Prometheus Biosciences (RXDX) 10-Q 12 May 22 2022 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2022	May 10, 2022
Cover [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Mar. 31, 2022
Document Fiscal Year Focus	2022
Document Fiscal Period Focus	Q1
Current Fiscal Year End Date	--12-31
Entity Registrant Name	PROMETHEUS BIOSCIENCES, INC.
Entity Central Index Key	0001718852
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Small Business	true
Entity Emerging Growth Company	true
Entity Ex Transition Period	false
Entity Shell Company	false
Entity Filer Category	Non-accelerated Filer
Entity Common Stock, Shares Outstanding		39,197,891
Entity File Number	001-40187
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	81-4282653
Entity Address, Address Line One	3050 Science Park Road
Entity Address, City or Town	San Diego
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	92121
City Area Code	858
Local Phone Number	422-4300
Title of 12(b) Security	Common Stock, $0.0001 par value per share
Trading Symbol	RXDX
Security Exchange Name	NASDAQ
Document Quarterly Report	true
Document Transition Report	false

Unaudited Condensed Balance She

Unaudited Condensed Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Current assets
Cash and cash equivalents	$ 227,034	$ 257,254
Accounts receivable	1,288	1,079
Prepaid expenses and other current assets	6,662	7,050
Total current assets	234,984	265,383
Property and equipment, net	2,453	1,447
Deferred financing costs	565
Right-of-use asset	14,608
Other assets	971	971
Total assets	253,581	267,801
Current liabilities
Accounts payable	1,812	1,153
Accrued compensation	1,616	5,378
Accrued expenses and other current liabilities	10,488	6,050
Payable to PLI	385	193
Deferred revenue	2,132	3,668
Lease liabilities, current portion	891
Total current liabilities	17,324	16,442
Deferred revenue, non-current	15,802	16,204
Lease liabilities, net of current portion	13,732
Total liabilities	46,858	32,646
Commitments and contingencies (Note 8)
Stockholders’ equity:
Preferred stock—$0.0001 par value; 40,000,000 shares authorized at March 31, 2022 and December 31, 2021; No shares issued and outstanding at March 31, 2022 and December 31, 2021
Common stock—$0.0001 par value; 400,000,000 shares authorized as of March 31, 2022 and December 31, 2021; 39,103,107 shares and 38,960,716 shares issued at March 31, 2022 and December 31, 2021, respectively; 39,089,812 shares and 38,943,110 shares outstanding at March 31, 2022 and December 31, 2021, respectively;	4	4
Additional paid-in capital	428,126	424,492
Accumulated deficit	(221,407)	(189,341)
Total stockholders’ equity	206,723	235,155
Total liabilities and stockholders’ equity	$ 253,581	$ 267,801

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - $ / shares	Mar. 31, 2022	Dec. 31, 2021
Statement Of Financial Position [Abstract]
Preferred stock, par value	$ 0.0001	$ 0.0001
Preferred stock, shares authorized	40,000,000	40,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value	$ 0.0001	$ 0.0001
Common stock, shares authorized	400,000,000	400,000,000
Common stock, shares issued	39,103,107	38,960,716
Common stock, shares outstanding	39,089,812	38,943,110

Unaudited Condensed Statements

Unaudited Condensed Statements of Operations - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Income Statement [Abstract]
Collaboration revenue	$ 3,919	$ 760
Operating expenses:
Research and development	27,930	7,758
General and administrative	8,085	5,222
Total operating expense	36,015	12,980
Loss from operations	(32,096)	(12,220)
Other income (expense), net:
Interest income	30	18
Interest expense		(658)
Change in fair value of preferred stock purchase right liability		(980)
Change in fair value of preferred stock warrant liability		(105)
Total other income (expense), net	30	(1,725)
Net loss	$ (32,066)	$ (13,945)
Net loss per share, basic and diluted	$ (0.82)	$ (1.67)
Weighted average shares outstanding, basic and diluted	39,006,794	8,338,892

Unaudited Condensed Statement_2

Unaudited Condensed Statements of Convertible Preferred Stock and Stockholders' Equity (Deficit) - USD ($) $ in Thousands	Total	Convertible Preferred Stock	Series D-2 Convertible Preferred Stock	Common Stock	Additional Paid-in Capital	Accumulated Deficit
Beginning Balance at Dec. 31, 2020	$ (97,541)				$ 1,605	$ (99,146)
Temporary Equity, Balance, shares at Dec. 31, 2020		160,864,434
Temporary Equity, Balance at Dec. 31, 2020		$ 126,023
Balance, shares at Dec. 31, 2020				1,713,622
Issuance of convertible preferred stock for cash, net of issuance costs			$ 73,763
Issuance of convertible preferred stock for cash, net of issuance costs, shares			86,775,740
Issuance of convertible preferred stock for settlement of deferred purchase price			$ 6,144
Issuance of convertible preferred stock for settlement of deferred purchase price, shares			7,219,560
Reclassification of convertible preferred stock purchase right liability		$ 4,880
Conversion of convertible preferred stock into common stock at initial public offering	210,810			$ 3	210,807
Temporary Equity, Conversion of convertible preferred stock into common stock at initial public offering, shares		(254,859,734)
Temporary Equity, Conversion of convertible preferred stock into common stock at initial public offering		$ (210,810)
Conversion of convertible preferred stock into common stock at initial public offering, shares				25,485,955
Issuance of shares of common stock in initial public offering for cash, net of issuance costs	199,838			$ 1	199,837
Issuance of shares of common stock in initial public offering for cash, net of issuance costs, shares				11,500,000
Reclassification of convertible preferred stock warrants	169				169
Issuance of common stock in exchange for services	3				3
Issuance of common stock in exchange for services, shares				500
Issuance of common stock upon exercise of stock options	64				64
Issuance of common stock upon exercise of stock options, shares				56,645
Vesting of early exercised stock options	9				9
Vesting of early exercised stock options, shares				12,981
Stock-based compensation	792				792
Net loss	(13,945)					(13,945)
Ending Balance at Mar. 31, 2021	300,199			$ 4	413,286	(113,091)
Balance, shares at Mar. 31, 2021				38,769,703
Beginning Balance at Dec. 31, 2021	$ 235,155			$ 4	424,492	(189,341)
Balance, shares at Dec. 31, 2021	38,943,110			38,943,110
Issuance of common stock upon exercise of stock options	$ 349				349
Issuance of common stock upon exercise of stock options, shares	142,391			142,391
Vesting of early exercised stock options	$ 6				6
Vesting of early exercised stock options, shares				4,311
Stock-based compensation	3,279				3,279
Net loss	(32,066)					(32,066)
Ending Balance at Mar. 31, 2022	$ 206,723			$ 4	$ 428,126	$ (221,407)
Balance, shares at Mar. 31, 2022	39,089,812			39,089,812

Unaudited Condensed Statement_3

Unaudited Condensed Statements of Convertible Preferred Stock and Stockholders' Equity (Deficit) (Parenthetical) $ in Thousands	3 Months Ended
	Mar. 31, 2021USD ($)
Series D-2 Convertible Preferred Stock
Temporary stock, issuance costs	$ 94
Common Stock
Stock issuance costs	$ 18,662

Unaudited Condensed Statement_4

Unaudited Condensed Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Cash flows from operating activities
Net loss	$ (32,066)	$ (13,945)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	87	39
Stock-based compensation expenses	3,279	792
Change in fair value of preferred stock purchase right liability		980
Change in fair value of preferred stock warrant liability		105
Common stock issued in exchange for services		3
Noncash interest expense		508
Changes in operating assets and liabilities:
Accounts receivable	(209)	113
Prepaid expenses and other current assets	388	(4,258)
Other assets		(468)
Accounts payable	746	609
Accrued compensation	(3,762)	(1,119)
Accrued expenses and other current liabilities	3,879	(1,051)
Payable to PLI	192	(897)
Deferred revenue	(1,937)	(405)
Operating lease right-of-use assets and liabilities, net	15
Net cash used in operating activities	(29,388)	(18,994)
Cash flows from investing activities
Purchase of property and equipment	(955)	(298)
Net cash used in investing activities	(955)	(298)
Cash flows from financing activities
Proceeds from issuance of convertible preferred stock, net of issuance costs		73,749
Proceeds from sale of common stock in initial public offering		218,500
Payment of financing costs		(16,001)
Deferred financing costs	(226)
Proceeds from issuance of common stock upon stock option exercises	349	74
Net cash provided by financing activities	123	276,322
Net increase in cash and cash equivalents	(30,220)	257,030
Cash and cash equivalents at beginning of period	257,254	54,201
Cash and cash equivalents cash at end of period	227,034	311,231
Supplemental schedule of non-cash investing and financing activities
Conversion of convertible preferred stock into common stock upon completion of initial public offering		210,810
Reclassification of preferred stock purchase right liability to equity due to issuance of Series D convertible preferred stock		4,880
Reclassification of warrant liability to equity due to conversion from preferred stock warrant to common stock warrant upon completion of initial public offering		169
Issuance of Series D-2 convertible preferred stock for the settlement of deferred purchase price		6,144
Financing costs incurred, but not paid, included in accrued expenses and accounts payable	339	1,209
Vesting of early exercised stock options	6	9
Costs incurred, but not paid, in connection with capital expenditures included in accounts payable	$ 291	$ 237

Organization

Organization	3 Months Ended
	Mar. 31, 2022
Accounting Policies [Abstract]
Organization	1. Organization Prometheus Biosciences, Inc. (the Company) was incorporated in the state of Delaware on October 26, 2016 under the name Precision IBD, Inc. and is headquartered in San Diego, California. The Company changed its name to Prometheus Biosciences, Inc. on October 1, 2019. The Company’s business is focused on the discovery, development and commercialization of novel therapeutic and companion diagnostic products for the treatment of immune-mediated diseases, starting first with inflammatory bowel disease (IBD). In June 2019, the Company acquired Prometheus Laboratories, Inc. (PLI) and the related intangible assets used by PLI. PLI was wholly owned by Nestlé Health Science US Holdings, Inc. and the related intangible assets were owned by Societé Des Produits Nestlé S.A (together, Nestlé). PLI markets and conducts several laboratory developed tests useful to gastroenterologists in monitoring their IBD patients’ disease state and informing their therapeutic decisions. On December 31, 2020, the Company completed the spinoff of PLI by making an in-kind distribution of 100% of its interest in PLI to the Company’s stockholders of record on December 30, 2020. Reverse Stock Split On March 5, 2021, the Company effected a one-for-ten Initial Public Offering On March 16, 2021, the Company completed its initial public offering (IPO) with the sale of 11,500,000 shares of common stock, which included the exercise in full by the underwriters of their option to purchase 1,500,000 additional shares, at an initial public offering price of $19.00 per share and received gross proceeds of $218.5 million, which resulted in net proceeds to the Company of approximately $199.8 million, after deducting underwriting discounts and commissions of approximately $15.3 million and offering-related transaction costs of approximately $3.4 million. In addition, in connection with the completion of the IPO, all outstanding shares of convertible preferred stock were converted into 25,485,955 shares of the Company’s common stock; outstanding warrants to purchase 148,848 shares of convertible preferred stock were converted into warrants to purchase 14,884 shares of the Company’s common stock; and the Company’s certificate of incorporation was amended and restated to authorize 400,000,000 shares of common stock and 40,000,000 shares of undesignated preferred stock. Liquidity The Company has incurred net losses since inception, experienced negative cash flows from operations, and as of March 31, 2022, has an accumulated deficit of $221.4 million The Company will be required to raise additional capital, however, there can be no assurance as to whether additional financing will be available on terms acceptable to the Company, if at all. If sufficient funds on acceptable terms are not available when needed, it would have a negative impact on the Company’s financial condition and could force the Company to delay, limit, reduce, or terminate product development or future commercialization efforts or grant rights to develop and market product candidates or testing products that the Company would otherwise plan to develop.

