Tcr2 Therapeutics (TCRR) 10-Q 8 Nov 22 2022 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2022	Nov. 01, 2022
Cover [Abstract]
Entity Shell Company	false
Title of 12(b) Security	Common Stock, $0.0001 Par Value
City Area Code	617
Entity Address, Address Line One	100 Binney Street
Entity Incorporation, State or Country Code	DE
Entity File Number	001-38811
Document Transition Report	false
Document Quarterly Report	true
Entity Registrant Name	TCR2 Therapeutics Inc.
Entity Central Index Key	0001750019
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Document Period End Date	Sep. 30, 2022
Document Fiscal Year Focus	2022
Document Fiscal Period Focus	Q3
Document Type	10-Q
Amendment Flag	false
Entity Emerging Growth Company	true
Entity Small Business	true
Entity Ex Transition Period	false
Entity Common Stock, Shares Outstanding		38,657,061
Entity Tax Identification Number	47-4152751
Entity Address, Address Line Two	Suite 710
Entity Address, City or Town	Cambridge
Entity Address, State or Province	MA
Entity Address, Postal Zip Code	02142
Local Phone Number	949-5200
Trading Symbol	TCRR
Security Exchange Name	NASDAQ
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes

Unaudited Consolidated Balance

Unaudited Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
Current assets
Cash and cash equivalents	$ 54,006	$ 222,564
Investments	121,980	43,029
Prepaid expenses and other current assets	8,093	10,534
Total current assets	184,079	276,127
Property and equipment, net	29,083	17,075
Right-of-use assets, operating leases	57,704	28,283
Restricted cash	1,152	1,156
Other assets, non-current	909	730
Total assets	272,927	323,371
Liabilities and stockholders’ equity
Accounts payable	2,963	2,144
Accrued expenses and other current liabilities	13,185	13,094
Operating lease liabilities	20,545	3,367
Total current liabilities	36,693	18,605
Operating lease liabilities, non-current	37,684	22,996
Other liabilities	0	293
Total liabilities	74,377	41,894
Commitments and contingencies (Note 7)
Stockholders’ equity
Preferred stock, $0.0001 par value; 10,000,000 shares authorized, no shares issued or outstanding as of June 30, 2022 and December 31, 2021, respectively.	0	0
Common stock, $0.0001 par value; 150,000,000 shares authorized; 38,598,916 and 38,496,484 shares issued and outstanding as of June 30, 2022 and December 31, 2021, respectively.	4	4
Additional paid-in capital	639,981	631,008
Accumulated other comprehensive income (loss)	(596)	(13)
Accumulated deficit	(440,839)	(349,522)
Total stockholders’ equity	198,550	281,477
Total liabilities and stockholders’ equity	$ 272,927	$ 323,371

Unaudited Consolidated Balanc_2

Unaudited Consolidated Balance Sheets (Parenthetical) - $ / shares	Sep. 30, 2022	Dec. 31, 2021
Preferred stock, par value (USD per share)	$ 0.0001	$ 0.0001
Preferred stock, shares authorized (shares)	10,000,000	10,000,000
Preferred stock, shares issued (shares)	0	0
Preferred stock, shares outstanding (shares)	0	0
Common stock, par value (USD per share)	$ 0.0001	$ 0.0001
Common stock, shares authorized (shares)	150,000,000	150,000,000
Common stock, shares issued (shares)	38,657,061	38,496,484
Common stock, shares outstanding (shares)	38,657,061	38,496,484

Unaudited Consolidated Statemen

Unaudited Consolidated Statements of Operations - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Operating expenses
Research and development	$ 24,791	$ 20,277	$ 73,441	$ 54,828
General and administrative	6,312	5,963	18,636	17,297
Total operating expenses	31,103	26,240	92,077	72,125
Loss from operations	(31,103)	(26,240)	(92,077)	(72,125)
Interest income, net	510	38	925	186
Loss before income tax expense	(30,593)	(26,202)	(91,152)	(71,939)
Income tax expense	1	42	165	129
Net loss	$ (30,594)	$ (26,244)	$ (91,317)	$ (72,068)
Per share information
Net loss per share of common stock, basic	$ (0.79)	$ (0.69)	$ (2.37)	$ (1.91)
Net loss per share of common stock, diluted	$ (0.79)	$ (0.69)	$ (2.37)	$ (1.91)
Weighted average shares outstanding, basic	38,620,751	38,197,929	38,567,331	37,816,345
Weighted average shares outstanding, diluted	38,620,751	38,197,929	38,567,331	37,816,345

Unaudited Consolidated Statem_2

Unaudited Consolidated Statements of Comprehensive Loss - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Statement of Comprehensive Income [Abstract]
Net loss	$ (30,594)	$ (26,244)	$ (91,317)	$ (72,068)
Unrealized gain (loss) on investments, net	75	4	(583)	(78)
Comprehensive loss	$ (30,519)	$ (26,240)	$ (91,900)	$ (72,146)

Unaudited Consolidated Statem_3

Unaudited Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Accumulated Deficit	Accumulated Other Comprehensive Income (Loss)
Beginning balance at Dec. 31, 2020	$ 236,548	$ 3	$ 486,197	$ (249,715)	$ 63
Beginning balance (shares) at Dec. 31, 2020		33,516,795
Issuance of common stock, net of issuance costs	131,330	$ 1	131,329
Issuance of common stock, net of issuance costs (shares)		4,590,164
Exercise of stock options	376		376
Exercise of stock options (shares)		52,243
Stock-based compensation expense	3,120		3,120
Unrealized gain (loss) on investments, net	(107)				(107)
Net loss	(21,512)			(21,512)
Ending balance at Mar. 31, 2021	349,755	$ 4	621,022	(271,227)	(44)
Ending balance (shares) at Mar. 31, 2021		38,159,202
Beginning balance at Dec. 31, 2020	$ 236,548	$ 3	486,197	(249,715)	63
Beginning balance (shares) at Dec. 31, 2020		33,516,795
Exercise of stock options (shares)	95,596
Unrealized gain (loss) on investments, net	$ (78)
Net loss	(72,068)
Ending balance at Sep. 30, 2021	306,270	$ 4	628,064	(321,783)	(15)
Ending balance (shares) at Sep. 30, 2021		38,220,444
Beginning balance at Mar. 31, 2021	349,755	$ 4	621,022	(271,227)	(44)
Beginning balance (shares) at Mar. 31, 2021		38,159,202
Exercise of stock options	204		204
Exercise of stock options (shares)		22,129
Stock-based compensation expense	3,219		3,219
Unrealized gain (loss) on investments, net	25				25
Net loss	(24,312)			(24,312)
Ending balance at Jun. 30, 2021	328,891	$ 4	624,445	(295,539)	(19)
Ending balance (shares) at Jun. 30, 2021		38,181,331
Exercise of stock options	433		433
Exercise of stock options (shares)		39,113
Stock-based compensation expense	3,186		3,186
Unrealized gain (loss) on investments, net	4				4
Net loss	(26,244)			(26,244)
Ending balance at Sep. 30, 2021	306,270	$ 4	628,064	(321,783)	(15)
Ending balance (shares) at Sep. 30, 2021		38,220,444
Beginning balance at Dec. 31, 2021	$ 281,477	$ 4	631,008	(349,522)	(13)
Beginning balance (shares) at Dec. 31, 2021	38,496,484	38,496,484
Exercise of stock options	$ 115		115
Exercise of stock options (shares)		49,861
Stock-based compensation expense	3,177		3,177
Unrealized gain (loss) on investments, net	(331)				(331)
Net loss	(29,122)			(29,122)
Ending balance at Mar. 31, 2022	255,316	$ 4	634,300	(378,644)	(344)
Ending balance (shares) at Mar. 31, 2022		38,546,345
Beginning balance at Dec. 31, 2021	$ 281,477	$ 4	631,008	(349,522)	(13)
Beginning balance (shares) at Dec. 31, 2021	38,496,484	38,496,484
Exercise of stock options (shares)	49,581
Unrealized gain (loss) on investments, net	$ (583)
Net loss	(91,317)
Ending balance at Sep. 30, 2022	$ 198,550	$ 4	639,981	(440,839)	(596)
Ending balance (shares) at Sep. 30, 2022	38,657,061	38,657,061
Beginning balance at Mar. 31, 2022	$ 255,316	$ 4	634,300	(378,644)	(344)
Beginning balance (shares) at Mar. 31, 2022		38,546,345
Issuance of common stock, net of issuance costs (shares)		10,498
Exercise of stock options	28		28
Exercise of stock options (shares)		42,073
Stock-based compensation expense	2,847		2,847
Unrealized gain (loss) on investments, net	(327)				(327)
Net loss	(31,601)			(31,601)
Ending balance at Jun. 30, 2022	226,263	$ 4	637,175	(410,245)	(671)
Ending balance (shares) at Jun. 30, 2022		38,598,916
Exercise of stock options	113		113
Exercise of stock options (shares)		58,145
Stock-based compensation expense	2,693		2,693
Unrealized gain (loss) on investments, net	75				75
Net loss	(30,594)			(30,594)
Ending balance at Sep. 30, 2022	$ 198,550	$ 4	$ 639,981	$ (440,839)	$ (596)
Ending balance (shares) at Sep. 30, 2022	38,657,061	38,657,061

Unaudited Consolidated Statem_4

Unaudited Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021
Operating activities
Net loss	$ (91,317)	$ (72,068)
Adjustments to reconcile net loss to cash used in operating activities:
Depreciation and amortization	2,300	1,976
Stock-based compensation expense	8,717	9,525
(Accretion) / Amortization on investments	(403)	626
Deferred tax liabilities	(293)	105
Changes in operating assets and liabilities:
Prepaid expenses and other current assets	2,618	(41)
Operating leases, net	2,445	(2,811)
Accounts payable	(637)	2,066
Accrued expenses and other liabilities	66	2,299
Cash used in operating activities	(76,504)	(58,323)
Investing activities
Purchases of equipment	(12,681)	(4,352)
Software development costs	(330)	(308)
Purchases of investments	(215,619)	(40,732)
Proceeds from sale or maturity of investments	136,488	140,622
Cash provided by (used in) investing activities	(92,142)	95,230
Financing activities
Proceeds from public offering of common stock, net of issuance costs	0	131,330
Proceeds from the exercise of stock options	256	1,013
Payment of deferred offering costs	(172)	(336)
Cash provided by financing activities	84	132,007
Net change in cash, cash equivalents, and restricted cash	(168,562)	168,914
Cash, cash equivalents, and restricted cash at beginning of year	223,720	94,738
Cash, cash equivalents, and restricted cash at end of period	55,158	263,652
Supplemental disclosure of noncash activities
Property and equipment additions in accounts payable and accrued expenses	1,973	481
Right-of-use assets obtained in exchange for operating lease liabilities	40,628	21,315
Operating cash flows used in operating leases	$ 14,704	$ 9,171

