135,441 135,441 — 135,441 — Corporate equity securities 27,670 27,670 27,670 — — Total assets $ 1,026,738 $ 1,026,738 $ 244,708 $ 782,030 $ — Liabilities Success payment liability – Harvard $ 6,200 $ 6,200 $ — $ — $ 6,200 Success payment liability – Broad Institute 6,500 6,500 — — 6,500 Contingent consideration liability – Technology 6,168 6,168 — — 6,168 Contingent consideration liability – Product 6,591 6,591 — — 6,591 Total liabilities $ 25,459 $ 25,459 $ — $ — $ 25,459 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) Recorded Due To Changes In Fair Value Of Corporate Equity Securities Held	The following table summarizes other income (expense) recorded due to changes in the fair value of corporate equity securities held (in thousands): Three Months Ended March 31, 2023 2022 Other income (expense) $ ( 12,797 ) $ ( 7,685 )
Success Payment Liabilities
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 March 31, December 31, March 31, December 31, Fair value of common stock (per share) $ 30.62 $ 39.11 $ 30.62 $ 39.11 Expected volatility 80 % 82 % 79 % 82 % Expected term (years) 0.08 - 6.25 0.08 - 6.49 0.08 - 7.11 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): Three Months Ended March 31, 2023 Harvard Broad Institute Total Balance at December 31, 2022 $ 9,000 $ 9,300 $ 18,300 Change in fair value ( 2,800 ) ( 2,800 ) ( 5,600 ) Balance at March 31, 2023 $ 6,200 $ 6,500 $ 12,700
Contingent Consideration Liabilities
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 March 31, December 31, March 31, December 31, Discount Rate 10.00 % 10.00 % 10.00 % 10.00 % Probability of Achievement 5 - 15 % 5 - 15 % 2 - 15 % 2 - 15 % Projected Year of Achievement 2024 - 2025 2024 - 2025 2025 - 2030 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): Three Months Ended March 31, 2023 Technology Milestones Product Milestones Total Balance at December 31, 2022 $ 6,025 $ 6,438 $ 12,463 Change in fair value 143 153 296 Balance at March 31, 2023 $ 6,168 $ 6,591 $ 12,759

Marketable Securities (Tables)

Marketable Securities (Tables)	3 Months Ended
	Mar. 31, 2023
Investments, Debt and Equity Securities [Abstract]
Summary of Marketable Securities Held	The following table summarizes the Company’s marketable securities held at March 31, 2023 (in thousands): Amortized Cost Gross Gross Fair Value Commercial paper $ 588,410 $ 60 $ ( 448 ) $ 588,022 U.S. Treasury securities 58,749 — ( 182 ) 58,567 U.S. Government securities 135,636 77 ( 272 ) 135,441 Corporate equity securities 27,670 — — 27,670 Total $ 810,465 $ 137 $ ( 902 ) $ 809,700 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)	3 Months Ended
	Mar. 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): March 31, December 31, Research costs $ 7,769 $ 4,844 Professional fees 7,111 6,751 Process development and manufacturing costs 6,246 5,080 Employee compensation and related benefits 5,622 19,122 Other 11,099 12,262 Total $ 37,847 $ 48,059

License Agreements (Tables)

License Agreements (Tables)	3 Months Ended
	Mar. 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): March 31, December 31, Harvard success payment liability $ 6,200 $ 9,000 The following table summarizes the Company’s success payment liability for Broad Institute (in thousands): March 31, December 31, Broad Institute success payment liability $ 6,500 $ 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): Three Months Ended March 31, 2023 2022 Change in fair value of Harvard success payment liability $ ( 2,800 ) $ ( 6,800 ) The following table summarizes the expense resulting from the change in the fair value of the success payment liability for Broad Institute (in thousands): Three Months Ended March 31, 2023 2022 Change in fair value of Broad Institute success payment liability $ ( 2,800 ) $ ( 6,800 )

