Monte Rosa Therapeutics (GLUE) 10-K 16 Mar 23 2022 FY Annual report Financial data

Document And Entity Information

Document And Entity Information - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Mar. 10, 2023	Jun. 30, 2022
Cover [Abstract]
Document Type	10-K
Document Period End Date	Dec. 31, 2022
Amendment Flag	false
Trading Symbol	GLUE
Entity Registrant Name	Monte Rosa Therapeutics, Inc.
Entity Central Index Key	0001826457
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Well-known Seasoned Issuer	No
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2022
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	true
Entity Shell Company	false
Document Fiscal Period Focus	FY
Entity Public Float			$ 302.6
Entity Common Stock, Shares Outstanding		49,359,033
Entity Ex Transition Period	false
ICFR Auditor Attestation Flag	false
Entity File Number	001-40522
Entity Tax Identification Number	84-3766197
Entity Address, Address Line One	645 Summer Street
Entity Address, Address Line Two	Suite 102
Entity Address, City or Town	Boston
Entity Address, State or Province	MA
Entity Address, Postal Zip Code	02210
City Area Code	617
Local Phone Number	949-2643
Entity Interactive Data Current	Yes
Title of 12(b) Security	Common stock, par value $0.0001 per share
Security Exchange Name	NASDAQ
Entity Incorporation, State or Country Code	DE
Document Annual Report	true
Document Transition Report	false
Documents Incorporated by Reference	Portions of registrant's definitive proxy statement for its annual meeting of shareholders to be filed within 120 days after the close of the registrant's fiscal year are incorporated by reference to into Part III of this annual report on Form 10-K.
Auditor Name	Deloitte & Touche LLP
Auditor Location	Boston, Massachusetts
Auditor Firm ID	34

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Current assets:
Cash and cash equivalents	$ 54,912	$ 346,071
Marketable securities	207,914	0
Other receivables	7,656	0
Prepaid expenses and other current assets	4,444	2,595
Current restricted cash	960	0
Total current assets	275,886	348,666
Property and equipment, net	27,075	12,325
Operating lease right-of-use assets	34,832	0
Restricted cash, net of current	4,318	5,338
Other long-term assets	278	0
Total assets	342,389	366,329
Current liabilities:
Accounts payable	7,862	6,558
Accrued expenses and other current liabilities	14,580	10,080
Current portion of operating lease liability	3,127	0
Total current liabilities	25,569	16,638
Defined benefit plan liability	1,533	2,176
Operating lease liability	43,874	0
Total liabilities	70,976	18,814
Commitments and contingencies
Stockholders equity (deficit)
Preferred stock, $0.0001 par value, 10,000,000 shares authorized, no shares issued and outstanding	0	0
Common stock, $0.0001 par value; 500,000,000 shares authorized, 49,445,802 shares issued and 49,323,531 shares outstanding as of December 31, 2022; and 500,000,000 shares authorized, 46,794,295 shares issued and 46,535,966 shares outstanding as of December 31, 2021	5	5
Additional paid-in capital	503,696	471,566
Accumulated other comprehensive loss	(1,752)	(2,021)
Accumulated deficit	(230,536)	(122,035)
Total stockholders' equity	271,413	347,515
Total liabilities and stockholders' equity	$ 342,389	$ 366,329

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets - Parenthetical (Unaudited) - $ / shares	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Preferred stock, par value	$ 0.0001	$ 0.0001
Preferred stock, shares authorized	10,000,000	10,000,000
Preferred stock, shares Issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par or stated value per share	$ 0.0001	$ 0.0001
Common stock, shares authorized	500,000,000	500,000,000
Common stock, shares, issued	49,445,802	46,794,295
Common stock shares outstanding	49,323,531	46,535,966
Convertible Preferred Stock
Convertible preferred stock, shares outstanding			53,631,514

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations and Comprehensive Income (Loss) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Operating expenses:
Research and development	$ 85,061	$ 57,155
General and administrative	27,323	15,727
Total operating expenses	112,384	72,882
Operating Income (Loss), Total	(112,384)	(72,882)
Other income (expense):
Interest income, net	3,764	46
Foreign currency exchange gain (loss), net	10	(162)
Gain on disposal of fixed assets	109	0
Changes in fair value of preferred stock tranche obligations, net	0	(960)
Total other income (expense)	3,883	(1,076)
Net loss	$ (108,501)	$ (73,958)
Net loss per share attributable to common stockholders - basic	$ (2.30)	$ (2.96)
Net loss per share attributable to common stockholders - diluted	$ (2.30)	$ (2.96)
Weighted-average number of shares outstanding used in computing net loss per common share - basic	47,227,370	25,000,124
Weighted-average number of shares outstanding used in computing net loss per common share - diluted	47,227,370	25,000,124
Comprehensive loss:
Net loss	$ (108,501)	$ (73,958)
Other comprehensive gain (loss):
Provision for pension benefit obligation	718	(965)
Unrealized loss on available-for-sale securities	(449)	0
Comprehensive loss	$ (108,232)	$ (74,923)

Combined and Consolidated State

Combined and Consolidated Statements of Convertible Preferred Stock and Stockholders' Deficit - USD ($) $ in Thousands	Total	Convertible Preferred Stock	Series B Convertible Preferred Stock	Series C Convertible Preferred Stock	Common Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Loss	Accumulated Deficit
Balance at Dec. 31, 2020		$ 67,764
Balance (in shares) at Dec. 31, 2020		53,631,514			1,685,534
Balance, amount at Dec. 31, 2020	$ (48,728)				$ 1	$ 404	$ (1,056)	$ (48,077)
Issuance of convertible preferred stock, net of issuance costs			$ 68,571	$ 94,837
Issuance of convertible preferred stock, net of issuance costs, shares			24,000,000	32,054,521
Conversion of convertible preferred stock into common stock	231,173	$ (231,172)			$ 3	231,170
Conversion of convertible preferred stock into common stock, shares		(109,686,035)			31,068,102
Issuance of common stock in connection with initial public offering, net of issuance costs, shares					13,455,000
Issuance of common stock in connection with initial public offering, net of issuance costs, amount	234,645				$ 1	234,644
Restricted common stock vesting, shares					236,949
Exercise of common stock options	148					148
Exercise of common stock options, shares					90,381
Stock-based compensation expense	5,200					5,200
Provision for pension benefit obligation	(965)						(965)
Unrealized loss on available-for-sale securities	0
Net loss	(73,958)							(73,958)
Balance, shares at Dec. 31, 2021					46,535,966
Balance, amount at Dec. 31, 2021	347,515				$ 5	471,566	(2,021)	(122,035)
Restricted common stock vesting, shares					136,058
Exercise of common stock options	$ 439					439
Exercise of common stock options, shares	117,552				117,552
Stock-based compensation expense	$ 11,664					11,664
Provision for pension benefit obligation	718						718
Issuance of common stock, net of issuance costs, shares					2,482,008
Issuance of common stock, net of issuance costs, amount	19,691					19,691
Unrealized loss on available-for-sale securities	(449)						(449)
Issuance of shares under employee stock purchase plan	336					336
Issuance of shares under employee stock purchase plan, shares					51,947
Net loss	(108,501)							(108,501)
Balance, shares at Dec. 31, 2022					49,323,531
Balance, amount at Dec. 31, 2022	$ 271,413				$ 5	$ 503,696	$ (1,752)	$ (230,536)

Combined and Consolidated Sta_2

Combined and Consolidated Statements of Convertible Preferred Stock and Stockholders' Equity (Deficit) (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Stock issuance costs	$ 0	$ 231
Series B Convertible Preferred Stock
Stock issuance costs of convertible securities		68
Series C Convertible Preferred Stock
Stock issuance costs of convertible securities		163
Common Stock
Stock issuance costs		$ 21,001
Issuance of common stock, net of issuance costs, amount	$ 984

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Cash flows from operating activities:
Net loss	$ (108,501)	$ (73,958)
Adjustments to reconcile net loss to net cash used in operating activities
Stock-based compensation expense	11,664	5,200
Depreciation	3,745	2,132
Noncash Lease Expense	4,814	0
Net accretion of discounts/premiums on marketable securities	(1,945)	0
Changes in fair value of preferred stock tranche obligations	0	960
(Gain) Loss on disposal of property and equipment	(109)	17
Changes in operating assets and liabilities
Other receivables	(187)	0
Prepaid expenses and other current assets	(2,127)	(704)
Accounts payable	(744)	(706)
Accrued expenses and other current liabilities	1,031	6,587
Defined benefit plan liability	74	1,109
Right-of-use assets and operating lease liabilities	(181)	0
Net cash used in operating activities	(92,466)	(59,363)
Cash flows from investing activities:
Purchases of property and equipment	(12,911)	(9,732)
Proceeds from sale of property and equipment	109	79
Purchases of marketable securities	(384,417)	0
Proceeds from maturities of marketable securities	178,000	0
Net cash used in investing activities	(219,219)	(9,653)
Cash flows from financing activities:
Proceeds from issuance of convertible preferred stock	0	143,000
Payment of convertible preferred stock issuance costs	0	(231)
Proceeds from initial public offering, net of underwriting discount of $17,895	0	237,750
Issuance of common stock, net of issuance cost of $620	20,055	0
Payment of initial public offering issuance costs	0	(3,106)
Payment of common stock issuance costs	(364)	0
Proceeds from exercise of employee stock options	439	149
Proceeds from employee stock purchase plan	336	0
Net cash provided by financing activities	20,466	377,562
Net (decrease) increase in cash, cash equivalents and restricted cash	(291,219)	308,546
Cash, cash equivalents and restricted cash—beginning of year	351,409	42,863
Cash, cash equivalents and restricted cash—end of year	60,190	351,409
Reconciliation of cash, cash equivalents and restricted cash
Cash and cash equivalents	54,912	346,071
Restricted cash	5,278	5,338
Total cash, cash equivalents and restricted cash	60,190	351,409
Supplemental disclosure of noncash items
Conversion of convertible preferred stock into common stock	0	231,172
Settlement of preferred stock tranche obligation	0	20,640
Reduction of right-of-use assets for lease incentives receivable	7,469	0
Purchases of property and equipment in accounts payable and accrued expenses	$ 6,240	$ 656

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Cash Flows (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Statement of Cash Flows [Abstract]
Proceeds from initial public offering, net of underwriting discount	$ 17,895	$ 17,895
Issuance of common stock, net of underwriting discount	$ 620	$ 620

Description of Business, Contri

Description of Business, Contribution and Exchange, and Liquidity	12 Months Ended
	Dec. 31, 2022
Accounting Policies [Abstract]
Description of Business, Contribution and Exchange, and Liquidity	1. Description of business and liquidity Business Monte Rosa Therapeutics, Inc. is a biotechnology company developing a portfolio of novel small molecule precision medicines that employ the body’s natural mechanisms to selectively degrade therapeutically-relevant proteins. As used in these consolidated financial statements, unless the context otherwise requires, references to the Company or Monte Rosa refer to Monte Rosa Therapeutics, Inc. and its wholly owned subsidiaries Monte Rosa Therapeutics AG and Monte Rosa Therapeutics Securities Corp. Monte Rosa Therapeutics AG, a Swiss operating company, was incorporated under the laws of Switzerland in April 2018. Monte Rosa Therapeutics, Inc. was incorporated in Delaware in November 2019. The Company is headquartered in Boston, Massachusetts with research operations in both Boston and Basel, Switzerland. Risks and uncertainties The Company is subject to risks common to companies in the biotechnology industry including, but not limited to, the successful discovery and development of its product candidates, new technological innovations, protection of proprietary technology, dependence on key personnel, compliance with government regulations and the need to obtain additional financing. Liquidity considerations Since inception, the Company has devoted substantially all its efforts to business planning, research and development, recruiting management and technical staff, and raising capital and has financed its operations primarily through the issuance of convertible preferred shares and public offerings of the Company's common stock. The Company’s continued discovery and development of its product candidates will require significant additional research and development efforts, including extensive preclinical and clinical testing and regulatory approval prior to commercialization. These efforts require significant amounts of additional capital, adequate personnel and infrastructure and extensive compliance-reporting capabilities. Even if product development efforts are successful, it is uncertain when, if ever, the Company will realize significant revenue from product sales. As of December 31, 2022, the Company had an accumulated deficit of $ 230.5 million. The Company has incurred losses and negative cash flows from operations since inception, including net losses of $ 108.5 million and $ 74.0 million for the years ended December 31, 2022, and 2021, respectively. The Company expects that its operating losses and negative cash flows will continue for the foreseeable future as the Company continues to develop its product candidates. The Company currently expects that its cash, cash equivalents and marketable securities of $ 262.8 million as of December 31, 2022 , will be sufficient to fund operating expenses and capital requirements for at least 12 months from the date the consolidated financial statements are issued. However, additional funding will be necessary to fund future discovery research, pre-clinical and clinical activities. The Company will seek additional funding through public financings, debt financings, collaboration agreements, strategic alliances and licensing arrangements. Although it has been successful in raising capital in the past, there is no assurance that the Company will be successful in obtaining such additional financing on terms acceptable to it, if at all, and the Company may not be able to enter into collaborations or other arrangements. If the Company is unable to obtain funding, it could be forced to delay, reduce or eliminate its research and development programs, product portfolio expansion or commercialization efforts, which could adversely affect the Company’s business prospects, even the ability to continue operations.