Summary of Significant Accounti

Summary of Significant Accounting Policies	3 Months Ended
	Mar. 31, 2022
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	2. Summary of Significant Accounting Policies Basis of Presentation and Use of Estimates The preparation of financial statements in conformity with accounting principles generally accepted in the United States (GAAP) requires management to make estimates and assumptions that impact the reported amounts of assets, liabilities, and expenses and the disclosure of contingent assets and liabilities in the Company’s condensed financial statements and accompanying notes. Although these estimates are based on the Company’s knowledge of current events and actions it may undertake in the future, actual results may materially differ from these estimates and assumptions. On an ongoing basis, management evaluates its estimates, primarily related to revenue recognition, stock-based compensation, fair value of common stock, fair value of the convertible preferred stock, fair value of the preferred stock purchase right liability, and accrued research and development costs. These estimates are based on historical data and experience, as well as various other factors 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 that are not readily apparent from other sources. Estimates relating to the valuation of stock require the selection of appropriate valuation methodologies and models, and significant judgment in evaluating ranges of assumptions and financial inputs. Unaudited Interim Financial Information The unaudited financial statements at March 31, 2022, and for the three months ended March 31, 2022 and 2021, have been prepared in accordance with the rules and regulations of the Securities and Exchange Commission (SEC), and with GAAP applicable to interim financial statements. These unaudited financial statements have been prepared on the same basis as the audited financial statements and include all adjustments, consisting of only normal recurring accruals, which in the opinion of management are necessary to present fairly the Company’s financial position as of the interim date and results of operations for the interim periods presented. Interim results are not necessarily indicative of results for a full year or future periods. The preparation of financial statements requires management 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 the reported amounts of expenses during the reporting period. Actual results could differ materially from those estimates. These unaudited financial statements should be read in conjunction with the Company’s audited financial statements for the year ended December 31, 2021, included in the Annual Report on Form 10-K filed with the SEC on March 9, 2022. Segment Reporting Operating segments are identified as components of an enterprise about which separate discrete financial information is available for evaluation by management in making decisions regarding resource allocation and assessing performance. The Company manages its operations as a single operating segment in the United States for the purposes of assessing performance and making operating decisions. Cash and Cash Equivalents The Company considers all highly liquid investments with an original maturity of three months or less when purchased to be cash equivalents. The cash and cash equivalents balance at March 31, 2022 and December 31, 2021 represents cash in readily available checking and money market accounts. Concentration of Credit Risk Financial instruments, which potentially subject the Company to concentration of credit risk, consist primarily of cash, cash equivalents, and accounts receivable. The Company maintains deposits in federally insured financial institutions in excess of federally insured limits. Management believes that the Company is not exposed to significant credit risk due to the financial position of the depository institutions in which those deposits are held. Accounts Receivable Accounts receivable is stated at the original invoice amount and consists of certain clinical trial costs subject to reimbursement under the Company’s collaboration agreements. The Company did not record any allowance for doubtful accounts as of March 31, 2022 and December 31, 2021. Property and Equipment, Net Property and equipment is stated at cost less accumulated depreciation. Depreciation is recorded using the straight-line method over the estimated useful lives of the related assets, which ranges from two to seven years. Repairs and maintenance charges that do not increase the useful life of the assets are charged to operating expenses as incurred. Long-Lived Assets The Company’s long-lived assets are comprised principally of its property and equipment. If the Company identifies a change in the circumstances related to its long-lived assets that indicates the carrying value of any such asset may not be recoverable, the Company will perform an impairment analysis. A long-lived asset is not recoverable when the undiscounted cash flows expected to be generated by the asset (or asset group) are less than the asset’s carrying amount. Any required impairment loss would be measured as the amount by which the asset’s carrying value exceeds its fair value, and would be recorded as a reduction in the carrying value of the related asset and a charge to operating expense. Deferred Financing Costs Deferred financing costs consist of legal, accounting, and underwriting commissions that the Company has capitalized that are directly related to the Company’s “at the market” offering. Deferred financing costs associated with the offering will be reclassified to additional paid-in capital as the Company sells common stock pursuant to the Open Sale Market Agreement. Revenue Recognition The Company recognizes revenue in accordance with ASC Topic 606, Revenue from Contracts with Customers (ASC 606). In accordance with ASC 606, the Company performs the following steps in determining the appropriate amount of revenue to be recognized as it fulfills its obligations under each of these agreements: (i) identification of the promised goods or services in the contract; (ii) determination of whether the promised goods or services are performance obligations including whether they are distinct in the context of the contract; (iii) measurement of the transaction price, including the constraint on variable consideration; (iv) allocation of the transaction price to the performance obligations; and (v) recognition of revenue when, or as, the Company satisfies each performance obligation. At contract inception, once the contract is determined to be within the scope of ASC 606, the Company assesses the goods or services promised within each contract and determines those that are performance obligations and assesses whether each promised good or service is distinct. The Company then recognizes as revenue the amount of the transaction price that is allocated to the respective performance obligation when (or as) the performance obligation is satisfied. To date, all of the Company’s collaboration revenue has been derived from its collaboration agreement with Dr. Falk Pharma GmbH and its collaboration agreement with Millennium Pharmaceuticals, Inc., a subsidiary of Takeda Pharmaceutical Company Limited (collectively, Takeda) as described in Note 5. The terms of these arrangements include the following types of payments to the Company: non-refundable, up-front license fees; development, regulatory and commercial milestone payments; payments for research and development services provided by the Company; and royalties on net sales of licensed products. At the initiation of an agreement, the Company analyzes whether each unit of account results in a contract with a customer under ASC 606 or in an arrangement with a collaborator subject to guidance under ASC 808, Collaborative Arrangements (ASC 808). The Company considers a variety of factors in determining the appropriate estimates and assumptions under these arrangements, such as whether the elements are distinct performance obligations, whether there are observable stand-alone prices, and whether any licenses are functional or symbolic. The Company evaluates each performance obligation to determine if it can be satisfied and recognized as revenue at a point in time or over time. Typically, license fees, non-refundable upfront fees, and funding of research activities are considered fixed, while milestone payments are identified as variable consideration which must be evaluated to determine if it is constrained and, therefore, excluded from the transaction price. The Company estimates the amount of variable consideration using the most likely amount, as milestone payments typically only have two possible outcomes. The Company recognizes revenue for sales-based royalty promised in exchange for the license of intellectual property only when the subsequent sale occurs. The Company may allocate transaction price using a number of methods including estimating standalone selling price of performance obligations and using the residual approach when the standalone selling price of the license is highly variable or uncertain, and observable standalone selling prices exist for the other goods or services promised in the contract. The Company receives payments from its collaborators based on terms established in each contract. Upfront payments and other payments may require deferral of revenue recognition to a future period until the Company is unconditional. The Company does not assess whether a contract has a significant financing component if the expectation at contract inception is such that the payment by the customer is akin to a deposit for research and development services. Research and Development and Clinical Trial Accruals Research and development costs are charged to expense as incurred. Research and development expenses include certain payroll and personnel expenses, laboratory supplies, consulting costs, external contract research and development expenses, and allocated overhead, including rent, property and equipment depreciation and utilities. Advance payments for goods or services for future research and development activities are deferred and expensed as the goods are delivered or the related services are performed. The Company estimates preclinical studies and clinical trial expenses based on the services performed pursuant to contracts with research institutions and clinical research organizations that conduct and manage preclinical studies and clinical trials on the Company’s behalf. In addition, clinical study and trial materials are manufactured by contract manufacturing organizations. In accruing for these services, the Company estimates the time period over which services will be performed and the level of effort to be expended in each period. These estimates are based on communications with the third-party service providers and the Company’s estimates of accrued expenses and on information available at each balance sheet date. If the actual timing of the performance of services or the level of effort varies from the estimate, the Company will adjust the accrual accordingly. Fair Value Measurements Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. As such, fair value is a market-based measurement that should be determined based on assumptions that market participants would use in pricing an asset or liability. Stock-Based Compensation The Company expenses stock-based compensation to employees and non-employees related to stock options, restricted stock units, and shares granted under the Company’s 2021 Employee Stock Purchase Plan (the ESPP). Stock-based compensation expense represents the cost of the grant date fair value of applicable awards recognized over the requisite service period (usually the vesting period) on a straight-line basis, net of actual forfeitures during the period. The Company estimates the fair value of stock options and shares purchased under the ESPP using the Black-Scholes option pricing model, and the assumptions used in calculating the fair value of stock-based awards represent management’s best estimates and involve inherent uncertainties and the application of management’s judgment. Valuation of Common Stock Prior to the IPO, given the absence of a public trading market for the Company’s common stock, the Company’s board of directors exercised their judgment and considered a number of objective and subjective factors to determine the best estimate of the fair value of the Company’s common stock, such as: contemporaneous valuations performed by independent third-party specialists, its stage of development, including the status of its research and development efforts of its product candidates, the material risks related to its businesses and industry, its results of operations before discontinued operations and financial position, including its levels of capital resources, the prices at which its sold shares of its convertible preferred stock, the rights, preferences and privileges of its convertible preferred stock relative to those of its common stock, the conditions in the biotechnology industry and the economy in general, the stock price performance and volatility of comparable life sciences public companies, as well as recently completed mergers and acquisitions of peer companies, the likelihood of achieving a liquidity event for the holders of its common stock or convertible preferred stock, such as an IPO or a sale of the Company given prevailing market conditions, trends and developments in its industry, external market conditions affecting the life sciences and biotechnology sectors, and the lack of liquidity of its common stock, among other factors. After the completion of the IPO, the fair value of each share of common stock is based on the closing price of the Company’s common stock as reported by the Nasdaq Global Select Market. Preferred Stock Purchase Right Liabilities From time to time, the Company entered into convertible preferred stock financings where, in addition to the initial closing, investors agreed to buy, and the Company agreed to sell, additional shares of that convertible preferred stock at a fixed price in the event that certain conditions are met, or agreed upon milestones are achieved. The Company evaluated this purchase right and assessed whether it met the definition of a freestanding instrument and, if so, determined the fair value of the purchase right liability and recorded it on the balance sheet with the remainder of the proceeds raised allocated to convertible preferred stock. The preferred stock purchase right liability was revalued at each reporting period with changes in the fair value of the liability recorded as change in fair value of preferred stock purchase right liability in the statements of operations. Upon the issuance of the shares of Series D-2 convertible preferred stock in January 2021, the no longer required liability accounting and the then fair value of the was reclassified into stockholders’ equity. The Company performed the final remeasurement of the preferred stock purchase right liability Net Loss Per Share Basic net loss per share attributable to common stockholders is calculated by dividing the net loss attributable to common stockholders by the weighted-average number of common shares outstanding during the period. Diluted net loss per share attributable to common stockholders is computed by dividing the net loss attributable to common stockholders by the weighted-average number of common stock equivalents outstanding for the period determined using the treasury-stock method. The Company has excluded 16,169 and 47,999 weighted-average shares subject to repurchase or forfeiture from the weighted-average number of common shares outstanding for the three months ended March 31, 2022 and 2021, respectively. Dilutive common stock equivalents are comprised of options outstanding under the Company’s equity incentive plan, warrants to purchase common stock, and 2021 Employee Stock Purchase Plan (ESPP) shares pending issuance. Basic and diluted net loss attributable to common holders per share is presented in conformity with the two- class method required for participating securities as the convertible preferred stock are considered participating securities. The Company’s participating securities do not have a contractual obligation to share in the Company’s losses. As such, the net loss was attributed entirely to common stockholders. Accordingly, for the three months ended March 31, 2022 and 2021, there is no difference in the number of shares used to calculate basic and diluted shares outstanding. Potentially dilutive securities not included in the calculation of diluted net loss per share because to do so would be anti-dilutive are as follows (in common stock equivalent shares): March 31, 2022 2021 Common stock options issued and outstanding 6,340,791 5,023,579 Warrants to purchase common stock 14,884 14,884 ESPP shares pending issuance 17,210 — Total 6,372,885 5,038,463 Recent Accounting Standards From time to time, new accounting standards are issued by the Financial Accounting Standards Board (FASB) or other standard setting bodies and adopted by the Company as of the specified effective date. Unless otherwise discussed, the impact of recently issued standards that are not yet effective will not have a material impact on the Company’s financial position or results of operations upon adoption. New Accounting Standards Not Yet Adopted In April 2012, the Jump-Start Our Business Startups Act (the JOBS Act) was signed into law. The JOBS Act contains provisions that, among other things, reduce certain reporting requirements for an emerging growth company. As an emerging growth company, the Company may elect to adopt new or revised accounting standards when they become effective for non-public companies, which typically is later than when public companies must adopt the standards. The Company has elected to take advantage of the extended transition period afforded by the JOBS Act and, as a result, will comply with new or revised accounting standards on the relevant dates on which adoption of such standards is required for emerging growth companies.