Organization and Description of

Organization and Description of Business	9 Months Ended
	Sep. 30, 2022
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization and Description of Business	1. Organizat ion and Description of Business TCR 2 Therapeutics Inc. (the Company) is a clinical-stage cell therapy company with a pipeline of novel T cell therapies for cancer patients suffering from solid tumors. The Company was incorporated under the laws of the State of Delaware on May 29, 2015 under the name TCR 2 , Inc. In November 2016, the Company changed its name to TCR 2 Therapeutics Inc. The Company’s principal operations are located in Cambridge, Massachusetts. Shelf registration statement On March 16, 2021, the Company filed an automatic shelf registration statement on Form S-3 (the Shelf), with the Securities and Exchange Commission (SEC), which covers the offering, issuance and sale of an indeterminate amount of the Company’s common stock, preferred stock, debt securities, warrants and/or units of any combination thereof. The Shelf was automatically effective when filed. On March 22, 2022, the Company amended the Shelf to cover the offering, issuance and sale of up to an aggregate of $ 300.0 million of the Company's common stock, preferred stock, debt securities, warrants and/or units of any combination thereof. T he amendment to the Shelf was declared effective by the SEC on March 23, 2022. The Company previously entered into a sales agreement with Jefferies LLC, as sales agent, to provide for the issuance and sale by the Company of up to $ 100.0 million of our common stock from time to time in “at-the-market” offerings under the Shelf, which we refe r to as the ATM Program. Equity offerings On January 22, 2021, the Company closed a public offering of its common stock pursuant to which it issued and sold 4,590,164 shares of its common stock at a price to the public of $ 30.50 per share. The aggregate net proceeds received by the Company from the offering were approximately $ 131.3 million after deducting $ 8.7 million relating to underwriting discounts and commissions and offering expenses.

Liquidity

Liquidity	9 Months Ended
	Sep. 30, 2022
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Liquidity	2. Liquidity The Company’s operations to date have focused on organization and staffing, business planning, raising capital, acquiring technology and assets, manufacturing, and conducting preclinical studies and clinical activities. The Company does not have any product candidates approved for sale and has not generated any revenue from product sales. The Company’s product candidates are subject to long development cycles and the Company may be unsuccessful in its efforts to develop, obtain regulatory approval for or market its product candidates. The Company is subject to a number of risks including, but not limited to, the need to obtain adequate additional funding for the ongoing and planned clinical development of its product candidates. Because of the numerous risks and uncertainties associated with pharmaceutical products and development, the Company is unable to accurately predict the timing or amount of funds required to complete development of its product candidates, and costs could exceed the Company’s expectations for a number of reasons, including reasons beyond the Company’s control. The Company is also subject to a number of other risks including possible failure of preclinical studies or clinical trials, the need to obtain marketing approval for its product candidates, the development of new technological innovations by competitors, the need to successfully commercialize and gain market acceptance of any of the Company’s products that are approved and uncertainty around intellectual property matters. If the Company does not successfully commercialize any of its products, it will be unable to generate product revenue or achieve profitability. The Company expects to continue to generate losses for the foreseeable future. The Company expects that its cash, cash equivalents and investments as of September 30, 2022 of $ 176.0 million will be sufficient to fund its operating expenses and capital expenditure requirements through at least 12 months from the date of issuance of these unaudited consolidated financial statements.

Summary of Significant Accounti

Summary of Significant Accounting Policies	9 Months Ended
	Sep. 30, 2022
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	3. Summary of Significant Accounting Policies Principles of consolidation and basis of presentation The unaudited consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (U.S. GAAP) for interim financial information and in accordance with Article 10 of Regulation S-X of the SEC, and reflect the financial position, results of operations and cash flows of the Company's business. Accordingly, they do not include all of the disclosures required by U.S. GAAP for a complete set of annual audited financial statements. All significant intercompany accounts and transactions are eliminated in consolidation. The unaudited consolidated financial statements include the accounts of the Company and its wholly owned subsidiaries. The accompanying financial information should be read in conjunction with the consolidated financial statements and notes thereto contained in the Company's Annual Report on Form 10-K filed with the SEC on March 22, 2022 for the year ended December 31, 2021 (the 2021 Form 10-K). In the opinion of the Company's management, all adjustments (consisting of normal and recurring adjustments) considered necessary for a fair statement of the results for the interim periods presented have been included. Use of estimates The preparation of the accompanying unaudited consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the unaudited consolidated financial statements and reported amounts of expenses during the reporting period. Significant estimates and assumptions reflected in these unaudited consolidated financial statements include, but are not limited to, the measurement of right-of-use assets and lease liabilities, accrued expenses, the fair value of the royalty transfer agreement obligations, and the fair value of stock-based compensation awards granted under the Company’s equity-based compensation plans. Due to the uncertainty of factors surrounding the estimates or judgments used in the preparation of the unaudited consolidated financial statements, actual results may materially vary from these estimates. Estimates and assumptions are periodically reviewed and the effects of revisions are reflected in the consolidated financial statements in the period they are determined to be necessary. Concentrations of credit risk and of manufacturing risk Financial instruments that potentially subject the Company to a concentration of credit risk consist of cash, cash equivalents and investments. The Company’s cash, cash equivalents and investments are held by financial institutions in the United States. Amounts on deposit may at times exceed federally insured limits. Management believes that the financial institutions are financially sound, and accordingly, minimal credit risk exists with respect to the financial institutions. As of September 30, 2022 , the Company has manufacturing arrangements with vendors for the supply of materials for use in preclinical and clinical studies. If the Company were to experience any disruptions in the vendors' ability or willingness to continue to provide manufacturing services, the Company may experience significant delays in its product development timelines and may incur substantial costs to secure alternative sources of manufacturing. Fair value of financial instruments As of September 30, 2022 and December 31, 2021 , the Company’s financial instruments consist of money market funds, U.S. Treasury securities, and corporate bonds and are included in investments. The carrying value of investments is the estimated fair value. Fair value is defined as the exchange price that would be received for an asset or paid to transfer a liability in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. Cash equivalents The Company considers all highly liquid investments purchased with an original maturity of three months or less to be cash equivalents. As of September 30, 2022 and December 31, 2021 , cash equivalents consisted of U.S treasuries, corporate bonds, and government-backed money market funds. Investments As of September 30, 2022 , all investments were classified as available-for-sale and were carried at their estimated fair value. We report available-for-sale investments at fair value at each balance sheet date, and include any unrealized holding gains and losses (the adjustment to fair value) in accumulated other comprehensive income (loss), a component of stockholders' equity. Realized gains and losses are determined using the specific-identification method, and are included in interest income, net in our consolidated statement of operations. The Company classifies its available-for-sale marketable securities as current or non-current based on each instrument’s underlying effective maturity date and for which the Company has the intent and ability to hold the investment for a period of greater than 12 months. Marketable securities with maturities of less than 12 months are classified as current and are included in investments in the consolidated balance sheets. Marketable securities with maturities greater than 12 months for which the Company has the intent and ability to hold the investment for greater than 12 months are classified as non-current and are included in investments, non-current in the consolidated balance sheets. Assets not placed in service Assets not placed in service includes direct costs related to the acquisition of property and equipment including leasehold improvements. Such costs are not depreciated until the asset is completed and placed into service. Impairment of long-lived assets Long-lived assets are reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable. Recoverability of assets to be held and used is measured by a comparison of the carrying amount of an asset to future undiscounted net cash flows expected to be generated. Impairment charges are recognized at the amount by which the carrying amount of an asset exceeds the fair value of the asset. Assets to be disposed of are reported at the lower of the carrying amount or the fair value less costs to sell. During the year ended December 31, 2021, the Company recognized impairment of long-lived assets in association with the wind down of its manufacturing operations in the United Kingdom. See Note 11, Restructuring. No impairments of long-lived assets for the three-month and nine-month periods ended September 30, 2022 were recognized. Restricted cash Cash accounts that are restricted as to withdrawal or usage are presented as restricted cash in the Company's balance sheets. Restricted cash includes amounts held as a security deposit in the form of a letter of credit for the Company’s leased facilities. Deferred offering costs The Company capitalizes costs that are directly associated with in-process equity financings until such financings are consummated at which time such costs are recorded against the gross proceeds of the offering. Should the in-process equity financing be abandoned, the deferred offering costs will be expensed immediately as a charge to operating expenses in the consolidated statements of operations. Stock-based compensation The Company measures stock-based awards at grant-date fair value and records compensation expense on a straight-line basis over the requisite service period, which is generally the vesting period of the respective award. The Company accounts for forfeitures as they occur. The Company issues share-based compensation awards with service-only and performance- and service- based criteria. For performance-based awards, share-based compensation is based on estimated performance until the performance measurement date. At the performance measurement date, share-based compensation is adjusted to actual performance. Estimating the fair value of stock options and warrants requires the input of subjective assumptions, including the expected life of the instrument and stock price volatility. The Company uses the Black-Scholes option pricing model to value its stock option awards and warrants. As a result, if factors change and management uses different assumptions, stock-based compensation expense could be materially different for future awards. The Company classifies stock-based compensation expense in its statements of operations in the same manner in which the award recipient’s payroll costs are classified or in which the award recipient’s service payments are classified. Leases At the inception of an arrangement, the Company determines whether the arrangement is or contains a lease based on the unique facts and circumstances present in the arrangement. Leases are classified at their commencement date, which is defined as the date on which the lessor makes the underlying asset available for use by the lessee, as either operating or finance leases based on the economic substance of the agreement. The Company recognizes lease right-of-use assets and related liabilities in its consolidated balance sheets for both operating and finance leases. Lease liabilities are measured at the lease commencement date as the present value of the future lease payments using the interest rate implicit in the lease, or the incremental borrowing rate if the rate implicit in the lease is not readily determinable. Lease right-of-use assets are measured as the lease liability plus initial direct costs and prepaid lease payments less expected lease incentives. The lease term is the non-cancelable period of the lease and includes options to extend or terminate the lease when it is reasonably certain that an option will be exercised. The Company recognizes operating lease costs in operating expenses in its consolidated statements of operations, inclusive of rent escalation provisions and rent holidays, on a straight-line basis over the respective lease term. Research and development expenses Research and development costs are expensed as incurred and consist primarily of funds paid for employee wages and funds paid to third parties for the provision of services for product candidate development, clinical and preclinical development and related supply and manufacturing costs, and regulatory compliance costs. At the end of the reporting period, the Company compares payments made to third-party service providers to the estimated progress toward completion of the research or development objectives. Such estimates are subject to change as additional information becomes available. Depending on the timing of payments to the service providers and the progress that the Company estimates has been made as a result of the service provided, the Company may record net prepaid or accrued expense relating to these costs. Upfront milestone payments made to third parties who perform research and development services on the Company’s behalf are expensed as services are rendered. Income taxes Income taxes are accounted for under the asset and liability method. Deferred tax assets and liabilities are recognized for the future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases and operating loss and tax credit carryforwards. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in income in the period that includes the enactment date. A reduction in the carrying value of the deferred tax assets is required when it is not more likely than not that such deferred tax assets are realizable. Net loss per share Basic and diluted net loss per common share is determined by dividing net loss attributable to common stockholders by the weighted-average shares of common stock outstanding during the period. In periods in which the Company reports a net loss attributable to common stockholders, diluted net loss per share attributable to common stockholders is the same as basic net loss per share attributable to common stockholders, since dilutive shares of common stock are not assumed to have been issued if their effect is anti-dilutive. Therefore, the weighted-average shares used to calculate both basic and diluted loss per share are the same. The following potentially dilutive securities, on an as converted basis, have been excluded from the computation of diluted weighted-average shares outstanding as of September 30, 2022 and 2021, as they would be antidilutive: As of September 30, 2022 2021 Stock options outstanding 5,588,987 5,495,365 Common stock warrants 203,676 203,676 Restricted stock units 1,066,992 - Employee stock purchase plan 15,971 4,011 Total 6,875,626 5,703,052 Comprehensive loss Comprehensive loss is defined as the change in equity of a business enterprise during a period from transactions and other events and circumstances from non-owner sources (which excludes investments from owners). The Company’s only element of other comprehensive loss is unrealized gains and losses on investments. Common stock Each share of common stock entitles the holder to one vote on all matters submitted to a vote of the Company’s stockholders. Preferred stock The Board of Directors or any authorized committee thereof is expressly authorized, to the fullest extent permitted by law, to provide by resolution or resolutions for, out of the unissued shares of Undesignated Preferred Stock, the issuance of the shares of Undesignated Preferred Stock in one or more series of such stock, and by filing a certificate of designations pursuant to applicable law of the State of Delaware, to establish or change from time to time the number of shares of each such series, and to fix the designations, powers, including voting powers, full or limited, or no voting powers, preferences and the relative, participating, optional or other special rights of the shares of each series and any qualifications, limitations and restrictions thereof. As of September 30, 2022 , there are no preferred shares issued. Reconciliation of cash, cash equivalents and restricted cash as presented in the statements of cash flows The following table provides a reconciliation of cash, cash equivalents and restricted cash reported within the unaudited consolidated balance sheets to the total of the same such amounts shown in the unaudited consolidated statements of cash flows for the nine months ended September 30, 2022 and 2021. As of September 30, 2022 2021 Cash and cash equivalents $ 54,006 $ 262,497 Restricted cash 1,152 1,155 Cash, cash equivalents and restricted cash shown in the statements of cash flows $ 55,158 $ 263,652 Segment information Operating segments are defined as components of an enterprise about which separate discrete information is available for evaluation by the chief operating decision maker, or decision-making group, in deciding how to allocate resources and in assessing performance. The Company views its operations and manages its business in one consolidated operating segment. JOBS Act accounting election The Company is an emerging growth company, as defined in the Jumpstart Our Business Startups Act of 2012 (the JOBS Act). Under the JOBS Act, emerging growth companies can delay adopting new or revised accounting standards issued subsequent to the enactment of the JOBS Act until such time as those standards apply to private companies. The Company has elected to use this extended transition period for complying with new or revised accounting standards that have different effective dates for public and private companies until the earlier of the date that it is (i) no longer an emerging growth company or (ii) affirmatively and irrevocably opt out of the extended transition period provided in the JOBS Act. As a result, these consolidated financial statements may not be comparable to companies that comply with the new or revised accounting pronouncements as of public company effective dates.