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2022
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	2. Summary of significant accounting policies Basis of presentation The accompanying consolidated financial statements have been prepared in conformity with accounting principles generally accepted in the United States of America, or GAAP, and are stated in U.S. dollars. Any reference in these notes to applicable guidance is meant to refer to the authoritative GAAP as found in the Accounting Standards Codification and Accounting Standards Updates, or ASUs, of the Financial Accounting Standards Board, or FASB. All intercompany balances and transactions have been eliminated in combination or consolidation. Use of estimates The preparation of the consolidated financial statements in conformity with GAAP requires the Company to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosures of contingent assets and liabilities at the date of the financial statements and reported amounts of expenses during the reporting periods. Actual results could differ from those estimates. On an ongoing basis, the Company evaluates its estimates, including those related to accrued research and development expenses, other long-lived assets, pension benefit obligation, stock-based compensation and the valuation of deferred tax assets. The Company bases its estimates using historical experience, Company forecasts and future plans, current economic conditions, and information from third-party professionals that management believes to be reasonable under the circumstances, the results of which form the basis for making judgments about the carrying value of assets and liabilities and recorded amounts of expenses that are not readily apparent from other sources and adjusts those estimates and assumptions when facts and circumstances dictate. Currency and currency translation The consolidated financial statements are presented in U.S. dollars, the Company’s reporting currency. The functional currency of the Company’s wholly owned subsidiary, Monte Rosa Therapeutics AG, is the U.S. dollar. Adjustments that arise from exchange rate changes on transactions denominated in a currency other than the functional currency are included in foreign currency exchange gain (loss), net in the consolidated statements of operations. Cash, cash equivalents and restricted cash The Company considers all highly liquid investments with original maturities at the date of purchase of three months or less to be cash equivalents. Cash and cash equivalents are stated at fair value and may include money market funds, U.S. Treasury and U.S. government-sponsored agency securities, corporate debt, commercial paper and certificates of deposit. The Company’s cash equivalents at December 31, 2022 and 2021 consist of bank demand deposits and money market fund investments. The Company had restricted cash of $ 5.3 million as of December 31, 2022, and 2021 , primarily related to security deposits on its leases for offices in Boston, Massachusetts and Basel, Switzerland. Marketable securities Investments in marketable securities are classified as available-for-sale. Available-for-sale securities are measured and reported at fair value using quoted prices in active markets for similar securities. Unrealized gains and losses on available-for-sale securities are reported as a separate component of stockholders’ equity. Premiums or discounts from par value are amortized to investment income over the life of the underlying investment. All of the Company’s available-for-sale securities are available to the Company for use in current operations. As a result, the Company classified all of these securities as current assets even though the stated maturity of some individual securities may be one year or more beyond the balance sheet date. The cost of securities sold is determined on a specific identification basis, and realized gains and losses are included in other income (expense) within the consolidated statements of operations and comprehensive loss. If any adjustment is required to reflect a decline in the value of the investment that the Company considers to be “other than temporary”, the Company recognizes a charge to the consolidated statement of operations and comprehensive loss. No such adjustments were necessary during the periods presented. Concentrations of credit risk and off-balance sheet risk Financial instruments that potentially subject the Company to a concentration of credit risk consist primarily of cash and cash equivalents. The Company has invested in cash and cash equivalents at December 31, 2022 and 2021 , held in a financial institution that management believes is creditworthy. These deposits may exceed federally insured limits. The Company has not experienced any losses historically in these accounts and believes it in not exposed to significant credit risk in its cash and cash equivalents. The Company has no significant off-balance sheet concentrations of credit risk, such as foreign currency exchange contracts, option contracts, or other hedging arrangements. Fair value of financial instruments Assets and liabilities recorded at fair value on a recurring basis in the balance sheets are categorized based upon the level of judgment associated with the inputs used to measure their fair values. Fair value is defined as the exchange price that would be received for an asset or an exit price that would be 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. Valuation techniques used to measure fair value must maximize the use of observable inputs and minimize the use of unobservable inputs. The authoritative guidance on fair value measurements establishes a three-tier fair value hierarchy for disclosure of fair value measurements as follows: Level 1—Observable inputs such as unadjusted, quoted prices in active markets for identical assets or liabilities at the measurement date. Level 2—Inputs (other than quoted prices included in Level 1) that are either directly or indirectly observable for the asset or liability. These include quoted prices for similar assets or liabilities in active markets and quoted prices for identical or similar assets or liabilities in markets that are not active. Level 3—Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities. To the extent that the valuation is based on models or inputs that are less observable or unobservable in the market, the determination of fair value requires more judgment. Accordingly, the degree of judgment exercised by the Company in determining fair value is greatest for instruments categorized in Level 3. A financial instrument’s level within the fair value hierarchy is based on the lowest level of any input that is significant to the fair value instrument. Property and equipment Property and equipment are stated at cost, subject to adjustments for impairments, less accumulated depreciation. Purchased assets that are not yet in service are classified as construction-in-process and no depreciation expense is recorded. Depreciation is calculated using the straight-line method over the estimated useful life of the asset as follows: Asset Estimated useful life Laboratory equipment Five years Computer hardware Three years Furniture and fixtures Five Years Leasehold Improvements Shorter of useful life or remaining lease term Maintenance and repairs that do not improve or extend the life of the respective asset are expensed as incurred. Upon disposal of an asset, the related cost and accumulated depreciation are removed from the accounts and any resulting gain or loss is included in the results of operations. Leasehold improvements are amortized over the shorter of the useful life or remaining term of the lease. Impairment of long-lived assets The Company evaluates whether current facts or circumstances indicate that the carrying values of its long-lived assets may not be recoverable. If such facts or circumstances are determined to exist, an estimate of the undiscounted future cash flows of these assets is compared to the carrying value the assets to determine whether impairment exists. If the assets are determined to be impaired, the loss is measured based on the difference between the fair value and carrying value of the assets. No material impairment losses were recorded during the periods presented. Research and development expenses Research and development costs are expensed as incurred. The Company’s research and development expenses consist primarily of costs incurred for the research and development of its product candidates and include expenses incurred under agreements with consultants to conduct preclinical and clinical studies, costs to acquire supplies for preclinical and clinical studies, salaries and related personnel costs, including stock-based compensation, depreciation and other allocated facility-related and overhead expenses. Accrued research and development costs The Company records accruals for estimated costs of discovery research activities, preclinical, and clinical studies. A portion of the Company’s research and development activities are conducted by third-party service providers. The financial terms of these contracts are subject to negotiation, which vary by contract and may result in payments that do not match the periods over which materials or services are provided. The Company accrues the costs incurred under the agreements based on an estimate of actual work completed in accordance with the agreements. In the event the Company makes advance payments for goods or services that will be used or rendered for future research and development activities, the payments are deferred and capitalized as a prepaid expense and recognized as expense as the goods are received or the related services are rendered. Such payments are evaluated for current or long-term classification based on when they are expected to be realized. If the Company does not identify costs that have begun to be incurred or if the Company underestimates or overestimates the level of services performed or the costs of these services, actual expenses could differ from the Company’s estimates. Preferred stock tranche obligations Included in the terms of the Series A and Series B Preferred Stock Purchase Agreements were certain rights, or Tranche Rights, granted to the investors who purchased the Series A and Series B Preferred. The Series A Tranche Rights gave the investor the option to purchase up to an aggregate of 15,000,000 additional shares of Series A Preferred at $ 1.00 per share. The Series B Tranche Rights gave investors the option to purchase up to an aggregate of 24,000,000 shares of Series B Preferred at $ 2.00 per share. The Company concluded that both the Series A and the Series B Tranche Rights met the definition of a freestanding financial instrument, as the Series A and Series B Tranche Rights were legally detachable and separately exercisable from the Series A and Series B Preferred. At initial recognition, the Company recorded these Series A and Series B Tranche Rights as a liability on the balance sheets at its estimated fair value. The Series A and Series B Preferred Stock Tranche Obligations are subject to remeasurement at each balance sheet date, with changes in fair value recognized in changes in fair value of Preferred Stock Tranche Obligations on the Company’s consolidated statements of operations and comprehensive loss. Immediately prior to consummation of our IPO in June 2021, all outstanding shares of the Company's Series A, Series A-2, Series B and Series C convertible preferred stock were converted into 31,068,102 shares of common stock. As such, there was no value recorded for preferred stock tranche obligations on the consolidated balance sheets as of December 31, 2022 and 2021 . Stock-based compensation Stock-based compensation expense related to stock options granted to employees, directors and non-employees is recognized based on the grant-date estimated fair values of the awards using the Black-Scholes option pricing model, or Black-Scholes. Stock-based compensation expense related to stock options and other stock based awards granted to employees and non-employees is recognized based on the grant-date fair value of the Company’s common stock. The value is recognized as expense ratably over the requisite service period, which is generally the vesting term of the award. For stock options with performance-based vesting conditions, the Company records the expense for these awards based upon the fair value of the awards on the date of grant and the number of shares expected to vest based on the terms of the underlying award agreement and the requisite service periods. The Company adjusts the expense for actual forfeitures as they occur. Stock-based compensation expense is classified in the accompanying consolidated statements of operations based on the function to which the related services are provided. Income taxes The Company uses the liability method to account for income taxes. Under this method, deferred tax assets and liabilities are determined based on differences between the financial statement carrying amounts of existing assets and liabilities and their tax bases. Deferred tax assets and liabilities are measured using enacted tax rates applied to taxable income in the years in which those temporary differences are expected to be recovered or settled. A valuation allowance is established when necessary to reduce deferred tax assets to the amount expected to be realized. The Company assesses the likelihood of deferred tax assets being realized. A valuation allowance is provided when it is more likely than not that some portion or all of a deferred tax asset will not be realized. In assessing the realizability of deferred tax assets, the Company considers whether it is more likely than not that some portion or all of the deferred tax assets will not be realized. The ultimate realization of deferred tax assets is dependent upon the generation of future taxable income during the periods in which the temporary differences representing net future deductible amounts become deductible. The Company files U.S. federal and state income tax returns, as well as Swiss income tax returns. The Company’s tax positions are subject to audit. Financial statement effects of uncertain tax positions are recognized when it is more likely than not, based on the technical merits of the position, that it will be sustained upon examination. The Company evaluates uncertain tax positions on a regular basis. The evaluations are based on a number of factors, including changes in facts and circumstances, changes in tax law, correspondence with tax authorities during the course of the audit, and effective settlement of audit issues. Interest and penalties related to unrecognized tax benefits are included within the provision for income tax. To date, the Company has not been subject to any interest and penalties. Defined pension benefit obligation The Company maintains a mandatory pension for its employees in Switzerland through affiliation with the Swiss Life Collective BVG Foundation. All benefits in accordance with the regulations are reinsured in their entirety with Swiss Life Ltd within the framework of the corresponding contract. This plan is considered to be a defined benefit plan under GAAP. The Company recognizes an asset for the plan’s overfunded status or a liability for the plan’s underfunded status in its consolidated balance sheets. Additionally, the Company measures the plan’s assets and obligations that determine its funded status as of the end of the year and recognizes the change in the funded status within the consolidated statements of operations and comprehensive loss. The Company uses an actuarial valuation to determine its pension benefit costs and credits. The amounts calculated depend on a variety of key assumptions, including discount rates and expected return on plan assets. Details of the assumptions used to determine the net funded status are described in Note 12. The Company’s pension plan assets are assigned to their respective levels in the fair value hierarchy in accordance with the valuation principles described in the Fair Value of Financial Instruments section above. Segments Operating segments are defined as components of an entity for which separate financial information is available and that is regularly reviewed by the chief operating decision maker, or CODM, in deciding how to allocate resources to an individual segment and in assessing performance. The Company’s CODM is its chief executive officer. The Company manages its operations as a single segment for the purposes of assessing performance and making operating decisions. Comprehensive income (loss) Comprehensive income (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. The Company’s other comprehensive income (loss) includes adjustments to unrecognized pension benefit costs for Monte Rosa Therapeutics AG and changes in unrealized gains and losses from available-for-sale investments. The Company reported other comprehensive income of $ 0.3 million and incurred other comprehensive loss of $ 1.0 million, for the years ended December 31, 2022 and 2021 , respectively. Recently issued accounting pronouncements The Company has elected to use the extended transition period for complying with new or revised accounting standards as available under the Jumpstart Our Business Startups Act (JOBS Act). In June 2016, the FASB issued Accounting Standards Update No. 2016-13, Financial Instruments-Credit Losses: Measurement of Credit Losses on Financial Instruments . ASU 2016-13 requires measurement and recognition of expected credit losses for financial assets. In April 2019, the FASB issued clarification to ASU 2016-13 within ASU 2019-04, Codification Improvements to Topic 326, Financial Instruments-Credit Losses, Topic 815, Derivatives and Hedging , and Topic 825, Financial Instruments , or ASU 2016-13. The guidance is effective for fiscal years beginning after December 15, 2022. The Company does not expect for ASU 2016-13 to have a material impact on its financial statements. In August 2020, the FASB issued ASU No. 2020-06, Debt—Debt with Conversion and Other Options (Subtopic 470-20) and Derivatives and Hedging Contracts in Entity s Own Equity (Subtopic 815-40): Accounting for Convertible Instruments and Contracts in an Entity’s Own Equity . ASU 2020-06 will simplify the accounting for convertible instruments by reducing the number of accounting models for convertible debt instruments and convertible preferred stock. Limiting the accounting models results in fewer embedded conversion features being separately recognized from the host contract as compared with current GAAP. Convertible instruments that continue to be subject to separation models are (i) those with embedded conversion features that are not clearly and closely related to the host contract, that meet the definition of a derivative, and that do not qualify for a scope exception from derivative accounting and (ii) convertible debt instruments issued with substantial premiums for which the premiums are recorded as paid-in capital. ASU 2020-06 also amends the guidance for the derivatives scope exception for contracts in an entity’s own equity to reduce form-over-substance-based accounting conclusions. ASU 2020-06 will be effective for the Company beginning after December 15, 2023. Early adoption is permitted, but no earlier than fiscal years beginning after December 15, 2020, including interim periods within those fiscal years. The Company is currently assessing the impact adoption of ASU 2020-06 will have on the financial statements and disclosures. Recently adopted accounting pronouncements On January 1, 2022, the Company adopted Accounting Standard Update or ASU No. 2016-02, Leases (Topic 842) , and its associated amendments using the modified retrospective transition approach by applying the new standard to all leases existing at the date of initial application and not restating comparative periods. There was no cumulative-effect adjustment recorded to retained earnings upon adoption. Under Topic 842, a lessee is required to recognize a lease liability and right-of-use (ROU) asset for all leases, unless the lease qualifies for the short-term lease exception. The new guidance also modified the classification criteria and requires additional disclosures to enable users of financial statements to understand the amount, timing, and uncertainty of cash flows arising from leases. Consistent with current guidance, a lessee’s recognition, measurement, and presentation of expenses and cash flows arising from a lease continues to depend primarily on its classification. The Company elected the package of practical expedients permitted under the transition guidance, which allowed the Company to carryforward its historical lease classification, its assessment on whether a contract was or contains a lease, and its initial direct costs for any leases that existed prior to January 1, 2022. In addition, the Company elected the following transitional practical expedients: (1) the short-term lease exception and (2) to not separate its non-lease components for its real estate, vehicle and equipment leases. Upon the adoption of this standard, the Company recorded operating lease right-of-use assets of $ 7.3 million and corresponding operating lease liabilities of $ 7.4 million as of January 1, 2022. The difference between the value of the right-of-use assets and lease liabilities is due to the reclassification of existing deferred rent as of January 1, 2022. In December 2019, the FASB issued ASU 2019-12, Simplifying the Accounting for Income Taxes , or ASU 2019-12. ASU 2019-12 eliminates certain exceptions related to the approach for intra-period tax allocation, the methodology for calculating income taxes in an interim period and the recognition of deferred tax liabilities for outside basis differences. It also clarifies and simplifies other aspects of the accounting for income taxes. This guidance is effective for fiscal years beginning after December 15, 2021, and interim periods within fiscal years beginning after December 15, 2022. The Company adopted ASU 2019-12 on January 1, 2022. The adoption of the standard was immaterial to the accompanying consolidated financial statements.