Fair Value Measurements and Fai

Fair Value Measurements and Fair Value of Financial Instruments	3 Months Ended
	Mar. 31, 2022
Fair Value Disclosures [Abstract]
Fair Value Measurements and Fair Value of Financial Instruments	3. The accounting guidance defines fair value, establishes a consistent framework for measuring fair value and expands disclosure for each major asset and liability category measured at fair value on either a recurring or nonrecurring basis. Fair value is defined as an exit price, representing the amount that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants. As such, fair value is a market-based measurement that should be determined based on assumptions that market participants would use in pricing an asset or liability. As a basis for considering such assumptions, the accounting guidance establishes a three-tier fair value hierarchy, which prioritizes the inputs used in measuring fair value as follows: Level 1 — Quoted prices in active markets for identical assets or liabilities. Level 2 — Observable inputs other than Level 1 prices, such as quoted prices for similar assets or liabilities, quoted prices in markets that are not active, or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities. 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. Assets and liabilities measured at fair value are classified in their entirety based on the lowest level of input that is significant to the fair value measurement. The Company’s assessment of the significance of a particular input to the fair value measurement in its entirety requires management to make judgments and consider factors specific to the asset or liability. The carrying amounts of cash and cash equivalents, prepaid and other assets, accounts payable and accrued liabilities are considered to be representative of their respective fair values because of the short-term nature of those instruments. Based on the borrowing rates currently available to the Company for loans with similar terms, which is considered a Level 2 input, the Company believes that the fair value of long-term debt approximates its carrying value. The Company’s financial instruments that are carried at fair value consist of Level 3 liabilities. There were no transfers within the hierarchy during the three months ended March 31, 2022 and 2021. At December 31, 2020, Level 3 liabilities that were measured at fair value on a recurring basis consisted of warrants to purchase shares of convertible preferred stock and a preferred stock purchase right liability. The Company had no Level 3 liabilities at March 31, 2022 and December 31, 2021 as the liabilities for the warrants to purchase shares of convertible preferred stock and the preferred stock purchase right was remeasured and reclassified to stockholders’ equity upon the closing of the Company’s IPO in March 2021 and the issuance of shares of Series D-2 convertible preferred stock in January 2021, respectively. Convertible Preferred Stock Warrant Liability The convertible preferred stock warrant liability was recorded at fair value utilizing the Black-Scholes option pricing model using significant unobservable inputs consistent with the inputs used for the Company’s stock-based compensation expense adjusted for the preferred stock warrants’ expected term and the fair value of the underlying preferred stock. The assumptions used in the Black-Scholes option pricing model to determine the fair value of the convertible preferred stock warrant liability at the date of the IPO were as follows: IPO Date Fair value of underlying preferred stock $ 1.90 Risk-free interest rate 1.70 % Expected volatility 70.00 % Expected term (in years) 9.0 Expected dividend yield —% Preferred Stock Purchase Right Liability Upon the issuance of the shares of Series D-2 convertible preferred stock in January 2021, the liability was remeasured using a valuation model that considered: (i) the risk-free rate commensurate with the expected milestone timing of 0.09%; (ii) the probability of the Series D-2 tranche of 80.0%; (iii) volatility of 80.0%; (iv) consideration received for the Series D-1 preferred stock; (v) the number of shares to be issued to satisfy the preferred stock purchase right and at what price; and (vi) certain implied and provided assumptions needed to calibrate the Series D-1 value and the Series D-2 purchase right, and as Activity of Liabilities Using Fair Value Level 3 Measurements The following table summarizes the activity of the financial instruments valued using Level 3 inputs (in thousands): Convertible Preferred Stock Warrant Liability Series D Convertible Preferred Stock Purchase Right Liability Balance at December 31, 2020 $ 64 $ 3,900 Change in fair value 105 980 Conversion/Settlement during 2021 (169 ) (4,880 ) Balance at March 31, 2021 $ — $ —

Balance Sheet Details

Balance Sheet Details	3 Months Ended
	Mar. 31, 2022
Balance Sheet Related Disclosures [Abstract]
Balance Sheet Details	4. Prepaid Expenses and Other Current Assets Prepaid expenses and other current assets consist of the following (in thousands): March 31, 2022 December 31, 2021 Prepaid contract manufacturing expenses $ 881 $ 3,808 Prepaid clinical trial expenses 2,802 1,397 Prepaid research and development expenses 300 627 Other prepaid expenses 2,679 1,218 Total $ 6,662 $ 7,050 Property and equipment, Net Property and equipment, net, consist of the following (in thousands): March 31, 2022 December 31, 2021 Laboratory equipment $ 2,250 $ 1,830 Computer equipment 223 24 Office equipment and furniture 474 — 2,947 1,854 Less accumulated depreciation (494 ) (407 ) Total $ 2,453 $ 1,447 Depreciation expense related to property and equipment was $0.1 million and $39,000 for the three months ended March 31, 2022 and 2021, respectively. Accrued Expenses and Other Current Liabilities Accrued expenses and other current liabilities consist of the following (in thousands): March 31, 2022 December 31, 2021 Accrued research and development $ 2,900 $ 2,123 Accrued clinical trial expenses 2,070 1,999 Accrued contract manufacturing expenses 4,337 906 Accrued legal expenses 407 531 Unvested early exercise liability 29 35 Accrued other 746 456 Total $ 10,488 $ 6,050

Collaboration and License Agree

Collaboration and License Agreements	3 Months Ended
	Mar. 31, 2022
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Collaboration and License Agreements	5. Collaboration and License Agreements Exclusive License Agreement with Cedars-Sinai Medical Center In September 2017, the Company entered into an Exclusive License Agreement with Cedars-Sinai Medical Center (Cedars-Sinai), a related party, as amended and restated (the Cedars-Sinai Agreement). Under the terms of the Cedars-Sinai Agreement, Cedars-Sinai granted the Company an exclusive, worldwide, royalty bearing license with respect to certain patent rights, information and materials related to therapeutic targets and companion diagnostic products, in each case to conduct research, develop, and commercialize therapeutic and diagnostic products for human use. The licensed technology includes information and materials arising out of Cedars-Sinai’s database and biobank, as well as exclusive access to this database and biobank, which is an integral part of the Company’s Prometheus360 platform. In August 2021, the Company and Cedars-Sinai amended and restated the Cedars-Sinai Agreement to, among other things, add a joint steering committee and cover new intellectual property. As consideration for the license rights, in September 2017 the Company issued (i) 257,500 shares of fully vested common stock, and (ii) 335,000 shares of unvested restricted common stock, all of which is vested as of December 31, 2020. The fair value of all of the shares were measured at the date of issuance. The shares of unvested restricted common stock had vesting conditions tied to continuing services required of certain Cedars-Sinai employees pursuant to consulting agreements with the Company. One third of the restricted shares were released from restriction annually on the anniversary of the Cedars-Sinai Agreement over a three-year period. Additionally, the Company is obligated to pay Cedars-Sinai low- to mid-single digit percentage royalties on net sales of products covered under the Cedars-Sinai Agreement. The term of, and the Company’s royalty obligations under, the Cedars-Sinai Agreement expires on a licensed product-by-product and country-by-country basis on the later of ten years from the date of first commercial sale or when there is no longer a valid patent claim covering such licensed product in such country. Co-Development and Manufacturing Agreement with Dr. Falk Pharma GmbH In July 2020, the Company entered into a Co-Development and Manufacturing Agreement (the Falk Agreement) with Dr. Falk Pharma GMBH (Falk), pursuant to which the parties will co-develop and commercialize, exclusively in their respective territories, therapeutic product candidates targeting members of the TNF super family for the treatment of UC and CD under the Company’s PR600 program. Under the Falk Agreement, the Company is obligated to use commercially reasonable efforts to conduct development activities under an agreed development plan and the Company is responsible for regulatory approvals and commercialization of any products in the United States and the rest of the world, other than the Falk territory. Falk is responsible for regulatory approvals and commercialization of any products in the European Union, United Kingdom, Switzerland, the countries of the European Economic Area (excluding Malta and the Republic of Cyprus), Australia and New Zealand (Falk territory). Falk agreed to fund 25% of the Company’s third-party development costs set forth in the development plan. Under the agreement, Falk paid the Company an upfront payment of $2.5 million and made a second payment of $2.5 million following the parties’ mutual agreement on the development plan. In addition, in June 2021, Falk made a milestone payment to the Company of $10 million upon the selection of a clinical candidate for the PR600 program and, in December 2021, Falk made the final milestone payment of $5 million, based on the Company’s . The Company has identified one performance obligation for all the deliverables under the Falk Agreement. Accordingly, the Company is recognizing revenue for the transaction price allocated to the performance obligation in an amount proportional to the collaboration expenses incurred and the total estimated collaboration expenses over the eight-year eight-year . Companion Diagnostics Development Agreement with Millennium Pharmaceuticals, Inc. In March 2019, the Company entered into a Companion Diagnostics Development and Collaboration Agreement (the Takeda Agreement) with Millennium Pharmaceuticals, Inc., a wholly-owned subsidiary of Takeda, pursuant to which the Company agreed to develop a companion diagnostic product for drug targets selected by Takeda, and Takeda agreed to develop and commercialize any therapeutic clinical candidates that it develops directed against any selected drug targets for the treatment of IBD. The Company had identified one performance obligation per target for all the deliverables under the agreement since the delivered elements are not distinct within the context of the contract. Accordingly, the Company recognized revenue for the transaction price in an amount proportional to the collaboration expenses incurred and the total estimated collaboration expenses over the four-year period over which it expected to satisfy its performance obligations. The Company included one milestone in the transaction price as it was deemed not probable of significant reversal at the inception of the agreement. Due to the uncertainty in the achievement of the developmental and commercial milestones, the variable consideration associated with these future milestone payments was fully constrained (excluded) from the transaction price. These estimates were re-assessed at each reporting period. In March 2022, the Company and Takeda mutually agreed to terminate the agreement, effective April 2022, and the Company plans to focus its companion diagnostics resources on its proprietary targets and programs. As no remaining performance obligation existed at the time of signing of this agreement, all remaining deferred revenue was recognized in March 2022 . A reconciliation of deferred revenue related to the Falk Agreement and the Takeda Agreement for the three months ended March 31, 2022 is as follows (in thousands): Falk Agreement Takeda Agreement Total Balance at December 31, 2021 $ 18,691 $ 1,181 $ 19,872 Amounts received in 2022 1,981 — $ 1,981 Revenue recognized in 2022 (2,738 ) (1,181 ) $ (3,919 ) Balance at March 31, 2022 $ 17,934 $ — $ 17,934

Long Term Debt

Long Term Debt	3 Months Ended
	Mar. 31, 2022
Debt Disclosure [Abstract]
Long Term Debt	6 . Long Term Debt In January 2020, the Company entered into a Loan and Security Agreement (the Loan Agreement) with Oxford Finance LLC and its affiliates (Oxford) (the Oxford Loan) which provided up to $25.0 million, of which $7.5 million was drawn upon execution of the agreement. Interest accrued at an annual rate at the greater of (a) the 30-day U.S. LIBOR rate reported the last business day of the month that immediately precedes the month in which the interest will accrue, or (b) 2.01%, plus 5.98%, with a minimum annual rate of 7.99%. From March 1, 2020 through February 28, 2023, the Company was required to make interest only payments. Beginning March 1, 2023, in addition to interest payments, the monthly payments were to include an amount equal to the outstanding principal divided by 24 months. At maturity (or earlier prepayment), the Company was also required to make a final payment equal to 4.0% of the original principal amount borrowed and 3% of the future amount to be funded. The Loan Agreement was collateralized by substantially all of our assets, excluding intellectual property, which was subject to a negative pledge. In connection with execution of the Loan Agreement, the Company issued Oxford a warrant to purchase 112,500 shares of the Company’s Series C convertible preferred stock at an exercise price of $1.00 per share, exercisable at any time following issuance. The preferred stock warrant has a term of ten years. The warrant became exercisable for an aggregate of 14,884 shares of the Company’s common stock at an exercise price of $7.558 per share upon the completion of the Company’s IPO. In July 2021, the Company voluntarily prepaid the aggregate outstanding principal balance of $7.5 million plus an additional $0.5 million consisting of the prepayment penalty, accrued interest, and final payment due under the terms of the Oxford Loan, and the Loan Agreement was terminated in accordance with its terms. All liens and security interests securing the Oxford Loan were released upon termination. The Company recognized a $0.6 million loss on extinguishment on the Company’s condensed statements of operations for the year ended December 31, 2021.