Stock Option and Grant Plan (Ta

Stock Option and Grant Plan (Tables)	3 Months Ended
	Mar. 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 condensed consolidated statements of operations and other comprehensive loss is as follows (in thousands): Three Months Ended 2023 2022 Research and development $ 14,222 $ 11,294 General and administrative 9,695 6,741 Total stock-based compensation expense $ 23,917 $ 18,035
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 Outstanding at December 31, 2022 7,548,392 $ 41.77 Granted 1,770,350 43.07 Exercised ( 375,805 ) 9.02 Forfeitures ( 129,457 ) 63.25 Outstanding at March 31, 2023 8,813,480 43.11 Exercisable as of March 31, 2023 3,912,166 31.31
Summary of Restricted Stock Activity	The following table summarizes the Company’s restricted stock activity: Shares Weighted- Unvested as of December 31, 2022 1,692,819 $ 65.49 Issued 874,025 30.62 Vested ( 284,858 ) 66.43 Forfeited ( 35,872 ) 64.97 Unvested as of March 31, 2023 2,246,114 $ 51.82

Net Loss per Share (Tables)

Net Loss per Share (Tables)	3 Months Ended
	Mar. 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 because including them would have had an anti-dilutive effect: As of March 31, 2023 2022 Unvested restricted stock 2,246,114 1,542,526 Outstanding options to purchase common stock 8,813,480 7,264,403 Total 11,059,594 8,806,929
Summary of Computation of Basic and Diluted Net Loss per Share	The following table summarizes the computation of basic and diluted net loss per share of the Company (in thousands, except share and per share amounts): Three Months Ended March 31, 2023 2022 Numerator: Net loss $ ( 96,460 ) $ ( 69,214 ) Denominator: Weighted average common shares outstanding, basic and diluted 72,273,829 68,703,864 Net loss per common share, basic and diluted $ ( 1.33 ) $ ( 1.01 )

Nature of the Business and Ba_2

Nature of the Business and Basis of Presentation - Additional Information (Details) - USD ($)	1 Months Ended	3 Months Ended		4 Months Ended	21 Months Ended
	Apr. 30, 2021	Mar. 31, 2023	Mar. 31, 2022	Jul. 31, 2021	Mar. 31, 2023	Dec. 31, 2022	Jul. 07, 2021
Nature Of Business And Basis Of Presentation [Line Items]
Accumulated deficit		$ 1,153,822,000			$ 1,153,822,000	$ 1,057,362,000
Cash, cash equivalents, and marketable securities		$ 1,100,000,000			1,100,000,000
Common Stock
Nature Of Business And Basis Of Presentation [Line Items]
Shares issued and sold		2,431,770	874,770
Jeffries LLC Amended Sales Agreement
Nature Of Business And Basis Of Presentation [Line Items]
Gross proceeds from issuance of common stock					$ 418,100,000
Jeffries LLC Amended Sales Agreement | Common Stock
Nature Of Business And Basis Of Presentation [Line Items]
Shares issued and sold					6,340,059
Public offering price per share		$ 65.95			$ 65.95
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							$ 500,000,000
Jeffries LLC Sales Agreement
Nature Of Business And Basis Of Presentation [Line Items]
Stock sold during period shares, new issues				2,908,009
Gross proceeds from issuance of common stock				$ 300,000,000
Price per share of shares issued				$ 103.16
Jeffries LLC Sales Agreement | Common Stock
Nature Of Business And Basis Of Presentation [Line Items]
Stock sold during period shares, new issues				2,908,009
Price per share of shares issued				$ 103.16
Jeffries LLC Sales Agreement | Maximum | ATM Offering
Nature Of Business And Basis Of Presentation [Line Items]
Commission rate	3%
Aggregate gross proceeds of shares authorized under ATM sales agreement	$ 300,000,000

Summary of Significant Accoun_4

Summary of Significant Accounting Policies - Reconciliation of Cash, Cash Equivalents, and Restricted Cash (Details) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022	Mar. 31, 2022	Dec. 31, 2021
Accounting Policies [Abstract]
Cash and cash equivalents	$ 249,771	$ 232,767	$ 296,821
Restricted cash	9,802	12,754	12,746
Total cash, cash equivalents, and restricted cash	$ 259,573	$ 245,521	$ 309,567	$ 572,740

