Intellia Therapeutics (NTLA) 10-Q 4 Aug 22 2022 Q2 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	6 Months Ended
	Jun. 30, 2022	Aug. 01, 2022
Cover [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Jun. 30, 2022
Document Fiscal Year Focus	2022
Document Fiscal Period Focus	Q2
Trading Symbol	NTLA
Entity Registrant Name	INTELLIA THERAPEUTICS, INC.
Entity Central Index Key	0001652130
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Common Stock, Shares Outstanding		76,011,784
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Shell Company	false
Entity File Number	001-37766
Entity Tax Identification Number	36-4785571
Entity Address, Address Line One	40 Erie Street
Entity Address, Address Line Two	Suite 130
Entity Address, City or Town	Cambridge
Entity Address, State or Province	MA
Entity Address, Postal Zip Code	02139
City Area Code	857
Local Phone Number	285-6200
Entity Incorporation, State or Country Code	DE
Title of 12(b) Security	Common Stock, par value $0.0001 per share
Security Exchange Name	NASDAQ
Document Quarterly Report	true
Document Transition Report	false

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Current Assets:
Cash and cash equivalents	$ 147,781	$ 123,406
Marketable securities	726,494	625,282
Accounts receivable ($0 million and $0.1 million respectively from related party)	2,854	2,031
Prepaid expenses and other current assets	18,304	18,584
Total current assets	895,433	769,303
Marketable securities - noncurrent	32,604	337,361
Property and equipment, net	25,868	20,968
Operating lease right-of-use assets	73,775	79,143
Equity method investment	45,616	58,131
Investments and other assets ($10.0 million at the end of each period from related party)	37,128	29,558
Total Assets	1,110,424	1,294,464
Current Liabilities:
Accounts payable	7,515	9,653
Accrued expenses ($0.1 million and $0 million respectively from related party)	44,871	43,309
Current portion of operating lease liability	9,568	9,112
Current portion of deferred revenue ($39.3 million at the end of each period from related party)	61,806	63,759
Total current liabilities	123,760	125,833
Deferred revenue, net of current portion ($2.9million and $ 19.9million respectively from related party)	35,330	63,476
Long-term operating lease liability	59,997	64,911
Other long-term liabilities	10,790	0
Commitments and contingencies (Note 6)
Stockholders’ Equity:
Common stock, $0.0001 par value; 120,000,000 shares authorized; 76,000,745 and 74,485,883 shares issued and outstanding at June 30, 2022 and December 31, 2021, respectively	8	7
Additional paid-in capital	1,840,644	1,745,870
Accumulated other comprehensive loss	(9,554)	(2,632)
Accumulated deficit	(950,551)	(703,001)
Total stockholders’ equity	880,547	1,040,244
Total Liabilities and Stockholders’ Equity	$ 1,110,424	$ 1,294,464

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Unaudited) (Parenthetical) - USD ($) $ in Millions	Jun. 30, 2022	Dec. 31, 2021
Statement of Financial Position [Abstract]
Accounts receivable, related party	$ 0	$ 0.1
Accrued expense from related party	0.1	0
Investments and Other Assets from Related Parties Current	10	10
Current portion of deferred revenue, related party	39.3	41.2
Deferred revenue, net of current portion, related party	$ 2.9	$ 19.9
Common stock, par value	$ 0.0001	$ 0.0001
Common stock, shares authorized	120,000,000	120,000,000
Common stock, shares issued	76,000,745	74,485,883
Common stock, shares outstanding	76,000,745	74,485,883

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations and Comprehensive Loss (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Income Statement [Abstract]
Collaboration revenue	$ 14,030	$ 6,550	$ 25,282	$ 12,995
Type of Revenue [Extensible List]	us-gaap:LicenseAndServiceMember	us-gaap:LicenseAndServiceMember	us-gaap:LicenseAndServiceMember	us-gaap:LicenseAndServiceMember
Operating expenses:
Research and development	$ 90,199	$ 58,884	$ 223,294	$ 98,160
General and administrative	22,132	16,683	44,535	30,277
Total operating expenses	112,331	75,567	267,829	128,437
Operating loss	(98,301)	(69,017)	(242,547)	(115,442)
Other (expense) income, net:
Interest income	703	211	1,243	431
Loss from equity method investment	(3,252)	0	(5,997)	0
Change in fair value of contingent consideration	172	0	(249)	0
Total other (expense) income, net	(2,377)	211	(5,003)	431
Net loss	$ (100,678)	$ (68,806)	$ (247,550)	$ (115,011)
Net Loss Per Share, Basic	$ (1.33)	$ (1.01)	$ (3.29)	$ (1.70)
Net Loss Per Share, Diluted	$ (1.33)	$ (1.01)	$ (3.29)	$ (1.70)
Weighted average shares outstanding, basic	75,823	68,164	75,282	67,675
Weighted average shares outstanding, diluted	75,823	68,164	75,282	67,675
Other comprehensive loss:
Unrealized loss on marketable securities	$ (932)	$ (1)	$ (6,060)	$ (14)
Other comprehensive loss from equity method investment	(560)	0	(862)	0
Comprehensive loss	$ (102,170)	$ (68,807)	$ (254,472)	$ (115,025)

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Operations and Comprehensive Loss (Unaudited) (Parenthetical) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Income Statement [Abstract]
Revenue from related party	$ 7,767	$ 0	$ 13,151	$ 0

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021
CASH FLOWS FROM OPERATING ACTIVITIES:
Net loss	$ (247,550)	$ (115,011)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	3,591	3,225
Equity-based compensation	41,559	17,038
Amortization of investment premiums	4,428	2,868
Loss from equity method investment	5,997	0
Deferral of equity method investment intra-entity profit on sales	5,656	0
Change in fair value of contingent consideration	249	0
In-process research and development charge	55,990	0
Changes in operating assets and liabilities:
Accounts receivable	(824)	137
Prepaid expenses and other current assets	434	(8,703)
Operating lease right-of-use assets	5,368	4,018
Other assets	(802)	(229)
Accounts payable	(3,710)	(2,606)
Accrued expenses	(721)	10,135
Deferred revenue	(30,099)	(11,179)
Operating lease liabilities	(4,458)	(5,050)
Net cash used in operating activities	(164,892)	(105,357)
CASH FLOWS FROM INVESTING ACTIVITIES:
Purchases of property and equipment	(5,409)	(5,350)
Purchases of marketable securities	(31,524)	(185,431)
Maturities of marketable securities	224,583	198,499
Acquired in-process research and development, net of cash acquired of $287	(44,832)	0
Net cash provided by investing activities	142,818	7,718
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from issuance of common stock through at-the-market offerings, net of issuance costs	38,885	45,255
Proceeds from options exercised	13,262	19,503
Issuance of shares through employee stock purchase plan	1,068	970
Net cash provided by financing activities	53,215	65,728
Net increase (decrease) in cash and cash equivalents and restricted cash equivalents	31,141	(31,911)
Cash and cash equivalents and restricted cash equivalents, beginning of period	125,486	164,606
Cash and cash equivalents and restricted cash equivalents, end of period	156,627	132,695
Reconciliation of cash and cash equivalents and restricted cash equivalents to condensed consolidated balance sheet:
Cash and cash equivalents	147,781	129,879
Restricted cash equivalents, included in investments and other assets	8,846	2,816
Total cash and cash equivalents and restricted cash equivalents	156,627	132,695
SUPPLEMENTAL DISCLOSURES OF CASH FLOW INFORMATION:
Purchases of property and equipment unpaid at period end	3,750	1,969
Right-of-use assets acquired under operating leases	0	41,974
Contingent consideration liability assumed in asset acquisition	10,541	0
Offering costs unpaid at period end	$ 0	$ 208

Condensed Consolidated Statem_4

Condensed Consolidated Statements of Cash Flows (Unaudited) (Parenthetical) $ in Thousands	6 Months Ended
	Jun. 30, 2022 USD ($)
Net of cash acquired	$ 287

Overview and Basis of Presentat

Overview and Basis of Presentation	6 Months Ended
	Jun. 30, 2022
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Overview and Basis of Presentation	1. Overview and Basis of Presentation Intellia Therapeutics, Inc. (“Intellia” or the “Company”) is a leading clinical-stage genome editing company, focused on developing novel, potentially curative therapeutics leveraging CRISPR/Cas9-based technologies. CRISPR/Cas9, an acronym for C lustered, R egularly I nterspaced S hort P alindromic R epeats (“CRISPR”)/CRISPR associated 9 (“Cas9”), is a technology for genome editing, the process of altering selected sequences of genomic deoxyribonucleic acid (“DNA”). To fully realize the transformative potential of CRISPR/Cas9-based technologies, Intellia is building a full-spectrum genome editing company, by leveraging its modular platform, to advance in vivo and ex vivo therapies for diseases with high unmet need by pursuing two primary approaches. The Company's in vivo programs use intravenously administered CRISPR as the therapy, in which proprietary delivery technology enables highly precise editing of disease-causing genes directly within specific target tissues. The Company's ex vivo programs use CRISPR to create the therapy by using engineered human cells to treat cancer and autoimmune diseases. The Company's deep scientific, technical and clinical development experience, along with its robust intellectual property (“IP”) portfolio, have enabled it to take a leadership role in harnessing the full potential of genome editing to create new classes of genetic medicine. The condensed consolidated financial statements of the Company included herein have been prepared, without audit, pursuant to the rules and regulations of the Securities and Exchange Commission (“SEC”). Certain information and footnote disclosures normally included in annual financial statements prepared in accordance with accounting principles generally accepted in the United States of America (“U.S. GAAP”) have been condensed or omitted from this report, as is permitted by such rules and regulations. Accordingly, these condensed consolidated financial statements should be read in conjunction with the financial statements and notes thereto included in the Company’s Annual Report on Form 10-K (“Annual Report”) for the year ended December 31, 2021. On February 2, 2022, the Company entered into an Agreement and Plan of Merger (the “Merger Agreement”) with RW Acquisition Corp., a Delaware corporation and a wholly-owned subsidiary of the Company (“Merger Sub”), Rewrite Therapeutics, Inc., a Delaware corporation (“Rewrite”) and Shareholder Representative Services LLC, a Colorado limited liability company, solely in its capacity as the representative of the Rewrite Holders (as defined below). On the effective date of the Merger Agreement, Merger Sub merged with and into Rewrite, with Rewrite surviving as a wholly-owned subsidiary of the Company. Pursuant to the Merger Agreement, and subject to the terms and conditions thereof, the Company paid Rewrite’s former stockholders and optionholders (the “Rewrite Holders”) upfront consideration in an aggregate amount of approximately $ 45.0 million payable in cash, excluding customary purchase price adjustments. In addition, the Rewrite Holders will be eligible to receive up to an additional $ 155.0 million in milestone payments upon the achievement of certain pre-specified research and regulatory approval milestones, payable through a mixture of $ 130.0 million in cash and $ 25.0 million in shares of common stock, par value $ 0.0001 per share (“Common Stock”) of the Company. The shares of Common Stock will be valued using the volume-weighted average price of Common Stock of the Company over the ten consecutive trading day period ending on and including the trading day that is two trading days immediately prior to the issuance of the consideration issued in connection with the applicable milestone. The unaudited condensed consolidated financial statements include the accounts of Intellia Therapeutics, Inc. and its wholly- owned subsidiaries, Intellia Securities Corp. and Rewrite Therapeutics, Inc. All intercompany balances and transactions have been eliminated in consolidation. Comprehensive loss is comprised of net loss, unrealized gain/loss on marketable securities and other comprehensive loss from equity method investment. The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates, judgments and assumptions that affect the amounts reported in the financial statements and accompanying notes. Significant estimates in these condensed consolidated financial statements have been made in connection with the calculation of revenues, research and development expenses, valuation of equity and fair value method investments, contingent consideration and equity-based compensation expense. The Company bases its estimates on historical experience and various other assumptions that management believes to be reasonable under the circumstances at the time such estimates are made. Actual results could differ from those estimates. The Company periodically reviews its estimates in light of changes in circumstances, facts and experience. The extent of the impact of the coronavirus disease 19 (“COVID-19”) pandemic on the Company’s operational and financial performance will depend on certain developments, including the length and severity of this pandemic, as well as its effect on the Company’s employees, collaborators and vendors, all of which are uncertain and cannot be predicted. The Company cannot reasonably estimate the extent to which the disruption may materially impact its consolidated results of operations or financial position. The effects of material revisions in estimates are reflected in the condensed consolidated financial statements prospectively from the date of the change in estimate. In the opinion of management, the information furnished reflects all adjustments, all of which are of a normal and recurring nature, necessary for a fair presentation of the results for the reported interim periods. The Company considers events or transactions that occur after the balance sheet date but before the financial statements are issued to provide additional evidence relative to certain estimates or to identify matters that require additional disclosure. The results of operations for interim periods are not necessarily indicative of results to be expected for the full year or any other interim period. Liquidity Since its inception through June 30, 2022, the Company has raised an aggregate of approximately $ 1,861.1 million to fund its operations through its initial public offering (“IPO”) and concurrent private placements, follow-on public offerings, at-the-market offerings and the sale of convertible preferred stock, as well as through its collaboration agreements. The Company expects that its cash, cash equivalents and marketable securities as of June 30, 2022 will enable the Company to fund its ongoing operating expenses and capital expenditure requirements for at least the twelve-month period following the issuance of these condensed consolidated financial statements .