Investments and Fair Value Meas

Investments and Fair Value Measurements	9 Months Ended
	Sep. 30, 2022
Fair Value And Debt Securities Available For Sale [Abstract]
Investments and Fair Value Measurements	4. Investments and Fair Value Measurements As of September 30, 2022, investments were comprised of the following: Amortized Unrealized Unrealized Fair U.S. Treasury securities $ 122,576 $ - $ ( 596 ) $ 121,980 As of December 31, 2021, investments were comprised of the following: Amortized Unrealized Unrealized Fair Corporate bonds $ 33,048 $ - $ ( 11 ) $ 33,037 U.S. Treasury securities 9,994 - ( 2 ) 9,992 Total $ 43,042 $ - $ ( 13 ) $ 43,029 Investments in corporate bonds are in accordance with our corporate investment policy which requires investment in Investment Grade Bonds as defined by the three major bond-ratings agency. The amortized cost and estimated fair value of marketable securities, by contractual maturity: September 30, 2022 Amortized Fair Value Due within one year or less $ 122,576 $ 121,980 December 31, 2021 Amortized Fair Value Due within one year or less $ 43,042 $ 43,029 The Company follows FASB’s accounting guidance on fair value measurements for financial assets and liabilities measured on a recurring basis. Fair value is defined as the price at which an asset could be exchanged in a current transaction between knowledgeable, willing parties. Where available, fair value is based on observable market prices, or parameters derived from such prices. Where observable prices or inputs are not available, valuation models are applied. This hierarchy requires the use of observable market data when available and to minimize the use of unobservable inputs when determining fair value. These valuation techniques involve some level of management estimation and judgment. The degree of management estimation and judgment is dependent on the price transparency for the instruments, or market, and the instruments’ complexity. The guidance requires fair value measurements to be classified and disclosed in one of the following three categories: Level 1—Quoted prices (unadjusted in active markets for identical assets or liabilities) Level 2—Inputs other than quoted prices in active markets that are observable either directly or indirectly Level 3—Unobservable inputs in which there is little or no market data, which require the Company to develop its own assumptions As of September 30, 2022, the Company has classified assets measured at fair value on a recurring basis as follows: Fair Value Measurement Based on Amortized Quoted Significant Significant Cost Fair Value (Level 1) (Level 2) (Level 3) Cash equivalents (1) $ 51,693 $ 51,693 $ 51,693 $ - $ - U.S. Treasury securities 122,576 121,980 - 121,980 - Total $ 174,269 $ 173,673 $ 51,693 $ 121,980 $ - As of December 31, 2021, the Company has classified assets measured at fair value on a recurring basis as follows: Fair Value Measurement Based on Amortized Quoted Significant Significant Cost Fair Value (Level 1) (Level 2) (Level 3) Cash equivalents (1) $ 219,162 $ 219,162 $ 219,162 $ - $ - Corporate bonds 33,048 33,037 - 33,037 - U.S. Treasury securities 9,994 9,992 - 9,992 - Total $ 262,204 $ 262,191 $ 219,162 $ 43,029 $ - (1) Includes cash sweep accounts, U.S. Treasury money market mutual fund, bank certificates of deposit, U.S. Treasury bills and corporate bonds that have a maturity of three months or less from the original acquisition da te.

Property and Equipment

Property and Equipment	9 Months Ended
	Sep. 30, 2022
Property, Plant and Equipment [Abstract]
Property and Equipment	5. Property and Equipment Property and equipment, net, consisted of: As of September 30, 2022 December 31, 2021 Laboratory equipment $ 12,013 $ 13,115 Computer hardware and equipment - 54 Furniture and fixtures 326 376 Leasehold improvements 477 551 Assets not placed in service 22,360 7,592 35,176 21,688 Less: accumulated depreciation ( 6,093 ) ( 4,613 ) $ 29,083 $ 17,075 Depreciation expense was $ 2.0 million and $ 1.1 million for the nine months ended September 30, 2022 and 2021 , respectively

Accrued Expenses and Other Curr

Accrued Expenses and Other Current Liabilities	9 Months Ended
	Sep. 30, 2022
Payables and Accruals [Abstract]
Accrued Expenses and Other Current Liabilities	6. Accrued Expenses and Other Current Liabilities Accrued expenses and other current liabilities consisted of: As of September 30, 2022 December 31, 2021 Employee compensation and related benefits $ 4,511 $ 4,631 Professional fees 660 413 Contract manufacturing organization fees 1,055 1,261 Contract research organization fees 5,218 2,810 Property received not yet invoiced 1,097 748 Accrued restructuring charges - 2,401 Other 644 830 $ 13,185 $ 13,094

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2022
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	7. Commitments and Contingencies Litigation The Company is not currently party to any material legal proceedings. At each reporting date, the Company evaluates whether or not a potential loss amount or a potential range of loss is probable and reasonably estimable under the provisions of the authoritative guidance that addresses accounting for contingencies. The Company expenses as incurred the costs related to such legal proceedings. Royalty transfer agreement In connection with the sale of Series A redeemable convertible preferred stock, certain investors are entitled to receive, in the aggregate, a royalty from the Company equal to one percent of (i) all global net sales of any Company products and (ii) any license income on intellectual property that was in existence at the time of the Series A preferred stock financing. The Company has elected to account for this liability at fair value with changes recognized in the statements of operations. Given the early-stage nature of the underlying technology and inherent risks associated with obtaining regulatory approval and achieving commercialization, the Company ascribed no value to the royalty agreement at inception and as of September 30, 2022 and December 31, 2021 . The Company currently does no t have any net sales or license income and as a result has paid no royalties under this obligation for the three and nine months ended September 30, 2022 and 2021 no r has the Company accrued any liability as of September 30, 2022 or December 31, 2021 .