Property and Equipment, Net - S

Property and Equipment, Net - Schedule of Property and Equipment (Details) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Property Plant And Equipment [Line Items]
Total property and equipment	$ 156,639	$ 145,790
Less accumulated depreciation	(34,817)	(30,170)
Property and equipment, net	121,822	115,620
Leasehold Improvements
Property Plant And Equipment [Line Items]
Total property and equipment	86,680	85,804
Lab Equipment
Property Plant And Equipment [Line Items]
Total property and equipment	50,614	47,383
Furniture and Fixtures
Property Plant And Equipment [Line Items]
Total property and equipment	4,450	4,332
Computer Equipment
Property Plant And Equipment [Line Items]
Total property and equipment	3,073	3,073
Construction in Process
Property Plant And Equipment [Line Items]
Total property and equipment	$ 11,822	$ 5,198

Property and Equipment, Net -_2

Property and Equipment, Net - Summary of Depreciation Expense Incurred (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Property, Plant and Equipment [Abstract]
Depreciation expense	$ 4,647	$ 3,262

Fair Value of Financial Instr_3

Fair Value of Financial Instruments - Schedule of Fair Value of Financial Assets and Liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Commercial Paper
Assets
Marketable securities	$ 588,022	$ 577,728
Harvard
Liabilities
Success payment liability	6,200	9,000
Broad Institute
Liabilities
Success payment liability	6,500	9,300
Recurring | Carrying Amount
Assets
Total assets	1,026,738	1,078,134
Liabilities
Total liabilities	25,459	30,763
Recurring | Carrying Amount | Money Market Funds
Assets
Cash equivalents	217,038	218,794
Recurring | Carrying Amount | Commercial Paper
Assets
Cash equivalents		10,475
Marketable securities	588,022	577,728
Recurring | Carrying Amount | Corporate Notes
Assets
Cash equivalents		3,498
Marketable securities		18,996
Recurring | Carrying Amount | U.S. Treasury Securities
Assets
Marketable securities	58,567	145,312
Recurring | Carrying Amount | U.S Government securities
Assets
Marketable securities	135,441	62,864
Recurring | Carrying Amount | Corporate Equity Securities
Assets
Equity securities included in marketable securities	27,670	40,467
Recurring | Carrying Amount | Consideration of Technology Liabilities
Liabilities
Contingent consideration liability	6,168	6,025
Recurring | Carrying Amount | Contingent Consideration of Product Liabilities
Liabilities
Contingent consideration liability	6,591	6,438
Recurring | Fair Value
Assets
Total assets	1,026,738	1,078,134
Liabilities
Total liabilities	25,459	30,763
Recurring | Fair Value | Money Market Funds
Assets
Cash equivalents	217,038	218,794
Recurring | Fair Value | Commercial Paper
Assets
Cash equivalents		10,475
Marketable securities	588,022	577,728
Recurring | Fair Value | Corporate Notes
Assets
Cash equivalents		3,498
Marketable securities		18,996
Recurring | Fair Value | U.S. Treasury Securities
Assets
Marketable securities	58,567	145,312
Recurring | Fair Value | U.S Government securities
Assets
Marketable securities	135,441	62,864
Recurring | Fair Value | Corporate Equity Securities
Assets
Equity securities included in marketable securities	27,670	40,467
Recurring | Fair Value | Consideration of Technology Liabilities
Liabilities
Contingent consideration liability	6,168	6,025
Recurring | Fair Value | Contingent Consideration of Product Liabilities
Liabilities
Contingent consideration liability	6,591	6,438
Recurring | Fair Value | Level 1
Assets
Total assets	244,708	259,261
Recurring | Fair Value | Level 1 | Money Market Funds
Assets
Cash equivalents	217,038	218,794
Recurring | Fair Value | Level 1 | Corporate Equity Securities
Assets
Equity securities included in marketable securities	27,670	40,467
Recurring | Fair Value | Level 2
Assets
Total assets	782,030	818,873
Recurring | Fair Value | Level 2 | Commercial Paper
Assets
Cash equivalents		10,475
Marketable securities	588,022	577,728
Recurring | Fair Value | Level 2 | Corporate Notes
Assets
Cash equivalents		3,498
Marketable securities		18,996
Recurring | Fair Value | Level 2 | U.S. Treasury Securities
Assets
Marketable securities	58,567	145,312
Recurring | Fair Value | Level 2 | U.S Government securities
Assets
Marketable securities	135,441	62,864
Recurring | Fair Value | Level 3
Liabilities
Total liabilities	25,459	30,763
Recurring | Fair Value | Level 3 | Consideration of Technology Liabilities
Liabilities
Contingent consideration liability	6,168	6,025
Recurring | Fair Value | Level 3 | Contingent Consideration of Product Liabilities
Liabilities
Contingent consideration liability	6,591	6,438
Recurring | Harvard | Carrying Amount
Liabilities
Success payment liability	6,200	9,000
Recurring | Harvard | Fair Value
Liabilities
Success payment liability	6,200	9,000
Recurring | Harvard | Fair Value | Level 3
Liabilities
Success payment liability	6,200	9,000
Recurring | Broad Institute | Carrying Amount
Liabilities
Success payment liability	6,500	9,300
Recurring | Broad Institute | Fair Value
Liabilities
Success payment liability	6,500	9,300
Recurring | Broad Institute | Fair Value | Level 3
Liabilities
Success payment liability	$ 6,500	$ 9,300