Summary of Significant Accounti

Summary of Significant Accounting Policies	6 Months Ended
	Jun. 30, 2022
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	2. Summary of Significant Accounting Policies The Company’s significant accounting policies are described in Note 2, “Summary of Significant Accounting Policies” to the consolidated financial statements included in the Annual Report for the year ended December 31, 2021. There have been no material changes during the six months ended June 30, 2022 except for the following. Asset acquisitions At the time of acquisition, the Company determines if a transaction should be accounted for as a business combination or acquisition of assets. The Company measures and recognizes asset acquisitions that are not deemed to be business combinations based on the cost to acquire the assets, which includes transaction costs, and the consideration is allocated to the items acquired based on a relative fair value methodology. Goodwill is not recognized in asset acquisitions. In an asset acquisition, the cost allocated to acquire in-process research and development with no alternative future use is charged to research and development expense at the acquisition date. Contingent consideration The Company accounts for contingent consideration identified in an asset acquisition, that is payable in cash and does not meet the definition of a derivative under Accounting Standard Codification (“ASC”) 815, Derivatives and Hedging , when the contingency is resolved and the consideration is paid or becomes payable. The Company accounts for contingent consideration identified in an asset acquisition that is settled in shares of common stock under ASC 480, Distinguishing Liabilities from Equity (“ASC 480”). The contingent consideration liability will be recorded at fair value at the end of each reporting period with changes in estimated fair values recorded in other (expense) income in the condensed consolidated statements of operations and comprehensive loss. The estimated fair value of the contingent consideration liability related to the Rewrite acquisition (see Notes 4 and 9) is determined based on a probability adjusted discounted cash flow model that includes significant estimates and assumptions pertaining to research and development. Significant changes in any of the probabilities of success or in the probabilities as to the periods in which the milestone would be achieved would result in a significantly higher or lower fair value measurement. The Company will continue to adjust the liability for changes in fair value until the obligation is settled or the research is abandoned.

Marketable Securities

Marketable Securities	6 Months Ended
	Jun. 30, 2022
Investments, Debt and Equity Securities [Abstract]
Marketable Securities	3. Marketable Securities The following table summarizes the Company’s available-for-sale marketable securities as of June 30, 2022 and December 31, 2021 at net book value: June 30, 2022 Amortized Gross Unrealized Gross Unrealized Estimated Fair (In thousands) Marketable securities: U.S. Treasury and other government securities $ 295,742 $ - $ ( 4,454 ) $ 291,288 Financial institution debt securities 303,294 - ( 2,296 ) 300,998 Corporate debt securities 52,575 - ( 724 ) 51,851 Other asset-backed securities 115,671 - ( 710 ) 114,961 Total $ 767,282 $ - $ ( 8,184 ) $ 759,098 December 31, 2021 Amortized Gross Unrealized Gross Unrealized Estimated Fair (In thousands) Marketable securities: U.S. Treasury and other government securities $ 301,493 $ - $ ( 1,016 ) $ 300,477 Financial institution debt securities 441,068 - ( 652 ) 440,416 Corporate debt securities 62,500 - ( 151 ) 62,349 Other asset-backed securities 159,707 - ( 306 ) 159,401 Total $ 964,768 $ - $ ( 2,125 ) $ 962,643 The amortized cost of available-for-sale securities is adjusted for amortization of premiums and accretion of discounts to maturity. At June 30, 2022 and December 31, 2021, the balance in the Company’s accumulated other comprehensive loss was composed of activity related to the Company’s available-for-sale marketable securities and equity method investment. There were no realized gains or losses in the six months ended June 30, 2022 or for the year ended December 31, 2021. The Company did not reclassify any amounts out of accumulated other comprehensive loss during this period. The Company generally does not intend to sell any investments prior to recovery of their amortized cost basis for any investment in an unrealized loss position. As such, the Company has classified these losses as temporary in nature. The Company's available-for-sale securities that are classified as short-term marketable securities in the condensed consolidated balance sheet mature within one year or less as of the balance sheet date. Available-for-sale securities that are classified as noncurrent in the condensed consolidated balance sheet are those that mature after one year but within five years from the balance sheet date and that the Company does not intend to dispose of within the next twelve months. At June 30, 2022 and December 31, 2021, the Company did no t hold any investments that matured beyond five years of the balance sheet date.

Fair Value Measurements

Fair Value Measurements	6 Months Ended
	Jun. 30, 2022
Fair Value Disclosures [Abstract]
Fair Value Measurements	4. Fair Value Measurements The Company classifies fair value-based measurements using a three-level hierarchy that prioritizes the inputs used to measure fair value. This hierarchy requires entities to maximize the use of observable inputs and minimize the use of unobservable inputs. The three levels of inputs used to measure fair value are as follows: Level 1, quoted market prices (unadjusted) in active markets for identical assets or liabilities; Level 2, observable inputs other than quoted market prices included in Level 1, such as quoted market prices for markets that are not active or other inputs that are observable or can be corroborated by observable market data; and Level 3, unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities, including certain pricing models, discounted cash flow methodologies and similar techniques that use significant unobservable inputs. As of June 30, 2022 and December 31, 2021, the Company’s financial assets and liabilities recognized at fair value on a recurring basis consisted of the following: Fair Value as of June 30, 2022 Total Level 1 Level 2 Level 3 (In thousands) Assets Cash equivalents and restricted cash equivalents $ 156,323 $ 156,323 $ - $ - Marketable securities: U.S. Treasury and other government securities 291,288 276,278 15,010 - Financial institution debt securities 300,998 - 300,998 - Corporate debt securities 51,851 - 51,851 - Other asset-backed securities 114,961 - 114,961 - Total marketable securities 759,098 276,278 482,820 - Total Assets $ 915,421 $ 432,601 $ 482,820 $ - Liabilities Contingent consideration liability - research $ 10,790 $ - $ - $ 10,790 Total Liabilities $ 10,790 $ - $ - $ 10,790 Fair Value as of December 31, 2021 Total Level 1 Level 2 Level 3 (In thousands) Assets Cash equivalents and restricted cash equivalents $ 124,636 $ 124,636 $ - $ - Marketable securities: U.S. Treasury and other government securities 300,477 280,085 20,392 - Financial institution debt securities 440,416 - 440,416 - Corporate debt securities 62,349 - 62,349 - Other asset-backed securities 159,401 - 159,401 - Total marketable securities 962,643 280,085 682,558 - Total Assets $ 1,087,279 $ 404,721 $ 682,558 $ - Certain of the Company’s financial assets, including cash equivalents, restricted cash equivalents and marketable securities, have been initially valued at the transaction price, and subsequently revalued at the end of each reporting period, utilizing third party pricing services or other observable market data. The pricing services utilize industry standard valuation models and observable market inputs to determine value. After completing its validation procedures, the Company did not adjust or override any fair value measurements provided by the pricing services as of June 30, 2022 or December 31, 2021. Other financial instruments, including accounts receivable, accounts payable and accrued expense, are carried at cost, which approximates fair value due to the short duration and term to maturity. The Company's investment in AvenCell Therapeutics, Inc. (“AvenCell”) was initially recorded at fair value, determined according to Level 3 inputs in the fair value hierarchy described above. Refer to Note 8 for further details. The Company's investment in SparingVision SAS (“SparingVision”) was initially recorded at fair value, determined according to Level 3 inputs in the fair value hierarchy described above. The Company's investment in Kyverna Therapeutics, Inc. (“Kyverna”) was recorded at cost, which is representative of fair value. Refer to Note 8 for further details. The SparingVision and Kyverna investments (the “investments”) are included in “Investments and other assets” on the condensed consolidated balance sheet. There were no changes in observable prices of these investments as of June 30, 2022. As discussed further in Note 9, Rewrite Acquisition , under the Merger Agreement, the Rewrite Holders are eligible to receive up to an additional $ 25.0 million in research 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 such research milestone is payable in the Company’s common stock, the milestone payment results in liability classification under ASC 480. This contingent consideration liability is 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. The contingent consideration liability, which is recorded in “Other long-term liabilities” on the condensed consolidated balance sheet, is classified within Level 3 of the fair value hierarchy. The following table reconciles the change in fair value of the contingent consideration liability based on the level 3 inputs listed below (in thousands): For the six months ended June 30, 2022 Balance at February 2, 2022 (at inception) $ 10,541 Change in fair value 249 Balance at June 30, 2022 $ 10,790 As of inception (February 2, 2022) As of June 30, 2022 Discount rate 7 % 11 % Probability of achievement 50 % 50 % Projected year of achievement 2023 - 2024 2023 - 2024

Accrued Expenses

Accrued Expenses	6 Months Ended
	Jun. 30, 2022
Payables and Accruals [Abstract]
Accrued Expenses	5. Accrued Expenses Accrued expenses consisted of the following: June 30, December 31, 2022 2021 (In thousands) Accrued research and development $ 25,278 $ 16,979 Employee compensation and benefits 12,879 20,359 Accrued legal and professional expenses 1,955 3,100 Accrued other 4,759 2,871 Total accrued expenses $ 44,871 $ 43,309

Commitments and Contingencies

Commitments and Contingencies	6 Months Ended
	Jun. 30, 2022
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	6. Commitments and Contingencies Litigation There have been no material changes to any of the outstanding litigation, nor is the Company a party to any new litigation, since December 31, 2021. For further information please see the notes to the consolidated financial statements included in the Company’s Annual Report for the year ended December 31, 2021. License Agreements The Company is party to license agreements, which include contingent payments. These payments will become payable if and when certain development, regulatory and commercial milestones are achieved. As of June 30, 2022, the satisfaction and timing of the contingent payments is uncertain and not reasonably estimable.