Stockholders' Equity (Deficit)

Stockholders' Equity (Deficit)	3 Months Ended
	Mar. 31, 2022
Equity [Abstract]
Stockholders' Equity (Deficit)	7 . Amended Articles of Incorporation In March 2021, the Company amended its Certificate of Incorporation to authorize 400,000,000 shares of common stock and 40,000,000 shares of preferred stock. Convertible Preferred Stock In connection with the completion of the Company’s IPO on March 16, 2021, all outstanding shares of convertible preferred stock were converted into 25,485,955 shares of the Company’s common stock and outstanding warrants to purchase 148,848 shares of convertible preferred stock were converted into warrants to purchase 14,884 shares of the Company’s common stock. Series D Convertible Preferred Stock In October 2020, the Company entered into a Series D convertible preferred stock purchase agreement (Series D SPA) under which it issued 61,066,216 shares of Series D-1 convertible preferred stock, for cash, at a price of $0.7558 per share, for net proceeds of $46.2 million (the Initial Series D Closing). In addition, 5,088,851 shares of Series D-1 convertible preferred stock were issued to Nestlé in satisfaction of a deferred purchase price obligation of $3.8 million. The Series D SPA contained provisions that potentially obligated the Company to issue an additional 94,007,051 shares of Series D-2 convertible preferred stock at $0.8510 per share in an additional closing, 7,231,311 of which was issuable to Nestlé for satisfaction of deferred purchase price obligations of $6.2 million, upon the approval by the Company’s board of directors, or at the option of the investors who participated in the Initial Series D Closing, or upon the achievement of certain milestones as defined in the Series D SPA, which purchase right terminates upon certain specified events, including an initial public offering of the Company, if any. The Company determined its obligation to issue additional shares of the Company’s Series D-2 convertible preferred stock in the Initial Series D Closing represented a freestanding financial instrument that required liability accounting. This freestanding preferred stock purchase right liability for the additional closing was recorded at fair value, with changes in fair value recognized in the statements of operations. As of the Initial Series D Closing, the estimated fair value of the preferred stock purchase right liability was $3.9 million. In January 2021, preferred stock purchase right liability was remeasured to fair value and the change in fair value of $1.0 million was recorded in the statement of operations for the three months ended March 31, 2021. The liability was then reclassified to stockholders’ equity. Equity Incentive Plan In 2017, the Company adopted the 2017 Equity Incentive Plan (the 2017 Plan), which as amended, had 5,524,354 shares of common stock reserved for issuance. Under the 2017 Plan, the Company could grant stock options, stock appreciation rights, restricted stock, restricted stock units and other awards to individuals who are employees, non-employee directors or consultants of the Company or its subsidiaries. The maximum term of the options granted under the 2017 Plan was no more than ten years. The 2017 Plan allowed for the early exercise of all stock options granted if authorized by the board of directors at the time of grant. In February 2021, the board of directors adopted, and the Company’s stockholders approved, the 2021 Incentive Award Plan (the 2021 Plan), which became effective in connection with the IPO. Pursuant to the 2021 Plan, the Company ceased granting awards under the 2017 Plan. Under the 2021 Plan, the Company may grant stock options, restricted stock, dividend equivalents, restricted stock units, stock appreciation rights, and other stock or cash-based awards to individuals who are then employees, officers, non-employee directors or consultants of the Company. The number of shares initially available for issuance under awards granted pursuant to the 2021 Plan is the sum of (1) 3,600,000 shares of common stock, plus (2) any shares subject to outstanding awards under the 2017 Plan as of the effective date of the 2021 Plan that become available for issuance under the 2021 Plan thereafter in accordance with its terms Grants generally vest at 25% one year from the vesting commencement date and ratably each month thereafter for a period of 36 months, subject to continuous service. The Company’s stock option activity for the three months ended March 31, 2022 is summarized in the following table: Number Weighted- Average Exercise Price Weighted- Average Remaining Contractual Term (in Years) Aggregate Intrinsic Value (in thousands) Outstanding at December 31, 2021 6,474,039 $ 12.18 8.5 $ 177,130 Granted 61,700 $ 40.00 Exercised (142,391 ) $ 2.45 Cancelled/forfeited (52,557 ) $ 20.71 Outstanding at March 31, 2022 6,340,791 $ 12.60 8.3 $ 159,544 Vested or expected to vest at March 31, 2022 6,340,791 $ 12.60 8.3 $ 159,544 Exercisable at March 31, 2022 2,015,832 $ 4.48 6.6 $ 67,087 The weighted-average grant date fair value of options granted during the three months ended March 31, 2022 and 2021 was $26.14 and $5.13, respectively. The intrinsic value of options exercised during the three months ended March 31, 2022 and 2021 was $1.8 million and $0.2 million, respectively. The grant date fair value of stock options was determined using the Black-Scholes option pricing model with the following assumptions: Three Months Ended March 31, 2022 2021 Risk-free interest rate 1.5 – 1.7% 0.6 – 1.0% Expected volatility 73.2 – 74.6% 95.2% Expected term (in years) 6.1 5.8 – 6.1 Expected dividend yield —% —% Expected Term —The expected term of options granted represents the period of time that the options are expected to be outstanding. Due to the lack of historical exercise history, the expected term of the Company’s employee stock options has been determined utilizing the simplified method for awards that qualify as plain-vanilla options. Expected Volatility —The estimated volatility was based on the historical volatility of the common stock of a group of publicly traded companies deemed comparable to the Company. Risk-Free Interest Rate —The risk-free interest rate is the implied yield in effect at the time of the option grant based on U.S. Treasury securities with contract maturities similar to the expected term of the Company’s stock options. Dividend Rate —The Company has not paid any cash dividends on common stock since inception and does not anticipate paying any dividends in the foreseeable future. Consequently, an expected dividend yield of zero was used. Early Exercise Liability The unvested shares of the early-exercised options are held in escrow until the stock option becomes fully vested or until the employee’s termination, whichever occurs first. The right to repurchase these shares lapses over the four-year The following table summarizes the activity of the unvested common stock issued pursuant to an early exercise of stock option awards for the three months ended March 31, 2022: Unvested at beginning of period 17,606 Vested or cancelled during the period (4,311 ) Unvested at end of period 13,295 Employee Stock Purchase Plan In February 2021, the Company’s board of directors approved the 2021 Employee Stock Purchase Plan (the ESPP), which became effective upon the pricing of the Company’s IPO on March 16, 2021. The ESPP permits participants to purchase common stock through payroll deductions of up to 20% of their eligible compensation. Initially, a total of 360,000 shares of common stock were reserved for issuance under the ESPP. In addition, the number of shares of common stock available for issuance under the ESPP will be annually increased on the first day of each fiscal year during the term of the ESPP, beginning with the 2022 fiscal year, by an amount equal to the lessor of: (i) 1% of the total number of shares of common stock outstanding on December 31st of the preceding calendar year; or (ii) such other amount as the Company’s board of directors may determine. The number of shares of common stock available for issuance under the ESPP increased by 1% at January 1, 2022. Stock compensation expense for the three months ended March 31, 2022 related to the ESPP was $0.1 million. As of March 31, 2022, the Company has The fair value of stock of the stock purchase right under the ESPP was determined using the Black-Scholes option pricing model with the following assumptions: Three Months Ended March 31, 2022 Risk-free interest rate 0.03– 0.33% Expected volatility 71.6 – 83.9% Expected term (in years) 0.5 – 1.64 Expected dividend yield —% Stock-Based Compensation Expense The following table summarizes the components of stock-based compensation expense recognized in the accompanying statements of operations (in thousands): Three Months Ended March 31, 2022 2021 Research and development $ 1,136 $ 171 General and administrative 2,143 621 Total stock-based compensation $ 3,279 $ 792 As of March 31, 2022, approximately $43.2million of total unrecognized compensation expense related to unvested stock options is expected to be recognized over a weighted average period of 3.4 years. Common Stock Reserved for Future Issuance Common stock reserved for future issuance consists of the following: March 31, 2022 December 31, 2021 Common stock options issued and outstanding 6,340,791 6,474,039 Warrants to purchase common stock 14,884 14,884 Shares available for issuance under equity incentive plan 3,794,954 1,856,063 Shares available for issuance under the ESPP 723,457 333,850 Total 10,874,086 8,678,836

Commitments and Contingencies

Commitments and Contingencies	3 Months Ended
	Mar. 31, 2022
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	8 . Commitments and Contingencies Leases In March 2021, the Company executed a non-cancellable lease agreement for office and laboratory space in San Diego, California (“Second Floor Lease”). The Second Floor Lease and related monthly payments commenced in March 2022, and has an initial term of ten years with an option to extend the lease for an additional five-year In October 2021, the Company executed an amendment to the lease agreement to expand the leased premises (“First Floor Lease”). The amended lease extends the initial term of the original lease to 127 months following the commencement date of the expansion premises, with an option to extend the lease term for an additional five-year Company’s condensed balance sheet . The First Floor L ease provides for initial monthly rental payments for the expansion premises of an additional approximately $ 0.2 million with rent escalation and the Company is also responsible for certain operating expenses and taxes throughout the lease term. In addition, the Company is entitled to up to an additional $ 6.3 million of tenant improvement allowance for the expansion premises. In connection with the PLI spinoff on December 31, 2020, the Company entered into a sublease agreement for approximately 40,000 square feet currently occupied in the PLI facility. The sublease agreement was for one year with an option to renew for an additional year. The sublease agreement was extended through June 2022 during the year ended December 31, 2021. The monthly payment is $80,000 and total remaining payment obligations at March 31, 2022 is $0.2 million. The Company recorded $0.3 million and $0.2 million in operating lease expense for the three months ended March 31, 2022 and 2021, respectively. As of March 31, 2022 the remaining lease term of the Company’s operating lease was 132 months and the discount rate on the Company’s operating lease was 8.0%. Future minimum operating lease payments for the Second Floor Lease and information related to the lease liability as of March 31, 2022 are as follows (in thousands): Remainder of 2022 $ 468 2023 1,912 2024 1,970 2025 2,029 2026 2,090 Thereafter 14,552 Total lease payments 23,021 Imputed interest (8,398 ) Lease liability 14,623 Less current portion of lease liability 891 Lease liability, net of current portion $ 13,732 Litigation From time to time, the Company may become involved in legal proceedings or be subject to claims arising in the ordinary course of its business. Regardless of outcome, legal proceedings or claims can have an adverse impact on the company because of defense and settlement costs, diversion of resources and other factors, and there can be no assurances that favorable outcomes will be obtained. Indemnification Agreements In the ordinary course of business, the Company may provide indemnification of varying scope and terms to vendors, lessors, business partners and other parties with respect to certain matters including, but not limited to, losses arising out of breech of such agreements or from intellectual property infringement claims made by third parties. In addition, the Company has entered into indemnification agreements with officers and members of its board of directors that will require the Company, among other things, to indemnify them against certain liabilities that may arise by reason of their status or service as directors or officers. The maximum potential amount of future payments the Company could be required to make under these indemnification agreements is, in many cases, unlimited. To date, the Company has not incurred any material costs as a result of such indemnifications. At March 31, 2022, no claims exist under indemnification arrangements and accordingly, no amounts have been accrued in its condensed financial statements as of March 31, 2022.