Fair Value of Financial Instr_4

Fair Value of Financial Instruments - Additional Information (Details) - USD ($) $ in Millions	Mar. 31, 2023	Feb. 23, 2021
Verve Therapeutics, Inc.
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Equity securities	$ 7.9
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	$ 19.8
Prime Medicine Inc | Common Stock
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Equity shares held	1,608,337
Technology Milestones | Guide Therapeutics, Inc. | Maximum | Merger Agreement | Former Stockholders and Optionholders
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Potential milestone payable in form of common stock		$ 100
Product Milestones | Guide Therapeutics, Inc. | Maximum | Merger Agreement | Former Stockholders and Optionholders
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Potential milestone payable in form of common stock		$ 220

Fair Value of Financial Instr_5

Fair Value of Financial Instruments - Summarizes Other Income ( Expense) Recorded Due To Changes In Fair Value Of Corporate Equity Securities Held (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Fair Value Disclosures [Abstract]
Other income (expense)	$ (12,797)	$ (7,685)

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	3 Months Ended	12 Months Ended
	Mar. 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	30.62	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	30.62	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	29 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	29 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	6 years 3 months	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	7 years 1 month 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 $ in Thousands	3 Months Ended
	Mar. 31, 2023 USD ($)
Fair Value Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Beginning Balance	$ 18,300
Change in fair value	(5,600)
Ending Balance	12,700
Harvard
Fair Value Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Beginning Balance	9,000
Change in fair value	(2,800)
Ending Balance	6,200
Broad Institute
Fair Value Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Beginning Balance	9,300
Change in fair value	(2,800)
Ending Balance	$ 6,500

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 $ in Thousands	3 Months Ended
	Mar. 31, 2023 USD ($)
Fair Value Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Beginning Balance	$ 12,463
Change in fair value	296
Ending Balance	12,759
Technology Milestones
Fair Value Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Beginning Balance	6,025
Change in fair value	143
Ending Balance	6,168
Product Milestones
Fair Value Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Beginning Balance	6,438
Change in fair value	153
Ending Balance	$ 6,591