Leases

Leases	9 Months Ended
	Sep. 30, 2022
Leases [Abstract]
Leases	8. Leases The Company leases all of its offices and facilities under operating leases. The Company has entered into various non-cancellable lease arrangements for facilities expiring at various times through 2036. Certain of these arrangements have free rent periods or escalating rent payment provisions. None of our leases include residual value guarantees. Fixed fees for use of property or equipment and other services are included in the right-of-use assets and lease liabilities. Rent expense is recognized on a straight-line basis for total rent over the lease period. Variable service costs are included in the lease expense as incurred. The Company is generally obligated for the cost of property taxes, insurance, common area maintenance, and other administrative fees relating to its leases, which are considered variable lease costs and are expensed as incurred. In addition, the Company enters into contracts that have different service obligations. These contracts are considered multiple-element service contracts. When leases are embedded in multiple-element service contracts, all contract services are accounted for as a single lease component since the Company elected the practical expedient to not separate lease components and non-lease components. Operating leases Office space and lab facility, Cambridge, Massachusetts In March 2018, the Company entered into a lease for office and laboratory facilities that expires in July 2025 . Under the terms of the lease, the Company placed a $ 0.3 million letter of credit into a restricted cash account as security for the facility. Office space, Cambridge, Massachusetts In September 2019, the Company entered into a lease for office facilities that expires in August 2024 . Under the terms of the lease, the Company placed a $ 0.1 million letter of credit into a restricted cash account as security for the facility. Lab facility, Cambridge Massachusetts In November 2020, the Company entered into a lease for office and laboratory facilities that expires in January 2024 . Under the terms of the lease, the Company placed a $ 0.2 million letter of credit into a restricted cash account as security for the facility. Manufacturing facility, Waltham, Massachusetts In November 2020, the Company entered into a manufacturing agreement with ElevateBio LLC (ElevateBio) which includes identified space dedicated to the Company. The Company determined that the agreement contained an embedded lease. The lease began in February 2021 when the Company obtained control of the dedicated manufacturing space and was for a contractual period ended July 2022. In February 2022, the Company executed an agreement that expanded its partnership with ElevateBio by obtaining a second GMP manufacturing suite at ElevateBio BaseCamp in Waltham, Massachusetts through December 2023, and also updated terms in the original agreement including extending the contractual period through December 2023. As a result of this agreement, the Company recorded additional right-of-use assets and operating lease liabilities of approximately $ 28.8 million to reflect this new agreement during the period ending March 31, 2022. Manufacturing facility, Rockville, Maryland In March 2021, the Company entered into a lease for a new manufacturing facility for an initial term of 15 years through June 2036 . The Company also has an option to extend the term of the lease for two consecutive terms of five years each. The Company placed a $ 0.6 million letter of credit into a restricted cash account as security for the facility. During the second quarter of 2022, our right-of-use asset and associated lease liabilities related to the Rockville, Maryland facility increased by $ 11.8 million due to a change in expected reimbursements. Right-of-use assets and lease liabilities: September 30, December 31, Assets: Right-of-use assets, operating leases $ 57,704 $ 28,283 Liabilities Operating lease liabilities $ 20,545 $ 3,367 Operating lease liabilities, non-current 37,684 22,996 Total lease liabilities $ 58,229 $ 26,363 The components of the lease costs for the nine months ended September 30, 2022 and 2021, were as follows: September 30, September 30, Operating lease costs $ 16,545 $ 5,579 Short-term lease costs 549 395 Variable lease costs 4,846 3,130 Total lease costs $ 21,940 $ 9,104 Weighted average remaining lease term and discount rate as of September 30, 2022 were as follows: September 30, Weighted-average remaining lease term (in years) Operating leases 7.5 Weighted-average discount rate: Operating leases 14.1 % The following table presents future minimum lease payments under operating leases as of September 30, 2022: September 30, 2022 2022 $ 6,816 2023 26,864 2024 6,351 2025 5,255 2026 4,327 Thereafter 48,144 Total minimum payments required 97,757 Less amounts representing imputed interest ( 39,528 ) Present value of lease liabilities $ 58,229

Stock-based Compensation

Stock-based Compensation	9 Months Ended
	Sep. 30, 2022
Share-Based Payment Arrangement [Abstract]
Stock-based Compensation	9. Stock-based Compensation 2018 Stock Option and Incentive Plan In February 2019, the Company’s Board of Directors and stockholders approved the 2018 Stock Option and Incentive Plan (the 2018 Plan), which replaced the 2015 Stock Option and Grant Plan (the 2015 Plan). The shares under the 2015 Plan which were not issued were rolled into the 2018 Plan. The 2018 Plan provides for the grant of incentive stock options, non-statutory stock options, restricted stock awards, restricted stock units (RSUs), stock appreciation rights and other stock-based awards. The Company’s officers, employees, directors, and other key persons (including consultants) are eligible to receive awards under the 2018 Plan. The maximum number of authorized shares to be issued under the 2018 Plan is 8,934,465 shares of common stock. The number of shares of common stock reserved for issuance under the 2018 Plan shall be cumulatively increased on January 1, 2019 and each January 1 thereafter by 4 % of the total number of shares of common stock outstanding on December 31 of the preceding calendar year or a lesser number of shares determined by the Company's Board of Directors. The amount, terms of grants, and exercisability provisions are determined and set by the Compensation Committee of the Company’s Board of Directors. The term of the options may be up to 10 years , and options are exercisable in cash or as otherwise determined by the Board of Directors. As of September 30, 2022 , there were 2,045,061 shares of common stock available for future issuance under the 2018 Plan. Generally, options vest over a four-year period and RSUs vest over a two- or three-year period. 2022 Inducement Plan On February 11, 2022, our Board of Directors approved the TCR 2 Therapeutics Inc. 2022 Inducement Plan (Inducement Plan) pursuant to Listing Rule 5635(c)(4) of the corporate governance rules of the NASDAQ Stock Market, and reserved 1,400,000 s hares of our Common Stock for issuance employees of the Company under the Inducement Plan. The Inducement Plan provides for the grant of non-qualified stock options, stock appreciation rights, restricted stock units, restricted stock awards, unrestricted stock awards, and dividend equivalent rights. The purpose of the Inducement Plan is to encourage and enable the Company to grant equity awards to induce highly qualified prospective officers and employees to accept employment and provide them a proprietary interest in the Company. The maximum number of authorized shares to be issued under the Inducement Plan is 1,400,000 shares of com mon stock. The amount, terms of grants, and exercisability provisions are determined and set by the Compensation Committee of the Company’s Board of Directors. The term of the options may be up to 10 years , and options are exercisable in cash or as otherwise determined by the Board of Directors. As of September 30, 2022 , there were 876,026 shares of common stock available for future issuance under the Inducement Plan. Generally, options vest over a four-year period. No RSUs have been issued from the Inducement Plan. The Company recorded stock-based compensation expense in the following expense categories of its accompanying unaudited consolidated statements of operations for the three and nine months ended September 30, 2022 and 2021: Three Months Ended September 30, Nine Months Ended September 30, 2022 2021 2022 2021 Research and development $ 1,105 $ 1,336 $ 3,687 $ 4,147 General and administrative 1,588 1,850 5,030 5,378 $ 2,693 $ 3,186 $ 8,717 $ 9,525 Stock options During the nine months ended September 30, 2021 , there were 803,103 grants of stock options, 223,491 options forfeited, and 95,596 options exercised. The following table summarizes the activity related to stock option grants to employees and non-employees for the nine months ended September 30, 2022: Shares Weighted Weighted Balance as of December 31, 2021 6,181,335 $ 13.32 6.1 Granted 778,502 3.13 Exercised ( 49,581 ) 0.74 Forfeited ( 1,329,286 ) 13.08 Balance as of September 30, 2022 5,580,970 $ 12.08 7.7 Exercisable as of September 30, 2022 2,738,500 13.48 6.4 Vested and expected to vest as of September 30, 2022 5,580,970 $ 12.08 As of September 30, 2022 , there was $ 18.1 million in unrecognized compensation cost that is expected to be recognized over an estimated weighted-average amortization period of 2.2 years. The fair value of options is estimated using the Black-Scholes option pricing model, which takes into account inputs such as the exercise price, the value of the underlying common stock at the grant date, expected term, expected volatility, risk-free interest rate and dividend yield. The fair value of each grant of options for the nine months ended September 30, 2022 and 2021 was determined using the methods and assumptions discussed below: ▪ The expected term of employee options is determined using the “simplified” method, as prescribed in the SEC Staff Accounting Bulletin (SAB) No. 107, whereby the expected life equals the arithmetic average of the vesting term and the original contractual term of the option due to the Company’s lack of sufficient historical data. The expected term of non-employee options is equal to the contractual term. ▪ The expected volatility was based on the historical stock volatility of several comparable publicly traded companies over a period of time equal to the expected term of the options, as we do not have sufficient trading history to use the volatility of our own common stock. ▪ The estimated annual dividend yield is 0 % because the Company has not historically paid and does not expect for the foreseeable future to pay, a dividend on its common stock. ▪ The Company is traded on the Nasdaq Global Select Market. Fair value of the underlying common stock is determined by the stock price quoted on Nasdaq. The grant date fair value of all option grants was estimated at the time of grant using the Black-Scholes option-pricing model using the following weighted-average assumptions: Nine Months Ended September 30, 2022 2021 Risk-free interest rate 2.6 % 0.9 % Expected term (in years) 6.1 6.1 Expected volatility 72.0 % 72.6 % Annual dividend yield 0 % 0 % Fair value of common stock $ 1.96 $ 11.61 Restricted stock units During the nine months ended September 30, 2021, the Company granted no RSUs to employees. Restricted Stock Units Weighted Average Price Per Share Balance as of December 31, 2021 66,000 $ 4.80 Granted 1,023,992 3.24 Vested ( 1,907 ) 4.80 Forfeited ( 21,093 ) 4.12 Balance as of September 30, 2022 1,066,992 $ 3.32 During the quarter ended September 30, 2022, the Company granted 373,255 performance-based RSUs (PRSUs). Performance is based upon attaining specified operational metrics. The performance criteria will be measured at December 31, 2022 and March 31, 2023. The PRSUs also have service-based vesting criteria for two years after the measurement date. As of September 30, 2022, there was $ 3.4 million of unrecognized compensation cost related to unvested employee RSUs. This amount is expected to be recognized over a weighted-average period of 1.9 years. Warrants As of September 30, 2022 and December 31, 2021 , there were 203,676 warrants outstanding. During the nine months ended September 30, 2022 and 2021 , the Company granted no warrants, there were no forfeitures, or exercises. Employee stock purchase plan (ESPP) In February 2019, the Company’s Board of Directors adopted and the Company’s stockholders approved the 2018 Employee Stock Purchase Plan (2018 ESPP). The 2018 ESPP enables eligible employees to purchase shares of the Company's common stock at the end of each six-month offering period at a price equal to 85 % of the fair market value of the shares on the first business day or the last business day of the offering period, whichever is lower. Eligible employees generally included all employees. Offering periods begin on the first trading day of September and March of each year and end on the last trading day in February and August of each year. Share purchases are funded through payroll deductions of up to 15 % of an employee’s eligible compensation for each payroll period, or $ 25 each calendar year. During the nine months ended September 30, 2022 and 2021, there w ere 98,591 sha res and 17,889 share s issued under the 2018 ESPP, respectively.