Fair value measurements

Fair value measurements	12 Months Ended
	Dec. 31, 2022
Fair Value Disclosures [Abstract]
Fair Value Measurements	3. Fair value measurements The following tables present information about the Company’s financial assets and liabilities measured at fair value on a recurring basis and indicate the level of the fair value hierarchy utilized to determine such fair values (in thousands): As of December 31, 2022 Level 1 Level 2 Level 3 Total Current assets Money market funds $ 50,633 $ — $ — $ 50,633 Pension plan assets — 5,320 — 5,320 Corporate debt securities — 127,351 — 127,351 U.S. Treasury securities — 80,563 — 80,563 Total assets measured at fair value $ 50,633 $ 213,234 $ — $ 263,867 As of December 31, 2021 Level 1 Level 2 Level 3 Total Current assets Money market funds $ 317,004 $ — $ — $ 317,004 Pension plan assets — 3,796 — 3,796 Total assets measured at fair value $ 317,004 $ 3,796 $ — $ 320,800 Money market funds are highly liquid investments and are actively traded. The pricing information on the Company’s money market funds are based on quoted prices in active markets for identical securities. This approach results in the classification of these securities as Level 1 of the fair value hierarchy. The fair value of pension plan assets has been determined as the surrender value of the portfolio of active insured members held within the Swiss Life Collective BVG Foundation collective investment fund and are classified within Level 2 of the fair value hierarchy. Marketable securities consist of corporate debt securities and U.S. Treasury securities which are classified as available-for-sale pursuant to ASC 320, Investments—Debt and Equity Securities. Marketable securities are classified within Level 2 of the fair value hierarchy because pricing inputs are other than quoted prices in active markets. The fair values of these investments are estimated by taking into consideration valuations obtained from third-party pricing services. The pricing services utilize industry standard valuation models, including both income- and market-based approaches, for which all significant inputs are observable, either directly or indirectly, to estimate fair value. These inputs include reported trades of and broker/dealer quotes on the same or similar securities, issuer credit spreads, benchmark securities based on historical data and other observable inputs. There were no transfers among Level 1, Level 2 or Level 3 categories in the years ended December 31, 2022 or 2021 .

Marketable securities

Marketable securities	12 Months Ended
	Dec. 31, 2022
Investments, Debt and Equity Securities [Abstract]
Marketable securities	4. Marketable securities Marketable securities as of December 31, 2022, consisted of the following (in thousands): Amortized Unrealized Unrealized Fair Cost Gains Losses Value Description Corporate debt securities $ 127,565 $ 27 $ ( 241 ) $ 127,351 U.S Treasury securities 80,798 2 ( 237 ) 80,563 Total $ 208,363 $ 29 $ ( 478 ) $ 207,914 As of December 31, 2022, the Company held 40 marketable securities, 31 of which were in an unrealized loss position. The aggregate fair value of securities in a loss position is $ 164.9 million. There were no individual securities that were in a significant unrealized loss position as of December 31, 2022. The Company evaluates securities for other-than-temporary impairments based on quantitative and qualitative factors, and considers the decline in market value as of December 31, 2022 , to be primarily attributable to the then current economic and market conditions. The Company neither intends to sell these investments nor concludes that it is more-likely-than-not that the Company will have to sell them before recovery of their carrying values. The Company also believes that it will be able to collect both principal and interest amounts due to it at maturity.

Property and Equipment, net

Property and Equipment, net	12 Months Ended
	Dec. 31, 2022
Property, Plant and Equipment [Abstract]
Property, Plant and Equipment, net	5. Property and equipment, net Property and equipment, net, consist of the following (in thousands): December 31, 2022 2021 Laboratory equipment $ 17,766 $ 12,315 Computer hardware and software 499 299 Furniture and fixtures 388 443 Leasehold improvements 2,660 1,119 Construction in process 12,013 852 Total property and equipment, at cost $ 33,326 $ 15,028 Less: accumulated depreciation ( 6,251 ) ( 2,703 ) Property and equipment, net $ 27,075 $ 12,325 Depreciation expense for the years ended December 31, 2022, and 2021 was $ 3.7 million and $ 2.1 million, respectively.

Accrued expenses and other curr

Accrued expenses and other current liabilities	12 Months Ended
	Dec. 31, 2022
Accounts Payable and Accrued Liabilities, Current [Abstract]
Accrued expenses and other current liabilities	6. Accrued expenses and other current liabilities Accrued expenses and other current liabilities consist of the following (in thousands): December 31, 2022 2021 Compensation and benefits $ 5,624 $ 4,303 Accrued research and development 3,936 4,937 Other 5,020 840 Total other current liabilities $ 14,580 $ 10,080

Leases

Leases	12 Months Ended
	Dec. 31, 2022
Leases [Abstract]
Lessee, Operating Leases [Text Block]	7. Leases The Company determines if an arrangement is a lease at inception. Operating leases are included in operating lease right-of-use or ROU assets and operating lease liabilities in the consolidated balance sheets. The Company has no finance leases as of December 31, 2022. ROU assets represent the right to use an underlying asset for the lease term and lease liabilities represent the obligation to make lease payments arising from the lease. Operating lease ROU assets and liabilities are recognized at commencement date based on the present value of lease payments over the lease term. As the Company’s leases do not provide an implicit rate, management estimated the incremental borrowing rate based on the rate of interest the Company would have to pay to borrow a similar amount on a collateralized basis over a similar term. The Company uses its incremental borrowing rate based on the information available at commencement date in determining the present value of lease payments. Summer Street Lease In September 2020, the Company entered into an operating lease agreement to lease 16,748 square feet of office and laboratory space at 645 Summer Street, Boston, Massachusetts or the Summer Street Lease with OPG MP Parcel Owner (DE) LLC or the Landlord. The original term of the Summer Street Lease expires in March 2026 . On May 5, 2022, the Company entered into an Agreement for Termination of Lease with the Landlord which, subject to the Landlord executing a lease with a new tenant, provides the Company with the option to terminate the existing Summer Street Lease. On August 8, 2022, the termination condition was met. As a result, the operating lease ROU asset and operating lease liability were reduced by $ 3.7 million to $ 1.3 million and $ 1.4 million, respectively, and the $ 1.0 million security deposit associated with the lease was reclassified from long-term restricted cash to current restricted cash on the consolidated balance sheet. The Summer Street lease will terminate on June 1, 2023 . Klybeck Lease In March 2021, the Company entered into an operating lease agreement for office and lab space that occupies approximately 21,422 square feet located at Hochbergerstrasse 60C, 4057 Basel, Basel-City, Switzerland. The current term of the lease expires in March 2026. Harrison Avenue Lease In December 2021, the Company entered into a non-cancelable lease agreement for 63,327 square feet of office and laboratory space to support its expanding operations or the Harrison Avenue Lease. The term of the lease commenced on April 1, 2022 and the Company’s obligation to pay rent began on December 21, 2022. The initial term of the lease is 128 months following the commencement date at which point the Company has the option to extend the lease an additional 5 years . As of the lease commencement date, the Company has determined that it is not reasonably certain to exercise the option to extend the lease and has not included the extension period in the lease term. The annual base rent under the Harrison Avenue Lease is $ 95.00 per square foot for the first year, which is subject to scheduled annual increases of 3 %, plus certain costs, operating expenses and property management fees. Pursuant to the terms of the Harrison Avenue Lease, the landlord will reimburse the Company for $ 13 million of tenant improvements. The Company will reduce the ROU asset and record an asset for construction in progress as costs are incurred and reimbursed. These costs will be reclassified from construction in progress to leasehold improvements upon completion of the project. As of December 31, 2022, the Company had $ 7.5 million receivable in reimbursable tenant improvements which is recorded as an other receivable on the consolidated balance sheet. The components of lease expense for the year ended December 31, 2022, are as follows (in thousands): Year ended December 31, 2022 Operating lease expense $ 6,924 Variable lease expense 1,898 Total lease expense $ 8,822 The variable lease expenses generally include common area maintenance and property taxes. Of the total lease expense, $ 7.8 million was recorded within research and development expenses and $ 1.0 million was recorded within general and administrative expenses in the consolidated statements of operations and comprehensive income (loss). There were no short-term lease costs in the year ended December 31, 2022. The weighted average remaining lease term and discount rate related to the Company's leases are as follows: December 31, 2022 Weighted average remaining lease term (years) 9.7 Weighted average discount rate 9.9 % Supplemental cash flow information relating to the Company's leases for the year ended December 31, 2022 are as follows (in thousands): Year ended December 31, 2022 Right-of-use assets obtained in exchange for operating lease obligations $ 48,488 Cash paid for amounts included in the measurement of lease liabilities $ 1,654 The amortization of the ROU assets for the year ended December 31, 2022 was $ 3.3 million. Future undiscounted lease payments under non-cancelable leases as of December 31, 2022 for each of the years ending December 31 are as follows (in thousands): Undiscounted lease payments 2023 $ 7,562 2024 6,982 2025 7,182 2026 7,053 2027 7,151 Thereafter 38,414 Total undiscounted lease payments 74,344 Less: Imputed interest ( 27,343 ) Total operating lease liability $ 47,001 Prior to January 1, 2022, the Company accounted for its leases in accordance with ASC Topic 840, Leases . As of December 31, 2021, the Company was committed under operating leases for its laboratory spaces and corporate offices. The future minimum lease payments under non-cancelable operating leases as of December 31, 2021 were as follows (in thousands): 2022 $ 3,160 2023 8,353 2024 8,583 2025 8,820 2026 7,298 Thereafter 44,784 Total future minimum lease payments $ 80,998

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2022
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	8. Commitments and contingencies License, collaboration and investment agreements In April 2018, the Company entered into license, collaboration and investment agreements with Cancer Research Technology Limited, or CRT, and The Institute of Cancer Research, or the ICR, for the purpose of development in the field of cereblon-mediated protein degradation, to support the Company’s early product development activities as the Company built its internal capabilities (the “License and Collaboration”). Pursuant to the License and Collaboration, CRT and the ICR granted the Company exclusive and non-exclusive, worldwide, and sublicensable licenses under CRT’s and the ICR’s intellection property rights in the field of cereblon mediated protein degradation to discover, research, develop, have developed, use, keep, make, have made, market, import, offer for sale, and sell products in the field of cereblon-mediated protein degradation. In consideration for the rights granted under the License Agreement, the Company issued an aggregate of 1,132,984 common shares to CRT, the ICR and affiliated founding scientists pursuant to the Formation and Investment Agreement and paid CRT a technology access fee. The License Agreement will remain effective until terminated by written agreement between the Company, CRT and the ICR. Upon execution of the License and Collaboration, the Company paid an immaterial access fee which was expensed to research and development in 2018. The research program conducted with the ICR with respect to cereblon-mediated protein degradation was completed as of December 31, 2020. However, the License and Collaboration Agreement continues until it is otherwise terminated under the terms and conditions stated within the agreement. There was no activity under this agreement for the year ended December 31, 2022. Under the License and Collaboration, the Company may be obligated to make certain milestone payments for achieving specific clinical progression events for certain products, solely to the extent such products are subject to the License and Collaboration. If owed, such milestones would aggregate up to $ 7 million for any covered first product candidate and $ 3.5 million for any covered subsequent product candidate. In addition, the Company may be obligated to pay low single-digit royalties on net sales for any covered product successfully developed and commercialized in the field of cereblon-mediated protein degradation under the terms of the License and Collaboration on a country by country basis until the later of (i) the date when the manufacture, use, offer for sale, sale or importation of such product is no longer covered by a valid claim in the country of sale, use or manufacture; (ii) ten years from the first commercial sale of such product in the relevant country; and (iii) the expiry of any extended exclusivity period granted with respect to an orphan drug designation, pediatric designation or other exclusivity in the relevant country. The License and Collaboration will remain effective until (i) the termination by either the Company or the ICR and CRT upon the bankruptcy or uncured breach of the other party, (ii) by the ICR and CRT if the Company should abandon all discovery, development and commercialization efforts for all products covered under the License and Collaboration; (iii) by the Company if it is determined the continued development of products covered under the License and Collaboration would be commercially unreasonable, scientifically unviable, illegal, unethical or impossible, with a 90-day notification period; or (iv) for any/no reason by written agreement of the Company and the ICR and CRT. Indemnification The Company, as permitted under Delaware law and in accordance with its certification of incorporation and bylaws and pursuant to indemnification agreements with certain of its officers and directors, indemnifies its officers and directors for certain events or occurrences, subject to certain limits, which the officer or director is or was serving at the Company’s request in such capacity. The Company enters into certain types of contracts that contingently require the Company to indemnify various parties against claims from third parties. These contracts primarily relate to (i) the Company’s bylaws, under which the Company must indemnify directors and executive officers, and may indemnify other officers and employees, for liabilities arising out of their relationship, (ii) contracts under which the Company must indemnify directors and certain officers and consultants for liabilities arising out of their relationship, and (iii) procurement, service or license agreements under which the Company may be required to indemnify vendors, service providers or licensees for certain claims, including claims that may be brought against them arising from the Company’s acts or omissions with respect to the Company’s products, technology, intellectual property or services. From time to time, the Company may receive indemnification claims under these contracts in the normal course of business. In the event that one or more of these matters were to result in a claim against the Company, an adverse outcome, including a judgment or settlement, may cause a material adverse effect on the Company’s future business, operating results or financial condition. As of December 31, 2022 and 2021 , the Company was not aware of any claims under indemnification arrangements and does not expect significant claims related to these indemnification obligations and, consequently, concluded that the fair value of these obligations is negligible. Therefore, no related reserves have been established.

Equity

Equity	12 Months Ended
	Dec. 31, 2022
Equity [Abstract]
Equity	9. Equity Undesignated Preferred Stock The Company had 10,000,000 shares authorized of undesignated preferred stock, par value of $ 0.0001 , of which no shares were issued and outstanding as of December 31, 2022. Common Stock The Company had 500,000,000 shares of common stock authorized, of which 49,445,802 shares were issued and 49,323,531 shares were outstanding at December 31, 2022. The holders of common stock are entitled to dividends when and if declared by the board of directors, subject to the preferences applicable to outstanding shares of Convertible Preferred Stock. The board of directors has no t declared any dividends and the Company has no t paid any dividends. The holders of common stock are entitled to one vote per share on all matters to be voted upon by the stockholders. The Company has issued restricted stock to founders, employees and consultants, and expense for this restricted stock is recognized on a straight-line basis (see Note 10) . The restricted stock generally vests monthly over 4 years . At-the-Market Offering In July 2022, the Company entered into a sales agreement, (the “Sales Agreement”), with Jefferies LLC, or Jefferies, pursuant to which the Company may offer and sell shares of its common stock having aggregate gross proceeds of up to $ 100 million from time to time in “at-the-market” offerings through Jefferies, as the Company’s sales agent. The Company agreed to pay Jefferies a commission of up to 3.0 % of the gross proceeds of any shares sold by Jefferies under the Sales Agreement. During the year ended December 31, 2022, the Company sold 2,482,008 shares of its common stock resulting in proceeds to the Company of $ 19.7 million, net of offering costs of $ 1.0 million.