Related Party Transactions

Related Party Transactions	3 Months Ended
	Mar. 31, 2022
Related Party Transactions [Abstract]
Related Party Transactions	9. Related Party Transactions As discussed in Note 5, in September 2017, the Company entered into the Cedars-Sinai Agreement. A related-party relationship exists with Cedars-Sinai due to its percentage of common stock ownership and representation on the Company’s board of directors. As consideration for the license rights, the Company issued (i) 257,500 common stock shares at par value of $0.0001 per share, and (ii) 335,000 unvested restricted common stock shares at par value of $0.0001 per share. The parties also entered into additional license agreements as well as research agreements, under which the parties can provide research services to each other at pricing specified in the individual statements of work. During the three months ended March 31, 2022 and 2021 , no services were provided under the research agreements. As disclosed in Note 7, in January 2021, deferred purchase price obligations of $6.1 million due to was satisfied with the issuance of 7,219,560 shares of Series D-2 convertible preferred stock in January 2021. As a result of the PLI spinoff on December 31, 2020, the Company entered into a transition services agreement with PLI, pursuant to which the Company is providing PLI certain transitional services, including general and administrative, finance and clinical operations support, and PLI is providing the Company with certain transitional services, including providing for the use of facilities under a sublease, in each case for specified monthly service fees. The initial term of the agreement was for one year, subject to earlier termination and extension thereafter. During the three months ended March 31, 2022 and 2021, the Company paid PLI $0.9 million and $1.6 million, respectively, in accordance with the terms of this agreement. The transition services agreement was extended during the year ended December 31, 2021 and includes providing for the use of facilities under a sublease through June 2022.

401(K) Plan

401(K) Plan	3 Months Ended
	Mar. 31, 2022
Compensation And Retirement Disclosure [Abstract]
401(K) Plan	1 0 . Effective January 1, 2018, the Company maintains a defined contribution 401(k) plan available to eligible employees. Employee contributions are voluntary and are determined on an individual basis, limited to the maximum amount allowable under federal tax regulations. The Company, at its discretion, may make certain contributions to the 401(k) plan. Company contributions made during the three months ended March 31, 2022 and 2021 were $0.4 million and $43,000, respectively.

COVID-19 Pandemic

COVID-19 Pandemic	3 Months Ended
	Mar. 31, 2022
Extraordinary And Unusual Items [Abstract]
COVID-19 Pandemic	1 1 . The COVID-19 worldwide pandemic has presented substantial public health and economic challenges and has affected, and may continue to affect the Company’s employees, patients, physicians and other healthcare providers, communities and business operations, as well as the U.S. and global economies and financial markets. International and U.S. governmental authorities in impacted regions have taken, and are continuing to take, actions in an effort to slow the spread of COVID-19 and variants of the virus. The COVID-19 pandemic continues to rapidly evolve. The extent to which the COVID-19 pandemic may impact the Company’s business, including its preclinical studies, planned and ongoing clinical trials, and financial condition will depend on future developments, which are highly uncertain and cannot be predicted with confidence, such as the continued geographic spread of variants, the duration of the pandemic, the timing and effectiveness of vaccine distribution, travel restrictions and social distancing in the United States and other countries, business closures or business disruptions and the effectiveness of actions taken in the United States and other countries to contain and treat the disease.

Subsequent Events

Subsequent Events	3 Months Ended
	Mar. 31, 2022
Subsequent Events [Abstract]
Subsequent Events	12. On April 1, 2022, the Company entered into an Open Market Sale Agreement (the “Sale Agreement”) with Jefferies LLC (the “Agent”), pursuant to which the Company may offer and sell shares of the Company’s common stock having an aggregate offering price of up to $150.0 million from time to time, in “at the market” offerings through the Agent. Sales of the shares of common stock, if any, will be made at prevailing market prices at the time of sale, or as otherwise agreed with the Agent. The Agent will receive a commission from the Company of 3.0% of the gross proceeds of any shares of common stock sold under the Sale Agreement. The Company is not obligated to sell, and the Agent is not obligated to buy or sell, any shares of common stock under the Sale Agreement. No assurance can be given that the Company will sell any shares of common stock under the Sale Agreement, or, if it does, as to the price or amount of shares of common stock that it sells or the dates when such sales will take place. As of May 10, 2022, the Company has sold 69,870 shares of its common stock under the Sale Agreement at a weighted average price of $36.14 resulting in gross proceeds of approximately $2.5 million.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	3 Months Ended
	Mar. 31, 2022
Accounting Policies [Abstract]
Basis of Presentation and Use of Estimates	Basis of Presentation and Use of Estimates The preparation of financial statements in conformity with accounting principles generally accepted in the United States (GAAP) requires management to make estimates and assumptions that impact the reported amounts of assets, liabilities, and expenses and the disclosure of contingent assets and liabilities in the Company’s condensed financial statements and accompanying notes. Although these estimates are based on the Company’s knowledge of current events and actions it may undertake in the future, actual results may materially differ from these estimates and assumptions. On an ongoing basis, management evaluates its estimates, primarily related to revenue recognition, stock-based compensation, fair value of common stock, fair value of the convertible preferred stock, fair value of the preferred stock purchase right liability, and accrued research and development costs. These estimates are based on historical data and experience, as well as various other factors 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 that are not readily apparent from other sources. Estimates relating to the valuation of stock require the selection of appropriate valuation methodologies and models, and significant judgment in evaluating ranges of assumptions and financial inputs.
Unaudited Interim Financial Information	Unaudited Interim Financial Information The unaudited financial statements at March 31, 2022, and for the three months ended March 31, 2022 and 2021, have been prepared in accordance with the rules and regulations of the Securities and Exchange Commission (SEC), and with GAAP applicable to interim financial statements. These unaudited financial statements have been prepared on the same basis as the audited financial statements and include all adjustments, consisting of only normal recurring accruals, which in the opinion of management are necessary to present fairly the Company’s financial position as of the interim date and results of operations for the interim periods presented. Interim results are not necessarily indicative of results for a full year or future periods. The preparation of financial statements requires management 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 the reported amounts of expenses during the reporting period. Actual results could differ materially from those estimates. These unaudited financial statements should be read in conjunction with the Company’s audited financial statements for the year ended December 31, 2021, included in the Annual Report on Form 10-K filed with the SEC on March 9, 2022.
Segment Reporting	Segment Reporting Operating segments are identified as components of an enterprise about which separate discrete financial information is available for evaluation by management in making decisions regarding resource allocation and assessing performance. The Company manages its operations as a single operating segment in the United States for the purposes of assessing performance and making operating decisions.
Cash and Cash Equivalents	Cash and Cash Equivalents The Company considers all highly liquid investments with an original maturity of three months or less when purchased to be cash equivalents. The cash and cash equivalents balance at March 31, 2022 and December 31, 2021 represents cash in readily available checking and money market accounts.
Concentration of Credit Risk	Concentration of Credit Risk Financial instruments, which potentially subject the Company to concentration of credit risk, consist primarily of cash, cash equivalents, and accounts receivable. The Company maintains deposits in federally insured financial institutions in excess of federally insured limits. Management believes that the Company is not exposed to significant credit risk due to the financial position of the depository institutions in which those deposits are held.
Accounts Receivable	Accounts Receivable Accounts receivable is stated at the original invoice amount and consists of certain clinical trial costs subject to reimbursement under the Company’s collaboration agreements. The Company did not record any allowance for doubtful accounts as of March 31, 2022 and December 31, 2021.
Property and Equipment, Net	Property and Equipment, Net Property and equipment is stated at cost less accumulated depreciation. Depreciation is recorded using the straight-line method over the estimated useful lives of the related assets, which ranges from two to seven years. Repairs and maintenance charges that do not increase the useful life of the assets are charged to operating expenses as incurred.
Long-Lived Assets	Long-Lived Assets The Company’s long-lived assets are comprised principally of its property and equipment. If the Company identifies a change in the circumstances related to its long-lived assets that indicates the carrying value of any such asset may not be recoverable, the Company will perform an impairment analysis. A long-lived asset is not recoverable when the undiscounted cash flows expected to be generated by the asset (or asset group) are less than the asset’s carrying amount. Any required impairment loss would be measured as the amount by which the asset’s carrying value exceeds its fair value, and would be recorded as a reduction in the carrying value of the related asset and a charge to operating expense.
Deferred Financing Costs	Deferred Financing Costs Deferred financing costs consist of legal, accounting, and underwriting commissions that the Company has capitalized that are directly related to the Company’s “at the market” offering. Deferred financing costs associated with the offering will be reclassified to additional paid-in capital as the Company sells common stock pursuant to the Open Sale Market Agreement.
Revenue Recognition	Revenue Recognition The Company recognizes revenue in accordance with ASC Topic 606, Revenue from Contracts with Customers (ASC 606). In accordance with ASC 606, the Company performs the following steps in determining the appropriate amount of revenue to be recognized as it fulfills its obligations under each of these agreements: (i) identification of the promised goods or services in the contract; (ii) determination of whether the promised goods or services are performance obligations including whether they are distinct in the context of the contract; (iii) measurement of the transaction price, including the constraint on variable consideration; (iv) allocation of the transaction price to the performance obligations; and (v) recognition of revenue when, or as, the Company satisfies each performance obligation. At contract inception, once the contract is determined to be within the scope of ASC 606, the Company assesses the goods or services promised within each contract and determines those that are performance obligations and assesses whether each promised good or service is distinct. The Company then recognizes as revenue the amount of the transaction price that is allocated to the respective performance obligation when (or as) the performance obligation is satisfied. To date, all of the Company’s collaboration revenue has been derived from its collaboration agreement with Dr. Falk Pharma GmbH and its collaboration agreement with Millennium Pharmaceuticals, Inc., a subsidiary of Takeda Pharmaceutical Company Limited (collectively, Takeda) as described in Note 5. The terms of these arrangements include the following types of payments to the Company: non-refundable, up-front license fees; development, regulatory and commercial milestone payments; payments for research and development services provided by the Company; and royalties on net sales of licensed products. At the initiation of an agreement, the Company analyzes whether each unit of account results in a contract with a customer under ASC 606 or in an arrangement with a collaborator subject to guidance under ASC 808, Collaborative Arrangements (ASC 808). The Company considers a variety of factors in determining the appropriate estimates and assumptions under these arrangements, such as whether the elements are distinct performance obligations, whether there are observable stand-alone prices, and whether any licenses are functional or symbolic. The Company evaluates each performance obligation to determine if it can be satisfied and recognized as revenue at a point in time or over time. Typically, license fees, non-refundable upfront fees, and funding of research activities are considered fixed, while milestone payments are identified as variable consideration which must be evaluated to determine if it is constrained and, therefore, excluded from the transaction price. The Company estimates the amount of variable consideration using the most likely amount, as milestone payments typically only have two possible outcomes. The Company recognizes revenue for sales-based royalty promised in exchange for the license of intellectual property only when the subsequent sale occurs. The Company may allocate transaction price using a number of methods including estimating standalone selling price of performance obligations and using the residual approach when the standalone selling price of the license is highly variable or uncertain, and observable standalone selling prices exist for the other goods or services promised in the contract. The Company receives payments from its collaborators based on terms established in each contract. Upfront payments and other payments may require deferral of revenue recognition to a future period until the Company is unconditional. The Company does not assess whether a contract has a significant financing component if the expectation at contract inception is such that the payment by the customer is akin to a deposit for research and development services.
Research and Development and Clinical Trial Accruals	Research and Development and Clinical Trial Accruals Research and development costs are charged to expense as incurred. Research and development expenses include certain payroll and personnel expenses, laboratory supplies, consulting costs, external contract research and development expenses, and allocated overhead, including rent, property and equipment depreciation and utilities. Advance payments for goods or services for future research and development activities are deferred and expensed as the goods are delivered or the related services are performed. The Company estimates preclinical studies and clinical trial expenses based on the services performed pursuant to contracts with research institutions and clinical research organizations that conduct and manage preclinical studies and clinical trials on the Company’s behalf. In addition, clinical study and trial materials are manufactured by contract manufacturing organizations. In accruing for these services, the Company estimates the time period over which services will be performed and the level of effort to be expended in each period. These estimates are based on communications with the third-party service providers and the Company’s estimates of accrued expenses and on information available at each balance sheet date. If the actual timing of the performance of services or the level of effort varies from the estimate, the Company will adjust the accrual accordingly.
Fair Value Measurements	Fair Value Measurements Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. As such, fair value is a market-based measurement that should be determined based on assumptions that market participants would use in pricing an asset or liability.
Stock-Based Compensation	Stock-Based Compensation The Company expenses stock-based compensation to employees and non-employees related to stock options, restricted stock units, and shares granted under the Company’s 2021 Employee Stock Purchase Plan (the ESPP). Stock-based compensation expense represents the cost of the grant date fair value of applicable awards recognized over the requisite service period (usually the vesting period) on a straight-line basis, net of actual forfeitures during the period. The Company estimates the fair value of stock options and shares purchased under the ESPP using the Black-Scholes option pricing model, and the assumptions used in calculating the fair value of stock-based awards represent management’s best estimates and involve inherent uncertainties and the application of management’s judgment.
Valuation of Common Stock	Valuation of Common Stock Prior to the IPO, given the absence of a public trading market for the Company’s common stock, the Company’s board of directors exercised their judgment and considered a number of objective and subjective factors to determine the best estimate of the fair value of the Company’s common stock, such as: contemporaneous valuations performed by independent third-party specialists, its stage of development, including the status of its research and development efforts of its product candidates, the material risks related to its businesses and industry, its results of operations before discontinued operations and financial position, including its levels of capital resources, the prices at which its sold shares of its convertible preferred stock, the rights, preferences and privileges of its convertible preferred stock relative to those of its common stock, the conditions in the biotechnology industry and the economy in general, the stock price performance and volatility of comparable life sciences public companies, as well as recently completed mergers and acquisitions of peer companies, the likelihood of achieving a liquidity event for the holders of its common stock or convertible preferred stock, such as an IPO or a sale of the Company given prevailing market conditions, trends and developments in its industry, external market conditions affecting the life sciences and biotechnology sectors, and the lack of liquidity of its common stock, among other factors. After the completion of the IPO, the fair value of each share of common stock is based on the closing price of the Company’s common stock as reported by the Nasdaq Global Select Market.
Preferred Stock Purchase Right Liabilities	Preferred Stock Purchase Right Liabilities From time to time, the Company entered into convertible preferred stock financings where, in addition to the initial closing, investors agreed to buy, and the Company agreed to sell, additional shares of that convertible preferred stock at a fixed price in the event that certain conditions are met, or agreed upon milestones are achieved. The Company evaluated this purchase right and assessed whether it met the definition of a freestanding instrument and, if so, determined the fair value of the purchase right liability and recorded it on the balance sheet with the remainder of the proceeds raised allocated to convertible preferred stock. The preferred stock purchase right liability was revalued at each reporting period with changes in the fair value of the liability recorded as change in fair value of preferred stock purchase right liability in the statements of operations. Upon the issuance of the shares of Series D-2 convertible preferred stock in January 2021, the no longer required liability accounting and the then fair value of the was reclassified into stockholders’ equity. The Company performed the final remeasurement of the preferred stock purchase right liability
Net Loss Per Share	Net Loss Per Share Basic net loss per share attributable to common stockholders is calculated by dividing the net loss attributable to common stockholders by the weighted-average number of common shares outstanding during the period. Diluted net loss per share attributable to common stockholders is computed by dividing the net loss attributable to common stockholders by the weighted-average number of common stock equivalents outstanding for the period determined using the treasury-stock method. The Company has excluded 16,169 and 47,999 weighted-average shares subject to repurchase or forfeiture from the weighted-average number of common shares outstanding for the three months ended March 31, 2022 and 2021, respectively. Dilutive common stock equivalents are comprised of options outstanding under the Company’s equity incentive plan, warrants to purchase common stock, and 2021 Employee Stock Purchase Plan (ESPP) shares pending issuance. Basic and diluted net loss attributable to common holders per share is presented in conformity with the two- class method required for participating securities as the convertible preferred stock are considered participating securities. The Company’s participating securities do not have a contractual obligation to share in the Company’s losses. As such, the net loss was attributed entirely to common stockholders. Accordingly, for the three months ended March 31, 2022 and 2021, there is no difference in the number of shares used to calculate basic and diluted shares outstanding. Potentially dilutive securities not included in the calculation of diluted net loss per share because to do so would be anti-dilutive are as follows (in common stock equivalent shares): March 31, 2022 2021 Common stock options issued and outstanding 6,340,791 5,023,579 Warrants to purchase common stock 14,884 14,884 ESPP shares pending issuance 17,210 — Total 6,372,885 5,038,463
Recent Accounting Standards	Recent Accounting Standards From time to time, new accounting standards are issued by the Financial Accounting Standards Board (FASB) or other standard setting bodies and adopted by the Company as of the specified effective date. Unless otherwise discussed, the impact of recently issued standards that are not yet effective will not have a material impact on the Company’s financial position or results of operations upon adoption. New Accounting Standards Not Yet Adopted In April 2012, the Jump-Start Our Business Startups Act (the JOBS Act) was signed into law. The JOBS Act contains provisions that, among other things, reduce certain reporting requirements for an emerging growth company. As an emerging growth company, the Company may elect to adopt new or revised accounting standards when they become effective for non-public companies, which typically is later than when public companies must adopt the standards. The Company has elected to take advantage of the extended transition period afforded by the JOBS Act and, as a result, will comply with new or revised accounting standards on the relevant dates on which adoption of such standards is required for emerging growth companies.