Related party transactions

Related party transactions	9 Months Ended
	Sep. 30, 2022
Related Party Transactions [Abstract]
Related party transactions	10. Related-party transactions Manufacturing agreement During November 2020, the Company entered into a manufacturing partnership with ElevateBio, which was amended in February 2022. Dr. Ansbert Gadicke is a member of the board of directors at the Company and ElevateBio. The agreement is to establish a manufacturing partnership with ElevateBio for production of the Company’s clinical trial products. During the nine months ended September 30, 2022, the Company has incurred $ 14.6 million i n expenses and has incurred additional costs of $ 0.1 million for equipment owned by the Company for use by ElevateBio. During the nine months ended September 30, 2021, the Company incurred $ 0.9 million in expenses and incurred additional costs of $ 0.3 million for equipment owned by the Company for use by ElevateBio.

Restructuring

Restructuring	9 Months Ended
	Sep. 30, 2022
Restructuring and Related Activities [Abstract]
Restructuring	11. Restructuring During December 2021, the Company decided to wind down its operations in the United Kingdom and consolidated manufacturing operations in the United States. The Company completed the restructuring during the second quarter of 2022. Restructuring expenses During the nine months ended September 30, 2021, the Company did not incur any restructuring costs . In December 2021, the Company elected to cease manufacturing operations at its Catapult facility. As a result, the Company recognized a $ 1.5 million variable lease cost as of December 31, 2021 reflecting its estimated obligation for the 12-month termination period associated with the Catapult lease agreement, as well as other restructuring related expenses incurred as a result of the decision to cease manufacturing operations at Catapult. During the nine months ended September 30, 2022, the Company incurred the following expenses associated with the restructuring which are included in research and development expenses on the statements of operations. Nine Months Ended September 30, 2022 Severance and Related Costs Lease and Other costs Asset Impairment Costs Total Expenses $ 306 $ 228 $ - $ 534 Accrued restructuring expenses Balances related to this restructuring included in accrued expenses on the balance sheet are as follows: Accrued Expenses Severance and Related Costs Lease and Other costs Total Balance as of January 1, 2021 $ - $ - $ - Expenses 885 2,217 3,102 Cash payments ( 701 ) - ( 701 ) Balance as of December 31, 2021 184 2,217 2,401 Expenses 306 285 591 Adjustment of expenses - ( 57 ) ( 57 ) Cash payments ( 490 ) ( 2,445 ) ( 2,935 ) Balance as of September 30, 2022 $ - $ - $ -

Subsequent event

Subsequent event	9 Months Ended
	Sep. 30, 2022
Subsequent Events [Abstract]
Subsequent event	12. Subsequent Event On October 19, 2022, the Company filed a Schedule TO with the SEC in connection with a tender offer to eligible employees of the Company to exchange stock options granted under the 2018 Plan with an exercise price over $ 10.00 per share for a reduced number of restricted stock units with time-based vesting requirements as determined on an approximate value-for-value basis. There were 2,574,615 eligible stock options at the time of the offering. Employees may, but are not required to participate. If all eligible stock options are offered for exchange, the Company expects it could issue 756,679 restricted stock units. Any new restricted stock units granted in connection with the tender offer shall be governed by the 2018 Plan. The offer is expected to close during the fourth quarter of 2022.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2022
Accounting Policies [Abstract]
Principles of consolidation and basis of presentation	Principles of consolidation and basis of presentation The unaudited consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (U.S. GAAP) for interim financial information and in accordance with Article 10 of Regulation S-X of the SEC, and reflect the financial position, results of operations and cash flows of the Company's business. Accordingly, they do not include all of the disclosures required by U.S. GAAP for a complete set of annual audited financial statements. All significant intercompany accounts and transactions are eliminated in consolidation. The unaudited consolidated financial statements include the accounts of the Company and its wholly owned subsidiaries. The accompanying financial information should be read in conjunction with the consolidated financial statements and notes thereto contained in the Company's Annual Report on Form 10-K filed with the SEC on March 22, 2022 for the year ended December 31, 2021 (the 2021 Form 10-K). In the opinion of the Company's management, all adjustments (consisting of normal and recurring adjustments) considered necessary for a fair statement of the results for the interim periods presented have been included.
Use of estimates	Use of estimates The preparation of the accompanying unaudited consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the unaudited consolidated financial statements and reported amounts of expenses during the reporting period. Significant estimates and assumptions reflected in these unaudited consolidated financial statements include, but are not limited to, the measurement of right-of-use assets and lease liabilities, accrued expenses, the fair value of the royalty transfer agreement obligations, and the fair value of stock-based compensation awards granted under the Company’s equity-based compensation plans. Due to the uncertainty of factors surrounding the estimates or judgments used in the preparation of the unaudited consolidated financial statements, actual results may materially vary from these estimates. Estimates and assumptions are periodically reviewed and the effects of revisions are reflected in the consolidated financial statements in the period they are determined to be necessary.
Concentrations of credit risk and of manufacturing risk	Concentrations of credit risk and of manufacturing risk Financial instruments that potentially subject the Company to a concentration of credit risk consist of cash, cash equivalents and investments. The Company’s cash, cash equivalents and investments are held by financial institutions in the United States. Amounts on deposit may at times exceed federally insured limits. Management believes that the financial institutions are financially sound, and accordingly, minimal credit risk exists with respect to the financial institutions. As of September 30, 2022 , the Company has manufacturing arrangements with vendors for the supply of materials for use in preclinical and clinical studies. If the Company were to experience any disruptions in the vendors' ability or willingness to continue to provide manufacturing services, the Company may experience significant delays in its product development timelines and may incur substantial costs to secure alternative sources of manufacturing.
Fair value of financial instruments	Fair value of financial instruments As of September 30, 2022 and December 31, 2021 , the Company’s financial instruments consist of money market funds, U.S. Treasury securities, and corporate bonds and are included in investments. The carrying value of investments is the estimated fair value. Fair value is defined as the exchange price that would be received for an asset or paid to transfer a liability in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date.
Cash equivalents	Cash equivalents The Company considers all highly liquid investments purchased with an original maturity of three months or less to be cash equivalents. As of September 30, 2022 and December 31, 2021 , cash equivalents consisted of U.S treasuries, corporate bonds, and government-backed money market funds.
Investments	Investments As of September 30, 2022 , all investments were classified as available-for-sale and were carried at their estimated fair value. We report available-for-sale investments at fair value at each balance sheet date, and include any unrealized holding gains and losses (the adjustment to fair value) in accumulated other comprehensive income (loss), a component of stockholders' equity. Realized gains and losses are determined using the specific-identification method, and are included in interest income, net in our consolidated statement of operations. The Company classifies its available-for-sale marketable securities as current or non-current based on each instrument’s underlying effective maturity date and for which the Company has the intent and ability to hold the investment for a period of greater than 12 months. Marketable securities with maturities of less than 12 months are classified as current and are included in investments in the consolidated balance sheets. Marketable securities with maturities greater than 12 months for which the Company has the intent and ability to hold the investment for greater than 12 months are classified as non-current and are included in investments, non-current in the consolidated balance sheets.
Assets not placed in service	Assets not placed in service Assets not placed in service includes direct costs related to the acquisition of property and equipment including leasehold improvements. Such costs are not depreciated until the asset is completed and placed into service.
Impairment of long-lived assets	Impairment of long-lived assets Long-lived assets are reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable. Recoverability of assets to be held and used is measured by a comparison of the carrying amount of an asset to future undiscounted net cash flows expected to be generated. Impairment charges are recognized at the amount by which the carrying amount of an asset exceeds the fair value of the asset. Assets to be disposed of are reported at the lower of the carrying amount or the fair value less costs to sell. During the year ended December 31, 2021, the Company recognized impairment of long-lived assets in association with the wind down of its manufacturing operations in the United Kingdom. See Note 11, Restructuring. No impairments of long-lived assets for the three-month and nine-month periods ended September 30, 2022 were recognized.
Restricted cash	Restricted cash Cash accounts that are restricted as to withdrawal or usage are presented as restricted cash in the Company's balance sheets. Restricted cash includes amounts held as a security deposit in the form of a letter of credit for the Company’s leased facilities.
Deferred offering costs	Deferred offering costs The Company capitalizes costs that are directly associated with in-process equity financings until such financings are consummated at which time such costs are recorded against the gross proceeds of the offering. Should the in-process equity financing be abandoned, the deferred offering costs will be expensed immediately as a charge to operating expenses in the consolidated statements of operations.
Stock-based compensation	Stock-based compensation The Company measures stock-based awards at grant-date fair value and records compensation expense on a straight-line basis over the requisite service period, which is generally the vesting period of the respective award. The Company accounts for forfeitures as they occur. The Company issues share-based compensation awards with service-only and performance- and service- based criteria. For performance-based awards, share-based compensation is based on estimated performance until the performance measurement date. At the performance measurement date, share-based compensation is adjusted to actual performance. Estimating the fair value of stock options and warrants requires the input of subjective assumptions, including the expected life of the instrument and stock price volatility. The Company uses the Black-Scholes option pricing model to value its stock option awards and warrants. As a result, if factors change and management uses different assumptions, stock-based compensation expense could be materially different for future awards. The Company classifies stock-based compensation expense in its statements of operations in the same manner in which the award recipient’s payroll costs are classified or in which the award recipient’s service payments are classified.
Leases	Leases At the inception of an arrangement, the Company determines whether the arrangement is or contains a lease based on the unique facts and circumstances present in the arrangement. Leases are classified at their commencement date, which is defined as the date on which the lessor makes the underlying asset available for use by the lessee, as either operating or finance leases based on the economic substance of the agreement. The Company recognizes lease right-of-use assets and related liabilities in its consolidated balance sheets for both operating and finance leases. Lease liabilities are measured at the lease commencement date as the present value of the future lease payments using the interest rate implicit in the lease, or the incremental borrowing rate if the rate implicit in the lease is not readily determinable. Lease right-of-use assets are measured as the lease liability plus initial direct costs and prepaid lease payments less expected lease incentives. The lease term is the non-cancelable period of the lease and includes options to extend or terminate the lease when it is reasonably certain that an option will be exercised. The Company recognizes operating lease costs in operating expenses in its consolidated statements of operations, inclusive of rent escalation provisions and rent holidays, on a straight-line basis over the respective lease term.
Research and development expenses	Research and development expenses Research and development costs are expensed as incurred and consist primarily of funds paid for employee wages and funds paid to third parties for the provision of services for product candidate development, clinical and preclinical development and related supply and manufacturing costs, and regulatory compliance costs. At the end of the reporting period, the Company compares payments made to third-party service providers to the estimated progress toward completion of the research or development objectives. Such estimates are subject to change as additional information becomes available. Depending on the timing of payments to the service providers and the progress that the Company estimates has been made as a result of the service provided, the Company may record net prepaid or accrued expense relating to these costs. Upfront milestone payments made to third parties who perform research and development services on the Company’s behalf are expensed as services are rendered.
Income taxes	Income taxes Income taxes are accounted for under the asset and liability method. Deferred tax assets and liabilities are recognized for the future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases and operating loss and tax credit carryforwards. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in income in the period that includes the enactment date. A reduction in the carrying value of the deferred tax assets is required when it is not more likely than not that such deferred tax assets are realizable.
Net loss per share	Net loss per share Basic and diluted net loss per common share is determined by dividing net loss attributable to common stockholders by the weighted-average shares of common stock outstanding during the period. In periods in which the Company reports a net loss attributable to common stockholders, diluted net loss per share attributable to common stockholders is the same as basic net loss per share attributable to common stockholders, since dilutive shares of common stock are not assumed to have been issued if their effect is anti-dilutive. Therefore, the weighted-average shares used to calculate both basic and diluted loss per share are the same. The following potentially dilutive securities, on an as converted basis, have been excluded from the computation of diluted weighted-average shares outstanding as of September 30, 2022 and 2021, as they would be antidilutive: As of September 30, 2022 2021 Stock options outstanding 5,588,987 5,495,365 Common stock warrants 203,676 203,676 Restricted stock units 1,066,992 - Employee stock purchase plan 15,971 4,011 Total 6,875,626 5,703,052
Comprehensive loss	Comprehensive loss Comprehensive loss is defined as the change in equity of a business enterprise during a period from transactions and other events and circumstances from non-owner sources (which excludes investments from owners). The Company’s only element of other comprehensive loss is unrealized gains and losses on investments.
Common stock	Common stock Each share of common stock entitles the holder to one vote on all matters submitted to a vote of the Company’s stockholders.
Preferred stock	Preferred stock The Board of Directors or any authorized committee thereof is expressly authorized, to the fullest extent permitted by law, to provide by resolution or resolutions for, out of the unissued shares of Undesignated Preferred Stock, the issuance of the shares of Undesignated Preferred Stock in one or more series of such stock, and by filing a certificate of designations pursuant to applicable law of the State of Delaware, to establish or change from time to time the number of shares of each such series, and to fix the designations, powers, including voting powers, full or limited, or no voting powers, preferences and the relative, participating, optional or other special rights of the shares of each series and any qualifications, limitations and restrictions thereof. As of September 30, 2022 , there are no preferred shares issued.
Reconciliation of cash, cash equivalents and restricted cash as presented in the statements of cash flows	Reconciliation of cash, cash equivalents and restricted cash as presented in the statements of cash flows The following table provides a reconciliation of cash, cash equivalents and restricted cash reported within the unaudited consolidated balance sheets to the total of the same such amounts shown in the unaudited consolidated statements of cash flows for the nine months ended September 30, 2022 and 2021. As of September 30, 2022 2021 Cash and cash equivalents $ 54,006 $ 262,497 Restricted cash 1,152 1,155 Cash, cash equivalents and restricted cash shown in the statements of cash flows $ 55,158 $ 263,652
Segment information	Segment information Operating segments are defined as components of an enterprise about which separate discrete information is available for evaluation by the chief operating decision maker, or decision-making group, in deciding how to allocate resources and in assessing performance. The Company views its operations and manages its business in one consolidated operating segment.
JOBS Act accounting election	JOBS Act accounting election The Company is an emerging growth company, as defined in the Jumpstart Our Business Startups Act of 2012 (the JOBS Act). Under the JOBS Act, emerging growth companies can delay adopting new or revised accounting standards issued subsequent to the enactment of the JOBS Act until such time as those standards apply to private companies. The Company has elected to use this extended transition period for complying with new or revised accounting standards that have different effective dates for public and private companies until the earlier of the date that it is (i) no longer an emerging growth company or (ii) affirmatively and irrevocably opt out of the extended transition period provided in the JOBS Act. As a result, these consolidated financial statements may not be comparable to companies that comply with the new or revised accounting pronouncements as of public company effective dates.