Collaborations and Other Arrang

Collaborations and Other Arrangements	6 Months Ended
	Jun. 30, 2022
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Collaborations and Other Arrangements	7. Collaborations and Other Arrangements To accelerate the development and commercialization of CRISPR/Cas9-based products in multiple therapeutic areas, the Company has formed, and intends to seek other opportunities to form, strategic alliances with collaborators who can augment its leadership in CRISPR/Cas9 therapeutic development. As of June 30, 2022, the Company’s accounts receivable were related to its collaboration with Regeneron Pharmaceuticals, Inc. (“Regeneron”), and the Company's contract liabilities were related to its collaborations with Regeneron, AvenCell, SparingVision and Kyverna. As of December 31, 2021, the Company’s accounts receivable were related to its collaborations with Regeneron and AvenCell and the Company's contract liabilities were related to its collaborations with Regeneron, AvenCell, SparingVision and Kyverna. The following table presents changes in the Company’s accounts receivable and contract liabilities during the six months ended June 30, 2022 and 2021 (in thousands): Balance at Additions Deductions Balance at End Six Months Ended June 30, 2022 Accounts receivable $ 2,031 $ 4,655 $ ( 3,832 ) $ 2,854 Contract liabilities - deferred revenue $ 127,235 $ - $ ( 30,099 ) $ 97,136 Balance at Additions Deductions Balance at End Six Months Ended June 30, 2021 Accounts receivable $ 2,130 $ 3,079 $ ( 3,216 ) $ 1,993 Contract liabilities - deferred revenue $ 73,931 $ - $ ( 11,179 ) $ 62,752 During the six months ended June 30, 2022 and 2021, the Company recognized the following revenues as a result of changes in the contract liability balance (in thousands): Six Months Ended June 30, Revenue recognized in the period from: 2022 2021 Amounts included in the contract liability at the beginning of the period $ 24,443 $ 11,179 Costs to obtain and fulfill a contract The Company did not incur any expenses to obtain collaboration agreements and costs to fulfill those contracts do not generate or enhance resources of the Company. As such, no costs to obtain or fulfill a contract have been capitalized in any period. Regeneron Pharmaceuticals, Inc. License and Collaboration Agreement In April 2016, the Company entered into a license and collaboration agreement with Regeneron (the “2016 Regeneron Agreement”). The 2016 Regeneron Agreement has two principal components: i) a product development component under which the parties will research, develop and commercialize CRISPR/Cas-based therapeutic products primarily focused on genome editing in the liver, and ii) a technology collaboration component, pursuant to which the Company and Regeneron will engage in research-related activities aimed at discovering and developing novel technologies and improvements to CRISPR/Cas technology to enhance the Company’s genome editing platform. Under this agreement, the Company also may access the Regeneron Genetics Center and proprietary mouse models to be provided by Regeneron for a limited number of the Company’s liver programs. At the inception of the 2016 Regeneron Agreement, Regeneron selected the first of its 10 targets, transthyretin (“ATTR”) amyloidosis, which is subject to a co-development and co-promotion agreement between the Company and Regeneron (the “ATTR Co/Co”). On May 30, 2020, the Company entered into (i) amendment no. 1 (the “2020 Regeneron Amendment”) to the 2016 Regeneron Agreement, (ii) co-development and co-funding agreements for the treatment of hemophilia A and hemophilia B (the “Hemophilia Co/Co”) agreements and (iii) a stock purchase agreement. The collaboration expansion builds upon the jointly developed targeted transgene insertion capabilities designed to durably restore missing therapeutic protein, and to overcome the limitations of traditional gene therapy. The collaboration was extended until April 2024, at which point Regeneron has an option to renew for an additional two years. The 2020 Regeneron Amendment also grants Regeneron exclusive rights to develop products for five additional in vivo CRISPR/Cas-based therapeutic liver targets and non-exclusive rights to independently develop and commercialize up to 10 ex vivo gene edited products made using certain defined cell types. Since December 31, 2021, there have been no material changes to the key terms of the 2016 Regeneron Agreement and the 2020 Regeneron Amendment (the “Amended Agreements”). For further information on the terms and conditions of these agreements, please see the notes to the consolidated financial statements included in the Company’s Annual Report for the year ended December 31, 2021. Revenue Recognition – Collaboration Revenue. Through June 30, 2022, excluding amounts allocated to Regeneron’s purchase of the Company’s common stock, the Company recorded $ 145.0 million in upfront payments under the Amended Agreements and $ 38.9 million for research and development services, primarily under the ATTR Co/Co agreement. Through June 30, 2022 , the Company has recognized $ 161.1 million of collaboration revenue under all arrangements, including $ 6.3 million and $ 12.1 million during the three and six months ended June 30, 2022, respectively, and $ 5.5 million and $ 12.0 million during the three and six months ended June 30, 2021, respectively, in the condensed consolidated statements of operations and comprehensive loss. This includes $ 2.9 million and $ 4.7 million during the three and six months ended June 30, 2022, respectively, and $ 1.0 million and $ 1.8 million during the three and six months ended June 30, 2021, respectively, primarily representing payments due from Regeneron pursuant to the ATTR Co/Co agreement. These revenues are offset in part by contra-revenue related to the Hemophilia Co/Co agreements amounting to $ 2.2 million and $ 3.7 million during the three and six months ended June 30, 2022, respectively, and $ 1.0 million during the three and six months ended June 30, 2021 . As of June 30, 2022, there was approximately $ 40.2 million of the aggregate transaction price of the Amended Agreements remaining to be recognized, which the Company expects to be recognized during the research term through April 2024. As of June 30, 2022 and December 31, 2021, the Company had accounts receivable of $ 2.9 million and $ 2.0 million, respectively, related to the Amended Agreements. The Company had deferred revenue of $ 40.2 million and $ 51.4 million as of June 30, 2022 and December 31, 2021, respectively, related to the Amended Agreements. AvenCell Therapeutics, Inc. On July 30, 2021 (the “Effective Date”), the Company entered into two agreements with AvenCell, a privately held chimeric antigen receptor T (“CAR-T”) cell therapy company formed on that date in a joint venture between the Company, Cellex Cell Professionals GmbH (“Cellex”) and funds managed by Blackstone Life Sciences Advisors L.L.C. (“BXLS”): (i) a license and collaboration agreement (the “AvenCell LCA”), under which the Company will collaborate to develop allogeneic universal CAR-T cell therapies and which granted AvenCell a license to develop and commercialize genome edited universal CAR-T cell therapies (limited to its use with their switchable, universal CAR-T cell UniCAR and RevCAR platforms); and (ii) a co-development and co-funding agreement (the “AvenCell Co/Co”), under which the Company will co-develop and co-commercialize allogeneic universal CAR-T cell products for an immuno-oncology indication. Since December 31, 2021, there have been no material changes to the key terms of the AvenCell LCA and AvenCell Co/Co agreements. For further information on the terms and conditions of these agreements, please see the notes to the consolidated financial statements included in the Company's Annual Report for the year ended December 31, 2021. Revenue Recognition – Collaboration Revenue. The Company recognized $ 5.7 million and $ 11.3 million in revenue related to the AvenCell LCA for the three and six months ended June 30, 2022, respectively, after eliminating $ 2.8 million and $ 5.7 million during those respective periods in intra-entity profits, which will be deferred and recognized if and when AvenCell commercializes a product with the Company's license or abandons the related project. Until such time, the $ 5.7 million of revenue is indefinitely deferred and excluded from the results of operations of the Company. The Company recognized $ 0.1 million in revenue in the three months ended June 30, 2022 and $ 0.1 million in contra-revenue in the six months ended June 30, 2022 related to the AvenCell Co/Co agreement. As of June 30, 2022, there was approximately $ 37.1 million of the aggregate transaction price of the AvenCell LCA remaining to be recognized, which the Company expects to recognize through July 2023. As of June 30, 2022, the Company did no t have accounts receivable related to the AvenCell Co/Co or AvenCell LCA agreements. As of December 31, 2021, the Company had $ 0.1 million in accounts receivable related to the AvenCell Co/Co agreement. The Company had deferred revenue of $ 37.1 million and $ 54.1 million as of June 30, 2022 and December 31, 2021, respectively, related to the AvenCell LCA. SparingVision SAS In October 2021, the Company and SparingVision, a genomic medicine company developing vision saving treatments for ocular diseases, entered into a license and collaboration agreement (the “SparingVision LCA”) to develop novel genomic medicines utilizing CRISPR/Cas9 technology for the treatment of ocular diseases. Since December 31, 2021, there have been no material changes to the key terms of the SparingVision LCA agreement. For further information on the terms and conditions of these agreements, please see the notes to the consolidated financial statements included in the Company's Annual Report for the year ended December 31, 2021. The Company did no t recognize collaboration revenue in the three or six months ended June 30, 2022 and 2021 related to the SparingVision LCA. As of June 30, 2022 and December 31, 2021, the Company did no t have accounts receivable related to the SparingVision LCA. As of June 30, 2022 and December 31, 2021, the Company had deferred revenue of $ 14.8 million related to the SparingVision LCA, which is expected to be recognized over a three to five year period. Kyverna Therapeutics, Inc. In December 2021, the Company and Kyverna, a cell therapy company engineering a new class of therapies for autoimmune and inflammatory diseases, entered into a licensing and collaboration agreement (the “Kyverna LCA”), for the development of an allogeneic CD19 CAR-T cell therapy for the treatment of a variety of B cell-mediated autoimmune diseases. Since December 31, 2021, there have been no material changes to the key terms of the Kyverna LCA agreement. For further information on the terms and conditions of this agreement, please see the notes to the consolidated financial statements included in the Company's Annual Report for the year ended December 31, 2021. The Company recognized $ 2.0 million in revenue for the three and six months ended June 30, 2022, related to the Kyverna LCA. As of June 30, 2022 and December 31, 2021, the Company did no t have accounts receivable related to the Kyverna LCA. As of June 30, 2022 and December 31, 2021 the Company had deferred revenue of $ 5.0 million and $ 7.0 million, respectively, related to the Kyverna LCA, which is expected to be recognized through January 2023. ONK Therapeutics, Ltd. On February 12, 2022 the Company entered into a license, collaboration and option agreement (the “ONK LCA”) with ONK Therapeutics, Ltd. (“ONK”), an innovative company dedicated to developing optimally engineered natural killer (“NK”) cell therapies to cure patients with cancer. Scope: The agreement grants ONK a non-exclusive license to the Company's proprietary ex vivo CRISPR/Cas9-based genome editing platform and its Lipid Nanoparticle (“LNP”)-based delivery technologies for development of up to five allogeneic NK cell therapy products, which license is exclusive with respect to certain guide ribonucleic acids (“gRNAs”). Responsibilities in the earlier stage of the license and collaboration agreement (the “evaluation program”) will be shared between the two parties, with each party bearing their own cost burden. Upon completion of the evaluation program, ONK will identify up to five allogeneic targets for further development under a development program. Once these allogeneic targets have been selected by ONK, any further development costs incurred by the Company are eligible for reimbursement. ONK will be responsible for preclinical and clinical development for the engineered NK cell therapies enabled by the agreement. Financial Terms: The Company will be eligible to receive up to $ 184 million per product in future development and commercial milestone payments as achieved, as well as up to mid-single digit royalties on potential future sales. In addition, the agreement grants the Company options to co-develop and co-commercialize up to two products developed through the collaboration worldwide with rights to lead commercialization in the U.S. There is no fee related to the exercise of these co-development and co-commercialization options. Governance: The parties formed a joint steering committee, which is responsible for monitoring and managing the collaboration prior to program completion. ONK LCA – Accounting Analysis: The Company determined that the accounting for the ONK LCA is within the scope of Accounting Standards Update (“ASU”) 2014-09, Revenue from Contracts with Customers (Topic 606) and its related amendments (collectively known as ASC 606). The Company identified one combined performance obligation related to the license, evaluation and development programs. The LCA did not include an exchange of upfront consideration between the parties. As the ONK LCA progresses, the Company will incur certain expenses. Expenses incurred under the evaluation program will be accounted for under ASC 730, Research and Development . Reimbursements under the development programs represent variable constrained consideration, whereas the Company is acting as the principal, and revenue will be recognized as expenses are incurred. Milestone payments and royalties are constrained consideration and will be recorded as revenue upon achievement. There was no revenue recognized in the three or six months ended June 30, 2022 related to the ONK LCA. Novartis Institutes for BioMedical Research, Inc. In December 2014, the Company entered into a strategic collaboration agreement with Novartis Institutes for BioMedical Research, Inc. (“Novartis”) (the “2014 Novartis Agreement”), primarily focused on the research of new ex vivo CRISPR/Cas9-edited therapies using CAR-T cells and hematopoietic stem cells (“HSCs”). The agreement was amended in December 2018 (the “Novartis Amendment”) to also include research on ocular stem cells (“OSCs”). In December 2019, per the terms of the 2014 Novartis Agreement, the research term ended, although the 2014 Novartis Agreement remains in effect, for which the Company will be eligible to receive milestone and royalty payments in the future. In June 2021, the Company entered into Amendment No. 3 (the “Amendment”) to the 2014 Novartis Agreement. The Amendment amends Novartis’ rights with respect to all of the CAR-T Therapeutic Targets (as defined in the 2014 Novartis Agreement) that Novartis selected under the 2014 Novartis Agreement, including (a) making Novartis’ license non-exclusive for such CAR-T Therapeutic Targets, (b) removing Novartis’ diligence and related reporting obligations for such CAR-T Therapeutic Targets, and (c) refining the scope of Novartis’ sublicense rights for such CAR-T Therapeutic Targets. The Company made a one-time payment to Novartis of $ 10.0 million within 30 days after the effective date of the Amendment, which was recorded as research and development expense in the consolidated statement of operations and comprehensive loss for the year ended December 31, 2021. Since December 31, 2021, there have been no other material changes to the key terms of the 2014 Novartis Agreement and the Novartis Amendments. For further information on the terms and conditions of these agreements, please see the notes to the consolidated financial statements included in the Company’s Annual Report for the year ended December 31, 2021. Revenue Recognition – Milestone: No milestones under the 2014 Novartis Agreement and the Novartis Amendments were achieved during the three or six months ended June 30, 2022 and 2021. The Company is eligible to receive additional downstream success-based milestones and royalties. As of June 30, 2022 and December 31, 2021, the Company had no accounts receivable or deferred revenue related to the 2014 Novartis Agreement and the Novartis Amendments.

Equity-Method Investment and Ot

Equity-Method Investment and Other Investments	6 Months Ended
	Jun. 30, 2022
Equity Method Investments and Joint Ventures [Abstract]
Equity-Method Investment and Other Investments	8. Equity-Method Investment and Other Investments On July 30, 2021, the Company finalized a transaction in which the Company, Cellex and BXLS established AvenCell, a joint venture and privately held company. In exchange for contributing an exclusive license to the joint venture, the Company entered into a Preferred Stock Purchase Agreement with AvenCell for a 33.33 % equity interest in AvenCell at the time of the initial closing. Cellex and BXLS each equally owned the remaining 66.67 % at that time. The Company has significant influence over, but does not control, AvenCell through its noncontrolling representation on AvenCell’s Board of Directors and the Company’s equity interest in AvenCell. The Company has determined that the preferred stock it owns is in-substance common stock. The Company is not the primary beneficiary as it does not have the power to direct the activities of AvenCell that most significantly impact AvenCell’s economic performance. Accordingly, the Company does not consolidate the financial statements of AvenCell and accounts for its investment using the equity method of accounting. As of the closing date, the fair value of the Company’s investment in AvenCell was $ 62.9 million which represented the fair value of the preferred stock received in exchange for the exclusive license to the Company’s CRISPR/Cas9 allogeneic platform (see Note 7). In determining the fair value of the Company’s investment, the Company used an option pricing model which requires the input of certain subjective assumptions. The key assumptions used in the option pricing model, which are level 3 inputs, include the anticipated holding period to an exit and liquidity event, the volatility of market participants ( 76 %), the probability of AvenCell achieving certain milestones to obtain subsequent financings ( 75 %) and the discount for lack of marketability ( 11 %). The Company recorded the initial investment in AvenCell of $ 62.9 million in “Equity method investments” on its condensed consolidated balance sheet. Due to the timing and availability of AvenCell's financial information, the Company is recording its share of losses from AvenCell on a quarterly basis on a one-quarter lag. During the second quarter of 2022, the Company recorded its share of the three months of AvenCell's losses generated in the first quarter of 2022 in the Company's operating results and other comprehensive loss, resulting in a reduction of the Company's investment by $ 3.8 million and $ 6.9 million for the three and six months ended June 30, 2022, respectively. The elimination of the intra-entity profit component of $ 2.8 million and $ 5.7 million (see Note 7) in the three and six months ended June 30, 2022, respectively, resulted in a further reduction in the balance of the investment in AvenCell, bringing the carrying value of the investment to $ 45.6 million as of June 30, 2022. The Company is not aware of any material events or transactions during the quarter ended June 30, 2022 that would warrant additional disclosure or recognition in the financial statements. At June 30, 2022, the maximum exposure to loss is limited to the Company’s equity investment in the joint venture. SparingVision SAS In connection with the SparingVision LCA (see Note 7), the Company received 83,316 shares of SparingVision Series A2 Preferred Stock (“Series A2”). Attached to each share of Series A2, the Company received three warrants for the right to purchase additional Series A2 shares at designated prices that are subject to certain vesting conditions (collectively referred to as the “SparingVision investments”). The Company accounts for the SparingVision investments using the measurement alternative as SparingVision is a private company and there is no readily observable transaction price. In determining the fair value of the SparingVision investments, the Company used an option pricing model which requires the input of certain subjective assumptions. The key assumptions used in the option pricing model, which are level 3 inputs, include the anticipated holding period to an exit and liquidity event, the volatility of market participants ( 90 %), and the rate of return ( 65 %). The Company recorded the initial investment in SparingVision of $ 14.8 million in “Investments and other assets” on its condensed consolidated balance sheet. There was no change in the observable price or impairment of the SparingVision investment as of June 30, 2022. Kyverna Therapeutics, Inc. In connection with the Kyverna LCA (see Note 7), the Company received 3,739,515 shares of Kyverna Series B Preferred Stock (“Series B”) with a fair value of $ 7.0 million. The Company separately made an additional investment in Kyverna, purchasing 1,602,649 shares of Series B in exchange for $ 3.0 million in cash (collectively referred to as the “Kyverna investments”). The Company accounts for the Kyverna investments using the measurement alternative as Kyverna is a private company and there is no readily observable transaction price. The Company recorded the initial investment in Kyverna of $ 10.0 million in “Investments and other assets” on its condensed consolidated balance sheet. There was no change in the observable price or impairment of the Kyverna investment as of June 30, 2022.