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Tables)	3 Months Ended
	Mar. 31, 2022
Accounting Policies [Abstract]
Summary of Potentially Dilutive Securities Not Included in Calculation of Diluted Net Loss Per Share	Potentially dilutive securities not included in the calculation of diluted net loss per share because to do so would be anti-dilutive are as follows (in common stock equivalent shares): March 31, 2022 2021 Common stock options issued and outstanding 6,340,791 5,023,579 Warrants to purchase common stock 14,884 14,884 ESPP shares pending issuance 17,210 — Total 6,372,885 5,038,463

Fair Value Measurements and F_2

Fair Value Measurements and Fair Value of Financial Instruments (Tables)	3 Months Ended
	Mar. 31, 2022
Fair Value Disclosures [Abstract]
Summary of Assumptions Used in Black-Scholes Option Pricing Model	The assumptions used in the Black-Scholes option pricing model to determine the fair value of the convertible preferred stock warrant liability at the date of the IPO were as follows: IPO Date Fair value of underlying preferred stock $ 1.90 Risk-free interest rate 1.70 % Expected volatility 70.00 % Expected term (in years) 9.0 Expected dividend yield —%
Summary of Activity of Financial Instruments	The following table summarizes the activity of the financial instruments valued using Level 3 inputs (in thousands): Convertible Preferred Stock Warrant Liability Series D Convertible Preferred Stock Purchase Right Liability Balance at December 31, 2020 $ 64 $ 3,900 Change in fair value 105 980 Conversion/Settlement during 2021 (169 ) (4,880 ) Balance at March 31, 2021 $ — $ —

Balance Sheet Details (Tables)

Balance Sheet Details (Tables)	3 Months Ended
	Mar. 31, 2022
Balance Sheet Related Disclosures [Abstract]
Schedule of Prepaid Expenses and Other Current Assets	Prepaid expenses and other current assets consist of the following (in thousands): March 31, 2022 December 31, 2021 Prepaid contract manufacturing expenses $ 881 $ 3,808 Prepaid clinical trial expenses 2,802 1,397 Prepaid research and development expenses 300 627 Other prepaid expenses 2,679 1,218 Total $ 6,662 $ 7,050
Schedule of Equipment, Net	Property and equipment, net, consist of the following (in thousands): March 31, 2022 December 31, 2021 Laboratory equipment $ 2,250 $ 1,830 Computer equipment 223 24 Office equipment and furniture 474 — 2,947 1,854 Less accumulated depreciation (494 ) (407 ) Total $ 2,453 $ 1,447
Schedule of Accrued Expenses and Other Current Liabilities	Accrued expenses and other current liabilities consist of the following (in thousands): March 31, 2022 December 31, 2021 Accrued research and development $ 2,900 $ 2,123 Accrued clinical trial expenses 2,070 1,999 Accrued contract manufacturing expenses 4,337 906 Accrued legal expenses 407 531 Unvested early exercise liability 29 35 Accrued other 746 456 Total $ 10,488 $ 6,050

Collaboration and License Agr_2

Collaboration and License Agreements (Tables)	3 Months Ended
	Mar. 31, 2022
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Schedule of Reconciliation of Deferred Revenue	A reconciliation of deferred revenue related to the Falk Agreement and the Takeda Agreement for the three months ended March 31, 2022 is as follows (in thousands): Falk Agreement Takeda Agreement Total Balance at December 31, 2021 $ 18,691 $ 1,181 $ 19,872 Amounts received in 2022 1,981 — $ 1,981 Revenue recognized in 2022 (2,738 ) (1,181 ) $ (3,919 ) Balance at March 31, 2022 $ 17,934 $ — $ 17,934

Stockholders' Equity (Deficit)

Stockholders' Equity (Deficit) (Tables)	3 Months Ended
	Mar. 31, 2022
Equity [Abstract]
Summary of Stock Option Activity	The Company’s stock option activity for the three months ended March 31, 2022 is summarized in the following table: Number Weighted- Average Exercise Price Weighted- Average Remaining Contractual Term (in Years) Aggregate Intrinsic Value (in thousands) Outstanding at December 31, 2021 6,474,039 $ 12.18 8.5 $ 177,130 Granted 61,700 $ 40.00 Exercised (142,391 ) $ 2.45 Cancelled/forfeited (52,557 ) $ 20.71 Outstanding at March 31, 2022 6,340,791 $ 12.60 8.3 $ 159,544 Vested or expected to vest at March 31, 2022 6,340,791 $ 12.60 8.3 $ 159,544 Exercisable at March 31, 2022 2,015,832 $ 4.48 6.6 $ 67,087
Summary of Grant Date Fair Value of Stock Options	The grant date fair value of stock options was determined using the Black-Scholes option pricing model with the following assumptions: Three Months Ended March 31, 2022 2021 Risk-free interest rate 1.5 – 1.7% 0.6 – 1.0% Expected volatility 73.2 – 74.6% 95.2% Expected term (in years) 6.1 5.8 – 6.1 Expected dividend yield —% —%
Summary of Activity Unvested Common Stock Issued Pursuant Early Exercise of Stock Options Awards	The following table summarizes the activity of the unvested common stock issued pursuant to an early exercise of stock option awards for the three months ended March 31, 2022: Unvested at beginning of period 17,606 Vested or cancelled during the period (4,311 ) Unvested at end of period 13,295
Summary of Fair Value of Stock of the Stock Purchase Right Under ESPP	The fair value of stock of the stock purchase right under the ESPP was determined using the Black-Scholes option pricing model with the following assumptions: Three Months Ended March 31, 2022 Risk-free interest rate 0.03– 0.33% Expected volatility 71.6 – 83.9% Expected term (in years) 0.5 – 1.64 Expected dividend yield —%
Summary of Stock-based Compensation Expense	The following table summarizes the components of stock-based compensation expense recognized in the accompanying statements of operations (in thousands): Three Months Ended March 31, 2022 2021 Research and development $ 1,136 $ 171 General and administrative 2,143 621 Total stock-based compensation $ 3,279 $ 792
Summary of Common Stock Reserved for Future Issuance	Common stock reserved for future issuance consists of the following: March 31, 2022 December 31, 2021 Common stock options issued and outstanding 6,340,791 6,474,039 Warrants to purchase common stock 14,884 14,884 Shares available for issuance under equity incentive plan 3,794,954 1,856,063 Shares available for issuance under the ESPP 723,457 333,850 Total 10,874,086 8,678,836