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Tables)	9 Months Ended
	Sep. 30, 2022
Schedule of Dilutive Securities Not Included in Diluted Per Share Calculations	The following potentially dilutive securities, on an as converted basis, have been excluded from the computation of diluted weighted-average shares outstanding as of September 30, 2022 and 2021, as they would be antidilutive: As of September 30, 2022 2021 Stock options outstanding 5,588,987 5,495,365 Common stock warrants 203,676 203,676 Restricted stock units 1,066,992 - Employee stock purchase plan 15,971 4,011 Total 6,875,626 5,703,052
Schedule of Restricted Cash and Cash Equivalents	The following table provides a reconciliation of cash, cash equivalents and restricted cash reported within the unaudited consolidated balance sheets to the total of the same such amounts shown in the unaudited consolidated statements of cash flows for the nine months ended September 30, 2022 and 2021. As of September 30, 2022 2021 Cash and cash equivalents $ 54,006 $ 262,497 Restricted cash 1,152 1,155 Cash, cash equivalents and restricted cash shown in the statements of cash flows $ 55,158 $ 263,652

Investments and Fair Value Me_2

Investments and Fair Value Measurements (Tables)	9 Months Ended
	Sep. 30, 2022
Fair Value And Debt Securities Available For Sale [Abstract]
Summary of Amortized Cost and Fair Values of Investment Securities Available-for-sale	As of September 30, 2022, investments were comprised of the following: Amortized Unrealized Unrealized Fair U.S. Treasury securities $ 122,576 $ - $ ( 596 ) $ 121,980 As of December 31, 2021, investments were comprised of the following: Amortized Unrealized Unrealized Fair Corporate bonds $ 33,048 $ - $ ( 11 ) $ 33,037 U.S. Treasury securities 9,994 - ( 2 ) 9,992 Total $ 43,042 $ - $ ( 13 ) $ 43,029
Summary of Maturities	The amortized cost and estimated fair value of marketable securities, by contractual maturity: September 30, 2022 Amortized Fair Value Due within one year or less $ 122,576 $ 121,980 December 31, 2021 Amortized Fair Value Due within one year or less $ 43,042 $ 43,029
Summary of Classified Assets Measured at Fair Value on a Recurred Basis	As of September 30, 2022, the Company has classified assets measured at fair value on a recurring basis as follows: Fair Value Measurement Based on Amortized Quoted Significant Significant Cost Fair Value (Level 1) (Level 2) (Level 3) Cash equivalents (1) $ 51,693 $ 51,693 $ 51,693 $ - $ - U.S. Treasury securities 122,576 121,980 - 121,980 - Total $ 174,269 $ 173,673 $ 51,693 $ 121,980 $ - As of December 31, 2021, the Company has classified assets measured at fair value on a recurring basis as follows: Fair Value Measurement Based on Amortized Quoted Significant Significant Cost Fair Value (Level 1) (Level 2) (Level 3) Cash equivalents (1) $ 219,162 $ 219,162 $ 219,162 $ - $ - Corporate bonds 33,048 33,037 - 33,037 - U.S. Treasury securities 9,994 9,992 - 9,992 - Total $ 262,204 $ 262,191 $ 219,162 $ 43,029 $ - (1) Includes cash sweep accounts, U.S. Treasury money market mutual fund, bank certificates of deposit, U.S. Treasury bills and corporate bonds that have a maturity of three months or less from the original acquisition da te.

Property and Equipment (Tables)

Property and Equipment (Tables)	9 Months Ended
	Sep. 30, 2022
Property, Plant and Equipment [Abstract]
Summary of Property and Equipment	Property and equipment, net, consisted of: As of September 30, 2022 December 31, 2021 Laboratory equipment $ 12,013 $ 13,115 Computer hardware and equipment - 54 Furniture and fixtures 326 376 Leasehold improvements 477 551 Assets not placed in service 22,360 7,592 35,176 21,688 Less: accumulated depreciation ( 6,093 ) ( 4,613 ) $ 29,083 $ 17,075

Accrued Expenses and Other Cu_2

Accrued Expenses and Other Current Liabilities (Tables)	9 Months Ended
	Sep. 30, 2022
Payables and Accruals [Abstract]
Summary of Accrued Expenses and Other Current Liabilities	Accrued expenses and other current liabilities consisted of: As of September 30, 2022 December 31, 2021 Employee compensation and related benefits $ 4,511 $ 4,631 Professional fees 660 413 Contract manufacturing organization fees 1,055 1,261 Contract research organization fees 5,218 2,810 Property received not yet invoiced 1,097 748 Accrued restructuring charges - 2,401 Other 644 830 $ 13,185 $ 13,094

Lease (Tables)

Lease (Tables)	9 Months Ended
	Sep. 30, 2022
Leases [Abstract]
Schedule of Lease Related Right of Use Assets and Lease Liabilities	Right-of-use assets and lease liabilities: September 30, December 31, Assets: Right-of-use assets, operating leases $ 57,704 $ 28,283 Liabilities Operating lease liabilities $ 20,545 $ 3,367 Operating lease liabilities, non-current 37,684 22,996 Total lease liabilities $ 58,229 $ 26,363
Schedule of Components of Lease Costs	The components of the lease costs for the nine months ended September 30, 2022 and 2021, were as follows: September 30, September 30, Operating lease costs $ 16,545 $ 5,579 Short-term lease costs 549 395 Variable lease costs 4,846 3,130 Total lease costs $ 21,940 $ 9,104
Schedule of Weighted Average Remaining Lease Term and Discount Rate	Weighted average remaining lease term and discount rate as of September 30, 2022 were as follows: September 30, Weighted-average remaining lease term (in years) Operating leases 7.5 Weighted-average discount rate: Operating leases 14.1 %
Schedule of Future Minimum Lease Payments Under for Operating Leases	The following table presents future minimum lease payments under operating leases as of September 30, 2022: September 30, 2022 2022 $ 6,816 2023 26,864 2024 6,351 2025 5,255 2026 4,327 Thereafter 48,144 Total minimum payments required 97,757 Less amounts representing imputed interest ( 39,528 ) Present value of lease liabilities $ 58,229