Stock-based Compensation

Stock-based Compensation	12 Months Ended
	Dec. 31, 2022
Share-Based Payment Arrangement [Abstract]
Schedule of Fair Value of each Award Estimated Using Assumption	10. Stock-based compensation 2020 Stock incentive plan The Company's 2020 Stock Option and Grant Plan, or the 2020 Plan, provided for the Company to grant stock options, restricted stock, and other stock awards, to employees, non-employee directors, and consultants. Upon effectiveness of the 2021 Plan (as defined below), no further issuances will be made under the 2020 plan. 2021 Stock incentive plan The Company’s 2021 Stock Option and Incentive Plan, or the 2021 Plan, was approved by the Company’s board of directors on May 28, 2021, and the Company’s stockholders on June 17, 2021, and became effective on the date immediately prior to the date on which the registration statement for the Company’s IPO was declared effective. The 2021 Plan provides for the grant of incentive stock options, non-qualified stock options, stock appreciation rights, restricted stock units, restricted stock awards, unrestricted stock awards, cash-based awards and dividend equivalent rights to the Company’s officers, employees, directors and consultants. The number of shares initially reserved for issuance under the 2021 Plan was 4,903,145 , which will be automatically increased on each January 1st by 5 % of the outstanding number of shares of the Company’s common stock on the immediately preceding December 31st or such lesser number of shares as determined by the Compa ny’s compensation, nomination and corporate governance committee. As of December 31, 2022, 3,787,469 shares of common stock were available for issuance under 2021 Plan. 2021 Employee stock purchase plan The Company’s 2021 Employee Stock Purchase Plan, or the 2021 ESPP, was approved by the Company’s board of directors on May 28, 2021, and the Company’s stockholders on June 17, 2021, and became effective on the date immediately prior to the date on which the registration statement for the Company’s IPO was declared effective. A total of 439,849 shares of the Company’s common stock were initially reserved for issuance under the 2021 ESPP which will be automatically increased on each January 1st through January 1, 2031, by the least of (i) 439,849 shares of the Company’s common stock, (ii) 1 % of the outstanding number of shares of the Company’s common stock on the immediately preceding December 31 or (iii) such lesser number of shares of the Company’s common stock as determined by the plan administrator of the 2021 ESPP. As of December 31, 2022, 827,751 shares of common stock remained available for issuance under the 2021 ESPP. Stock option activity The following summarizes stock option activity: Number of Weighted Weighted Aggregate Outstanding—December 31, 2021 5,563,513 $ 7.92 9.2 $ 70,045 Granted 2,237,870 12.16 Exercised ( 117,552 ) 3.73 Forfeited ( 247,492 ) 11.70 Outstanding—December 31, 2022 7,436,339 $ 9.14 8.5 $ 12,440 Vested or expected to vest—December 31, 2022 7,436,339 $ 9.14 8.5 $ 12,440 Options exercisable—December 31, 2022 2,376,226 $ 7.32 8.2 $ 6,208 The aggregate intrinsic value of options granted is calculated as the difference between the exercise price of the options and the estimated fair value of the Company’s common stock. The weighted average grant date fair value of options granted in during the years ended December 31, 2022 and 2021 was $ 8.44 and $ 7.11 per share, respectively. Fair value of stock option awards The Company estimates the fair value of stock option awards on the grant date using Black-Scholes. The fair value of options granted were estimated using the following weighted-average assumptions: Year ended 2022 2021 Expected term (years) 6.25 6.25 Expected volatility 78.82 % 77.75 % Risk-free interest rate 2.02 % 1.25 % Expected dividend yield — % — % Black-Scholes requires the use of subjective assumptions which determine the fair value of stock-based awards. These assumptions include: Expected term : The Company’s expected term represents the period that options are expected to be outstanding and is determined using the simplified method. The Company does not have sufficient historical data to use any other method to estimate expected term. Expected volatility : The Company has limited information on the volatility of stock options as the shares were not actively traded on any public markets prior to June 24, 2021. The expected volatility was derived from historical stock volatilities of comparable peer public companies within its industry based on their similarities to the Company, including life cycle stage, therapeutic focus and size over a period equivalent to the expected term of the stock-based awards. Risk-free interest rate . The risk-free interest rate is based on the U.S. Treasury zero coupon issues in effect at the time of grant for periods corresponding with the expected term of the stock option grants. Expected dividend : The Company has never paid dividends on its common stock and has no plans to pay dividends on its common stock. Therefore, the Company used an expected dividend yield of zero. Restricted stock award activity Unvested restricted stock awards, or RSAs, as of December 31, 2022 and 2021, were granted to employees under the 2020 Plan. Restricted stock awards generally vest over a four year period provided the individual remains in continuous service of the Company. The following summarizes restricted stock activity: Number Weighted Unvested restricted stock as of December 31, 2021 258,329 $ 0.90 Vested ( 136,058 ) $ 0.78 Unvested restricted stock as of December 31, 2022 122,271 $ 1.04 The aggregate fair value of restricted stock that vested during the year ended December 31, 2022 and 2021 was $ 1.5 million and $ 5.2 million, respectively. The weighted average grant date fair value of restricted stock that vested during the year ended December 31, 2022 and 2021 was $ 0.78 and $ 1.13 per share, respectively. Restricted stock unit activity Starting in 2022, the Company granted restricted stock units, or RSUs, to employees under the 2021 Plan. Each of the RSUs represents the right to receive one share of the Company’s common stock upon vesting. The RSUs granted over two years provided the individual remains in continuous service of the Company. Accordingly, stock-based compensation expense for each RSU is recognized on a straight-line basis over the vesting term. The fair value of each RSU is based on the closing price of the Company’s common stock on the date of grant. The following summarizes restricted stock unit activity: Number Weighted Unvested restricted stock units as of December 31, 2021 — Granted 91,000 $ 10.11 Unvested restricted stock units as of December 31, 2022 91,000 $ 10.11 No RSUs vested during the year ended December 31, 2022 . Stock-based compensation expense Stock-based compensation expense is classified as follows (in thousands): Year ended 2022 2021 Research and development $ 5,582 $ 2,606 General and administrative 6,082 2,594 Total stock-based compensation expense $ 11,664 $ 5,200 As of December 31, 2022, total unrecognized stock–based compensation cost related to unvested stock options, restricted stock awards, and restricted stock units was $ 31.1 million, $ 0.1 million, and $ 0.7 million, respectively. The Company expects to recognize this remaining cost over a weighted average period of 2.5 years, 1.0 years, and 1.5 years, respectively.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2022
Income Tax Disclosure [Abstract]
Income Taxes	11. Income Taxes The Company has incurred net operating losses for all the periods presented. The Company has not reflected the benefit of any such net operating loss carryforwards in the accompanying consolidated financial statements. Domestic and foreign components of net loss are as follows (in thousands): Year ended 2022 2021 United States $ ( 17,232 ) $ ( 9,884 ) Foreign ( 91,269 ) ( 64,074 ) Net loss $ ( 108,501 ) $ ( 73,958 ) The effective tax rate for the years ended December 31, 2022 and 2021 is different from the federal statutory rate primarily due to the valuation allowance against deferred tax assets as a result of insufficient sources of income. The reconciliation of the federal statutory income tax rate to the Company’s effective income tax rate is as follows: Year ended 2022 2021 Income tax benefit at the federal statutory rate 21.0 % 21.0 % State income taxes, net of federal benefit 6.2 % 6.3 % Research and development tax credits 0.0 % 1.2 % Foreign rate differential ( 6.7 )% ( 6.9 )% Adjustment related to Preferred Stock Tranche Obligation — ( 0.3 )% Other ( 0.7 )% ( 1.6 )% Change in valuation allowance ( 19.8 )% ( 19.7 )% Total 0.0 % 0.0 % Deferred income taxes reflect the net effects of temporary differences between the carrying amounts of assets and liabilities for financial reporting purposes and the amounts used for income tax purposes. The principal components of the Company’s deferred tax assets consisted of the following (in thousands): December 31, 2022 2021 Deferred tax assets Federal and state net operating loss carryforwards $ 26,136 $ 14,529 Research and development tax credits 1,715 1,862 Capitalized research and development 1,151 — Lease liability 13,173 — Compensation related items 4,022 1,738 Other 149 58 Total deferred tax assets $ 46,346 $ 18,187 Less: valuation allowance ( 33,084 ) ( 17,777 ) Total net deferred tax assets $ 13,262 $ 410 Deferred tax liabilities Right-of-use asset ( 11,766 ) — Defined benefit plan adjustment ( 375 ) ( 125 ) Prepaid insurance ( 252 ) — Depreciation ( 869 ) ( 285 ) Total deferred tax liabilities ( 13,262 ) ( 410 ) Net deferred tax assets $ — $ — The Company has incurred annual net operating losses in each year since inception. The Company has not reflected the benefit of any such net operating loss carryforwards in the financial statements. Due to the Company’s history of losses, and lack of other positive evidence, the Company has determined that it is more likely than not that its net deferred tax assets will not be realized, and therefore, the net deferred tax assets are fully offset by a valuation allowance at December 31, 2022 and 2021 . The Company increased its valuation allowance by $ 15.3 million for the year ended December 31, 2022 in order to maintain a full valuation allowance against its deferred tax assets. As of December 31, 2022, the Company had federal net operating loss carryforwards, or NOLs, of $ 3.9 million and federal tax credits of $ 1.1 million available to offset tax liabilities. The Company’s federal NOLs have an indefinite life and federal tax credit carryforwards begin to expire in 2039. The Company also had gross foreign NOLs of $ 191.1 million that begin to expire in 2026. The Company also had gross state NOLs of $ 5.8 million and state tax credits of $ 0.6 million which are available to offset state tax liabilities. The state NOLs begin to expire in 2039 and the state tax credit carryforwards begin to expire in 2035 . Federal and state NOLs and tax credit carryforwards are also subject to annual limitations in the event that cumulative changes in the ownership interests of significant stockholders exceed 50 % over a three-year period, as defined under Sections 382 and 383 of the Internal Revenue Code of 1986. The Company has not completed an analysis to determine if the NOLs and tax credits are limited due to a change in ownership. Should there be ownership changes that occurred, the Company’s ability to utilize existing carryforwards could be substantially restricted. The Tax Cuts and Jobs Act resulted in significant changes to the treatment of research and development, or R&D, expenditures under Section 174. For tax years beginning after December 31, 2021, taxpayers are required to capitalize and amortize all R&D expenditures that are paid or incurred in connection with their trade or business. Specifically, costs for US-based R&D activities must be amortized over five years and costs for foreign R&D activities must be amortized over 15 years – both using a midyear convention. During the year ended December 31, 2022, the Company capitalized $ 4.0 million of R&D expenses. The Company determines its uncertain tax positions based on whether and how much of a tax benefit taken by the Company in its tax filings is more likely than not to be sustained upon examination by the relevant income tax authorities. A reconciliation of the beginning and ending amount of unrecognized tax benefits is as follows (in thousands): Year ended 2022 2021 Unrecognized tax benefits, beginning of year $ — $ — Additions for tax positions of prior years 2,235 — Reductions for tax provisions of prior years — — Unrecognized tax benefits, end of year $ 2,235 $ — The Company recognizes interest and penalties related to unrecognized tax benefits in U.S. Federal, state, and foreign income tax expense. For the year ended December 31, 2022, the unrecognized tax benefit generated was related to a reserve for the Federal and State Research and Development Credit of $ 2.2 million. The Company had approximately $ 2.2 million and $ 0.0 of unrecognized tax benefit as of December 31, 2022, and 2021, respectively. The Company files income tax returns in the U.S., Switzerland and Massachusetts. The Company is not currently under examination by any taxing authority for any open tax year. Due to net operating loss carryforwards, all years remain open for income tax examination. To the extent the Company has tax attribute carryforwards, the tax years in which the attribute was generated may still be adjusted upon examination by the Internal Revenue Service, or IRS, or state tax authorities to the extent utilized in a future period. No federal, foreign, or state tax audits are currently in process.

Employee Retirement Plans

Employee Retirement Plans	12 Months Ended
	Dec. 31, 2022
Retirement Benefits [Abstract]
Employee Retirement Plans	12. Employee retirement plans Defined benefit plan The Company, in compliance with Swiss Law, is contracted with the Swiss Life Collective BVG Foundation for the provision of pension benefits. All benefits are reinsured in their entirety with Swiss Life Ltd within the framework of the contract. The technical administration and management of the savings account are guaranteed by Swiss Life on behalf of the collective foundation. Insurance benefits due are paid directly to the entitled persons by Swiss Life in the name of and for the account of the collective foundation. The pension plan is financed by contributions of both employees and employer. The contract between the Company and the collective foundation can be terminated by either side. In the event of a termination, the Company would have an obligation to find alternative pension arrangements for its employees. Because there is no guarantee that the employee pension arrangements would be continued under the same conditions, there is a risk, albeit remote, that a pension obligation may fall on the Company. The pension assets are pooled for all affiliated companies; the investment of assets is done by the governing bodies of the collective foundation or by mandated parties. The risks of disability, death and longevity are reinsured in their entirety with Swiss Life Ltd. The following table represents the changes in benefit obligations and plan assets and the net amount recognized on the consolidated balance sheets (in thousands): Year ended 2022 2021 Change in benefit obligation: Benefit obligation—beginning of period $ 5,975 $ 2,284 Service cost employer 549 417 Contributions paid by employees 299 170 Interest cost 19 9 Contributions paid by plan participants 1,302 1,926 Benefits paid ( 452 ) ( 82 ) Plan Amendment ( 67 ) ( 42 ) Actuarial (gain) loss ( 774 ) 1,293 Benefit obligation—end of period $ 6,851 $ 5,975 Change in plan assets: Fair value of plan assets—beginning of period $ 3,799 $ 1,217 Actual return on plan assets ( 240 ) 226 Contributions paid by employer 610 340 Contributions paid by employees 299 175 Contributions paid by plan participants 1,302 1,926 Benefits paid ( 452 ) ( 85 ) Fair value of plan assets—end of period $ 5,318 $ 3,799 Defined benefit plan liability $ 1,533 $ 2,176 The net pension costs was as follows (in thousands): Year ended 2022 2021 Service cost $ 549 $ 417 Interest cost 19 9 Net pension cost $ 568 $ 426 The provision for pension benefit obligation recognized in other comprehensive loss was as follows (in thousands): Year ended 2022 2021 Actuarial gain (loss) arising from experience adjustments $ 774 $ ( 1,293 ) Defined benefit cost for the year recognized in other comprehensive loss $ 774 $ ( 1,293 ) The assumptions used to measure the projected benefit obligation and net pension costs were as follows: Year ended 2022 2021 Inflation rate 1.25 % 0.50 % Discount rate 2.30 % 0.35 % Interest rate on savings accounts 1.00 % 0.45 % Expected rate of return on assets 2.30 % 0.45 % Salary increase 1.25 % 1.00 % Social Security increase 1.25 % 0.50 % Pension increase 0.00 % 0.00 % Retirement age 100% Male 65 Female 64 100% Male 65 Female 64 Mortality and disability rates BVG 2020 Table BVG 2020 Table Estimated benefit payments, which reflect future expected service, are expected to be paid as follows (in thousands): December 31, 2023 $ 660 2024 $ 693 2025 $ 717 2026 $ 735 2027 $ 753 2028-2032 $ 4,239 Defined contribution plan In February 2021, the Company adopted a defined contribution plan intended to qualify under Section 401(k) of the Internal Revenue Code covering all eligible U.S. based employees of the Company. All employees are eligible to become participants of the plan immediately upon hire. Each active employee may elect, voluntarily, to contribute a percentage of their compensation to the plan each year, subject to certain limitations. The Company reserves the right, but is not obligated, to make additional contributions to this plan. The Company makes safe-harbor match contributions of 100 % of the first 4 % of each participant’s eligible compensation. The Company recorded $ 0.5 million and $ 0.3 million matching 401(k) contribution related expense during the years ended December 31, 2022 and 2021 , respectively.