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	3 Months Ended	12 Months Ended
	Mar. 31, 2023	Dec. 31, 2022
Technology Milestones | Minimum
Derivative Liability [Abstract]
Milestone liabilities projected year of achievement	2024	2024
Technology Milestones | Maximum
Derivative Liability [Abstract]
Milestone liabilities projected year of achievement	2025	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	2030	2030
Discount Rate | Technology Milestones
Derivative Liability [Abstract]
Contingent consideration liability measurement input	0.1000	0.1000
Discount Rate | Product Milestones
Derivative Liability [Abstract]
Contingent consideration liability measurement input	0.1000	0.1000
Probability of Achievement | Technology Milestones | Minimum
Derivative Liability [Abstract]
Contingent consideration liability measurement input	0.05	0.05
Probability of Achievement | Technology Milestones | Maximum
Derivative Liability [Abstract]
Contingent consideration liability measurement input	0.15	0.15
Probability of Achievement | Product Milestones | Minimum
Derivative Liability [Abstract]
Contingent consideration liability measurement input	0.02	0.02
Probability of Achievement | Product Milestones | Maximum
Derivative Liability [Abstract]
Contingent consideration liability measurement input	0.15	0.15

Marketable Securities - Summary

Marketable Securities - Summary of Marketable Securities (Details) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Debt Securities, Available-for-Sale [Line Items]
Marketable securities held, Amortized Cost	$ 810,465	$ 847,797
Marketable securities held, Gross Unrealized Gains	137	85
Marketable securities held, Gross Unrealized Losses	(902)	(2,515)
Marketable securities held, Fair Value	809,700	845,367
Commercial Paper
Debt Securities, Available-for-Sale [Line Items]
Available-for-sale, Amortized Cost	588,410	578,813
Available-for-sale, Gross Unrealized Gains	60	72
Available-for-sale, Gross Unrealized Losses	(448)	(1,157)
Available-for-sale, Fair Value	588,022	577,728
Corporate Notes
Debt Securities, Available-for-Sale [Line Items]
Available-for-sale, Amortized Cost		19,033
Available-for-sale, Gross Unrealized Losses		(37)
Available-for-sale, Fair Value		18,996
U.S. Treasury Securities
Debt Securities, Available-for-Sale [Line Items]
Available-for-sale, Amortized Cost	58,749	146,270
Available-for-sale, Gross Unrealized Losses	(182)	(958)
Available-for-sale, Fair Value	58,567	145,312
Corporate Equity Securities
Debt Securities, Available-for-Sale [Line Items]
Equity securities, Amortized Cost	27,670	40,467
Equity securities, Fair Value	27,670	40,467
Government Securities
Debt Securities, Available-for-Sale [Line Items]
Available-for-sale, Amortized Cost	135,636	63,214
Available-for-sale, Gross Unrealized Gains	77	13
Available-for-sale, Gross Unrealized Losses	(272)	(363)
Available-for-sale, Fair Value	$ 135,441	$ 62,864

Marketable Securities - Additio

Marketable Securities - Additional Information (Details) - USD ($)	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Investments, Debt and Equity Securities [Abstract]
Realized gains or losses recognized on sale or maturity of marketable securities	$ 0	$ 0

Accrued Expenses and Other Cu_3

Accrued Expenses and Other Current Liabilities - Schedule of Accrued Expenses and Other Current Liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Payables and Accruals [Abstract]
Research costs	$ 7,769	$ 4,844
Professional fees	7,111	6,751
Process development and manufacturing costs	6,246	5,080
Employee compensation and related benefits	5,622	19,122
Other	11,099	12,262
Total	$ 37,847	$ 48,059

Accrued Expenses and Other Cu_4

Accrued Expenses and Other Current Liabilities - Additional Information (Details) $ in Millions	Mar. 31, 2023 USD ($)
Dispute with Research Institution
Loss Contingencies [Line Items]
Accrual liability	$ 3.4

License Agreements - Harvard Li

License Agreements - Harvard License Agreement - Additional Information (Details) - Harvard		3 Months Ended
	Jun. 10, 2021 shares	Mar. 31, 2023 USD ($)	Mar. 31, 2022 USD ($)	May 31, 2021 USD ($)
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Success payment amount due		$ 0		$ 15,000,000
Milestone expense		0	$ 0
Non-royalty sublicense fees owed		0	$ 500,000
Common Stock
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
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 and beginning one year after the Company’s IPO, the Company will perform a calculation of any amounts owed to Harvard on each rolling 90-day period.