Commitments and Contingencies (

Commitments and Contingencies (Tables)	3 Months Ended
	Mar. 31, 2022
Leases [Abstract]
Future Minimum Operating Lease Payments for the Second Floor Lease and Information Related to Lease Liability	Future minimum operating lease payments for the Second Floor Lease and information related to the lease liability as of March 31, 2022 are as follows (in thousands): Remainder of 2022 $ 468 2023 1,912 2024 1,970 2025 2,029 2026 2,090 Thereafter 14,552 Total lease payments 23,021 Imputed interest (8,398 ) Lease liability 14,623 Less current portion of lease liability 891 Lease liability, net of current portion $ 13,732

Organization - Additional Infor

Organization - Additional Information (Details) $ / shares in Units, $ in Thousands	Mar. 16, 2021USD ($)$ / sharesshares	Mar. 05, 2021	Mar. 31, 2022USD ($)shares	Mar. 31, 2021USD ($)shares	Dec. 31, 2020	Dec. 31, 2021USD ($)shares
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Date of incorporation			Oct. 26, 2016
Percentage of spinoff in kind distribution					100.00%
Description of reverse stock split			Company effected a one-for-ten reverse stock split of the Company’s common stock
Reverse stock split, conversion ratio		0.1
Proceeds from sale of common stock in initial public offering | $				$ 218,500
Common stock, shares authorized	400,000,000		400,000,000	400,000,000		400,000,000
Preferred stock, shares authorized	40,000,000		40,000,000	40,000,000		40,000,000
Accumulated deficit | $			$ 221,407			$ 189,341
Convertible Preferred Stock
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Warrant to purchase of convertible preferred stock	148,848
Common Stock
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Issuance of common stock, shares				11,500,000
Conversion of convertible preferred stock into common stock at initial public offering, shares				25,485,955
Common Stock | Convertible Preferred Stock
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Conversion of convertible preferred stock into common stock at initial public offering, shares	25,485,955
Common Stock | Convertible Preferred Stock Warrant Liability
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Conversion of convertible preferred stock into common stock at initial public offering, shares	14,884
IPO
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Issuance of common stock, shares	11,500,000
Common stock price per share | $ / shares	$ 19
Gross proceeds from issuance initial public offering | $	$ 218,500
Proceeds from sale of common stock in initial public offering | $	199,800
Payments of underwriting discounts and commissions | $	15,300
Offering-related transaction costs | $	$ 3,400
Underwriters
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Issuance of common stock, shares	1,500,000

Summary of Significant Accoun_4

Summary of Significant Accounting Policies - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2021
Summary Of Significant Accounting Policies [Line Items]
Allowance for doubtful accounts	$ 0		$ 0
Weighted-average shares subject to repurchase or forfeiture	16,169	47,999
Series D-2 Convertible Preferred Stock
Summary Of Significant Accounting Policies [Line Items]
Change in fair value into other income (expense)	$ 1,000
Minimum
Summary Of Significant Accounting Policies [Line Items]
Property, plant and equipment, estimated useful lives	2 years
Maximum
Summary Of Significant Accounting Policies [Line Items]
Property, plant and equipment, estimated useful lives	7 years

Summary of Significant Accoun_5

Summary of Significant Accounting Policies - Summary of Potentially Dilutive Securities Not Included in Calculation of Diluted Net Loss Per Share (Details) - shares	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Total	6,372,885	5,038,463
Common Stock Options Issued and Outstanding
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Total	6,340,791	5,023,579
Warrants to Purchase Common Stock
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Total	14,884	14,884
ESPP Shares Pending Issuance
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Total	17,210

Fair Value Measurements and F_3

Fair Value Measurements and Fair Value of Financial Instruments - Additional Information (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2022USD ($)	Mar. 31, 2021USD ($)	Dec. 31, 2021USD ($)	Jan. 31, 2021
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Transfers within Level 3 hierarchy	$ 0	$ 0
Level 3 liabilities	$ 0		$ 0
Change in fair value		$ 1,000
Expected Risk-Free Rate
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Measurement input				0.0009
Probability of Tranche
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Measurement input				0.800
Expected Volatility
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Measurement input				0.800

Fair Value Measurements and F_4

Fair Value Measurements and Fair Value of Financial Instruments - Summary of Assumptions Used in Black-Scholes Option Pricing Model (Details)	Mar. 16, 2021$ / shares	Jan. 31, 2021
Convertible Preferred Stock Warrant Liability
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Fair value of underlying preferred stock	$ 1.90
Expected Risk-Free Rate
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Measurement input		0.0009
Expected Risk-Free Rate | Convertible Preferred Stock Warrant Liability
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Measurement input	0.0170
Expected Volatility
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Measurement input		0.800
Expected Volatility | Convertible Preferred Stock Warrant Liability
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Measurement input	0.7000
Expected Term | Convertible Preferred Stock Warrant Liability
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Expected term (in years)	9 years

Fair Value Measurements and F_5

Fair Value Measurements and Fair Value of Financial Instruments - Summary of Activity of Financial Instruments (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2021USD ($)
Fair Value Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Change in fair value	$ 1,000
Convertible Preferred Stock Warrant Liability
Fair Value Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Balance at December 31, 2020	64
Change in fair value	105
Conversion/Settlement during 2021	(169)
Balance at March 31, 2021	0
Series D Convertible Preferred Stock Warrant Liability
Fair Value Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Balance at December 31, 2020	3,900
Change in fair value	980
Conversion/Settlement during 2021	(4,880)
Balance at March 31, 2021	$ 0

Balance Sheet Details - Schedul

Balance Sheet Details - Schedule of Prepaid Expenses and Other Current Assets (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Prepaid Expense And Other Assets Current [Abstract]
Prepaid contract manufacturing expenses	$ 881	$ 3,808
Prepaid clinical trial expenses	2,802	1,397
Prepaid research and development expenses	300	627
Other prepaid expenses	2,679	1,218
Total	$ 6,662	$ 7,050

Balance Sheet Details - Sched_2

Balance Sheet Details - Schedule of Equipment, Net (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Property Plant And Equipment [Line Items]
Equipment, gross	$ 2,947	$ 1,854
Less accumulated depreciation	(494)	(407)
Total	2,453	1,447
Laboratory Equipment
Property Plant And Equipment [Line Items]
Equipment, gross	2,250	1,830
Computer Equipment
Property Plant And Equipment [Line Items]
Equipment, gross	223	$ 24
Office Equipment and Furniture
Property Plant And Equipment [Line Items]
Equipment, gross	$ 474

Balance Sheet Details - Additio

Balance Sheet Details - Additional Information (Details) - USD ($)	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Balance Sheet Related Disclosures [Abstract]
Depreciation expense	$ 100,000	$ 39,000

Balance Sheet Details - Sched_3

Balance Sheet Details - Schedule of Accrued Expenses and Other Current Liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Balance Sheet Related Disclosures [Abstract]
Accrued research and development	$ 2,900	$ 2,123
Accrued clinical trial expenses	2,070	1,999
Accrued contract manufacturing expenses	4,337	906
Accrued legal expenses	407	531
Unvested early exercise liability	29	35
Accrued other	746	456
Total	$ 10,488	$ 6,050

Collaboration and License Agr_3

Collaboration and License Agreements - Additional Information (Details) - USD ($)	1 Months Ended		3 Months Ended		12 Months Ended
	Jul. 31, 2020	Sep. 30, 2017	Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2021
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Common stock, shares issued			39,103,107		38,960,716
Revenue recognized			$ 3,919,000
Deferred revenue			17,934,000		$ 19,872,000
Cedars-Sinai Agreement | Cedars-Sinai
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
License agreement expiration term		3 years
Cedars-Sinai Agreement | Cedars-Sinai | Vested Common Stock
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Common stock, shares issued		257,500
Cedars-Sinai Agreement | Cedars-Sinai | Unvested Restricted Common Stock
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Common stock, shares issued		335,000
License Agreement | Cedars-Sinai
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
License agreement expiration term		10 years
Falk Agreement
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Revenue recognized			2,738,000
Deferred revenue			17,934,000		18,691,000
Falk Agreement | Falk
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Funding percentage third-party development costs set forth in development plan	25.00%
Collaboration agreement, upfront payment received upon agreement execution	$ 2,500,000
Collaboration agreement, pre-clinical development milestone payment received upon finalization of development plan					2,500,000
Collaboration agreement, pre-clinical development milestone payment received upon clinical candidate selected	10,000,000
Collaboration agreement additional pre-clinical development milestone payment eligible to receive	$ 5,000,000
Revenue recognized			2,700,000	$ 600,000
Deferred revenue			17,900,000		18,700,000
Takeda Agreement
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Revenue recognized			1,181,000
Deferred revenue					1,181,000
Takeda Agreement | Takeda Pharmaceutical Company Limited
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Revenue recognized			1,200,000	$ 200,000
Deferred revenue			$ 0		$ 1,200,000

Collaboration and License Agr_4

Collaboration and License Agreements - Additional Information (Details1) - Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2022-04-01	Mar. 31, 2022
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Revenue, remaining performance obligation, expected timing of satisfaction, period	8 years
Falk Agreement | Falk
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Revenue, remaining performance obligation, expected timing of satisfaction, period	8 years

Collaboration and License Agr_5

Collaboration and License Agreements - Schedule of Reconciliation of Deferred Revenue (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2022USD ($)
Disaggregation Of Revenue [Line Items]
Balance at December 31, 2021	$ 19,872
Amounts received in 2022	1,981
Revenue recognized in 2022	(3,919)
Balance at March 31, 2022	17,934
Falk Agreement
Disaggregation Of Revenue [Line Items]
Balance at December 31, 2021	18,691
Amounts received in 2022	1,981
Revenue recognized in 2022	(2,738)
Balance at March 31, 2022	17,934
Takeda Agreement
Disaggregation Of Revenue [Line Items]
Balance at December 31, 2021	1,181
Revenue recognized in 2022	$ (1,181)

Long Term Debt - Additional Inf

Long Term Debt - Additional Information (Details) - Oxford Finance LLC - USD ($)	Mar. 16, 2021	Jul. 31, 2021	Jan. 31, 2020	Dec. 31, 2021
Debt Instrument [Line Items]
Long term debt, maximum borrowing amount			$ 25,000,000
Long term debt, amount drawn upon execution of agreement			$ 7,500,000
Interest rate			2.01%
Additional interest rate			5.98%
Debt instrument minimum annual interest rate			7.99%
Percentage of final payment equal to original principal amount borrowed			4.00%
Percentage of future amount to be funded			3.00%
Prepayment of outstanding principal balance		$ 7,500,000
Prepayment penalty, accrued interest and final payment		$ 500,000
Loss on extinguishment of debt				$ (600,000)
Series C Convertible Preferred Stock
Debt Instrument [Line Items]
Warrant to purchase of convertible preferred stock			112,500
Exercise price of warrants	$ 7.558		$ 1
Expected term (in years)			10 years
Conversion of convertible preferred stock into common stock at initial public offering, shares	14,884