Rewrite Acquisition

Rewrite Acquisition	6 Months Ended
	Jun. 30, 2022
Business Combinations [Abstract]
Rewrite Acquisition	9. Rewrite Acquisition On February 2, 2022, the Company entered into the Rewrite Merger Agreement. Under the Rewrite Merger Agreement, the Company paid the Rewrite Holders upfront consideration in an aggregate amount of $ 45.0 million, excluding customary purchase price adjustments and closing costs, payable in cash. Pursuant to the Rewrite Merger Agreement, the Company acquired all of the issued and outstanding shares of Rewrite. The Rewrite transaction resulted in the acquisition of certain know-how and IP assets related to Rewrite’s proprietary DNA writing technology. The Company's management determined that the acquired assets do not meet the definition of a business pursuant to ASC 805, Business Combinations , as substantially all of the fair value of the acquired assets is concentrated into one identifiable asset, the DNA writing technology. As of the date of closing of the transactions contemplated by the Rewrite Merger Agreement (the “Rewrite Merger Agreement Date”), the asset acquired had no alternative future use and had not reached a stage of technological feasibility. As a result, all payment obligations have been recorded as research and development expense in the condensed consolidated statements of operations and other comprehensive loss in the amount of $ 56.0 million. The total transaction price was allocated to the assets acquired and liabilities assumed on a relative fair value basis. In addition, the Rewrite Holders are eligible to receive up to an additional $ 155.0 million in milestone payments upon the achievement of certain pre-specified research and regulatory approval milestones, payable through a mixture of $ 130.0 million in cash and $ 25.0 million in the Company’s common stock which will be valued using the volume-weighted average price of the Company’s Common Stock over the ten consecutive trading day period ending on and including the trading day that is two trading days immediately prior to the issuance of the consideration issued in connection with the applicable milestone. The Company determined that the research milestone settled in the Company’s common stock is classified as a contingent consideration liability under ASC 480 and therefore the Company recorded a liability for this milestone payment as of the Rewrite Merger Agreement Date at its fair value of $ 10.5 million. The contingent consideration liability is remeasured at fair value each financial reporting period, with the resulting impact reflected in the Company’s condensed consolidated statements of operations and other comprehensive loss, presented within other (expense) income. The milestones that will be settled in cash will be recorded when the contingency is resolved and the consideration is paid or becomes payable. As of June 30, 2022, none of the milestones that will be settled in cash were resolved. The transaction price was determined and allocated as follows (in thousands): Transaction Price Upfront cash consideration $ 43,730 Research contingent consideration liabilities 10,541 Transaction costs 1,838 Total transaction price $ 56,109 Transaction Price Allocated In-process research and development $ 55,990 Cash acquired 287 Other current assets acquired 153 Other liabilities assumed ( 321 ) Total transaction price $ 56,109

Leases

Leases	6 Months Ended
	Jun. 30, 2022
Leases [Abstract]
Leases	10. Leases In January 2022, the Company entered into an agreement to lease approximately 38,000 square feet of office and laboratory space at 730 Main Street, Cambridge, Massachusetts under an operating lease agreement (the “730 Main Lease”). The 730 Main Lease, including the obligation to pay rent, is expected to commence in October 2022 for an initial term of ten years . During the six months ended June 30, 2022 the Company did not record a right of use asset or liability related to the 730 Main Lease under ASC 842, Leases (Topic 842) ( “ ASC 842 ” ) as the Company had not taken control of the premises. The base rent under the 730 Main Lease is $ 130.00 per square foot per year during the first year of the term, which is subject to scheduled annual increases up to $ 169.62 per square foot per year during the last year of the initial term, plus certain operating expenses and taxes. In accordance with the 730 Main Lease, the Company is required to maintain a letter of credit in the amount of $ 2.4 million that is restricted for the term of the lease. The restricted cash equivalents are reported in “Investments and other assets” on the Company's condensed consolidated balance sheet. The Company has the option to extend the 730 Main Lease for one five-year term. In February 2022, the Company entered into an agreement to lease approximately 140,000 square feet of manufacturing space located at 840 Winter Street, Waltham, Massachusetts (the “840 Winter Lease”), which will provide the Company with the ability to manufacture its own products in a good manufacturing practice (“GMP”) compliant facility as well as to supplement the Company’s current leased premises in Cambridge, Massachusetts. The 840 Winter Lease, including the obligation to pay rent, is expected to commence in February 2024 for an initial term of twelve year s. The Company did not record a right of use asset or liability related to the 840 Winter Lease under ASC 842 during the six months ended June 30, 2022, as the Company had not taken control of the premises. The base rent under the 840 Winter Lease is $ 73.50 per square foot per year during the first year of the term, which is subject to scheduled 3 % annual increases, plus certain operating expenses and taxes. In accordance with the 840 Winter Lease, the Company is required to maintain an initial letter of credit in the amount of $ 2.6 million. On or before January 1, 2023, the Company will replace the initial letter of credit with a replacement letter of credit in the amount of $ 6.0 million. As of June 30, 2022, the restricted cash equivalents related to the initial letter of credit are reported in “Investments and other assets” on the Company's condensed consolidated balance sheet. The Company has the option to extend the 840 Winter Lease for two five-year terms. In June 2022, the Company entered into an agreement to lease approximately 62,000 square feet of office and laboratory space located at 640 Memorial Drive, Cambridge, Massachusetts under an operating lease agreement (the “640 Memorial Drive Lease”). The 640 Memorial Drive Lease, including the obligation to pay rent, is expected to commence in September 2022 for a term of five years . During the period ended June 30, 2022 the Company did not record a right of use asset or liability related to the 640 Memorial Drive Lease under ASC 842 as the Company had not taken control of the premises. The base rent under the 640 Memorial Drive Lease is approximately $ 97 per square foot per year during the first year of the term, which is subject to scheduled annual increases up to approximately $ 138 per square foot per year during the last year of the term, plus certain operating expenses and taxes. The landlord will also contribute approximately $ 1.2 million toward the cost of tenant improvements for the premises. In accordance with the 640 Memorial Drive Lease, the Company is required to maintain a letter of credit in the amount of $ 1.8 million that is restricted for the term of the lease. The restricted cash equivalents are reported in “Investments and other assets” on the Company's condensed consolidated balance sheet. The Company does not have an option to extend the 640 Memorial Drive Lease.

Equity-Based Compensation

Equity-Based Compensation	6 Months Ended
	Jun. 30, 2022
Share-Based Payment Arrangement [Abstract]
Equity-Based Compensation	11. Equity-Based Compensation Equity-based compensation expense is classified in the condensed consolidated statements of operations and comprehensive loss as follows: Three Months Ended June 30, Six Months Ended June 30, 2022 2021 2022 2021 (In thousands) Research and development $ 14,079 $ 6,135 $ 24,353 $ 9,626 General and administrative 8,989 4,479 17,206 7,412 Total $ 23,068 $ 10,614 $ 41,559 $ 17,038 Amended and Restated 2015 Stock Option and Incentive Plan In April 2016, the Company adopted the Amended and Restated 2015 Stock Option and Incentive Plan (the “2015 Plan”). The 2015 Plan provides for the grant of incentive stock options, non-qualified stock options, stock appreciation rights, restricted stock awards (“RSAs”), restricted stock units (“RSUs”) and other stock-based awards. Recipients of incentive stock options and non-qualified stock options are eligible to purchase shares of the Company’s common stock at an exercise price equal to the fair value of such stock on the grant date. Stock options granted under the 2015 Plan generally vest 25 % on the first anniversary of the original vesting date, with the balance vesting monthly over the remaining three years , unless they contain specific performance-based vesting provisions. The maximum term of stock options granted under the 2015 Plan is ten years . Effective July 1, 2022, the Company adopted a retirement policy for equity awards granted to all employees other than the Company’s CEO (the “Policy”). The Policy applies to all equity awards granted to employees who meet certain retirement eligibility criteria set forth in the Policy (the “Retirees”). Pursuant to the terms of the Policy, upon a Retiree’s eligible retirement: (i) all stock options held by the Retiree will continue to vest following the Retiree’s retirement date according to the original vesting schedule of the option until fully vested and all vested stock options held by such Retiree will remain exercisable until the earlier of the five-year anniversary of the Retiree’s retirement date or the original expiration date of the option, (ii) all unvested time-based RSUs held by the Retiree will vest in full on the Retiree’s retirement date and (iii) all unvested performance-based awards held by the Retiree will remain outstanding following the Retiree’s retirement date and the Retiree will remain eligible to earn a pro-rated portion of such performance-based awards at the end of the performance period based on actual performance during the performance period. As of June 30, 2022, there were 3,803,557 shares available for future issuance under the 2015 Plan. The number of shares reserved for issuance under the 2015 Plan will be cumulatively increased on each January 1 st by four percent of the number of shares of stock issued and outstanding on the immediately preceding December 31 or such lesser number of shares of stock as determined by the board of directors . Restricted Stock Units RSUs are measured at fair value based on the quoted price of the Company’s common stock. The following table summarizes the Company’s RSU activity for the six months ended June 30, 2022: Number of Weighted Unvested restricted stock units as of December 31, 2021 453,026 $ 71.03 Granted 1,327,420 76.57 Vested ( 91,181 ) 66.23 Cancelled ( 54,137 ) 74.32 Unvested restricted stock units as of June 30, 2022 1,635,128 $ 75.69 In March 2022, the Company granted 794,424 RSUs with a service condition to employees as part of their annual grant, which vest over a period of three years . The weighted average grant date fair value of these RSUs was $ 79.85 and the vesting start date for these RSUs was January 1, 2022. Also in March 2022, 55,144 RSUs were granted to senior executives as part of their annual grant . These RSUs have the potential to vest after a period of 3 years, with a vesting start date of January 1, 2022, and the number of shares to be delivered will depend on the Company's Total Shareholder Return (“TSR” ), a market condition, over that period relative to a defined group of biotechnology companies. The grant date fair value for these RSUs, calculated using a Monte Carlo valuation model, was $ 126.49 . The following assumptions were used to determine the grant date fair value: Risk free interest rate: 1.44 %; expected dividend yield: 0.0 %; expected volatility: 82.53 %; expected term (in years): 2.84 . The Company also granted 66,296 performance-based RSUs in March 2022 to certain non-executive employees that would vest upon obtaining certain scientific milestones. As of June 30, 2022 these performance milestones were considered not probable of achievement and, therefore, no stock-based compensation was recorded during the period then ending. The weighted-average grant date fair value of RSUs granted during the three and six months ended June 30, 2022 was $ 55.16 and $ 76.57 , respectively. The total fair value of RSUs vested (measured on the date of vesting) for the three and six months ended June 30, 2022 was $ 1.5 million and $ 8.0 million, respectively. The weighted-average grant date fair value of RSUs granted during the three and six months ended June 30, 2021 was $ 77.07 and $ 62.82 , respectively. The total fair value of RSUs vested (measured on the date of vesting) for the three and six months ended June 30, 2021 was $ 1.9 million. As of June 30, 2022, there was $ 105.1 million of unrecognized equity-based compensation expense related to RSUs that are expected to vest. These costs are expected to be recognized over a weighted average remaining vesting period of 2.5 years . Stock Options The weighted average grant date fair value of options, estimated as of the grant date using the Black-Scholes option pricing model, was $ 28.76 and $ 57.23 per option for those options granted during the three and six months ended June 30, 2022 and $ 48.44 and $ 38.70 per option for those options granted during the three and six months ended June 30, 2021 , respectively. The total intrinsic value (the amount by which the fair market value exceeded the exercise price) of stock options exercised during the three and six months ended June 30, 2022 was $ 10.5 million and $ 40.4 million, respectively, and during the three and six months ended June 30, 2021 was $ 29.7 million and $ 84.5 million, respectively . Weighted average assumptions used to apply this pricing model were as follows: Three Months Ended June 30, Six Months Ended June 30, 2022 2021 2022 2021 Risk-free interest rate 3.4 % 1.1 % 1.9 % 0.9 % Expected life of options 5.6 years 6.0 years 5.9 years 6.0 years Expected volatility of underlying stock 77.9 % 73.0 % 76.2 % 72.2 % Expected dividend yield 0.0 % 0.0 % 0.0 % 0.0 % Risk-free Interest Rate. The risk-free interest rate is based on the U.S. Treasury yield curve in effect at the time of grant with maturities approximately equal to the option’s expected term. Expected Dividend Yield. The expected dividend yield assumption is based on the fact that the Company has never paid cash dividends and has no present intention to pay cash dividends. Expected Volatility. The expected volatility was derived from a blend of the Company’s historical volatility and an average of the historical stock volatilities of several peer companies within the Company’s industry, both over a period equivalent to the expected term of the stock option grants. Expected Term. The expected term represents the period that stock option awards are expected to be outstanding. For option grants that are considered to be “plain vanilla,” the Company determines the expected term using the simplified method. The simplified method deems the term to be the average of the time-to-vesting and the contractual life of the options. The Company uses the simplified method because it does not have sufficient historical option exercise data to provide a reasonable basis upon which to estimate the expected term. The Company uses the market closing price of its common stock as reported on the Nasdaq Global Select Market to determine the fair value of the shares of common stock underlying stock options. The following is a summary of stock option activity for the six months ended June 30, 2022: Number of Weighted Weighted Aggregate (In years) (In thousands) Outstanding at December 31, 2021 6,305,156 $ 43.57 Granted 391,910 86.08 Exercised ( 819,577 ) 16.18 Forfeited ( 240,948 ) 51.76 Outstanding at June 30, 2022 5,636,541 $ 50.15 7.90 $ 105,931 Exercisable at June 30, 2022 2,523,936 $ 30.36 As of June 30, 2022, there was $ 120.9 million of unrecognized compensation cost related to stock options that have not yet vested. These costs are expected to be recognized over a weighted average remaining vesting period of 2.7 years. 2016 Employee Stock Purchase Plan In May 2016, the Company adopted the 2016 Employee Stock Purchase Plan (the “2016 Plan”). The 2016 Plan allows eligible employees to purchase shares of the Company’s common stock on the last day of each predetermined six-month offering period at 85 % of the lower of the fair market value per share at the beginning or end of the applicable offering period. The 2016 Plan provides for six-month offering periods beginning in January and July of each year. As of June 30, 2022, there were 1,272,886 shares available for future issuance under the 2016 Plan. The number of shares reserved for issuance under the 2016 Plan will be cumulatively increased on each January 1 st by the lesser of a) one percent of the number of shares of common stock issued and outstanding on the immediately preceding December 31, b) 500,000 shares of common stock, or c) such lesser number of shares of common stock as determined by the board of directors. During the six months ended June 30, 2022 and 2021 the Company issued 24,316 and 20,410 shares of common stock under the 2016 Plan, respectively. The weighted-average purchase prices of shares issued under the 2016 Plan were $ 44.00 and $ 47.52 per share for the six-month periods ended June 30, 2022 and 2021, respectively. The fair value of the awards issued under the 2016 Plan to employees was estimated at the beginning of the offering period using a Black-Scholes option-pricing model with the following assumptions: Three Months Ended June 30, Six Months Ended June 30, 2022 2021 2022 2021 Risk-free interest rate 0.22 % 0.09 % 0.22 % 0.09 % Expected term (in years) 0.5 years 0.5 years 0.5 years 0.5 years Expected volatility of underlying stock 63.6 % 77.5 % 63.6 % 77.5 % Expected dividend yield 0.0 % 0.0 % 0.0 % 0.0 %