License Agreements - Harvard _2

License Agreements - Harvard License Agreement - Success Payment Liability (Details) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Harvard
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Success payment liability	$ 6,200	$ 9,000

License Agreements - Harvard _3

License Agreements - Harvard License Agreement - Change in Fair Value of Success Payment Liability (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Change in fair value of derivative liabilities	$ (5,600)	$ (13,600)
Harvard
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Change in fair value of derivative liabilities	$ (2,800)	$ (6,800)

License Agreements - Broad Lice

License Agreements - Broad License Agreement - Additional Information (Details) - Broad Institute		3 Months Ended
	Jun. 10, 2021 shares	Mar. 31, 2023 USD ($)	Mar. 31, 2022 USD ($)	May 31, 2021 USD ($)
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.
Success payment amount due		$ 0		$ 15,000,000
Milestone expense		0	$ 0
Non-royalty sublicense fees paid			6,100,000
Non-royalty sublicense fees owed			$ 0
Common Stock
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
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]
Success payments		$ 105,000,000
Additional success payment amount due				$ 90,000,000
Non-royalty sublicense fees owed		$ 100,000
Maximum | Series A Preferred Stock
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Success Payments, valuation multiples		40

License Agreements - Broad Li_2

License Agreements - Broad License Agreement - Success Payment Liability (Details) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Broad Institute
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Success payment liability	$ 6,500	$ 9,300

License Agreements - Broad Li_3

License Agreements - Broad License Agreement - Change in Fair Value of Success Payment Liability (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Change in fair value of derivative liabilities	$ (5,600)	$ (13,600)
Broad Institute
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Change in fair value of derivative liabilities	$ (2,800)	$ (6,800)

Collaboration and License Agr_2

Collaboration and License Agreements - Additional Information (Details) - USD ($) $ in Thousands, shares in Millions	1 Months Ended						3 Months Ended
	Sep. 30, 2022	Jun. 30, 2022	Jan. 31, 2022	Dec. 31, 2021	Jul. 31, 2021	Jun. 30, 2021	Mar. 31, 2023	Mar. 31, 2022	Dec. 31, 2022
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Current portion of deferred revenue							$ 142,737		$ 135,974
Long-term portion of deferred revenue							171,708		$ 202,179
Apellis Pharmaceuticals, Inc
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Agreement description						In June 2021, the Company entered into a research collaboration agreement, or the Apellis Agreement, with Apellis Pharmaceuticals, Inc., or Apellis, focused on the use of certain of the Company’s base editing technology to discover new treatments for complement system-driven diseases. Under the terms of the Apellis Agreement, the Company will conduct preclinical research on six base editing programs that target specific genes within the complement system in various organs, including the eye, liver, and brain. Apellis has an exclusive option to license any or all of the six programs, or in each case, an Opt-In Right, and will assume responsibility for subsequent development. The Company may elect to enter into a 50-50 U.S. co-development and co-commercialization agreement with Apellis with respect to one program instead of a license. The collaboration is managed on an overall basis by an alliance steering committee formed by an equal number of representatives from the Company and Apellis.
Collaboration arrangement, initial term						5 years
Collaboration agreement performance obligation revenue recognized							5,400	$ 2,100
Collaboration agreement aggregate transaction price						$ 75,000
Upfront fee receivable upon signing contract						50,000
Upfront payment received under term of agreement					$ 50,000
Collaboration agreement first anniversary amount receivable						$ 25,000
Collaboration agreement first anniversary payment received		$ 25,000
Current portion of deferred revenue							31,600
Long-term portion of deferred revenue							25,700
Apellis Pharmaceuticals, Inc | Maximum
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Collaboration arrangement extension term						2 years
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
Nonrefundable upfront payment receivable				300,000
Collaboration agreement upfront payment received			$ 300,000
Collaboration agreement performance obligation revenue recognized							16,200	$ 6,300
Collaboration agreement aggregate transaction price				$ 300,000
Earn-out payment period				10 years
Deferred revenue liability				$ 300,000
Current portion of deferred revenue							102,700
Long-term portion of deferred revenue							132,900
Pfizer | Assigned to Company | Upon Participation Election
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Net profits as well as development and commercialization costs percentage				35%
Pfizer | Assigned to Pfizer | Upon Participation Election
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Net profits as well as development and commercialization costs percentage				65%
Pfizer | Maximum | Per Program
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Development regulatory and commercial milestones receivable				$ 350,000
Orbital
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Common stock shares received at closing	75
Percentage of fully diluted equity interest	31.50%
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 recognized							2,100
Collaboration agreement aggregate transaction price	$ 25,500
Collaboration agreement performance obligation revenue period for recognition	3 years
Current portion of deferred revenue							8,500
Long-term portion of deferred revenue							$ 12,800
Orbital | Exploitation Licenses
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Collaboration arrangement, initial term	3 years
Collaboration arrangement extension term description	which may be extended for up to two successive one-year periods
Orbital | Research Plan
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Collaboration arrangement, initial term	3 years