Net loss per common share

Net loss per common share	12 Months Ended
	Dec. 31, 2022
Earnings Per Share [Abstract]
Net Loss Per Common Share	13. Net loss per common share Basic and diluted net loss per share attributable to common stockholders is calculated as follows (in thousands except share and per share amounts): Year ended December 31, 2022 2021 Net loss $ ( 108,501 ) $ ( 73,958 ) Net loss per share attributable to common stockholders—basic and diluted $ ( 2.30 ) $ ( 2.96 ) Weighted-average number of common shares used in computing net loss 47,227,370 25,000,124 The following outstanding potentially dilutive securities have been excluded from the calculation of diluted net loss per common share, as their effect is anti-dilutive: December 31, 2022 2021 Stock options to purchase common stock 7,436,339 5,563,513 Restricted stock awards 122,271 258,329 Restricted stock units 91,000 —

Related Parties

Related Parties	12 Months Ended
	Dec. 31, 2022
Related Party Transactions [Abstract]
Related Parties	14. Related parties The Company paid $ 0.4 million in contract research and development expenses to Tempus Labs, Inc. for the years ended December 31, 2022, and 2021 . A member of the Company's Board of Directors served as an officer of Tempus Labs, Inc. until May 2022. Tempus Labs, Inc. is no longer a related party as of December 31, 2022 .

Subsequent Events

Subsequent Events	12 Months Ended
	Dec. 31, 2022
Subsequent Events [Abstract]
Subsequent events	15. Subsequent events On March 10, 2023, Silicon Valley Bank (SVB) was closed by the California Department of Financial Protection and Innovation, which appointed the Federal Deposit Insurance Corporation as receiver. At the time of the closure, the Company had cash totaling about 2 % of our total cash, cash equivalents, and marketable securities held in operating accounts and money market accounts at SVB. The Company received full access to this cash on March 13, 2023.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2022
Accounting Policies [Abstract]
Risks And Uncertainties	Risks and uncertainties The Company is subject to risks common to companies in the biotechnology industry including, but not limited to, the successful discovery and development of its product candidates, new technological innovations, protection of proprietary technology, dependence on key personnel, compliance with government regulations and the need to obtain additional financing.
Liquidity Consideration	Liquidity considerations Since inception, the Company has devoted substantially all its efforts to business planning, research and development, recruiting management and technical staff, and raising capital and has financed its operations primarily through the issuance of convertible preferred shares and public offerings of the Company's common stock. The Company’s continued discovery and development of its product candidates will require significant additional research and development efforts, including extensive preclinical and clinical testing and regulatory approval prior to commercialization. These efforts require significant amounts of additional capital, adequate personnel and infrastructure and extensive compliance-reporting capabilities. Even if product development efforts are successful, it is uncertain when, if ever, the Company will realize significant revenue from product sales. As of December 31, 2022, the Company had an accumulated deficit of $ 230.5 million. The Company has incurred losses and negative cash flows from operations since inception, including net losses of $ 108.5 million and $ 74.0 million for the years ended December 31, 2022, and 2021, respectively. The Company expects that its operating losses and negative cash flows will continue for the foreseeable future as the Company continues to develop its product candidates. The Company currently expects that its cash, cash equivalents and marketable securities of $ 262.8 million as of December 31, 2022 , will be sufficient to fund operating expenses and capital requirements for at least 12 months from the date the consolidated financial statements are issued. However, additional funding will be necessary to fund future discovery research, pre-clinical and clinical activities. The Company will seek additional funding through public financings, debt financings, collaboration agreements, strategic alliances and licensing arrangements. Although it has been successful in raising capital in the past, there is no assurance that the Company will be successful in obtaining such additional financing on terms acceptable to it, if at all, and the Company may not be able to enter into collaborations or other arrangements. If the Company is unable to obtain funding, it could be forced to delay, reduce or eliminate its research and development programs, product portfolio expansion or commercialization efforts, which could adversely affect the Company’s business prospects, even the ability to continue operations.
Basis of Presentation	Basis of presentation The accompanying consolidated financial statements have been prepared in conformity with accounting principles generally accepted in the United States of America, or GAAP, and are stated in U.S. dollars. Any reference in these notes to applicable guidance is meant to refer to the authoritative GAAP as found in the Accounting Standards Codification and Accounting Standards Updates, or ASUs, of the Financial Accounting Standards Board, or FASB. All intercompany balances and transactions have been eliminated in combination or consolidation.
Use of Estimates	Use of estimates The preparation of the consolidated financial statements in conformity with GAAP requires the Company to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosures of contingent assets and liabilities at the date of the financial statements and reported amounts of expenses during the reporting periods. Actual results could differ from those estimates. On an ongoing basis, the Company evaluates its estimates, including those related to accrued research and development expenses, other long-lived assets, pension benefit obligation, stock-based compensation and the valuation of deferred tax assets. The Company bases its estimates using historical experience, Company forecasts and future plans, current economic conditions, and information from third-party professionals that management believes to be reasonable under the circumstances, the results of which form the basis for making judgments about the carrying value of assets and liabilities and recorded amounts of expenses that are not readily apparent from other sources and adjusts those estimates and assumptions when facts and circumstances dictate.
Currency and Currency Translation	Currency and currency translation The consolidated financial statements are presented in U.S. dollars, the Company’s reporting currency. The functional currency of the Company’s wholly owned subsidiary, Monte Rosa Therapeutics AG, is the U.S. dollar. Adjustments that arise from exchange rate changes on transactions denominated in a currency other than the functional currency are included in foreign currency exchange gain (loss), net in the consolidated statements of operations.
Cash, Cash Equivalents and Restricted Cash	Cash, cash equivalents and restricted cash The Company considers all highly liquid investments with original maturities at the date of purchase of three months or less to be cash equivalents. Cash and cash equivalents are stated at fair value and may include money market funds, U.S. Treasury and U.S. government-sponsored agency securities, corporate debt, commercial paper and certificates of deposit. The Company’s cash equivalents at December 31, 2022 and 2021 consist of bank demand deposits and money market fund investments. The Company had restricted cash of $ 5.3 million as of December 31, 2022, and 2021 , primarily related to security deposits on its leases for offices in Boston, Massachusetts and Basel, Switzerland.
Marketable Securities	Marketable securities Investments in marketable securities are classified as available-for-sale. Available-for-sale securities are measured and reported at fair value using quoted prices in active markets for similar securities. Unrealized gains and losses on available-for-sale securities are reported as a separate component of stockholders’ equity. Premiums or discounts from par value are amortized to investment income over the life of the underlying investment. All of the Company’s available-for-sale securities are available to the Company for use in current operations. As a result, the Company classified all of these securities as current assets even though the stated maturity of some individual securities may be one year or more beyond the balance sheet date. The cost of securities sold is determined on a specific identification basis, and realized gains and losses are included in other income (expense) within the consolidated statements of operations and comprehensive loss. If any adjustment is required to reflect a decline in the value of the investment that the Company considers to be “other than temporary”, the Company recognizes a charge to the consolidated statement of operations and comprehensive loss. No such adjustments were necessary during the periods presented.
Concentrations of Credit Risk and Off-Balance Sheet Risk	Concentrations of credit risk and off-balance sheet risk Financial instruments that potentially subject the Company to a concentration of credit risk consist primarily of cash and cash equivalents. The Company has invested in cash and cash equivalents at December 31, 2022 and 2021 , held in a financial institution that management believes is creditworthy. These deposits may exceed federally insured limits. The Company has not experienced any losses historically in these accounts and believes it in not exposed to significant credit risk in its cash and cash equivalents. The Company has no significant off-balance sheet concentrations of credit risk, such as foreign currency exchange contracts, option contracts, or other hedging arrangements.
Fair Value of Financial Instruments	Fair value of financial instruments Assets and liabilities recorded at fair value on a recurring basis in the balance sheets are categorized based upon the level of judgment associated with the inputs used to measure their fair values. Fair value is defined as the exchange price that would be received for an asset or an exit price that would be 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. Valuation techniques used to measure fair value must maximize the use of observable inputs and minimize the use of unobservable inputs. The authoritative guidance on fair value measurements establishes a three-tier fair value hierarchy for disclosure of fair value measurements as follows: Level 1—Observable inputs such as unadjusted, quoted prices in active markets for identical assets or liabilities at the measurement date. Level 2—Inputs (other than quoted prices included in Level 1) that are either directly or indirectly observable for the asset or liability. These include quoted prices for similar assets or liabilities in active markets and quoted prices for identical or similar assets or liabilities in markets that are not active. Level 3—Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities. To the extent that the valuation is based on models or inputs that are less observable or unobservable in the market, the determination of fair value requires more judgment. Accordingly, the degree of judgment exercised by the Company in determining fair value is greatest for instruments categorized in Level 3. A financial instrument’s level within the fair value hierarchy is based on the lowest level of any input that is significant to the fair value instrument.
Property and Equipment	Property and equipment Property and equipment are stated at cost, subject to adjustments for impairments, less accumulated depreciation. Purchased assets that are not yet in service are classified as construction-in-process and no depreciation expense is recorded. Depreciation is calculated using the straight-line method over the estimated useful life of the asset as follows: Asset Estimated useful life Laboratory equipment Five years Computer hardware Three years Furniture and fixtures Five Years Leasehold Improvements Shorter of useful life or remaining lease term Maintenance and repairs that do not improve or extend the life of the respective asset are expensed as incurred. Upon disposal of an asset, the related cost and accumulated depreciation are removed from the accounts and any resulting gain or loss is included in the results of operations. Leasehold improvements are amortized over the shorter of the useful life or remaining term of the lease.
Impairment of Long-Lived Assets	Impairment of long-lived assets The Company evaluates whether current facts or circumstances indicate that the carrying values of its long-lived assets may not be recoverable. If such facts or circumstances are determined to exist, an estimate of the undiscounted future cash flows of these assets is compared to the carrying value the assets to determine whether impairment exists. If the assets are determined to be impaired, the loss is measured based on the difference between the fair value and carrying value of the assets. No material impairment losses were recorded during the periods presented.
Research and Development Expenses	Research and development expenses Research and development costs are expensed as incurred. The Company’s research and development expenses consist primarily of costs incurred for the research and development of its product candidates and include expenses incurred under agreements with consultants to conduct preclinical and clinical studies, costs to acquire supplies for preclinical and clinical studies, salaries and related personnel costs, including stock-based compensation, depreciation and other allocated facility-related and overhead expenses.
Accrued Research and Development Costs	Accrued research and development costs The Company records accruals for estimated costs of discovery research activities, preclinical, and clinical studies. A portion of the Company’s research and development activities are conducted by third-party service providers. The financial terms of these contracts are subject to negotiation, which vary by contract and may result in payments that do not match the periods over which materials or services are provided. The Company accrues the costs incurred under the agreements based on an estimate of actual work completed in accordance with the agreements. In the event the Company makes advance payments for goods or services that will be used or rendered for future research and development activities, the payments are deferred and capitalized as a prepaid expense and recognized as expense as the goods are received or the related services are rendered. Such payments are evaluated for current or long-term classification based on when they are expected to be realized. If the Company does not identify costs that have begun to be incurred or if the Company underestimates or overestimates the level of services performed or the costs of these services, actual expenses could differ from the Company’s estimates.
Preferred Stock Tranche Obligations	Preferred stock tranche obligations Included in the terms of the Series A and Series B Preferred Stock Purchase Agreements were certain rights, or Tranche Rights, granted to the investors who purchased the Series A and Series B Preferred. The Series A Tranche Rights gave the investor the option to purchase up to an aggregate of 15,000,000 additional shares of Series A Preferred at $ 1.00 per share. The Series B Tranche Rights gave investors the option to purchase up to an aggregate of 24,000,000 shares of Series B Preferred at $ 2.00 per share. The Company concluded that both the Series A and the Series B Tranche Rights met the definition of a freestanding financial instrument, as the Series A and Series B Tranche Rights were legally detachable and separately exercisable from the Series A and Series B Preferred. At initial recognition, the Company recorded these Series A and Series B Tranche Rights as a liability on the balance sheets at its estimated fair value. The Series A and Series B Preferred Stock Tranche Obligations are subject to remeasurement at each balance sheet date, with changes in fair value recognized in changes in fair value of Preferred Stock Tranche Obligations on the Company’s consolidated statements of operations and comprehensive loss. Immediately prior to consummation of our IPO in June 2021, all outstanding shares of the Company's Series A, Series A-2, Series B and Series C convertible preferred stock were converted into 31,068,102 shares of common stock. As such, there was no value recorded for preferred stock tranche obligations on the consolidated balance sheets as of December 31, 2022 and 2021 .
Share-Based Compensation	Stock-based compensation Stock-based compensation expense related to stock options granted to employees, directors and non-employees is recognized based on the grant-date estimated fair values of the awards using the Black-Scholes option pricing model, or Black-Scholes. Stock-based compensation expense related to stock options and other stock based awards granted to employees and non-employees is recognized based on the grant-date fair value of the Company’s common stock. The value is recognized as expense ratably over the requisite service period, which is generally the vesting term of the award. For stock options with performance-based vesting conditions, the Company records the expense for these awards based upon the fair value of the awards on the date of grant and the number of shares expected to vest based on the terms of the underlying award agreement and the requisite service periods. The Company adjusts the expense for actual forfeitures as they occur. Stock-based compensation expense is classified in the accompanying consolidated statements of operations based on the function to which the related services are provided.
Income Taxes	Income taxes The Company uses the liability method to account for income taxes. Under this method, deferred tax assets and liabilities are determined based on differences between the financial statement carrying amounts of existing assets and liabilities and their tax bases. Deferred tax assets and liabilities are measured using enacted tax rates applied to taxable income in the years in which those temporary differences are expected to be recovered or settled. A valuation allowance is established when necessary to reduce deferred tax assets to the amount expected to be realized. The Company assesses the likelihood of deferred tax assets being realized. A valuation allowance is provided when it is more likely than not that some portion or all of a deferred tax asset will not be realized. In assessing the realizability of deferred tax assets, the Company considers whether it is more likely than not that some portion or all of the deferred tax assets will not be realized. The ultimate realization of deferred tax assets is dependent upon the generation of future taxable income during the periods in which the temporary differences representing net future deductible amounts become deductible. The Company files U.S. federal and state income tax returns, as well as Swiss income tax returns. The Company’s tax positions are subject to audit. Financial statement effects of uncertain tax positions are recognized when it is more likely than not, based on the technical merits of the position, that it will be sustained upon examination. The Company evaluates uncertain tax positions on a regular basis. The evaluations are based on a number of factors, including changes in facts and circumstances, changes in tax law, correspondence with tax authorities during the course of the audit, and effective settlement of audit issues. Interest and penalties related to unrecognized tax benefits are included within the provision for income tax. To date, the Company has not been subject to any interest and penalties.
Defined Pension Benefit Obligation	Defined pension benefit obligation The Company maintains a mandatory pension for its employees in Switzerland through affiliation with the Swiss Life Collective BVG Foundation. All benefits in accordance with the regulations are reinsured in their entirety with Swiss Life Ltd within the framework of the corresponding contract. This plan is considered to be a defined benefit plan under GAAP. The Company recognizes an asset for the plan’s overfunded status or a liability for the plan’s underfunded status in its consolidated balance sheets. Additionally, the Company measures the plan’s assets and obligations that determine its funded status as of the end of the year and recognizes the change in the funded status within the consolidated statements of operations and comprehensive loss. The Company uses an actuarial valuation to determine its pension benefit costs and credits. The amounts calculated depend on a variety of key assumptions, including discount rates and expected return on plan assets. Details of the assumptions used to determine the net funded status are described in Note 12. The Company’s pension plan assets are assigned to their respective levels in the fair value hierarchy in accordance with the valuation principles described in the Fair Value of Financial Instruments section above.
Segments	Segments Operating segments are defined as components of an entity for which separate financial information is available and that is regularly reviewed by the chief operating decision maker, or CODM, in deciding how to allocate resources to an individual segment and in assessing performance. The Company’s CODM is its chief executive officer. The Company manages its operations as a single segment for the purposes of assessing performance and making operating decisions.
Comprehensive income (loss)	Comprehensive income (loss) Comprehensive income (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. The Company’s other comprehensive income (loss) includes adjustments to unrecognized pension benefit costs for Monte Rosa Therapeutics AG and changes in unrealized gains and losses from available-for-sale investments. The Company reported other comprehensive income of $ 0.3 million and incurred other comprehensive loss of $ 1.0 million, for the years ended December 31, 2022 and 2021 , respectively.
Recently Adopted Accounting Pronouncements	Recently issued accounting pronouncements The Company has elected to use the extended transition period for complying with new or revised accounting standards as available under the Jumpstart Our Business Startups Act (JOBS Act). In June 2016, the FASB issued Accounting Standards Update No. 2016-13, Financial Instruments-Credit Losses: Measurement of Credit Losses on Financial Instruments . ASU 2016-13 requires measurement and recognition of expected credit losses for financial assets. In April 2019, the FASB issued clarification to ASU 2016-13 within ASU 2019-04, Codification Improvements to Topic 326, Financial Instruments-Credit Losses, Topic 815, Derivatives and Hedging , and Topic 825, Financial Instruments , or ASU 2016-13. The guidance is effective for fiscal years beginning after December 15, 2022. The Company does not expect for ASU 2016-13 to have a material impact on its financial statements. In August 2020, the FASB issued ASU No. 2020-06, Debt—Debt with Conversion and Other Options (Subtopic 470-20) and Derivatives and Hedging Contracts in Entity s Own Equity (Subtopic 815-40): Accounting for Convertible Instruments and Contracts in an Entity’s Own Equity . ASU 2020-06 will simplify the accounting for convertible instruments by reducing the number of accounting models for convertible debt instruments and convertible preferred stock. Limiting the accounting models results in fewer embedded conversion features being separately recognized from the host contract as compared with current GAAP. Convertible instruments that continue to be subject to separation models are (i) those with embedded conversion features that are not clearly and closely related to the host contract, that meet the definition of a derivative, and that do not qualify for a scope exception from derivative accounting and (ii) convertible debt instruments issued with substantial premiums for which the premiums are recorded as paid-in capital. ASU 2020-06 also amends the guidance for the derivatives scope exception for contracts in an entity’s own equity to reduce form-over-substance-based accounting conclusions. ASU 2020-06 will be effective for the Company beginning after December 15, 2023. Early adoption is permitted, but no earlier than fiscal years beginning after December 15, 2020, including interim periods within those fiscal years. The Company is currently assessing the impact adoption of ASU 2020-06 will have on the financial statements and disclosures. Recently adopted accounting pronouncements On January 1, 2022, the Company adopted Accounting Standard Update or ASU No. 2016-02, Leases (Topic 842) , and its associated amendments using the modified retrospective transition approach by applying the new standard to all leases existing at the date of initial application and not restating comparative periods. There was no cumulative-effect adjustment recorded to retained earnings upon adoption. Under Topic 842, a lessee is required to recognize a lease liability and right-of-use (ROU) asset for all leases, unless the lease qualifies for the short-term lease exception. The new guidance also modified the classification criteria and requires additional disclosures to enable users of financial statements to understand the amount, timing, and uncertainty of cash flows arising from leases. Consistent with current guidance, a lessee’s recognition, measurement, and presentation of expenses and cash flows arising from a lease continues to depend primarily on its classification. The Company elected the package of practical expedients permitted under the transition guidance, which allowed the Company to carryforward its historical lease classification, its assessment on whether a contract was or contains a lease, and its initial direct costs for any leases that existed prior to January 1, 2022. In addition, the Company elected the following transitional practical expedients: (1) the short-term lease exception and (2) to not separate its non-lease components for its real estate, vehicle and equipment leases. Upon the adoption of this standard, the Company recorded operating lease right-of-use assets of $ 7.3 million and corresponding operating lease liabilities of $ 7.4 million as of January 1, 2022. The difference between the value of the right-of-use assets and lease liabilities is due to the reclassification of existing deferred rent as of January 1, 2022. In December 2019, the FASB issued ASU 2019-12, Simplifying the Accounting for Income Taxes , or ASU 2019-12. ASU 2019-12 eliminates certain exceptions related to the approach for intra-period tax allocation, the methodology for calculating income taxes in an interim period and the recognition of deferred tax liabilities for outside basis differences. It also clarifies and simplifies other aspects of the accounting for income taxes. This guidance is effective for fiscal years beginning after December 15, 2021, and interim periods within fiscal years beginning after December 15, 2022. The Company adopted ASU 2019-12 on January 1, 2022. The adoption of the standard was immaterial to the accompanying consolidated financial statements.