Loss Per Share

Loss Per Share	6 Months Ended
	Jun. 30, 2022
Earnings Per Share [Abstract]
Loss Per Share	12. Loss Per Share The Company calculates basic loss per share by dividing net loss for each respective period by the weighted average number of common shares outstanding for each respective period. The Company computes diluted loss per share after giving consideration to the dilutive effect of stock options and unvested restricted stock that are outstanding during the period, except where such securities would be anti-dilutive. Basic and diluted loss per share was calculated as follows: Three Months Ended June 30, Six Months Ended June 30, 2022 2021 2022 2021 (In thousands) Net loss $ ( 100,678 ) $ ( 68,806 ) $ ( 247,550 ) $ ( 115,011 ) Weighted average shares outstanding, basic 75,823 68,164 75,282 67,675 Net loss per share, basic and diluted $ ( 1.33 ) $ ( 1.01 ) $ ( 3.29 ) $ ( 1.70 ) The following common stock equivalents were excluded from the calculation of diluted loss per share because their inclusion would have been anti-dilutive: Three and Six Months Ended June 30, 2022 2021 (In thousands) Unvested restricted stock units 1,635 497 Stock options 5,637 7,264 7,272 7,761

Stockholders_ Equity

Stockholders’ Equity	6 Months Ended
	Jun. 30, 2022
Equity [Abstract]
Stockholders’ Equity	13. Stockholders’ Equity The following tables present changes in stockholders’ equity for the six-month periods ended June 30, 2022 and 2021 (in thousands, except share data): Additional Accumulated Other Total Common Paid-In Comprehensive Accumulated Stockholders’ Shares Amount Capital Loss Deficit Equity Balance at December 31, 2021 74,485,883 $ 7 $ 1,745,870 $ ( 2,632 ) $ ( 703,001 ) $ 1,040,244 Issuance of common stock through 164 579,788 1 38,885 - - 38,886 Exercise of stock options 503,830 - 8,435 - - 8,435 Vesting of restricted stock units 54,666 - - - - Equity-based compensation - - 18,491 - - 18,491 Other comprehensive loss - unrealized loss on marketable securities - - - ( 5,128 ) - ( 5,128 ) Other comprehensive loss - equity method investment - - - ( 302 ) - ( 302 ) Net loss - - - - ( 146,872 ) ( 146,872 ) Balance at March 31, 2022 75,624,167 8 1,811,681 ( 8,062 ) ( 849,873 ) 953,754 Exercise of stock options 315,747 - 4,827 - - 4,827 Vesting of restricted stock units 36,515 - - - - - Issuance of shares under employee 24,316 - 1,068 - - 1,068 Equity-based compensation - - 23,068 - - 23,068 Other comprehensive loss - unrealized loss on marketable securities - - - ( 932 ) - ( 932 ) Other comprehensive loss - equity method investment - - - ( 560 ) - ( 560 ) Net loss - - - - ( 100,678 ) ( 100,678 ) Balance at June 30, 2022 76,000,745 $ 8 $ 1,840,644 $ ( 9,554 ) $ ( 950,551 ) $ 880,547 Additional Accumulated Other Total Common Paid-In Comprehensive Accumulated Stockholders’ Shares Amount Capital Loss Deficit Equity Balance at December 31, 2020 66,234,056 $ 7 $ 962,173 $ 1 $ ( 435,109 ) $ 527,072 Issuance of common stock through 52 641,709 - 45,255 - - 45,255 Exercise of stock options 1,014,569 - 13,340 - - 13,340 Equity-based compensation - - 6,424 - - 6,424 Other comprehensive loss - unrealized loss on marketable securities - - - ( 13 ) - ( 13 ) Net loss - - - - ( 46,205 ) ( 46,205 ) Balance at March 31, 2021 67,890,334 7 1,027,192 ( 12 ) ( 481,314 ) 545,873 Exercise of stock options 394,801 - 6,163 - - 6,163 Vesting of restricted stock units 26,235 - - - - - Issuance of shares under employee 20,410 - 970 - - 970 Equity-based compensation - - 10,614 - - 10,614 Other comprehensive loss - unrealized loss on marketable securities - - - ( 1 ) - ( 1 ) Net loss - - - - ( 68,806 ) ( 68,806 ) Balance at June 30, 2021 68,331,780 $ 7 $ 1,044,939 $ ( 13 ) $ ( 550,120 ) $ 494,813 Follow-on Offering On June 29, 2021, the Company entered into an underwriting agreement related to a public offering of 4,758,620 shares of its common stock (inclusive of shares sold pursuant to the exercise of the underwriters’ option to purchase additional shares) at a public offering price of $ 145.00 per share. The offering closed on July 2, 2021, for aggregated net proceeds of $ 648.3 million after deducting $ 41.7 million in underwriting discounts and offering costs. At-the-Market Offering Programs In August 2019, the Company entered into an Open Market Sale Agreement (the “2019 Sale Agreement”) with Jefferies LLC (“Jefferies”), under which Jefferies was able to offer and sell, from time to time in “at-the-market” offerings, common stock having aggregate gross proceeds of up to $ 150.0 million. The Company agreed to pay Jefferies cash commissions of 3.0 % of the gross proceeds of sales of common stock under the 2019 Sale Agreement. During the six months ended June 30, 2022, the Company issued 579,788 shares of its common stock, in a series of sales, at an average price of $ 69.43 per share, in accordance with the 2019 Sale Agreement for aggregate net proceeds of $ 38.9 million, after payment of cash commissions to Jefferies and approximately $ 0.2 million related to legal, accounting and other fees in connection with the sales. As of June 30, 2022, $ 7.2 million in shares of common stock remain eligible for sale under the 2019 Sale Agreement. In February 2022, the Company entered into an Open Market Sale Agreement (the “2022 Sale Agreement”) with Jefferies, under which Jefferies will be able to offer and sell, from time to time in “at-the-market” offerings, common stock having aggregate gross proceeds of up to $ 400.0 million. The Company agreed to pay Jefferies cash commissions of 3.0 % of the gross proceeds of sales of common stock under the 2022 Sale Agreement. No shares of common stock were sold in the six months ended June 30, 2022 under the 2022 Sale Agreement.

Related Party Transactions

Related Party Transactions	6 Months Ended
	Jun. 30, 2022
Related Party Transactions [Abstract]
Related Party Transactions	14. Related Party Transactions In the ordinary course of business, the Company may purchase materials or supplies from entities that are associated with a party that meets the criteria of a related party of the Company. These transactions are reviewed quarterly and to date have not been material to the Company’s condensed consolidated financial statements. The Company and AvenCell are parties to the AvenCell LCA and AvenCell Co/Co, as described in Note 7. The Company’s relationship with AvenCell is considered to be as a related party due to the Company’s 33.33 % investment in AvenCell being accounted for under the equity method. The Company recognized $ 5.7 million and $ 11.3 million in revenue related to the AvenCell LCA for the three and six months ended June 30, 2022, respectively, after eliminating $ 2.8 million and $ 5.7 million during those respective periods in intra-entity profits, which will be deferred and recognized if and when AvenCell commercializes a product with the Company's license or abandons the related project. Until such time, the $ 5.7 million of revenue is indefinitely deferred and excluded from the results of operations of the Company. The Company recognized $ 0.1 million in revenue in the three months ended June 30, 2022 and $ 0.1 million in contra-revenue in the six months ended June 30, 2022 related to the AvenCell Co/Co agreement. As of June 30, 2022 the Company had deferred revenue of $ 37.1 million, comprised of $ 34.2 million in current deferred revenue and $ 2.9 million in non-current deferred revenue, related to the AvenCell LCA. The Company and Kyverna are parties to the Kyverna LCA and are considered to be related parties because they have a common board member (see Note 7). The Company owns preferred stock of Kyverna, the value of which is included in “Investments and other assets” in the condensed consolidated balance sheets. The value of this investment was $ 10.0 million as of June 30, 2022. T he Company recognized $ 2.0 million in revenue during the three and six months ended June 30, 2022 related to the Kyverna LCA. As of June 30, 2022, the Company had deferred revenue of $ 5.0 million related to the Kyverna LCA.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	6 Months Ended
	Jun. 30, 2022
Accounting Policies [Abstract]
Asset acquisitions	Asset acquisitions At the time of acquisition, the Company determines if a transaction should be accounted for as a business combination or acquisition of assets. The Company measures and recognizes asset acquisitions that are not deemed to be business combinations based on the cost to acquire the assets, which includes transaction costs, and the consideration is allocated to the items acquired based on a relative fair value methodology. Goodwill is not recognized in asset acquisitions. In an asset acquisition, the cost allocated to acquire in-process research and development with no alternative future use is charged to research and development expense at the acquisition date.
Contingent Consideration	Contingent consideration The Company accounts for contingent consideration identified in an asset acquisition, that is payable in cash and does not meet the definition of a derivative under Accounting Standard Codification (“ASC”) 815, Derivatives and Hedging , when the contingency is resolved and the consideration is paid or becomes payable. The Company accounts for contingent consideration identified in an asset acquisition that is settled in shares of common stock under ASC 480, Distinguishing Liabilities from Equity (“ASC 480”). The contingent consideration liability will be recorded at fair value at the end of each reporting period with changes in estimated fair values recorded in other (expense) income in the condensed consolidated statements of operations and comprehensive loss. The estimated fair value of the contingent consideration liability related to the Rewrite acquisition (see Notes 4 and 9) is determined based on a probability adjusted discounted cash flow model that includes significant estimates and assumptions pertaining to research and development. Significant changes in any of the probabilities of success or in the probabilities as to the periods in which the milestone would be achieved would result in a significantly higher or lower fair value measurement. The Company will continue to adjust the liability for changes in fair value until the obligation is settled or the research is abandoned.

Marketable Securities (Tables)

Marketable Securities (Tables)	6 Months Ended
	Jun. 30, 2022
Investments, Debt and Equity Securities [Abstract]
Summary of Available-for-sale Marketable Securities	The following table summarizes the Company’s available-for-sale marketable securities as of June 30, 2022 and December 31, 2021 at net book value: June 30, 2022 Amortized Gross Unrealized Gross Unrealized Estimated Fair (In thousands) Marketable securities: U.S. Treasury and other government securities $ 295,742 $ - $ ( 4,454 ) $ 291,288 Financial institution debt securities 303,294 - ( 2,296 ) 300,998 Corporate debt securities 52,575 - ( 724 ) 51,851 Other asset-backed securities 115,671 - ( 710 ) 114,961 Total $ 767,282 $ - $ ( 8,184 ) $ 759,098 December 31, 2021 Amortized Gross Unrealized Gross Unrealized Estimated Fair (In thousands) Marketable securities: U.S. Treasury and other government securities $ 301,493 $ - $ ( 1,016 ) $ 300,477 Financial institution debt securities 441,068 - ( 652 ) 440,416 Corporate debt securities 62,500 - ( 151 ) 62,349 Other asset-backed securities 159,707 - ( 306 ) 159,401 Total $ 964,768 $ - $ ( 2,125 ) $ 962,643

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	6 Months Ended
	Jun. 30, 2022
Fair Value Disclosures [Abstract]
Summary of Financial Assets Recognized at Fair Value on Recurring Basis	As of June 30, 2022 and December 31, 2021, the Company’s financial assets and liabilities recognized at fair value on a recurring basis consisted of the following: Fair Value as of June 30, 2022 Total Level 1 Level 2 Level 3 (In thousands) Assets Cash equivalents and restricted cash equivalents $ 156,323 $ 156,323 $ - $ - Marketable securities: U.S. Treasury and other government securities 291,288 276,278 15,010 - Financial institution debt securities 300,998 - 300,998 - Corporate debt securities 51,851 - 51,851 - Other asset-backed securities 114,961 - 114,961 - Total marketable securities 759,098 276,278 482,820 - Total Assets $ 915,421 $ 432,601 $ 482,820 $ - Liabilities Contingent consideration liability - research $ 10,790 $ - $ - $ 10,790 Total Liabilities $ 10,790 $ - $ - $ 10,790 Fair Value as of December 31, 2021 Total Level 1 Level 2 Level 3 (In thousands) Assets Cash equivalents and restricted cash equivalents $ 124,636 $ 124,636 $ - $ - Marketable securities: U.S. Treasury and other government securities 300,477 280,085 20,392 - Financial institution debt securities 440,416 - 440,416 - Corporate debt securities 62,349 - 62,349 - Other asset-backed securities 159,401 - 159,401 - Total marketable securities 962,643 280,085 682,558 - Total Assets $ 1,087,279 $ 404,721 $ 682,558 $ -
Schedule of change in fair value of the contingent consideration liabilities	The following table reconciles the change in fair value of the contingent consideration liability based on the level 3 inputs listed below (in thousands): For the six months ended June 30, 2022 Balance at February 2, 2022 (at inception) $ 10,541 Change in fair value 249 Balance at June 30, 2022 $ 10,790 As of inception (February 2, 2022) As of June 30, 2022 Discount rate 7 % 11 % Probability of achievement 50 % 50 % Projected year of achievement 2023 - 2024 2023 - 2024