Common Stock - Additional Infor

Common Stock - Additional Information (Details) - USD ($)	1 Months Ended	3 Months Ended		4 Months Ended	21 Months Ended
	Apr. 30, 2021	Mar. 31, 2023	Mar. 31, 2022	Jul. 31, 2021	Mar. 31, 2023	Jul. 07, 2021
Class Of Stock [Line Items]
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]
Shares issued and sold		2,431,770	874,770
Jeffries LLC Sales Agreement
Class Of Stock [Line Items]
Shares issued and sold				2,908,009
Price per share of shares issued				$ 103.16
Gross proceeds from issuance of common stock				$ 300,000,000
Jeffries LLC Sales Agreement | Common Stock
Class Of Stock [Line Items]
Shares issued and sold				2,908,009
Price per share of shares issued				$ 103.16
Jeffries LLC Amended Sales Agreement
Class Of Stock [Line Items]
Gross proceeds from issuance of common stock					$ 418,100,000
Jeffries LLC Amended Sales Agreement | Common Stock
Class Of Stock [Line Items]
Shares issued and sold					6,340,059
Price per share of shares issued		$ 65.95			$ 65.95
At-The-Market | Jeffries LLC Sales Agreement | Maximum
Class Of Stock [Line Items]
Aggregate gross proceeds of shares authorized under ATM sales agreement	$ 300,000,000
Commission rate	3%
At-The-Market | Jeffries LLC Amended Sales Agreement
Class Of Stock [Line Items]
Aggregate gross proceeds of shares authorized under ATM sales agreement						$ 500,000,000

Stock Option and Grant Plan - A

Stock Option and Grant Plan - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation expense	$ 23,917	$ 18,035
Weighted-average grant date fair value per share of options granted	$ 30.20
Stock Options
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unrecognized compensation expense related to unvested stock options	$ 169,400
Unrecognized compensation cost, cost to recognize over a weighted-average remaining vesting period	2 years 8 months 12 days
Restricted Stock
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unrecognized compensation cost, cost to recognize over a weighted-average remaining vesting period	3 years 3 months 18 days
Unrecognized stock-based compensation expense, expected to vest	$ 109,300
Restricted Stock | Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vesting period	4 years
Restricted Stock | Minimum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vesting period	2 years
2019 Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares reserved for future issuance	12,984,890
Number of shares available for future issuance	1,925,296
2019 Employee Stock Purchase Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares available for future issuance	2,312,352
Number of shares issued	65,620	28,990
Stock-based compensation expense	$ 400	$ 300