Stock-based Compensation (Table

Stock-based Compensation (Tables)	9 Months Ended
	Sep. 30, 2022
Share-Based Payment Arrangement [Abstract]
Schedule of Stock-based Compensation Expense	The Company recorded stock-based compensation expense in the following expense categories of its accompanying unaudited consolidated statements of operations for the three and nine months ended September 30, 2022 and 2021: Three Months Ended September 30, Nine Months Ended September 30, 2022 2021 2022 2021 Research and development $ 1,105 $ 1,336 $ 3,687 $ 4,147 General and administrative 1,588 1,850 5,030 5,378 $ 2,693 $ 3,186 $ 8,717 $ 9,525
Schedule of Stock Option Activity	The following table summarizes the activity related to stock option grants to employees and non-employees for the nine months ended September 30, 2022: Shares Weighted Weighted Balance as of December 31, 2021 6,181,335 $ 13.32 6.1 Granted 778,502 3.13 Exercised ( 49,581 ) 0.74 Forfeited ( 1,329,286 ) 13.08 Balance as of September 30, 2022 5,580,970 $ 12.08 7.7 Exercisable as of September 30, 2022 2,738,500 13.48 6.4 Vested and expected to vest as of September 30, 2022 5,580,970 $ 12.08
Schedule of Weighted-Average Assumptions	The grant date fair value of all option grants was estimated at the time of grant using the Black-Scholes option-pricing model using the following weighted-average assumptions: Nine Months Ended September 30, 2022 2021 Risk-free interest rate 2.6 % 0.9 % Expected term (in years) 6.1 6.1 Expected volatility 72.0 % 72.6 % Annual dividend yield 0 % 0 % Fair value of common stock $ 1.96 $ 11.61
Schedule Of Restricted stock units	Restricted Stock Units Weighted Average Price Per Share Balance as of December 31, 2021 66,000 $ 4.80 Granted 1,023,992 3.24 Vested ( 1,907 ) 4.80 Forfeited ( 21,093 ) 4.12 Balance as of September 30, 2022 1,066,992 $ 3.32

Restructuring (Tables)

Restructuring (Tables)	9 Months Ended
	Sep. 30, 2022
Restructuring and Related Activities [Abstract]
Schedule of Restructuring Costs	During the nine months ended September 30, 2022, the Company incurred the following expenses associated with the restructuring which are included in research and development expenses on the statements of operations. Nine Months Ended September 30, 2022 Severance and Related Costs Lease and Other costs Asset Impairment Costs Total Expenses $ 306 $ 228 $ - $ 534 Accrued restructuring expenses Balances related to this restructuring included in accrued expenses on the balance sheet are as follows: Accrued Expenses Severance and Related Costs Lease and Other costs Total Balance as of January 1, 2021 $ - $ - $ - Expenses 885 2,217 3,102 Cash payments ( 701 ) - ( 701 ) Balance as of December 31, 2021 184 2,217 2,401 Expenses 306 285 591 Adjustment of expenses - ( 57 ) ( 57 ) Cash payments ( 490 ) ( 2,445 ) ( 2,935 ) Balance as of September 30, 2022 $ - $ - $ -

Organization and Description _2

Organization and Description of Business - Narrative (Details) - USD ($) $ / shares in Units, $ in Millions	Mar. 23, 2022	Mar. 22, 2022	Jan. 22, 2021
Subsidiary Sale Of Stock [Line Items]
Shelf registration, maximum amount		$ 300
Equity Offerings
Subsidiary Sale Of Stock [Line Items]
Shares sold during public offering (shares)			4,590,164
Share price (USD per share)			$ 30.50
Proceeds from issuance of common stock after underwriting discounts and commissions and estimated offering expenses			$ 131.3
Underwriting discounts, commissions and estimated offering expenses			$ 8.7
ATM Program [Member]
Subsidiary Sale Of Stock [Line Items]
Common stock, maximum offering amount	$ 100

Liquidity - Narrative (Details)

Liquidity - Narrative (Details) $ in Millions	Sep. 30, 2022 USD ($)
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Cash, cash equivalents and investments	$ 176

Summary of Significant Accoun_4

Summary of Significant Accounting Policies - Schedule of Dilutive Securities Not Included in Diluted Per Share Calculations (Details) - shares	9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive securities (in shares)	6,875,626	5,703,052
Stock options outstanding
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive securities (in shares)	5,588,987	5,495,365
Common stock warrants
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive securities (in shares)	203,676	203,676
Restricted stock units
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive securities (in shares)	1,066,992	0
Employee stock purchase plan
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive securities (in shares)	15,971	4,011

Summary of Significant Accoun_5

Summary of Significant Accounting Policies - Reconciliation of Cash and Cash Equivalents and Restricted Cash as presented in the Statements of Cash Flows (Details) - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021	Sep. 30, 2021	Dec. 31, 2020
Accounting Policies [Abstract]
Cash and cash equivalents	$ 54,006	$ 222,564	$ 262,497
Restricted cash	1,152	1,156	1,155
Cash, cash equivalents and restricted cash shown in the statements of cash flows	$ 55,158	$ 223,720	$ 263,652	$ 94,738

Summary of Significant Accoun_6

Summary of Significant Accounting Policies - Narrative (Details) $ in Thousands	Sep. 30, 2022 USD ($) Vote shares	Dec. 31, 2021 USD ($) shares
Votes per each common stock share | Vote	1
Preferred stock, shares issued (shares) | shares	0	0
Right-of-use assets, operating leases	$ 57,704	$ 28,283
Operating Lease, Liability	$ 58,229	$ 26,363

Summary of Significant Accoun_7

Summary of Significant Accounting Policies - Schedule of Cumulative Effect of Accounting Policies on Consolidated Balance Sheet (Details) - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
Assets [Abstract]
Prepaid expenses and other current assets	$ 8,093	$ 10,534
Right-of-use assets, operating leases	57,704	28,283
Total assets	272,927	323,371
Liabilities and Equity [Abstract]
Accrued expenses and other current liabilities	13,185	13,094
Operating lease liabilities	20,545	3,367
Operating lease liabilities, non-current	37,684	22,996
Total liabilities and stockholders’ equity	$ 272,927	$ 323,371

Investments and Fair Value Me_3

Investments and Fair Value Measurements - Summary of Amortized Cost and Fair Values of Investment Securities Available-for-sale (Details) - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
Debt Securities, Available-for-sale [Line Items]
Amortized Cost		$ 43,042
Unrealized Gains		0
Unrealized Losses		(13)
Fair Value		43,029
Corporate bonds
Debt Securities, Available-for-sale [Line Items]
Amortized Cost		33,048
Unrealized Gains		0
Unrealized Losses		(11)
Fair Value		33,037
U.S. Treasury securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	$ 122,576	9,994
Unrealized Gains	0	0
Unrealized Losses	(596)	(2)
Fair Value	$ 121,980	$ 9,992

Investments and Fair Value Me_4

Investments and Fair Value Measurements - Summary of Maturities (Details) - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
Amortized Cost
Due within one year or less	$ 122,576	$ 43,042
Fair Value
Due within one year or less	$ 121,980	$ 43,029

Investments and Fair Value Me_5

Investments and Fair Value Measurements - Summary of Classified Assets Measured at Fair Value on a Recurred Basis (Details) - USD ($) $ in Thousands		Sep. 30, 2022	Dec. 31, 2021	Sep. 30, 2021
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash and cash equivalents		$ 54,006	$ 222,564	$ 262,497
Available-for-sale securities, amortized cost			43,042
Fair Value			43,029
U.S. Treasury securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Available-for-sale securities, amortized cost		122,576	9,994
Fair Value		121,980	9,992
Fair Value, Recurring
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash and cash equivalents	[1]	51,693	219,162
Cash equivalents, fair value	[1]	51,693	219,162
Fair Value		173,673
Available-for-sale securities, amortized cost		174,269	262,204
Available-for-sale securities, fair value			262,191
Fair Value, Recurring | Fair Value, Inputs, Level 1
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash equivalents, fair value	[1]	51,693	219,162
Fair Value		51,693
Available-for-sale securities, fair value			219,162
Fair Value, Recurring | Fair Value, Inputs, Level 2
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash equivalents, fair value	[1]	0	0
Fair Value		121,980
Available-for-sale securities, fair value			43,029
Fair Value, Recurring | Fair Value, Inputs, Level 3
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash equivalents, fair value	[1]	0	0
Fair Value
Available-for-sale securities, fair value			0
Fair Value, Recurring | Corporate bonds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Available-for-sale securities, amortized cost			33,048
Fair Value			33,037
Fair Value, Recurring | Corporate bonds | Fair Value, Inputs, Level 1
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair Value			0
Fair Value, Recurring | Corporate bonds | Fair Value, Inputs, Level 2
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair Value			33,037
Fair Value, Recurring | Corporate bonds | Fair Value, Inputs, Level 3
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair Value			0
Fair Value, Recurring | U.S. Treasury securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Available-for-sale securities, amortized cost		122,576	9,994
Fair Value		121,980	9,992
Fair Value, Recurring | U.S. Treasury securities | Fair Value, Inputs, Level 1
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair Value		0
Fair Value, Recurring | U.S. Treasury securities | Fair Value, Inputs, Level 2
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair Value		121,980	9,992
Fair Value, Recurring | U.S. Treasury securities | Fair Value, Inputs, Level 3
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair Value		$ 0
[1] (1) Includes cash sweep accounts, U.S. Treasury money market mutual fund, bank certificates of deposit, U.S. Treasury bills and corporate bonds that have a maturity of three months or less from the original acquisition da

Property and Equipment - Summar

Property and Equipment - Summary of Property and Equipment (Details) - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
Property Plant And Equipment [Line Items]
Property and equipment, gross	$ 35,176	$ 21,688
Less: accumulated depreciation	(6,093)	(4,613)
Property and equipment, net	29,083	17,075
Laboratory equipment
Property Plant And Equipment [Line Items]
Property and equipment, gross	12,013	13,115
Computer hardware and equipment
Property Plant And Equipment [Line Items]
Property and equipment, gross		54
Furniture and fixtures
Property Plant And Equipment [Line Items]
Property and equipment, gross	326	376
Leasehold improvements
Property Plant And Equipment [Line Items]
Property and equipment, gross	477	551
Assets Not Placed In Service
Property Plant And Equipment [Line Items]
Property and equipment, gross	$ 22,360	$ 7,592

Property and Equipment - Narrat

Property and Equipment - Narrative (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021
Property, Plant and Equipment [Abstract]
Depreciation expense	$ 2	$ 1.1

Accrued Expenses and Other Cu_3

Accrued Expenses and Other Current Liabilities - Summary of Accrued Expenses and Other Current Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
Payables and Accruals [Abstract]
Employee compensation and related benefits	$ 4,511	$ 4,631
Professional fees	660	413
Contract manufacturing organization fees	1,055	1,261
Contract research organization fees	5,218	2,810
Property received not yet invoiced	1,097	748
Accrued restructuring charges		2,401
Other	644	830
Accrued expenses and other current liabilities	$ 13,185	$ 13,094