Accrued Expenses (Tables)

Accrued Expenses (Tables)	6 Months Ended
	Jun. 30, 2022
Payables and Accruals [Abstract]
Schedule of Accrued Expenses	Accrued expenses consisted of the following: June 30, December 31, 2022 2021 (In thousands) Accrued research and development $ 25,278 $ 16,979 Employee compensation and benefits 12,879 20,359 Accrued legal and professional expenses 1,955 3,100 Accrued other 4,759 2,871 Total accrued expenses $ 44,871 $ 43,309

Collaborations and Other Arra_2

Collaborations and Other Arrangements (Tables)	6 Months Ended
	Jun. 30, 2022
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Summary of Changes in Accounts Receivable and Contract Liabilities	The following table presents changes in the Company’s accounts receivable and contract liabilities during the six months ended June 30, 2022 and 2021 (in thousands): Balance at Additions Deductions Balance at End Six Months Ended June 30, 2022 Accounts receivable $ 2,031 $ 4,655 $ ( 3,832 ) $ 2,854 Contract liabilities - deferred revenue $ 127,235 $ - $ ( 30,099 ) $ 97,136 Balance at Additions Deductions Balance at End Six Months Ended June 30, 2021 Accounts receivable $ 2,130 $ 3,079 $ ( 3,216 ) $ 1,993 Contract liabilities - deferred revenue $ 73,931 $ - $ ( 11,179 ) $ 62,752
Summary of Revenues Recognized Resulting From Changes in Contract Liability Balance	During the six months ended June 30, 2022 and 2021, the Company recognized the following revenues as a result of changes in the contract liability balance (in thousands): Six Months Ended June 30, Revenue recognized in the period from: 2022 2021 Amounts included in the contract liability at the beginning of the period $ 24,443 $ 11,179

Rewrite Acquisition (Tables)

Rewrite Acquisition (Tables)	6 Months Ended
	Jun. 30, 2022
Business Combinations [Abstract]
Summary of Transaction Price Determined and Allocated	The transaction price was determined and allocated as follows (in thousands): Transaction Price Upfront cash consideration $ 43,730 Research contingent consideration liabilities 10,541 Transaction costs 1,838 Total transaction price $ 56,109 Transaction Price Allocated In-process research and development $ 55,990 Cash acquired 287 Other current assets acquired 153 Other liabilities assumed ( 321 ) Total transaction price $ 56,109

Equity-Based Compensation (Tabl

Equity-Based Compensation (Tables)	6 Months Ended
	Jun. 30, 2022
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Schedule of Equity-Based Compensation Expense	Equity-based compensation expense is classified in the condensed consolidated statements of operations and comprehensive loss as follows: Three Months Ended June 30, Six Months Ended June 30, 2022 2021 2022 2021 (In thousands) Research and development $ 14,079 $ 6,135 $ 24,353 $ 9,626 General and administrative 8,989 4,479 17,206 7,412 Total $ 23,068 $ 10,614 $ 41,559 $ 17,038
Summary of Restricted Stock Activity	The following table summarizes the Company’s RSU activity for the six months ended June 30, 2022: Number of Weighted Unvested restricted stock units as of December 31, 2021 453,026 $ 71.03 Granted 1,327,420 76.57 Vested ( 91,181 ) 66.23 Cancelled ( 54,137 ) 74.32 Unvested restricted stock units as of June 30, 2022 1,635,128 $ 75.69
Summary of Weighted Average Assumptions Used to Compute Fair Value of Option Granted	Weighted average assumptions used to apply this pricing model were as follows: Three Months Ended June 30, Six Months Ended June 30, 2022 2021 2022 2021 Risk-free interest rate 3.4 % 1.1 % 1.9 % 0.9 % Expected life of options 5.6 years 6.0 years 5.9 years 6.0 years Expected volatility of underlying stock 77.9 % 73.0 % 76.2 % 72.2 % Expected dividend yield 0.0 % 0.0 % 0.0 % 0.0 %
Summary of Stock Option Activity	The following is a summary of stock option activity for the six months ended June 30, 2022: Number of Weighted Weighted Aggregate (In years) (In thousands) Outstanding at December 31, 2021 6,305,156 $ 43.57 Granted 391,910 86.08 Exercised ( 819,577 ) 16.18 Forfeited ( 240,948 ) 51.76 Outstanding at June 30, 2022 5,636,541 $ 50.15 7.90 $ 105,931 Exercisable at June 30, 2022 2,523,936 $ 30.36
2016 Employee Stock Purchase Plan [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Summary of Weighted Average Assumptions Used to Compute Fair Value of Option Granted	The fair value of the awards issued under the 2016 Plan to employees was estimated at the beginning of the offering period using a Black-Scholes option-pricing model with the following assumptions: Three Months Ended June 30, Six Months Ended June 30, 2022 2021 2022 2021 Risk-free interest rate 0.22 % 0.09 % 0.22 % 0.09 % Expected term (in years) 0.5 years 0.5 years 0.5 years 0.5 years Expected volatility of underlying stock 63.6 % 77.5 % 63.6 % 77.5 % Expected dividend yield 0.0 % 0.0 % 0.0 % 0.0 %

Loss Per Share (Tables)

Loss Per Share (Tables)	6 Months Ended
	Jun. 30, 2022
Earnings Per Share [Abstract]
Schedule of Basic and Diluted Net Loss Per Share	Basic and diluted loss per share was calculated as follows: Three Months Ended June 30, Six Months Ended June 30, 2022 2021 2022 2021 (In thousands) Net loss $ ( 100,678 ) $ ( 68,806 ) $ ( 247,550 ) $ ( 115,011 ) Weighted average shares outstanding, basic 75,823 68,164 75,282 67,675 Net loss per share, basic and diluted $ ( 1.33 ) $ ( 1.01 ) $ ( 3.29 ) $ ( 1.70 )
Potential Dilutive Securities Excluded from Computation of Diluted Net Loss Per Common Share	The following common stock equivalents were excluded from the calculation of diluted loss per share because their inclusion would have been anti-dilutive: Three and Six Months Ended June 30, 2022 2021 (In thousands) Unvested restricted stock units 1,635 497 Stock options 5,637 7,264 7,272 7,761

Stockholders_ Equity (Tables)

Stockholders’ Equity (Tables)	6 Months Ended
	Jun. 30, 2022
Equity [Abstract]
Schedule of Changes in Stockholders’ Equity	The following tables present changes in stockholders’ equity for the six-month periods ended June 30, 2022 and 2021 (in thousands, except share data): Additional Accumulated Other Total Common Paid-In Comprehensive Accumulated Stockholders’ Shares Amount Capital Loss Deficit Equity Balance at December 31, 2021 74,485,883 $ 7 $ 1,745,870 $ ( 2,632 ) $ ( 703,001 ) $ 1,040,244 Issuance of common stock through 164 579,788 1 38,885 - - 38,886 Exercise of stock options 503,830 - 8,435 - - 8,435 Vesting of restricted stock units 54,666 - - - - Equity-based compensation - - 18,491 - - 18,491 Other comprehensive loss - unrealized loss on marketable securities - - - ( 5,128 ) - ( 5,128 ) Other comprehensive loss - equity method investment - - - ( 302 ) - ( 302 ) Net loss - - - - ( 146,872 ) ( 146,872 ) Balance at March 31, 2022 75,624,167 8 1,811,681 ( 8,062 ) ( 849,873 ) 953,754 Exercise of stock options 315,747 - 4,827 - - 4,827 Vesting of restricted stock units 36,515 - - - - - Issuance of shares under employee 24,316 - 1,068 - - 1,068 Equity-based compensation - - 23,068 - - 23,068 Other comprehensive loss - unrealized loss on marketable securities - - - ( 932 ) - ( 932 ) Other comprehensive loss - equity method investment - - - ( 560 ) - ( 560 ) Net loss - - - - ( 100,678 ) ( 100,678 ) Balance at June 30, 2022 76,000,745 $ 8 $ 1,840,644 $ ( 9,554 ) $ ( 950,551 ) $ 880,547 Additional Accumulated Other Total Common Paid-In Comprehensive Accumulated Stockholders’ Shares Amount Capital Loss Deficit Equity Balance at December 31, 2020 66,234,056 $ 7 $ 962,173 $ 1 $ ( 435,109 ) $ 527,072 Issuance of common stock through 52 641,709 - 45,255 - - 45,255 Exercise of stock options 1,014,569 - 13,340 - - 13,340 Equity-based compensation - - 6,424 - - 6,424 Other comprehensive loss - unrealized loss on marketable securities - - - ( 13 ) - ( 13 ) Net loss - - - - ( 46,205 ) ( 46,205 ) Balance at March 31, 2021 67,890,334 7 1,027,192 ( 12 ) ( 481,314 ) 545,873 Exercise of stock options 394,801 - 6,163 - - 6,163 Vesting of restricted stock units 26,235 - - - - - Issuance of shares under employee 20,410 - 970 - - 970 Equity-based compensation - - 10,614 - - 10,614 Other comprehensive loss - unrealized loss on marketable securities - - - ( 1 ) - ( 1 ) Net loss - - - - ( 68,806 ) ( 68,806 ) Balance at June 30, 2021 68,331,780 $ 7 $ 1,044,939 $ ( 13 ) $ ( 550,120 ) $ 494,813

Overview and Basis of Present_2

Overview and Basis of Presentation - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands		6 Months Ended
	Feb. 02, 2022	Jun. 30, 2022	Jun. 30, 2021	Dec. 31, 2021
Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items]
Proceeds from common stock offering		$ 38,885	$ 45,255
Common stock, shares issued		76,000,745		74,485,883
Common stock, par value		$ 0.0001		$ 0.0001
Rewrite Therapeutics Delaware Corporation Member
Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items]
Upfront consideration payable in cash	$ 45,000
Milestone payments	155,000
Cash	$ 130,000
Common stock, shares issued	25,000,000
Common stock, par value	$ 0.0001
IPO [Member]
Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items]
Proceeds from common stock offering		$ 1,861,100

Marketable Securities - Summary

Marketable Securities - Summary of Available -for-sale Marketable Securities (Detail) - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Marketable Securities [Line Items]
Amortized Cost	$ 767,282	$ 964,768
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(8,184)	(2,125)
Estimated Fair Value	759,098	962,643
U.S. Treasury and Other Government Securities [Member]
Marketable Securities [Line Items]
Amortized Cost	295,742	301,493
Gross Unrealized Gains		0
Gross Unrealized Losses	(4,454)	(1,016)
Estimated Fair Value	291,288	300,477
Financial Institution Debt Securities [Member]
Marketable Securities [Line Items]
Amortized Cost	303,294	441,068
Gross Unrealized Gains		0
Gross Unrealized Losses	(2,296)	(652)
Estimated Fair Value	300,998	440,416
Corporate Debt Securities [Member]
Marketable Securities [Line Items]
Amortized Cost	52,575	62,500
Gross Unrealized Gains		0
Gross Unrealized Losses	(724)	(151)
Estimated Fair Value	51,851	62,349
Other Asset Backed Securities [Member]
Marketable Securities [Line Items]
Amortized Cost	115,671	159,707
Gross Unrealized Gains		0
Gross Unrealized Losses	(710)	(306)
Estimated Fair Value	$ 114,961	$ 159,401

Marketable Securities - Additio

Marketable Securities - Additional Information (Detail) - USD ($)	6 Months Ended	12 Months Ended
	Jun. 30, 2022	Dec. 31, 2021
Marketable Securities [Line Items]
Realized gains or losses on marketable securities	$ 0	$ 0
Investments that matured beyond five years	$ 0	$ 0
Minimum [Member]
Marketable Securities [Line Items]
Available-for-sales Securities, non-current, maturity period	1 year
Maximum [Member]
Marketable Securities [Line Items]
Available-for-sales Securities, non-current, maturity period	5 years

Fair Value Measurements - Summa

Fair Value Measurements - Summary of Financial Assets Recognized at Fair Value on Recurring Basis (Detail) - Fair Value on Recurring Basis [Member] - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Assets
Cash equivalents and restricted cash equivalents	$ 156,323	$ 124,636
Marketable securities:
Marketable securities	759,098	962,643
Total Assets	915,421	1,087,279
Liabilities
Liabilities measured at fair value	10,790
Contingent Consideration Liability - research [Member]
Liabilities
Liabilities measured at fair value	10,790
U.S. Treasury and Other Government Securities [Member]
Marketable securities:
Marketable securities	291,288	300,477
Financial Institution Debt Securities [Member]
Marketable securities:
Marketable securities	300,998	440,416
Corporate Debt Securities [Member]
Marketable securities:
Marketable securities	51,851	62,349
Other Asset Backed Securities [Member]
Marketable securities:
Marketable securities	114,961	159,401
Level 1 [Member]
Assets
Cash equivalents and restricted cash equivalents	156,323	124,636
Marketable securities:
Marketable securities	276,278	280,085
Total Assets	432,601	404,721
Level 1 [Member] | U.S. Treasury and Other Government Securities [Member]
Marketable securities:
Marketable securities	276,278
Total Assets		280,085
Level 2 [Member]
Marketable securities:
Marketable securities	482,820	682,558
Total Assets	482,820	682,558
Level 2 [Member] | U.S. Treasury and Other Government Securities [Member]
Marketable securities:
Marketable securities	15,010	20,392
Level 2 [Member] | Financial Institution Debt Securities [Member]
Marketable securities:
Marketable securities	300,998	440,416
Level 2 [Member] | Corporate Debt Securities [Member]
Marketable securities:
Marketable securities	51,851	62,349
Level 2 [Member] | Other Asset Backed Securities [Member]
Marketable securities:
Marketable securities	114,961	$ 159,401
Level 3 [Member]
Liabilities
Liabilities measured at fair value	10,790
Level 3 [Member] | Contingent Consideration Liability - research [Member]
Liabilities
Liabilities measured at fair value	$ 10,790