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2022
Accounting Policies [Abstract]
Schedule of Property and Equipment Estimated Useful Life	Depreciation is calculated using the straight-line method over the estimated useful life of the asset as follows: Asset Estimated useful life Laboratory equipment Five years Computer hardware Three years Furniture and fixtures Five Years Leasehold Improvements Shorter of useful life or remaining lease term

Fair value measurements (Tables

Fair value measurements (Tables)	12 Months Ended
	Dec. 31, 2022
Fair Value Disclosures [Abstract]
Schedule of Fair Value of Assets and Liabilities Measured On Recurring Basis	The following tables present information about the Company’s financial assets and liabilities measured at fair value on a recurring basis and indicate the level of the fair value hierarchy utilized to determine such fair values (in thousands): As of December 31, 2022 Level 1 Level 2 Level 3 Total Current assets Money market funds $ 50,633 $ — $ — $ 50,633 Pension plan assets — 5,320 — 5,320 Corporate debt securities — 127,351 — 127,351 U.S. Treasury securities — 80,563 — 80,563 Total assets measured at fair value $ 50,633 $ 213,234 $ — $ 263,867 As of December 31, 2021 Level 1 Level 2 Level 3 Total Current assets Money market funds $ 317,004 $ — $ — $ 317,004 Pension plan assets — 3,796 — 3,796 Total assets measured at fair value $ 317,004 $ 3,796 $ — $ 320,800

Marketable securities (Tables)

Marketable securities (Tables)	12 Months Ended
	Dec. 31, 2022
Investments, Debt and Equity Securities [Abstract]
Summary of Marketable securities	Marketable securities as of December 31, 2022, consisted of the following (in thousands): Amortized Unrealized Unrealized Fair Cost Gains Losses Value Description Corporate debt securities $ 127,565 $ 27 $ ( 241 ) $ 127,351 U.S Treasury securities 80,798 2 ( 237 ) 80,563 Total $ 208,363 $ 29 $ ( 478 ) $ 207,914

Property and Equipment, net (Ta

Property and Equipment, net (Tables)	12 Months Ended
	Dec. 31, 2022
Property, Plant and Equipment [Abstract]
Schedule of Property and Equipment	Property and equipment, net, consist of the following (in thousands): December 31, 2022 2021 Laboratory equipment $ 17,766 $ 12,315 Computer hardware and software 499 299 Furniture and fixtures 388 443 Leasehold improvements 2,660 1,119 Construction in process 12,013 852 Total property and equipment, at cost $ 33,326 $ 15,028 Less: accumulated depreciation ( 6,251 ) ( 2,703 ) Property and equipment, net $ 27,075 $ 12,325

Accrued expenses and other cu_2

Accrued expenses and other current liabilities (Tables)	12 Months Ended
	Dec. 31, 2022
Accounts Payable and Accrued Liabilities, Current [Abstract]
Schedule of Accrued Expenses and Other Current Liabilities	Accrued expenses and other current liabilities consist of the following (in thousands): December 31, 2022 2021 Compensation and benefits $ 5,624 $ 4,303 Accrued research and development 3,936 4,937 Other 5,020 840 Total other current liabilities $ 14,580 $ 10,080

Leases (Tables)

Leases (Tables)	12 Months Ended
	Dec. 31, 2022
Leases [Abstract]
Summary of Lease Expense	The components of lease expense for the year ended December 31, 2022, are as follows (in thousands): Year ended December 31, 2022 Operating lease expense $ 6,924 Variable lease expense 1,898 Total lease expense $ 8,822
Schedule Of Lease Terms And Discount Rate	The weighted average remaining lease term and discount rate related to the Company's leases are as follows: December 31, 2022 Weighted average remaining lease term (years) 9.7 Weighted average discount rate 9.9 %
Schedule Of Supplemental Cash Flow Information Related To Leases	Supplemental cash flow information relating to the Company's leases for the year ended December 31, 2022 are as follows (in thousands): Year ended December 31, 2022 Right-of-use assets obtained in exchange for operating lease obligations $ 48,488 Cash paid for amounts included in the measurement of lease liabilities $ 1,654
Schedule of Future Minimum Lease Payments Under Non-Cancelable Leases	Future undiscounted lease payments under non-cancelable leases as of December 31, 2022 for each of the years ending December 31 are as follows (in thousands): Undiscounted lease payments 2023 $ 7,562 2024 6,982 2025 7,182 2026 7,053 2027 7,151 Thereafter 38,414 Total undiscounted lease payments 74,344 Less: Imputed interest ( 27,343 ) Total operating lease liability $ 47,001
Schedule of Future Minimum Rental Payments of Operating Leases Under non- cancelable	The future minimum lease payments under non-cancelable operating leases as of December 31, 2021 were as follows (in thousands): 2022 $ 3,160 2023 8,353 2024 8,583 2025 8,820 2026 7,298 Thereafter 44,784 Total future minimum lease payments $ 80,998

Commitments and Contingencies (

Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2022
Commitments and Contingencies Disclosure [Abstract]
Schedule of Future Minimum Rental Payments of Operating Leases Under non- cancelable	The future minimum lease payments under non-cancelable operating leases as of December 31, 2021 were as follows (in thousands): 2022 $ 3,160 2023 8,353 2024 8,583 2025 8,820 2026 7,298 Thereafter 44,784 Total future minimum lease payments $ 80,998

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	12 Months Ended
	Dec. 31, 2022
Share-Based Payment Arrangement [Abstract]
Schedule of Stock Option Activity	The following summarizes stock option activity: Number of Weighted Weighted Aggregate Outstanding—December 31, 2021 5,563,513 $ 7.92 9.2 $ 70,045 Granted 2,237,870 12.16 Exercised ( 117,552 ) 3.73 Forfeited ( 247,492 ) 11.70 Outstanding—December 31, 2022 7,436,339 $ 9.14 8.5 $ 12,440 Vested or expected to vest—December 31, 2022 7,436,339 $ 9.14 8.5 $ 12,440 Options exercisable—December 31, 2022 2,376,226 $ 7.32 8.2 $ 6,208
Schedule of Fair Value of each Award Estimated Using Assumption	The fair value of options granted were estimated using the following weighted-average assumptions: Year ended 2022 2021 Expected term (years) 6.25 6.25 Expected volatility 78.82 % 77.75 % Risk-free interest rate 2.02 % 1.25 % Expected dividend yield — % — %
Schedule of Restricted Stock Award Activity	The following summarizes restricted stock activity: Number Weighted Unvested restricted stock as of December 31, 2021 258,329 $ 0.90 Vested ( 136,058 ) $ 0.78 Unvested restricted stock as of December 31, 2022 122,271 $ 1.04
Schedule of Restricted Stock Unit Activity	Number Weighted Unvested restricted stock units as of December 31, 2021 — Granted 91,000 $ 10.11 Unvested restricted stock units as of December 31, 2022 91,000 $ 10.11 No RSUs vested during the year ended December 31, 2022 .
Schedule of Stock Based Compensation Expense	Stock-based compensation expense is classified as follows (in thousands): Year ended 2022 2021 Research and development $ 5,582 $ 2,606 General and administrative 6,082 2,594 Total stock-based compensation expense $ 11,664 $ 5,200