Commitments and Contingencies -

Commitments and Contingencies - Narrative (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021	Dec. 31, 2021
Other Commitments [Line Items]
Royalty payments, percentage of license income			1%
Royalty agreement value	$ 0		$ 0		$ 0
Royalties paid	0	$ 0	0	$ 0
Accrued liabilities	0		0		$ 0
Intellectual License Income
Other Commitments [Line Items]
Revenue	$ 0	$ 0	$ 0	$ 0

Leases - Narrative (Details)

Leases - Narrative (Details) - USD ($) $ in Thousands	1 Months Ended				9 Months Ended
	Mar. 31, 2021	Nov. 30, 2020	Sep. 30, 2019	Mar. 31, 2018	Sep. 30, 2022	Mar. 31, 2022	Dec. 31, 2021
Lease facility expiration date		2024-01	2024-08	2025-07
Restricted cash	$ 600	$ 200	$ 100	$ 300
Right-of-use assets, operating leases					$ 57,704		$ 28,283
Operating Lease, Liability					$ 58,229		$ 26,363
Waltham Massachusetts [Member]
Right-of-use assets, operating leases						$ 28,800
Rockville Maryland [Member]
Lease facility expiration date	2036-06
Initial term	15 years
Lessee, Operating Lease, Existence of Option to Extend [true false]	true
Lessee, Operating Lease, Option to Extend					The Company also has an option to extend the term of the lease for two
Right-of-use assets, operating leases					$ 11,800
Operating Lease, Liability					$ 11,800

Leases - Schedule of Leases Rel

Leases - Schedule of Leases Related Right of Use Assets and Lease Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
Assets:
Right-of-use assets, operating leases	$ 57,704	$ 28,283
Liabilities
Operating lease liabilities	20,545	3,367
Operating lease liabilities, non-current	37,684	22,996
Total lease liabilities	$ 58,229	$ 26,363

Leases - Schedule of Components

Leases - Schedule of Components of Lease Costs (Details) - USD ($) $ in Thousands	1 Months Ended	9 Months Ended
	Dec. 31, 2021	Sep. 30, 2022	Sep. 30, 2021
Leases [Abstract]
Operating lease cost		$ 16,545	$ 5,579
Short-term lease cost		549	395
Variable lease costs	$ 1,500	4,846	3,130
Total lease costs		$ 21,940	$ 9,104

Lease - Weighted Average Remain

Lease - Weighted Average Remaining Lease Term and Discount Rate (Details)	Sep. 30, 2022
Leases [Abstract]
Operating leases Weighted-average Remaining lease term (in years)	7 years 6 months
Operating leases, Weighted-average Discount rate	14.10%

Lease - Schedule of Future Mini

Lease - Schedule of Future Minimum Lease Payment Under for Operating Lease (Details) - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
Leases [Abstract]
2022	$ 6,816
2023	26,864
2024	6,351
2025	5,255
2026	4,327
Thereafter	48,144
Total minimum payments required	97,757
Less amounts representing imputed interest	(39,528)
Present value of lease liabilities	$ 58,229	$ 26,363

Common Stock and Preferred Stoc

Common Stock and Preferred Stock - Narrative (Details)	Sep. 30, 2022 Vote
Equity [Abstract]
Votes per each common stock share	1

Stock-based Compensation - Narr

Stock-based Compensation - Narrative (Details) - USD ($)	1 Months Ended	9 Months Ended
	Feb. 28, 2019	Sep. 30, 2022	Sep. 30, 2021	Feb. 11, 2022	Dec. 31, 2021
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Award vesting period		4 years
Stock options granted (in shares)		778,502	803,103
Stock options forfeited (in shares)		1,329,286	223,491
Stock options exercised (in shares)		49,581	95,596
Unrecognized compensation costs		$ 18,100,000
Unrecognized compensation cost, period of recognition		2 years 2 months 12 days
Annual dividend yield		0%	0%
ESPP shares issued (in shares)		98,591	17,889
Employee stock purchase plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Purchase price of common stock, percentage of fair market value	85%
Stock purchase offering period		6 months
Maximum stock purchase value per employee, percent of eligible compensation	15%
Maximum stock purchase value per employee	$ 25,000
Common stock warrants
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Warrants outstanding (in shares)		203,676			203,676
Warrants granted (in shares)		0	0
Warrants forfeited (in shares)		0	0
Warrants exercised (in shares)		0	0
Restricted Stock [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares available for issuance (in shares)		0
Award vesting period		3 years
Unrecognized compensation costs		$ 3,400,000
Unrecognized compensation cost, period of recognition		1 year 10 months 24 days
Performance Based RSUs
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock options granted (in shares)		373,255
2018 Stock Option and Incentive Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares available for issuance (in shares)		2,045,061
2018 Stock Option and Incentive Plan | Stock options outstanding
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares authorized (in shares)		8,934,465
Shares available for issuance as a percentage of outstanding shares, maximum		4%
Term of options		10 years
2022 Inducement Plan [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares authorized (in shares)		1,400,000		1,400,000
Number of shares available for issuance (in shares)		876,026
Award vesting period		4 years
2022 Inducement Plan [Member] | Employee stock purchase plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Term of options		10 years

Stock-based Compensation - Stoc

Stock-based Compensation - Stock-based Compensation Expense (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation expense	$ 2,693	$ 3,186	$ 8,717	$ 9,525
Research and Development
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation expense	1,105	1,336	3,687	4,147
General and Administrative
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation expense	$ 1,588	$ 1,850	$ 5,030	$ 5,378

Stock-based Compensation - St_2

Stock-based Compensation - Stock Option Activity (Details) - $ / shares	9 Months Ended		12 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Dec. 31, 2021
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Options outstanding, beginning balance (in shares)	6,181,335
Options granted (in shares)	778,502	803,103
Options exercised (in shares)	(49,581)	(95,596)
Options forfeited (in shares)	(1,329,286)	(223,491)
Options outstanding, ending balance (in shares)	5,580,970		6,181,335
Options exercisable (in shares)	2,738,500
Options vested and expected to vest (in shares)	5,580,970
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract]
Options outstanding, weighted average exercise price per share, beginning balance (in dollars per share)	$ 13.32
Options granted, weighted average exercise price per share (in dollars per share)	3.13
Options exercised, weighted average exercise price per share (in dollars per share)	0.74
Options forfeited, weighted average exercise price per share (in dollars per share)	13.08
Options outstanding, weighted average exercise price per share, ending balance (in dollars per share)	12.08		$ 13.32
Options exercisable, weighted average exercise price per share, ending balance (in dollars per share)	13.48
Options vested and expected to vest, weighted average exercise price per share, ending balance (in dollars per share)	$ 12.08
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Options outstanding, weighted average remaining contractual life (in years)	7 years 8 months 12 days		6 years 1 month 6 days
Options exercisable, weighted average remaining contractual life (in years)	6 years 4 months 24 days

Stock-based Compensation - St_3

Stock-based Compensation - Stock Options Valuation Assumptions (Details) - $ / shares	9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021
Share-Based Payment Arrangement [Abstract]
Risk-free interest rate	2.60%	0.90%
Expected term (in years)	6 years 1 month 6 days	6 years 1 month 6 days
Expected volatility	72%	72.60%
Annual dividend yield	0%	0%
Fair value of common stock	$ 1.96	$ 11.61

Stock-based Compensation - Sche

Stock-based Compensation - Schedule of Restricted Stock Units (Details)	9 Months Ended
	Sep. 30, 2022 $ / shares shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Options outstanding, beginning balance (in shares)	6,181,335
Options outstanding, ending balance (in shares)	5,580,970
Restricted stock units
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Options outstanding, beginning balance (in shares)	66,000
Restricted Stock Units, Granted	1,023,992
Restricted Stock Units, Vested	(1,907)
Restricted Stock Units, Forfeited	21,093
Options outstanding, ending balance (in shares)	1,066,992
Weighted Average Price Per Share. Beginning Balance | $ / shares	$ 4.80
Weighted Average Price Per Share, Granted | $ / shares	3.24
Weighted Average Price Per Share, Vested | $ / shares	4.80
Weighted Average Price Per Share, Forfeited | $ / shares	4.12
Weighted Average Price Per Share, Ending Balance | $ / shares	$ 3.32

Related party transactions - Na

Related party transactions - Narrative (Details) - Dr Ansbert Gadicke - Director - Elevate Bio - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions	$ 14.6	$ 0.9
Related Party Transaction Expenses From Transactions With Related Party	$ 0.1	$ 0.3

Restructuring - Schedule of exp

Restructuring - Schedule of expenses which are included in research and development expenses on the statements of operations (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021
Restructuring Cost and Reserve [Line Items]
Lease and Other costs	$ 21,940	$ 9,104
Research and Development Expense [Member]
Restructuring Cost and Reserve [Line Items]
Severance and Related Costs	306
Lease and Other costs	228
Asset Impairment Costs	0
Restructuring Charges, Total	$ 534

Restructuring - Summary of Bala

Restructuring - Summary of Balances related to restructuring included in accrued expenses on the balance sheet (Details) - USD ($) $ in Thousands	9 Months Ended		12 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Dec. 31, 2021
Restructuring Cost and Reserve [Line Items]
Lease and Other costs	$ 21,940	$ 9,104
Expense [Member] | Accrued Restructuring Expenses [Member]
Restructuring Cost and Reserve [Line Items]
Severance and Related Costs	306		$ 885
Lease and Other costs	285		2,217
Restructuring charges	591		3,102
Cash Payments [Member] | Accrued Restructuring Expenses [Member]
Restructuring Cost and Reserve [Line Items]
Severance and Related Costs	(490)		(701)
Lease and Other costs	(2,445)		0
Restructuring charges	(2,935)		(701)
Adjustment of Expenses Member | Accrued Restructuring Expenses [Member]
Restructuring Cost and Reserve [Line Items]
Severance and Related Costs
Lease and Other costs	(57)
Restructuring charges	(57)
Accrued expense [Member] | Accrued Restructuring Expenses [Member]
Restructuring Cost and Reserve [Line Items]
Severance and Related Costs			184
Lease and Other costs			2,217
Restructuring charges			$ 2,401

Restructuring - Additional Info

Restructuring - Additional Information (Details) - USD ($) $ in Thousands	1 Months Ended	9 Months Ended
	Dec. 31, 2021	Sep. 30, 2022	Sep. 30, 2021
Restructuring and Related Activities [Abstract]
Variable lease costs	$ 1,500	$ 4,846	$ 3,130

Subsequent Event - Narrative (D

Subsequent Event - Narrative (Details) - Subsequent Event	Oct. 19, 2022 $ / shares shares
Subsequent Event [Line Items]
Employee Stock Option Offer Price | $ / shares	$ 10
Eligible Stock Options Offered	2,574,615
Expectaion of Issuance of Employee Stock Options	756,679