Fair Value Measurements - Sched

Fair Value Measurements - Schedule of change in fair value of the contingent consideration liabilities (Detail) - USD ($) $ in Thousands		6 Months Ended
	Feb. 02, 2022	Jun. 30, 2022
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Change in fair value		$ 249
Balance	$ 10,541	$ 10,790
Discount rate	7%	11%
Probability of achievement	50%	50%
Maximum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Projected year of achievement	2024	2024
Minimum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Projected year of achievement	2023	2023

Fair Value Measurements - Addit

Fair Value Measurements - Additional information (Detail) $ in Millions	6 Months Ended
	Jun. 30, 2022 USD ($)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Abstract]
Research milestone payments	$ 25

Accrued Expenses - Schedule of

Accrued Expenses - Schedule of Accrued Expenses (Detail) - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Payables and Accruals [Abstract]
Accrued research and development	$ 25,278	$ 16,979
Employee compensation and benefits	12,879	20,359
Accrued legal and professional expenses	1,955	3,100
Accrued other	4,759	2,871
Total accrued expenses	$ 44,871	$ 43,309

Collaborations and Other Arra_3

Collaborations and Other Arrangements - Additional Information (Detail) - USD ($)		3 Months Ended		6 Months Ended		12 Months Ended	75 Months Ended
	Feb. 12, 2022	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021	Dec. 31, 2021	Jun. 30, 2022	Dec. 31, 2020
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Capitalized Contract Cost, Gross		$ 0		$ 0			$ 0
Collaboration revenue		14,030,000	$ 6,550,000	25,282,000	$ 12,995,000
Accounts receivable						$ 0
Deferred revenue		97,136,000	62,752,000	97,136,000	62,752,000	127,235,000	97,136,000	$ 73,931,000
Revenue		2,800,000		5,700,000
Regeneron Pharmaceuticals Inc. [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Aggregate transaction price remaining to be recognized		40,200,000		40,200,000			40,200,000
Accounts receivable		2,900,000		2,900,000		2,000,000	2,900,000
Deferred revenue		40,200,000		40,200,000		51,400,000	40,200,000
Regeneron Pharmaceuticals Inc. [Member] | Hemophilia Co Co Agreements
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Collaboration revenue		2,200,000	1,000,000	3,700,000	1,000,000
Regeneron Pharmaceuticals Inc. [Member] | Regeneron Agreement [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Deferred revenue additions							145,000,000
Collaboration revenue		6,300,000	5,500,000	$ 12,100,000	12,000,000		161,100,000
Aggregate transaction price remaining to be recognized, period				Through June 30, 2022
Payments due		2,900,000	1,000,000	$ 4,700,000	1,800,000
Regeneron Pharmaceuticals Inc. [Member] | Regeneron Agreement [Member] | Research and Development Services [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Collaboration revenue							38,900,000
Novartis [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Strategic collaboration agreement amended date				2018-12
One time payment to novartis						10,000,000
Novartis [Member] | AvenCell Co Co Agreement [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Deferred revenue		0		$ 0		0	0
ONK Therapeutics [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Development And Commercial Milestone Payment To be Received	$ 184,000,000
Kyverna Therapeutics Inc [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Accounts receivable		0		0		0	0
Deferred revenue		5,000,000		5,000,000		7,000,000	5,000,000
Revenue		2,000,000		2,000,000
Sparing Vision [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Collaboration revenue		0	0	0	0
Accounts receivable			$ 0		$ 0
Deferred revenue		14,800,000		14,800,000		14,800,000	14,800,000
AvenCell [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Deferred revenue additions		2,800,000		5,700,000
Collaboration revenue		5,700,000		11,300,000
Accounts receivable		0		0			0
Deferred revenue		37,100,000		37,100,000		54,100,000	37,100,000
AvenCell [Member] | AvenCell Co Co Agreement [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Collaboration revenue				100,000
Accounts receivable						$ 100,000
Deferred revenue		$ 5,700,000		$ 5,700,000			$ 5,700,000

Collaborations and Other Arra_4

Collaborations and Other Arrangements - Summary of Changes in Accounts Receivable and Contract Liabilities (Detail) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021
Accounts receivable:
Accounts receivable, Balance at Beginning of Period	$ 2,031	$ 2,130
Accounts receivable, Additions	4,655	3,079
Accounts receivable, Deductions	3,832	3,216
Accounts receivable, Balance at End of Period	2,854	1,993
Contract liabilities:
Deferred revenue, Balance at Beginning of Period	127,235	73,931
Deferred revenue, Deductions	(30,099)	(11,179)
Deferred revenue, Balance at End of Period	$ 97,136	$ 62,752

Collaborations and Other Arra_5

Collaborations and Other Arrangements - Summary of Revenues Recognized Resulting From Changes in Contract Liability Balance (Detail) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021
Revenue from Contract with Customer [Abstract]
Amounts included in the contract liability at the beginning of the period	$ 24,443	$ 11,179

Equity-Method Investment and _2

Equity-Method Investment and Other Investments - Additional Information (Detail) - USD ($) $ in Thousands	1 Months Ended		3 Months Ended		6 Months Ended
	Oct. 31, 2021	Jul. 30, 2021	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021	Dec. 31, 2021
Schedule of Equity Method Investments [Line Items]
Investments in and Advances to Affiliates, at Fair Value, Gross Reductions			$ 3,800		$ 6,900
Loss from equity method investment			(3,252)	$ 0	(5,997)	$ 0
Equity method investment			45,616		45,616		$ 58,131
Preferred Stock Purchase Agreement [Member]
Schedule of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage		33.33%
Preferred Stock Purchase Agreement [Member] | Cellex and BXLS [Member]
Schedule of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage		66.67%
AvenCell [Member]
Schedule of Equity Method Investments [Line Items]
Investment Owned, at Fair Value		$ 62,900
Loss from equity method investment			2,800		5,700
Equity method investment			45,600		45,600
AvenCell [Member] | Measurement Input, Option Volatility [Member]
Schedule of Equity Method Investments [Line Items]
Equity securities measurement input, percentage		76%
AvenCell [Member] | Measurement Input Option Subsequent Financing [Member]
Schedule of Equity Method Investments [Line Items]
Equity securities measurement input, percentage		75%
AvenCell [Member] | Measurement Input, Discount for Lack of Marketability [Member]
Schedule of Equity Method Investments [Line Items]
Equity securities measurement input, percentage		11%
Sparing Vision [Member]
Schedule of Equity Method Investments [Line Items]
Investment Owned, at Fair Value	$ 14,800
Sparing Vision [Member] | Series A2 Preferred Stock [Member]
Schedule of Equity Method Investments [Line Items]
Sale of Stock, Number of Shares Issued in Transaction	83,316
Sparing Vision [Member] | Measurement Input, Option Volatility [Member]
Schedule of Equity Method Investments [Line Items]
Equity securities measurement input, percentage	90%
Sparing Vision [Member] | Measurement Input Option Rate Of Return [Member]
Schedule of Equity Method Investments [Line Items]
Equity securities measurement input, percentage	65%
Kyverna Therapeutics Inc [Member]
Schedule of Equity Method Investments [Line Items]
Investment Owned, at Fair Value			$ 10,000		$ 10,000
Kyverna Therapeutics Inc [Member] | Series B Preferred Stock [Member]
Schedule of Equity Method Investments [Line Items]
Sale of Stock, Number of Shares Issued in Transaction					3,739,515
Fair value of stock received					$ 7,000
Number of stock additionally invested					1,602,649
Cash consideration received on sale of common stock					$ 3,000

Rewrite Acquisition - Additiona

Rewrite Acquisition - Additional Information (Detail) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
	Feb. 02, 2022	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021	Dec. 31, 2021
Business Acquisition [Line Items]
Research and development		$ 90,199	$ 58,884	$ 223,294	$ 98,160
Common stock, shares issued		76,000,745		76,000,745		74,485,883
Rewrite Therapeutics Delaware Corporation Member
Business Acquisition [Line Items]
Upfront consideration payable in cash	$ 45,000
Research and development	56,000
Milestone payments	155,000
Cash	$ 130,000
Common stock, shares issued	25,000,000
Liability for milestone payment	$ 10,500			$ 0

Rewrite Acquisition - Summary o

Rewrite Acquisition - Summary of Transaction Price Determined and Allocated (Detail) $ in Thousands	6 Months Ended
	Jun. 30, 2022 USD ($)
Transaction Price
Upfront cash consideration	$ 43,730
Research contingent consideration liabilities	10,541
Transaction costs	1,838
Total transaction price	56,109
Transaction Price Allocated
In-process research and development	55,990
Cash acquired	287
Other current assets acquired	153
Other liabilities assumed	(321)
Total transaction price	$ 56,109

Leases - Additional Information

Leases - Additional Information (Detail) $ in Thousands		1 Months Ended			6 Months Ended	9 Months Ended
	Feb. 28, 2022 USD ($) ft²	Jun. 30, 2022 USD ($) ft²	Feb. 28, 2022 USD ($) ft²	Jan. 31, 2022 USD ($) ft²	Jun. 30, 2022 USD ($) ft²	Sep. 30, 2021	Jan. 01, 2023 USD ($)	Dec. 31, 2021 USD ($)
Lessee Lease Description [Line Items]
Operating lease right-of-use assets | $		$ 73,775			$ 73,775			$ 79,143
730 Main Lease [Member]
Lessee Lease Description [Line Items]
Area of space leased					38,000
Operating lease, description					In January 2022, the Company entered into an agreement to lease approximately 38,000 square feet of office and laboratory space at 730 Main Street, Cambridge, Massachusetts under an operating lease agreement (the “730 Main Lease”). The 730 Main Lease, including the obligation to pay rent, is expected to commence in October 2022 for an
Term of lease				10 years
Base rent per square foot for first year				130
Base rent per square foot for last year				169.62
Letter of credit | $				$ 2,400
Operating lease, options to extend					The Company has the option to extend the 730 Main Lease for one five-year term.
Albany Lease [Member]
Lessee Lease Description [Line Items]
Operating lease, existence of option to extend						true
840 Winter Street Lease [Member]
Lessee Lease Description [Line Items]
Area of space leased	140,000
Operating lease, description			In February 2022, the Company entered into an agreement to lease approximately 140,000 square feet of manufacturing space located at 840 Winter Street, Waltham, Massachusetts (the “840 Winter Lease”), which will provide the Company with the ability to manufacture its own products in a good manufacturing practice (“GMP”) compliant facility as well as to supplement the Company’s current leased premises in Cambridge, Massachusetts. The 840 Winter Lease, including the obligation to pay rent, is expected to commence in February 2024 for an
Term of lease	12 years		12 years
Base rent per square foot for first year			73.50
Letter of credit | $	$ 2,600		$ 2,600
Operating lease, options to extend					The Company has the option to extend the 840 Winter Lease for two five-year terms.
Percentage of Annual Increase					3%
840 Winter Street Lease [Member] | forecast Member
Lessee Lease Description [Line Items]
Letter of credit | $							$ 6,000
MemorialDrive640Member
Lessee Lease Description [Line Items]
Area of space leased		62,000
Operating lease, description		In June 2022, the Company entered into an agreement to lease approximately 62,000 square feet of office and laboratory space located at 640 Memorial Drive, Cambridge, Massachusetts under an operating lease agreement (the “640 Memorial Drive Lease”). The 640 Memorial Drive Lease, including the obligation to pay rent, is expected to commence in September 2022 for a
Term of lease		5 years			5 years
Base rent per square foot for first year		0.97
Base rent per square foot for last year		1.38
Letter of credit | $		$ 1,800			$ 1,800
cost of tenant improvements | $		$ 1,200
Operating lease, options to extend					The Company does not have an option to extend the 640 Memorial Drive Lease.