Stock Option and Grant Plan - S

Stock Option and Grant Plan - Summary of Stock-based Compensation Expense (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock-based compensation expense	$ 23,917	$ 18,035
Research and Development
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock-based compensation expense	14,222	11,294
General and Administrative
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock-based compensation expense	$ 9,695	$ 6,741

Stock Option and Grant Plan -_2

Stock Option and Grant Plan - Summary of Option Activity Under Equity Award Plans (Details)	3 Months Ended
	Mar. 31, 2023 $ / shares shares
Number of options
Outstanding at December 31, 2022 | shares	7,548,392
Granted | shares	1,770,350
Exercised | shares	(375,805)
Forfeitures | shares	(129,457)
Outstanding at March 31, 2023 | shares	8,813,480
Exercisable as of March 31, 2023 | shares	3,912,166
Weighted average exercise price
Outstanding at December 31, 2022 | $ / shares	$ 41.77
Granted | $ / shares	43.07
Exercised | $ / shares	9.02
Forfeitures | $ / shares	63.25
Outstanding at March 31, 2023 | $ / shares	43.11
Exercisable as of March 31, 2023 | $ / shares	$ 31.31

Stock Option and Grant Plan -_3

Stock Option and Grant Plan - Summary of Restricted Stock Activity (Details) - Restricted Stock	3 Months Ended
	Mar. 31, 2023 $ / shares shares
Shares
Unvested as of December 31, 2022 | shares	1,692,819
Issued | shares	874,025
Vested | shares	(284,858)
Forfeited | shares	(35,872)
Unvested as of March 31, 2023 | shares	2,246,114
Weighted-average grant date fair value
Unvested as of December 31, 2022 | $ / shares	$ 65.49
Issued | $ / shares	30.62
Vested | $ / shares	66.43
Cancelled | $ / shares	64.97
Unvested as of March 31, 2023 | $ / shares	$ 51.82

Net Loss per Share - Schedule o

Net Loss per Share - Schedule of Potential Common Shares Excluded from Computation of Diluted Net Loss per Share (Details) - shares	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive shares excluded from computation of diluted net loss per share	11,059,594	8,806,929
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	2,246,114	1,542,526
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	8,813,480	7,264,403

Net Loss per Share - Summary of

Net Loss per Share - Summary of Computation of Basic and Diluted Net Loss per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Numerator:
Net loss	$ (96,460)	$ (69,214)
Denominator:
Weighted - average common shares outstanding, basic	72,273,829	68,703,864
Weighted - average common shares outstanding, diluted	72,273,829	68,703,864
Net loss per common share, basic	$ (1.33)	$ (1.01)
Net loss per common share, diluted	$ (1.33)	$ (1.01)

Income Taxes - Additional Infor

Income Taxes - Additional Information (Details) - USD ($)	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Income Tax Disclosure [Abstract]
Provision (Benefit) for income tax	$ 0	$ 0

Related Party Transactions - Ad

Related Party Transactions - Additional Information (Details)	1 Months Ended	3 Months Ended
	Oct. 31, 2021 ft²	Mar. 31, 2023 USD ($) Founder shares	Mar. 31, 2022 USD ($)
Related Party Transaction [Line Items]
Number of founder shareholders | Founder		3
Other income (expense)		$ (12,797,000)	$ (7,685,000)
Prime Medicine Inc
Related Party Transaction [Line Items]
Equity securities		19,800,000
Income from related party			0
Expense from related party		$ 10,100,000	0
Prime Medicine Inc | Common Stock
Related Party Transaction [Line Items]
Equity shares held | shares		1,608,337
Founder Shareholders | Scientific Consulting and Other Expenses
Related Party Transaction [Line Items]
Payments received from (made to) related parties		$ 100,000	100,000
Verve Therapeutics, Inc.
Related Party Transaction [Line Items]
Equity securities		7,900,000
Other income (expense)		(2,700,000)	(7,700,000)
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	$ 300,000
Verve Therapeutics, Inc. | Common Stock
Related Party Transaction [Line Items]
Equity shares held | shares		546,970