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2022
Income Tax Disclosure [Abstract]
Schedule of Domestic And Foreign Components of Net Loss	Year ended 2022 2021 United States $ ( 17,232 ) $ ( 9,884 ) Foreign ( 91,269 ) ( 64,074 ) Net loss $ ( 108,501 ) $ ( 73,958 )
Schedule of Reconciliation of Federal Statutory Income Tax Rate to Effective Income Tax Rate	Year ended 2022 2021 Income tax benefit at the federal statutory rate 21.0 % 21.0 % State income taxes, net of federal benefit 6.2 % 6.3 % Research and development tax credits 0.0 % 1.2 % Foreign rate differential ( 6.7 )% ( 6.9 )% Adjustment related to Preferred Stock Tranche Obligation — ( 0.3 )% Other ( 0.7 )% ( 1.6 )% Change in valuation allowance ( 19.8 )% ( 19.7 )% Total 0.0 % 0.0 %
Summary of Components of Deferred Tax Assets (Liabilities)	December 31, 2022 2021 Deferred tax assets Federal and state net operating loss carryforwards $ 26,136 $ 14,529 Research and development tax credits 1,715 1,862 Capitalized research and development 1,151 — Lease liability 13,173 — Compensation related items 4,022 1,738 Other 149 58 Total deferred tax assets $ 46,346 $ 18,187 Less: valuation allowance ( 33,084 ) ( 17,777 ) Total net deferred tax assets $ 13,262 $ 410 Deferred tax liabilities Right-of-use asset ( 11,766 ) — Defined benefit plan adjustment ( 375 ) ( 125 ) Prepaid insurance ( 252 ) — Depreciation ( 869 ) ( 285 ) Total deferred tax liabilities ( 13,262 ) ( 410 ) Net deferred tax assets $ — $ —
Summary of Income Tax Contingencies [Table Text Block]	A reconciliation of the beginning and ending amount of unrecognized tax benefits is as follows (in thousands): Year ended 2022 2021 Unrecognized tax benefits, beginning of year $ — $ — Additions for tax positions of prior years 2,235 — Reductions for tax provisions of prior years — — Unrecognized tax benefits, end of year $ 2,235 $ —

Employee Retirement Plans (Tabl

Employee Retirement Plans (Tables)	12 Months Ended
	Dec. 31, 2022
Retirement Benefits [Abstract]
Schedule of Changes in Benefit Obligations, Plan Assets and Net Amount Recognized in Balance Sheets	The following table represents the changes in benefit obligations and plan assets and the net amount recognized on the consolidated balance sheets (in thousands): Year ended 2022 2021 Change in benefit obligation: Benefit obligation—beginning of period $ 5,975 $ 2,284 Service cost employer 549 417 Contributions paid by employees 299 170 Interest cost 19 9 Contributions paid by plan participants 1,302 1,926 Benefits paid ( 452 ) ( 82 ) Plan Amendment ( 67 ) ( 42 ) Actuarial (gain) loss ( 774 ) 1,293 Benefit obligation—end of period $ 6,851 $ 5,975 Change in plan assets: Fair value of plan assets—beginning of period $ 3,799 $ 1,217 Actual return on plan assets ( 240 ) 226 Contributions paid by employer 610 340 Contributions paid by employees 299 175 Contributions paid by plan participants 1,302 1,926 Benefits paid ( 452 ) ( 85 ) Fair value of plan assets—end of period $ 5,318 $ 3,799 Defined benefit plan liability $ 1,533 $ 2,176
Schedule of Net Pension Costs	The net pension costs was as follows (in thousands): Year ended 2022 2021 Service cost $ 549 $ 417 Interest cost 19 9 Net pension cost $ 568 $ 426
Schedule of Provision for Defined Benefit Plan Obligation Recognized in Other Comprehensive Loss	The provision for pension benefit obligation recognized in other comprehensive loss was as follows (in thousands): Year ended 2022 2021 Actuarial gain (loss) arising from experience adjustments $ 774 $ ( 1,293 ) Defined benefit cost for the year recognized in other comprehensive loss $ 774 $ ( 1,293 )
Schedule of Assumptions Used to Measure Projected Benefit Obligation and Net Pension Costs	The assumptions used to measure the projected benefit obligation and net pension costs were as follows: Year ended 2022 2021 Inflation rate 1.25 % 0.50 % Discount rate 2.30 % 0.35 % Interest rate on savings accounts 1.00 % 0.45 % Expected rate of return on assets 2.30 % 0.45 % Salary increase 1.25 % 1.00 % Social Security increase 1.25 % 0.50 % Pension increase 0.00 % 0.00 % Retirement age 100% Male 65 Female 64 100% Male 65 Female 64 Mortality and disability rates BVG 2020 Table BVG 2020 Table
Schedule of Estimated Future Benefit Payments	Estimated benefit payments, which reflect future expected service, are expected to be paid as follows (in thousands): December 31, 2023 $ 660 2024 $ 693 2025 $ 717 2026 $ 735 2027 $ 753 2028-2032 $ 4,239

Net loss per common share (Tabl

Net loss per common share (Tables)	12 Months Ended
	Dec. 31, 2022
Earnings Per Share [Abstract]
Schedule of Earnings Per Share, Basic and Diluted	Basic and diluted net loss per share attributable to common stockholders is calculated as follows (in thousands except share and per share amounts): Year ended December 31, 2022 2021 Net loss $ ( 108,501 ) $ ( 73,958 ) Net loss per share attributable to common stockholders—basic and diluted $ ( 2.30 ) $ ( 2.96 ) Weighted-average number of common shares used in computing net loss 47,227,370 25,000,124
Schedule of Antidilutive Securities Excluded from Earnings Per Share Calculation	The following outstanding potentially dilutive securities have been excluded from the calculation of diluted net loss per common share, as their effect is anti-dilutive: December 31, 2022 2021 Stock options to purchase common stock 7,436,339 5,563,513 Restricted stock awards 122,271 258,329 Restricted stock units 91,000 —

Description of Business, Cont_2

Description of Business, Contribution and Exchange, and Liquidity - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Subsidiary Or Equity Method Investee [Line Items]
Common stock, shares, issued	49,445,802	46,794,295
Common stock, par or stated value per share	$ 0.0001	$ 0.0001
Proceeds from initial public offering, net of underwriting discount	$ 0	$ 237,750
Issuance of common stock, net of issuance cost of $620	20,055	0
Accumulated deficit	(230,536)	(122,035)
Net loss	(108,501)	(73,958)
Restricted Cash and Cash Equivalents	262,800
Cash and cash equivalents and restricted cash	$ 60,190	$ 351,409	$ 42,863

Summary of Significant Accoun_4

Summary of Significant Accounting Policies - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Jan. 01, 2022
Summary Of Significant Accounting Policies [Line Items]
Restricted cash	$ 5,278	$ 5,338
Impairment of long-lived assets	0
Other comprehensive loss	300	(1,000)
Operating lease right-of-use assets	34,832	0	$ 7,300
Operating Lease liability			$ 7,400
Preferred stock tranche obligations	$ 0	0
Series A Tranche Rights [Member]
Summary Of Significant Accounting Policies [Line Items]
Maximum shares purchase rights to investors	15,000,000
Shares purchase price	$ 1
Series B Tranche Rights [Member]
Summary Of Significant Accounting Policies [Line Items]
Maximum shares purchase rights to investors	24,000,000
Shares purchase price	$ 2
SeriesCTrancheRights [Member]
Summary Of Significant Accounting Policies [Line Items]
Shares of common stock	31,068,102
Security Deposits [Member]
Summary Of Significant Accounting Policies [Line Items]
Restricted cash	$ 5,300	$ 5,300

Summary of Significant Accoun_5

Summary of Significant Accounting Policies - Schedule of Property and Equipment Estimated Useful Life (Details)	12 Months Ended
	Dec. 31, 2022
Laboratory Equipment
Property Plant And Equipment [Line Items]
Property and equipment, useful life	5 years
Computer Hardware
Property Plant And Equipment [Line Items]
Property and equipment, useful life	3 years
Furniture and Fixtures
Property Plant And Equipment [Line Items]
Property and equipment, useful life	5 years
Leasehold Improvements
Property Plant And Equipment [Line Items]
Property, Plant and Equipment, Useful Life, Description	Shorter of useful life or remaining lease term

Fair Value Measurements - Summa

Fair Value Measurements - Summary of Financial Assets Liabilities Measured on Recurring Basis (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Current assets
Total assets measured at fair value	$ 263,867	$ 320,800
Level 1 [Member]
Current assets
Total assets measured at fair value	50,633	317,004
Level 2 [Member]
Current assets
Total assets measured at fair value	213,234	3,796
Level 3 [Member]
Current assets
Total assets measured at fair value	0	0
Money Market Funds [Member]
Current assets
Total assets measured at fair value	50,633	317,004
Money Market Funds [Member] | Level 1 [Member]
Current assets
Total assets measured at fair value	50,633	317,004
Money Market Funds [Member] | Level 2 [Member]
Current assets
Total assets measured at fair value	0	0
Money Market Funds [Member] | Level 3 [Member]
Current assets
Total assets measured at fair value	0	0
Pension Plan Assets [Member]
Current assets
Total assets measured at fair value	5,320	3,796
Pension Plan Assets [Member] | Level 1 [Member]
Current assets
Total assets measured at fair value	0	0
Pension Plan Assets [Member] | Level 2 [Member]
Current assets
Total assets measured at fair value	5,320	3,796
Pension Plan Assets [Member] | Level 3 [Member]
Current assets
Total assets measured at fair value	0	$ 0
Corporate Debt Securities [Member]
Current assets
Total assets measured at fair value	127,351
Corporate Debt Securities [Member] | Level 1 [Member]
Current assets
Total assets measured at fair value	0
Corporate Debt Securities [Member] | Level 2 [Member]
Current assets
Total assets measured at fair value	127,351
Corporate Debt Securities [Member] | Level 3 [Member]
Current assets
Total assets measured at fair value	0
US Treasury Securities [Member]
Current assets
Total assets measured at fair value	80,563
US Treasury Securities [Member] | Level 1 [Member]
Current assets
Total assets measured at fair value	0
US Treasury Securities [Member] | Level 2 [Member]
Current assets
Total assets measured at fair value	80,563
US Treasury Securities [Member] | Level 3 [Member]
Current assets
Total assets measured at fair value	$ 0

Fair Value Measurements - Addit

Fair Value Measurements - Additional Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Measure at fair value, transfers among Level 1, Level 2 or Level 3	$ 0	$ 0

Marketable securities - Summary

Marketable securities - Summary of Marketable securities (Details) $ in Thousands	Dec. 31, 2022 USD ($)
Marketable Securities [Line Items]
Amortized Cost	$ 208,363
Unrealized Gains	29
Unrealized Losses	(478)
Fair Value	207,914
Corporate debt securities
Marketable Securities [Line Items]
Amortized Cost	127,565
Unrealized Gains	27
Unrealized Losses	(241)
Fair Value	127,351
U.S Treasury securities
Marketable Securities [Line Items]
Amortized Cost	80,798
Unrealized Gains	2
Unrealized Losses	(237)
Fair Value	$ 80,563

Marketable securities (Addition

Marketable securities (Additional Information) (Details) $ in Millions	12 Months Ended
	Dec. 31, 2022 USD ($) Security
Investments, Debt and Equity Securities [Abstract]
Debt Securities, Available-for-Sale, Unrealized Loss Position | $	$ 164.9
Number of marketable securities held | Security	40

Property and Equipment, net - S

Property and Equipment, net - Schedule of Property, Plant and Equipment (Detail) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Property Plant And Equipment [Line Items]
Total property and equipment, at cost	$ 33,326	$ 15,028
Less: accumulated depreciation	(6,251)	(2,703)
Property and equipment, net	27,075	12,325
Laboratory Equipment
Property Plant And Equipment [Line Items]
Total property and equipment, at cost	17,766	12,315
Furniture and Fixtures
Property Plant And Equipment [Line Items]
Total property and equipment, at cost	388	443
Computer Hardware and Software
Property Plant And Equipment [Line Items]
Total property and equipment, at cost	499	299
Leasehold Improvements
Property Plant And Equipment [Line Items]
Total property and equipment, at cost	2,660	1,119
Construction in Process
Property Plant And Equipment [Line Items]
Total property and equipment, at cost	$ 12,013	$ 852

Property and Equipment, net - A

Property and Equipment, net - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Property, Plant and Equipment [Abstract]
Depreciation	$ 3,745	$ 2,132

Accrued Expenses And Other Cu_3

Accrued Expenses And Other Current Liabilities - Schedule of Accrued Expenses and Other Current Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Accounts Payable and Accrued Liabilities, Current [Abstract]
Compensation and benefits	$ 5,624	$ 4,303
Accrued research and development	3,936	4,937
Other	5,020	840
Total other current liabilities	$ 14,580	$ 10,080

Leases - Schedule of components

Leases - Schedule of components of lease expense (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2022 USD ($)
Leases [Abstract]
Operating lease expense	$ 6,924
Variable lease expense	1,898
Total lease expense	$ 8,822

Leases - Schedule of Lease Term

Leases - Schedule of Lease Terms and Discount Rate (Details)	Dec. 31, 2022
Leases [Abstract]
Weighted average remaining lease term (years)	9 years 8 months 12 days
Weighted average discount rate	9.90%

Leases - Schedule of Schedule O

Leases - Schedule of Schedule Of Supplemental Cash Flow Information Related To Leases (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2022 USD ($)
Leases [Abstract]
Right-of-use assets obtained in exchange for operating lease obligations	$ 48,488
Cash paid for amounts included in the measurement of lease liabilities	$ 1,654

Leases - Schedule of Future Min

Leases - Schedule of Future Minimum Payments Under Non -cancelable Operating Leases (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Jan. 01, 2022
Finite-Lived Intangible Assets [Line Items]
Operating Lease liability		$ 7,400
Non-cancelable leases [Member]
Finite-Lived Intangible Assets [Line Items]
2023	$ 7,562
2024	6,982
2025	7,182
2026	7,053
2027	7,151
Thereafter	38,414
Total undiscounted lease payments	74,344
Less: Imputed interest	(27,343)
Operating Lease liability	$ 47,001

Leases - Schedule of Future M_2

Leases - Schedule of Future Minimum Rental Payments for Operating Leases under non-cancelable (Details) $ in Thousands	Dec. 31, 2021 USD ($)
Leases [Abstract]
2022	$ 3,160
2023	8,353
2024	8,583
2025	8,820
2026	7,298
Thereafter	44,784
Total future minimum lease payments	$ 80,998

Leases (Additional Information)

Leases (Additional Information) (Details)		12 Months Ended
	Dec. 14, 2021 USD ($) ft²	Dec. 31, 2022 USD ($)	Jan. 01, 2021 ft²	Jan. 01, 2020 ft²
Lessee, Lease, Description [Line Items]
Finance Lease		$ 0
Finance Lease, Liability, Statement of Financial Position [Extensible Enumeration]		Operating Lease, Right-of-Use Asset
Short-Term Lease		$ 0
Amortization of the ROU assets		$ 3,300,000
Lease Expiration Date		Mar. 31, 2026
Tenant Improvements		$ 13,000,000
Receivable in Tenant Improvements		7,500,000
Lease expenses		$ 8,822,000
Summer Street (Member)
Lessee, Lease, Description [Line Items]
Lease Expiration Date		Jun. 01, 2023
Land Subject to Ground Leases | ft²				16,748
Operating Lease Lability And Right of Use Asset		$ 3,700,000
Right of Use Assets Decreased Limit, Amount		1,300,000
Operating Lease Liabilities Decreased Limit, Amount		1,400,000
Reclassified Lease Amount		1,000,000
Hochbergerstrasse (Member)
Lessee, Lease, Description [Line Items]
Land Subject to Ground Leases | ft²			21,422
Harrison Street (Member)
Lessee, Lease, Description [Line Items]
Land Subject to Ground Leases | ft²	63,327
Lease Commencement Date	Apr. 01, 2022
Initial lease term	128 months
Renewal term	5 years
Lease annual base rent per square foot	$ 95
Increase in annual base rent (Percentage)	3%
Research and Development [Member]
Lessee, Lease, Description [Line Items]
Lease expenses		7,800,000
General and Administrative [Member]
Lessee, Lease, Description [Line Items]
Lease expenses		$ 1,000,000