Equity-Based Compensation - Add

Equity-Based Compensation - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Millions	1 Months Ended		3 Months Ended		6 Months Ended
	Mar. 31, 2022	May 31, 2016	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021	Dec. 31, 2021
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock, shares issued			76,000,745		76,000,745		74,485,883
Weighted Average Grant Date Fair Value per Share, Granted			$ 55.16	$ 77.07	$ 76.57	$ 62.82
Total fair value amount, Vested			$ 1.5	$ 1.9	$ 8
Number of Shares, Granted					1,327,420
Number of Shares, Vested					(91,181)
Risk-free interest rate			3.40%	1.10%	1.90%	0.90%
Expected dividend yield			0%	0%	0%	0%
Expected volatility			77.90%	73%	76.20%	72.20%
Expected term			5 years 7 months 6 days	6 years	5 years 10 months 24 days	6 years
Weighted average period of unrecognized compensation costs					2 years 8 months 12 days
Weighted average grant date fair value per share			$ 28.76	$ 48.44	$ 57.23	$ 38.70
Total intrinsic value of stock options exercised			$ 10.5	$ 29.7	$ 40.4	$ 84.5
Unrecognized compensation cost related to stock options			120.9		120.9
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized equity-based compensation expense related to restricted stock			$ 105.1		$ 105.1
Weighted average period of unrecognized compensation costs					2 years 6 months
RSUs [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Remaining vesting period	3 years
Weighted Average Grant Date Fair Value per Share, Granted	$ 79.85
Number of Shares, Granted	794,424
PSUs [Member] | Senior Executives [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Remaining vesting period	3 years
Weighted Average Grant Date Fair Value per Share, Granted	$ 126.49
Number of Shares, Granted	55,144
Risk-free interest rate	1.44%
Expected dividend yield	0%
Expected volatility	82.53%
Expected term	2 years 10 months 2 days
PSUs [Member] | Non-executive Employees [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Shares, Granted	66,296
2015 Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Remaining vesting period					3 years
Description of stock options granted under the Plan					Stock options granted under the 2015 Plan generally vest 25% on the first anniversary of the original vesting date, with the balance vesting monthly over the remaining three years, unless they contain specific performance-based vesting provisions. The maximum term of stock options granted under the 2015 Plan is ten years.Effective July 1, 2022, the Company adopted a retirement policy for equity awards granted to all employees other than the Company’s CEO (the “Policy”). The Policy applies to all equity awards granted to employees who meet certain retirement eligibility criteria set forth in the Policy (the “Retirees”). Pursuant to the terms of the Policy, upon a Retiree’s eligible retirement: (i) all stock options held by the Retiree will continue to vest following the Retiree’s retirement date according to the original vesting schedule of the option until fully vested and all vested stock options held by such Retiree will remain exercisable until the earlier of the five-year anniversary of the Retiree’s retirement date or the original expiration date of the option, (ii) all unvested time-based RSUs held by the Retiree will vest in full on the Retiree’s retirement date and (iii) all unvested performance-based awards held by the Retiree will remain outstanding following the Retiree’s retirement date and the Retiree will remain eligible to earn a pro-rated portion of such performance-based awards at the end of the performance period based on actual performance during the performance period.
Shares available for future issuance			3,803,557		3,803,557
Percentage of cumulative increase in number of shares for future issuance					4%
2015 Plan [Member] | First Anniversary of Original Vesting Date [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vest percentage on the first anniversary					25%
2016 Employee Stock Purchase Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Description of stock options granted under the Plan		The 2016 Plan allows eligible employees to purchase shares of the Company’s common stock on the last day of each predetermined six-month offering period at 85% of the lower of the fair market value per share at the beginning or end of the applicable offering period.
Percentage of fair market value of common stock		85%
Shares available for future issuance			1,272,886		1,272,886
Common stock, shares issued			24,316	20,410	24,316	20,410
Weighted Average Grant Date Fair Value per Share, Granted					$ 44	$ 47.52
Risk-free interest rate			0.22%	0.09%	0.22%	0.09%
Expected dividend yield			0%	0%	0%	0%
Expected volatility			63.60%	77.50%	63.60%	77.50%
Expected term			6 months	6 months	6 months	6 months
Maximum [Member] | 2015 Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Maximum term of stock options granted					10 years
Maximum [Member] | 2016 Employee Stock Purchase Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock, shares issued			500,000		500,000

Equity-Based Compensation - Sch

Equity-Based Compensation - Schedule of Equity-Based Compensation Expense (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Equity-based compensation expense	$ 23,068	$ 10,614	$ 41,559	$ 17,038
Research and Development [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Equity-based compensation expense	14,079	6,135	24,353	9,626
General and Administrative [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Equity-based compensation expense	$ 8,989	$ 4,479	$ 17,206	$ 7,412

Equity-Based Compensation - Sum

Equity-Based Compensation - Summary of Restricted Stock Activity (Detail) - $ / shares	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Share-Based Payment Arrangement [Abstract]
Number of Shares, Unvested, Beginning balance			453,026
Number of Shares, Granted			1,327,420
Number of Shares, Vested			(91,181)
Number of Shares, Cancelled			(54,137)
Number of Shares, Unvested, Ending balance	1,635,128		1,635,128
Weighted Average Grant Date Fair Value per Share, Unvested, Beginning balance			$ 71.03
Weighted Average Grant Date Fair Value per Share, Granted	$ 55.16	$ 77.07	76.57	$ 62.82
Weighted Average Grant Date Fair Value per Share, Vested			66.23
Weighted Average Grant Date Fair Value per Share, Cancelled			74.32
Weighted Average Grant Date Fair Value per Share, Unvested, Ending balance	$ 75.69		$ 75.69

Equity-Based Compensation - S_2

Equity-Based Compensation - Summary of Weighted Average Assumptions Used to Compute Fair Value of Option Granted (Detail)	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Risk-free interest rate	3.40%	1.10%	1.90%	0.90%
Expected term	5 years 7 months 6 days	6 years	5 years 10 months 24 days	6 years
Expected volatility of underlying stock	77.90%	73%	76.20%	72.20%
Expected dividend yield	0%	0%	0%	0%
2016 Employee Stock Purchase Plan [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Risk-free interest rate	0.22%	0.09%	0.22%	0.09%
Expected term	6 months	6 months	6 months	6 months
Expected volatility of underlying stock	63.60%	77.50%	63.60%	77.50%
Expected dividend yield	0%	0%	0%	0%

Equity-Based Compensation - S_3

Equity-Based Compensation - Summary of Stock Option Activity (Detail) - USD ($) $ / shares in Units, $ in Thousands	6 Months Ended
	Jun. 30, 2022
Share-Based Payment Arrangement [Abstract]
Number of Options, Outstanding, Beginning Balance	6,305,156
Number of options, Granted	391,910
Number of options, Exercised	(819,577)
Number of options, Forfeited	(240,948)
Number of Options, Outstanding, Ending Balance	5,636,541
Number of Options, Exercisable	2,523,936
Weighted Average Exercise Price per Share, Outstanding, Beginning Balance	$ 43.57
Weighted Average Exercise Price per Share, Granted	86.08
Weighted Average Exercise Price per Share, Exercised	16.18
Weighted Average Exercise Price per Share, Forfeited	51.76
Weighted Average Exercise Price per Share, Outstanding, Ending Balance	50.15
Weighted Average Exercise Price per Share, Exercisable	$ 30.36
Weighted Average Remaining Contractual Term, Outstanding	7 years 10 months 24 days
Aggregate Intrinsic Value, Outstanding	$ 105,931

Loss Per Share - Schedule of Ba

Loss Per Share - Schedule of Basic and Diluted Net Loss Per Share (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2022	Mar. 31, 2022	Jun. 30, 2021	Mar. 31, 2021	Jun. 30, 2022	Jun. 30, 2021
Earnings Per Share [Abstract]
Net loss	$ (100,678)	$ (146,872)	$ (68,806)	$ (46,205)	$ (247,550)	$ (115,011)
Weighted average shares outstanding, basic	75,823		68,164		75,282	67,675
Weighted average shares outstanding, diluted	75,823		68,164		75,282	67,675
Net Loss Per Share, Basic	$ (1.33)		$ (1.01)		$ (3.29)	$ (1.70)
Net Loss Per Share, Diluted	$ (1.33)		$ (1.01)		$ (3.29)	$ (1.70)

Loss Per Share - Potential Dilu

Loss Per Share - Potential Dilutive Securities Excluded from Computation of Diluted Net Loss Per Common Share (Detail) - shares shares in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potential dilutive securities excluded from computation of diluted net loss per common share	7,272	7,761	7,272	7,761
Unvested Restricted Stock Units [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potential dilutive securities excluded from computation of diluted net loss per common share	1,635	497	1,635	497
Stock Options [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potential dilutive securities excluded from computation of diluted net loss per common share	5,637	7,264	5,637	7,264

Stockholders' Equity - Schedule

Stockholders' Equity - Schedule of Changes in Stockholders Equity (Detail) - USD ($) $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2022	Mar. 31, 2022	Jun. 30, 2021	Mar. 31, 2021	Jun. 30, 2022	Jun. 30, 2021
Class Of Stock [Line Items]
Beginning balance	$ 953,754	$ 1,040,244	$ 545,873	$ 527,072	$ 1,040,244	$ 527,072
Beginning balance, shares		74,485,883			74,485,883
Exercise of stock options	4,827	$ 8,435	6,163	13,340
Exercise of stock options, shares					819,577
Issuance of shares under employee stock purchase plan	1,068		970
Equity-based compensation	23,068	18,491	10,614	6,424
Other comprehensive loss - unrealized loss on marketable securities	(932)	(5,128)	(1)	(13)
Other comprehensive loss from equity method investment	(560)	(302)	0		$ (862)	0
Net loss	(100,678)	(146,872)	(68,806)	(46,205)	(247,550)	(115,011)
Ending balance	$ 880,547	953,754	494,813	545,873	$ 880,547	494,813
Ending balance, shares	76,000,745				76,000,745
At The Market Offerings [Member]
Class Of Stock [Line Items]
Issuance of common stock		38,886		45,255
Common Stock [Member]
Class Of Stock [Line Items]
Beginning balance	$ 8	$ 7	$ 7	$ 7	$ 7	$ 7
Beginning balance, shares	75,624,167	74,485,883	67,890,334	66,234,056	74,485,883	66,234,056
Exercise of stock options, shares	315,747	503,830	394,801	1,014,569
Vesting of restricted stock units, shares	36,515	54,666	26,235
Issuance of shares under employee stock purchase plan, shares	24,316		20,410
Ending balance	$ 8	$ 8	$ 7	$ 7	$ 8	$ 7
Ending balance, shares	76,000,745	75,624,167	68,331,780	67,890,334	76,000,745	68,331,780
Common Stock [Member] | At The Market Offerings [Member]
Class Of Stock [Line Items]
Issuance of common stock		$ 1
Number of stock additionally invested		579,788		641,709
Additional Paid-In Capital [Member]
Class Of Stock [Line Items]
Beginning balance	$ 1,811,681	$ 1,745,870	$ 1,027,192	$ 962,173	$ 1,745,870	$ 962,173
Exercise of stock options	4,827	8,435	6,163	13,340
Issuance of shares under employee stock purchase plan	1,068		970
Equity-based compensation	23,068	18,491	10,614	6,424
Ending balance	1,840,644	1,811,681	1,044,939	1,027,192	1,840,644	1,044,939
Additional Paid-In Capital [Member] | At The Market Offerings [Member]
Class Of Stock [Line Items]
Issuance of common stock		38,885		45,255
Accumulated Other Comprehensive Loss [Member]
Class Of Stock [Line Items]
Beginning balance	(8,062)	(2,632)	(12)	1	(2,632)	1
Other comprehensive loss - unrealized loss on marketable securities	(932)	(5,128)	(1)	(13)
Other comprehensive loss from equity method investment	(560)	(302)
Ending balance	(9,554)	(8,062)	(13)	(12)	(9,554)	(13)
Accumulated Deficit [Member]
Class Of Stock [Line Items]
Beginning balance	(849,873)	(703,001)	(481,314)	(435,109)	(703,001)	(435,109)
Net loss	(100,678)	(146,872)	(68,806)	(46,205)
Ending balance	$ (950,551)	$ (849,873)	$ (550,120)	$ (481,314)	$ (950,551)	$ (550,120)

Stockholders' Equity - Schedu_2

Stockholders' Equity - Schedule of Changes in Stockholders Equity (Parenthetical) (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Class Of Stock [Line Items]
Stock issuance cost, net	$ 164	$ 52

Stockholders' Equity - Addition

Stockholders' Equity - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands			1 Months Ended		6 Months Ended
	Jul. 02, 2021	Jun. 29, 2021	Feb. 28, 2022	Aug. 31, 2019	Jun. 30, 2022	Jun. 30, 2021
Class Of Stock [Line Items]
Proceeds from common stock offering					$ 38,885	$ 45,255
2019 Sales Agreement [Member]
Class Of Stock [Line Items]
Proceeds from common stock offering					$ 38,900
Percentage of gross proceeds from common stock as sales agent cash commission				3%
Stock Issued During Period, Shares, New Issues					579,788
Common stock price per share					$ 69.43
Proceeds from common stock offering					$ 7,200
2019 Sales Agreement [Member] | General and Administrative Expenses [Member]
Class Of Stock [Line Items]
Legal accounting and other fees					$ 200
2019 Sales Agreement [Member] | Maximum [Member]
Class Of Stock [Line Items]
Proceeds from common stock offering				$ 150,000
2022 Sales Agreement
Class Of Stock [Line Items]
Percentage of gross proceeds from common stock as sales agent cash commission			3%
2022 Sales Agreement | Maximum [Member]
Class Of Stock [Line Items]
Proceeds from common stock offering			$ 400,000
Underwriting Agreement [Member] | Follow-on Offering [Member]
Class Of Stock [Line Items]
Proceeds from common stock offering	$ 648,300
Stock Issued During Period, Shares, New Issues		4,758,620
Common stock price per share		$ 145
Underwriting discounts and estimated offering costs	$ 41,700

Related Party Transaction - Add

Related Party Transaction - Additional information (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021	Dec. 31, 2021	Dec. 31, 2020
Related Party Transaction [Line Items]
Revenue	$ 2,800		$ 5,700
Deferred revenue	97,136	$ 62,752	97,136	$ 62,752	$ 127,235	$ 73,931
Deferred revenue current	61,806		61,806		63,759
Deferred revenue non-current	35,330		35,330		63,476
Investment	37,128		37,128		$ 29,558
Collaboration revenue	$ 14,030	$ 6,550	$ 25,282	$ 12,995
Avencelllca
Related Party Transaction [Line Items]
Equity method investment, ownership percentage	33.33%		33.33%
Revenue	$ 5,700
Deferred revenue	37,100		$ 37,100
Deferred revenue current	34,200		34,200
Deferred revenue non-current	2,900		2,900
Avencelllca | AvenCell Co Co Agreement [Member]
Related Party Transaction [Line Items]
Deferred revenue	5,700		5,700
Avencellcoco
Related Party Transaction [Line Items]
Revenue	100		11,300
Contra Revenue			100
Kyvernalca
Related Party Transaction [Line Items]
Deferred revenue	5,000		5,000
Investment	10,000		10,000
Collaboration revenue	$ 2,000		$ 2,000