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Details) - USD ($) $ in Thousands	1 Months Ended	12 Months Ended
	Apr. 30, 2018	Dec. 31, 2022	Dec. 31, 2021
Common stock, shares, issued		49,445,802	46,794,295
Research and development		$ 85,061	$ 57,155
CRT
Common stock, shares, issued	1,132,984
Milestone Payments, Maximum	$ 7,000
Milestone Payments	$ 3,500

Commitments and Contingencies_2

Commitments and Contingencies - Schedule of Future Minimum Lease Payments Under Noncancelable Operating Leases (Details) $ in Thousands	Dec. 31, 2021 USD ($)
Commitments and Contingencies Disclosure [Abstract]
2023	$ 8,353
2024	8,583
2025	8,820
2026	7,298
Thereafter	44,784
Total future minimum lease payments	$ 80,998

Convertible preferred stock - A

Convertible preferred stock - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Class Of Stock [Line Items]
Preferred stock, shares authorized	10,000,000	10,000,000
Preferred stock, par value	$ 0.0001	$ 0.0001
Preferred stock, shares Issued	0	0
Proceeds from issuance of convertible preferred stock	$ 0	$ 143,000
Stock issuance costs	$ 0	$ 231
Common stock, par or stated value per share	$ 0.0001	$ 0.0001
Proceeds from initial public offering, net of underwriting discount of $17,895	$ 0	$ 237,750

Equity (Additional Information)

Equity (Additional Information) (Details) - USD ($) $ / shares in Units, $ in Thousands		12 Months Ended
	Jul. 31, 2022	Dec. 31, 2022	Dec. 31, 2021
Class Of Stock [Line Items]
Common stock, shares authorized		500,000,000	500,000,000
Common stock, shares, issued		49,445,802	46,794,295
Common stock, shares, issued during the period		2,482,008
Common stock shares outstanding		49,323,531	46,535,966
Dividends declared		$ 0
Dividends paid		$ 0
Common stock, voting rights		one
Preferred stock, shares authorized		10,000,000	10,000,000
Preferred stock, par value		$ 0.0001	$ 0.0001
Preferred stock, shares Issued		0	0
Preferred Stock, Shares Outstanding		0	0
Gross Proceeds from sale of Common Stock		$ 19,700
Other Ownership Interests, Offering Costs		$ 1,000
Jefferies LLC [Member]
Class Of Stock [Line Items]
Gross Proceeds from sale of Common Stock	$ 100,000
Percentage of Commission payable to Related Party	3%
Restricted Stock Awards
Class Of Stock [Line Items]
Vesting term		4 years
Undesignated Preferred Stock
Class Of Stock [Line Items]
Preferred stock, shares authorized		10,000,000
Preferred stock, par value		$ 0.0001
Preferred stock, shares Issued		0
Preferred Stock, Shares Outstanding		0

Stock-Based Compensation - Addi

Stock-Based Compensation - Additional Information (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock option exercised	2,376,226
Weighted average grant fair value, granted	$ 8.44	$ 7.11
Number of options, granted	2,237,870
Aggregate fair value of restricted stock vested	$ 1.5	$ 5.2
Restricted Stock Awards
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Weighted average grant date fair value, vested	$ 0.78	$ 1.13
Unrecognized stock based compensation cost	$ 0.1
Unrecognized stock based compensation cost, units	$ 0.7
Weighted average remaining period	1 year
Expected remaining cost, weighted average period, units	1 year 6 months
Unvested Stock Option [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unrecognized stock based compensation cost	$ 31.1
Weighted average remaining period	2 years 6 months
2021 Stock incentive plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock reserved for future issuance	4,903,145
Increase in share percentage	5%
Issuance of common stock	3,787,469
2021 Employee stock purchase plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock reserved for future issuance	439,849
Increase in share percentage	1%
Issuance of common stock	827,751
Number of share increase	439,849

Stock-Based Compensation - Summ

Stock-Based Compensation - Summary of Stock Option Activity (Detail) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Share-Based Payment Arrangement [Abstract]
Number of options, beginning balance	5,563,513
Number of options, granted	2,237,870
Number of options, exercised	(117,552)
Number of options, forfeited	(247,492)
Number of options, vested or expected to vest	7,436,339
Number of options, ending balance	7,436,339	5,563,513
Number of options, exercisable	2,376,226
Weighted average exercise price, beginning balance	$ 7.92
Weighted average exercise price, granted	12.16
Weighted average exercise price, exercised	3.73
Weighted average exercise price, forfeited	11.70
Weighted average exercise price, vested or expected to vest	9.14
Weighted average exercise price, ending balance	9.14	$ 7.92
Weighted average exercise price, exercisable	$ 7.32
Weighted average remaining contractual term (years)	8 years 6 months	9 years 2 months 12 days
Weighted average remaining contractual term (years), vested or expected to vest	8 years 6 months
Weighted average remaining contractual term (years), exercisable	8 years 2 months 12 days
Aggregate intrinsic value, beginning balance	$ 70,045
Aggregate intrinsic value, ending balance	12,440	$ 70,045
Aggregate intrinsic value, vested or expected to vest	12,440
Aggregate intrinsic value, exercisable	$ 6,208

Stock-Based Compensation - Sche

Stock-Based Compensation - Schedule of Fair Value of each Award Estimated Using Assumption (Detail)	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Share-Based Payment Arrangement [Abstract]
Expected term (years)	6 years 3 months	6 years 3 months
Expected volatility	78.82%	77.75%
Risk-free interest rate	2.02%	1.25%
Expected dividend yield	0%	0%

Stock-Based Compensation - Sc_2

Stock-Based Compensation - Schedule of Restricted Stock Award Activity (Detail) - Restricted Stock Awards	12 Months Ended
	Dec. 31, 2022 $ / shares shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of Outstanding Shares, Beginning Balance | shares	258,329
Number of Shares, Vested | shares	(136,058)
Number of shares, Unvested, ending balance | shares	122,271
Weighted Average Grant Date Fair Value, Beginning Balance | $ / shares	$ 0.90
Weighted Average Grant Date Fair Value, Vested | $ / shares	0.78
Weighted average grant date fair value, ending balance | $ / shares	$ 1.04

Stock-based compensation - Sc_3

Stock-based compensation - Schedule of Restricted Stock Unit Activity (Details) - Restricted stock units	12 Months Ended
	Dec. 31, 2022 $ / shares shares
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Number of shares, Granted | shares	91,000
Number of shares, Unvested, ending balance | shares	91,000
Weighted average grant date fair value, Granted | $ / shares	$ 10.11
Weighted average grant date fair value, ending balance | $ / shares	$ 10.11

Stock-Based Compensation - Sc_4

Stock-Based Compensation - Schedule of Stock Based Compensation Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total stock-based compensation expense	$ 11,664	$ 5,200
Research and Development [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total stock-based compensation expense	5,582	2,606
General and Administrative [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total stock-based compensation expense	$ 6,082	$ 2,594

Income Taxes - Schedule of Dome

Income Taxes - Schedule of Domestic And Foreign Components of Net Loss (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Income Tax Disclosure [Abstract]
United States	$ (17,232)	$ (9,884)
Foreign	(91,269)	(64,074)
Net loss	$ (108,501)	$ (73,958)

Income Taxes - Schedule of Reco

Income Taxes - Schedule of Reconciliation of Federal Statutory Income Tax Rate to Effective Income Tax Rate (Detail)	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Income Tax Disclosure [Abstract]
Income tax benefit at the federal statutory rate	21%	21%
State income taxes, net of federal benefit	6.20%	6.30%
Research and development tax credits	0%	1.20%
Foreign rate differential	(6.70%)	(6.90%)
Adjustment related to Preferred Stock Tranche Obligation	(0.00%)	(0.30%)
Other	(0.70%)	(1.60%)
Change in valuation allowance	(19.80%)	(19.70%)
Total	0%	0%

Income Taxes - Summary of Signi

Income Taxes - Summary of Significant Components of Deferred Tax Assets (Liabilities) (Detail) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Deferred tax assets
Federal and state net operating loss carryforwards	$ 26,136	$ 14,529
Research and development tax credits	1,715	1,862
Capitalized research and development	1,151	0
Lease liability	13,173	0
Compensation related items	4,022	1,738
Other	149	58
Total deferred tax assets	46,346	18,187
Less: valuation allowance	(33,084)	(17,777)
Total net deferred tax assets	13,262	410
Deferred tax liabilities
Right-of-Use Asset	(11,766)	0
Defined benefit plan adjustment	(375)	(125)
Prepaid insurance	(252)	0
Depreciation	(869)	(285)
Total deferred tax liabilities	(13,262)	(410)
Net deferred tax assets	$ 0	$ 0

Income Taxes - Schedule of Unre

Income Taxes - Schedule of Unrecognized Tax Benefits (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Income Tax Disclosure [Abstract]
Unrecognized Tax Benefits, Beginning Balance	$ 0	$ 0
Additions for tax positions of prior years	2,235	0
Reductions for tax provisions of prior years	0
Unrecognized Tax Benefits, Ending Balance	$ 2,235	$ 0

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Disclosure - Income Taxes - Additional Information (Detail) [Line Items]
Valuation Allowance, Deferred Tax Asset, Increase (Decrease), Amount	$ 15,300
Unrecognized tax benefits	2,235	$ 0	$ 0
Federal and state research and development credit	2,235	$ 0
Research and Development Expense [Member]
Disclosure - Income Taxes - Additional Information (Detail) [Line Items]
Amount Capitalized	$ 4,000
R & D cost Amortized over, Period	15 years
Federal and state research and development credit	$ 2,200
Federal
Disclosure - Income Taxes - Additional Information (Detail) [Line Items]
Operating Loss Carryforwards	3,900
Tax Credit Carryforward, Amount	1,100
Foreign
Disclosure - Income Taxes - Additional Information (Detail) [Line Items]
Operating Loss Carryforwards	191,100
State
Disclosure - Income Taxes - Additional Information (Detail) [Line Items]
Operating Loss Carryforwards	5,800
Tax Credit Carryforward, Amount	$ 600
Ownership Interests of Significant Stockholders	50%
Operating Loss Carryforwards, Expiration Date	Dec. 31, 2039

Employee Retirement Plans - Sch

Employee Retirement Plans - Schedule of Changes in Benefit Obligations, Plan Assets and Net Amount Recognized in Balance Sheets (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Change in benefit obligation:
Benefit obligation—beginning of period	$ 5,975	$ 2,284
Service cost	549	417
Contributions paid by employees	299	170
Interest cost	19	9
Contributions paid by plan participants	1,302	1,926
Benefits paid	(452)	(82)
Plan Amendment	67	(42)
Actuarial loss	(774)	1,293
Benefit obligation—end of period	6,851	5,975
Change in plan assets:
Fair value of plan assets—beginning of period	3,799	1,217
Actual return on plan assets	(240)	226
Contributions paid by employer	610	340
Contributions paid by employees	299	175
Contributions paid by plan participants	1,302	1,926
Benefits paid	(452)	(85)
Fair value of plan assets—end of period	5,318	3,799
Change in defined benefit plan liability	$ 1,533	$ 2,176

Employee Retirement Plans - S_2

Employee Retirement Plans - Schedule of Net Pension Costs (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Retirement Benefits [Abstract]
Service cost	$ 549	$ 417
Interest cost	19	9
Net pension cost	$ 568	$ 426

Employee Retirement Plans - S_3

Employee Retirement Plans - Schedule of Provision for Defined Benefit Plan Obligation Recognized in Other Comprehensive Loss (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Retirement Benefits [Abstract]
Actuarial loss arising from experience adjustments	$ 774	$ (1,293)
Defined benefit cost for the year recognized in other comprehensive loss	$ 774	$ (1,293)

Employee Retirement Plans - S_4

Employee Retirement Plans - Schedule of Assumptions Used to Measure Projected Benefit Obligation and Net Pension Costs (Details)	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Retirement Benefits [Abstract]
Inflation rate%	1.25%	0.50%
Discount rate%	2.30%	0.35%
Interest rate on savings accounts%	1%	0.45%
Expected rate of return on assets%	2.30%	0.45%
Salary increase%	1.25%	1%
Social Security increase%	1.25%	0.50%
Pension increase%	0%	0%
Retirement age	100% Male 65 Female 64	100% Male 65 Female 64
Mortality and disability rates	BVG 2020 Table	BVG 2020 Table

Employee Retirement Plans - S_5

Employee Retirement Plans - Schedule of Estimated Future Benefit Payments (Details) $ in Thousands	Dec. 31, 2022 USD ($)
Retirement Benefits [Abstract]
2023	$ 660
2024	693
2025	717
2026	735
2027	753
2028-2032	$ 4,239

Employee Retirement Plans - Add

Employee Retirement Plans - Additional Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Retirement Benefits [Abstract]
Company matching contributions to maximum employees eligible compensation	100%
Percentage of company's matching contribution with respect to each participant's contribution	4%
Total company contributions to 401 (k) plan	$ 0.5	$ 0.3

Net loss per common share - Sch

Net loss per common share - Schedule of Earnings Per Share, Basic and Diluted (Detail) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Earnings Per Share [Abstract]
Net loss	$ (108,501)	$ (73,958)
Net loss per share attributable to common stockholders - basic	$ (2.30)	$ (2.96)
Net loss per share attributable to common stockholders - diluted	$ (2.30)	$ (2.96)
Weighted-average number of shares outstanding used in computing net loss per common share - basic	47,227,370	25,000,124
Weighted-average number of shares outstanding used in computing net loss per common share - diluted	47,227,370	25,000,124

Net loss per common share - S_2

Net loss per common share - Schedule of Antidilutive Securities Excluded from Earnings Per Share Calculation (Detail) - shares	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Options to Purchase Common Stock
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of EPS	7,436,339	5,563,513
Restricted Stock Awards
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of EPS	122,271	258,329
Restricted Stock Units
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of EPS	91,000	0

Related parties - Additional In

Related parties - Additional Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Related Party Transaction [Line Items]
Research and development	$ 85,061	$ 57,155
General and administrative	27,323	15,727
Tempus pharmaceuticals [Member]
Related Party Transaction [Line Items]
Research and development	400	$ 400
Costs and Expenses, Related Party	$ 0

Subsequent Events (Additional I

Subsequent Events (Additional Information) (Details)	Mar. 10, 2023
Subsequent Event [Member]
Subsequent Event [Line Items]
Percentage of total cash, cash equivalents, and marketable securities held in Silicon Valley Bank	2%