Stockholders' Equity (Deficit_2

Stockholders' Equity (Deficit) - Additional Information (Details) - USD ($)	Jan. 01, 2022	Mar. 16, 2021	Feb. 28, 2021	Jan. 31, 2021	Oct. 31, 2020	Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2017	Dec. 31, 2021
Class Of Stock [Line Items]
Common stock, shares authorized		400,000,000				400,000,000	400,000,000		400,000,000
Preferred stock, shares authorized		40,000,000				40,000,000	40,000,000		40,000,000
Net cash proceeds from sale of convertible preferred stock							$ 73,749,000
Common stock reserved for issuance						10,874,086			8,678,836
Weighted average grant date fair value of options granted						$ 26.14	$ 5.13
Total intrinsic value of options exercised						$ 1,800,000	$ 200,000
Unvested shares early exercised option right to repurchase shares vesting period						4 years
Early exercise liability						$ 29,000			$ 35,000
Stock compensation expense						3,279,000	$ 792,000
Unrecognized compensation cost related to unvested stock-based awards						$ 43,200,000
Unrecognized compensation cost is expected to be recognized over a weighted average period						3 years 4 months 24 days
2021 Employee Stock Purchase Plan
Class Of Stock [Line Items]
Common stock reserved for issuance			360,000
Common stock, shares available for grant						723,457
Annually increase amount equal to lessor of percentage of shares of common stock outstanding on the final day of the immediately preceding calendar year	1.00%		1.00%
Issuance of shares including automatic increase	389,607
Participants to purchase common stock through payroll deductions maximum percentage of eligible compensation			20.00%
Stock compensation expense						$ 100,000
Outstanding liability related to employee contributions for shares pending issuance						$ 300,000
2017 Equity Incentive Plan
Class Of Stock [Line Items]
Common stock reserved for issuance								5,524,354
Maximum options granted period								10 years
Award subject to continuous service						36 months
2017 Equity Incentive Plan | Tranche One
Class Of Stock [Line Items]
Percentage of award vested						25.00%
Award vesting period						1 year
2021 Incentive Award Plan
Class Of Stock [Line Items]
Common stock, shares available for grant			3,600,000			3,794,955
Annually increase amount equal to lessor of percentage of shares of common stock outstanding on the final day of the immediately preceding calendar year			5.00%
Issuance of shares including automatic increase	1,948,035
Convertible Preferred Stock
Class Of Stock [Line Items]
Warrant to purchase of convertible preferred stock		148,848
Series D-1 Convertible Preferred Stock
Class Of Stock [Line Items]
Issuance of convertible preferred stock for cash, net of issuance costs, shares					61,066,216
Shares issued, price per share					$ 0.7558
Net cash proceeds from sale of convertible preferred stock					$ 46,200,000
Convertible preferred stock issued for deferred purchase price obligation, shares					5,088,851
Convertible preferred stock, shares issued for deferred purchase price obligation, value					$ 3,800,000
Series D-2 Convertible Preferred Stock
Class Of Stock [Line Items]
Issuance of convertible preferred stock for cash, net of issuance costs, shares				93,995,300	94,007,051		86,775,740
Shares issued, price per share					$ 0.8510
Convertible preferred stock issued for deferred purchase price obligation, shares				7,219,560	7,231,311		7,219,560
Convertible preferred stock, shares issued for deferred purchase price obligation, value				$ 6,100,000	$ 6,200,000		$ 6,144,000
Change in fair value of preferred stock purchase right liability							$ 1,000,000
Series D Convertible Preferred Stock
Class Of Stock [Line Items]
Fair value of preferred stock purchase right liability					$ 3,900,000
Common Stock
Class Of Stock [Line Items]
Conversion of convertible preferred stock into common stock at initial public offering, shares							25,485,955
Common Stock | Convertible Preferred Stock
Class Of Stock [Line Items]
Conversion of convertible preferred stock into common stock at initial public offering, shares		25,485,955
Common Stock | Convertible Preferred Stock Warrant Liability
Class Of Stock [Line Items]
Conversion of convertible preferred stock into common stock at initial public offering, shares		14,884

Stockholders' Equity (Deficit_3

Stockholders' Equity (Deficit) - Summary of Stock Option Activity (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2022	Dec. 31, 2021
Equity [Abstract]
Number of shares, Outstanding at December 31, 2021	6,474,039
Number of shares, Granted	61,700
Number of shares, Exercised	(142,391)
Number of shares, Cancelled/forfeited	(52,557)
Number of shares, Outstanding at March 31, 2022	6,340,791	6,474,039
Number of shares, Vested or expected to vest at March 31, 2022	6,340,791
Number of shares, Exercisable at March 31, 2022	2,015,832
Weighted Average Exercise Price, Outstanding at December 31, 2021	$ 12.18
Weighted Average Exercise Price, Granted	40
Weighted Average Exercise Price, Exercised	2.45
Weighted Average Exercise Price, Cancelled/forfeited	20.71
Weighted Average Exercise Price, Outstanding at March 31, 2022	12.60	$ 12.18
Weighted Average Exercise Price, Vested or expected to vest at March 31, 2022	12.60
Weighted Average Exercise Price, Exercisable at March 31, 2022	$ 4.48
Weighted Average Remaining Contractual Terms (in Years), Outstanding at December 31, 2021	8 years 3 months 18 days	8 years 6 months
Weighted Average Remaining Contractual Terms (in Years), Vested or excepted to vest at March 31, 2022	8 years 3 months 18 days
Weighted Average Remaining Contractual Terms (in Years), Exercisable at March 31, 2022	6 years 7 months 6 days
Aggregate Intrinsic Value, Outstanding at December 31, 2021	$ 159,544	$ 177,130
Aggregate Intrinsic Value, Vested or excepted to vest at March 31, 2022	159,544
Aggregate Intrinsic Value, Exercisable at March 31, 2022	$ 67,087

Stockholders' Equity (Deficit_4

Stockholders' Equity (Deficit) - Summary of Grant Date Fair Value of Stock Options (Details)	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Risk-free interest rate, Minimum	1.50%	0.60%
Risk-free interest rate, Maximum	1.70%	1.00%
Expected volatility		95.20%
Expected volatility, Minimum	73.20%
Expected volatility, Maximum	74.60%
Expected term (in years)	6 years 1 month 6 days
Minimum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected term (in years)		5 years 9 months 18 days
Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected term (in years)		6 years 1 month 6 days

Stockholders' Equity (Deficit_5

Stockholders' Equity (Deficit) - Summary of Activity Unvested Common Stock Issued Pursuant Early Exercise of Stock Options Awards (Details)	3 Months Ended
	Mar. 31, 2022shares
Equity [Abstract]
Unvested at beginning of period	17,606
Vested or cancelled during the period	(4,311)
Unvested at end of period	13,295

Stockholders' Equity (Deficit_6

Stockholders' Equity (Deficit) - Summary of Fair Value of Stock of the Stock Purchase Right Under ESPP (Details)	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Risk-free interest rate, Minimum	1.50%	0.60%
Risk-free interest rate, Maximum	1.70%	1.00%
Expected volatility		95.20%
Expected volatility, Minimum	73.20%
Expected volatility, Maximum	74.60%
Expected term (in years)	6 years 1 month 6 days
2021 Employee Stock Purchase Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Risk-free interest rate, Minimum	0.03%
Risk-free interest rate, Maximum	0.33%
Expected volatility, Minimum	71.60%
Expected volatility, Maximum	83.90%
Minimum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected term (in years)		5 years 9 months 18 days
Minimum | 2021 Employee Stock Purchase Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected term (in years)	6 months
Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected term (in years)		6 years 1 month 6 days
Maximum | 2021 Employee Stock Purchase Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected term (in years)	1 year 7 months 20 days

Stockholders' Equity (Deficit_7

Stockholders' Equity (Deficit) - Summary of Stock-based Compensation Expense (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total stock-based compensation	$ 3,279	$ 792
Research and Development
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total stock-based compensation	1,136	171
General and Administrative
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total stock-based compensation	$ 2,143	$ 621

Stockholders' Equity (Deficit_8

Stockholders' Equity (Deficit) - Summary of Common Stock Reserved for Future Issuance (Details) - shares	Mar. 31, 2022	Dec. 31, 2021
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock reserved for issuance	10,874,086	8,678,836
Common Stock Options Issued and Outstanding
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock reserved for issuance	6,340,791	6,474,039
Warrants to Purchase Common Stock
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock reserved for issuance	14,884	14,884
Shares Available for Issuance Under Equity Incentive Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock reserved for issuance	3,794,954	1,856,063
ESPP Shares Pending Issuance
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock reserved for issuance	723,457	333,850

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Details)	1 Months Ended	3 Months Ended		12 Months Ended
	Mar. 31, 2022USD ($)	Mar. 31, 2022USD ($)	Mar. 31, 2021USD ($)	Dec. 31, 2020ft²	Oct. 31, 2021
Commitments And Contingencies [Line Items]
Operating lease right-of-use asset and liabilities	$ 14,600,000	$ 14,600,000
Operating lease expense		$ 300,000	$ 200,000
Operating lease, weighted average remaining lease term	132 months	132 months
Operating lease, weighted average discount rate, percent	8.00%	8.00%
Indemnification claims		$ 0
Accrued indemnification	$ 0	$ 0
PLI
Commitments And Contingencies [Line Items]
Area of land | ft²				40,000
Sublease agreement term				1 year
Sublease option to extend		true
Sublease option to extend, description		The sublease agreement was extended through June 2022 during the year ended December 31, 2021.
Sublease term expiration date		2022-06
Monthly payment		$ 80,000
Remaining payment obligations		$ 200,000
Office and Laboratory Space, San Diego
Commitments And Contingencies [Line Items]
Initial lease term	10 years	10 years			127 months
Option to extend additional lease term	5 years	5 years			5 years
Approximate monthly rental payment proceeds from lease	$ 200,000	$ 200,000
Option to extend lease	true	true
Lessee operating lease lease expect to commence year		2022-09
Office and Laboratory Space, San Diego | Maximum
Commitments And Contingencies [Line Items]
Tenant improvement allowance	$ 6,300,000	$ 6,300,000

Commitments and Contingencies_2

Commitments and Contingencies - Future Minimum Operating Lease Payments for the Second Floor Lease and Information Related to Lease Liability (Details) $ in Thousands	Mar. 31, 2022USD ($)
Commitments And Contingencies Disclosure [Abstract]
Remainder of 2022	$ 468
2023	1,912
2024	1,970
2025	2,029
2026	2,090
Thereafter	14,552
Total lease payments	23,021
Imputed interest	(8,398)
Lease liability	14,623
Less current portion of lease liability	891
Lease liability, net of current portion	$ 13,732

Related Party Transactions - Ad

Related Party Transactions - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended		3 Months Ended		12 Months Ended
	Jan. 31, 2021	Oct. 31, 2020	Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2020	Dec. 31, 2021	Sep. 30, 2017
Related Party Transaction [Line Items]
Common stock, shares issued			39,103,107			38,960,716
Common stock, par value			$ 0.0001			$ 0.0001
Series D-2 Convertible Preferred Stock
Related Party Transaction [Line Items]
Issuance of convertible preferred stock for settlement of deferred purchase price	$ 6,100	$ 6,200		$ 6,144
PLI | Series D-2 Convertible Preferred Stock
Related Party Transaction [Line Items]
Number of convertible preferred stock issued as deferred consideration for acquisition	7,219,560
Cedars-Sinai Agreement | Vested Common Stock | Cedars-Sinai
Related Party Transaction [Line Items]
Common stock, shares issued							257,500
Common stock, par value							$ 0.0001
Cedars-Sinai Agreement | Unvested Restricted Common Stock | Cedars-Sinai
Related Party Transaction [Line Items]
Common stock, shares issued							335,000
Unvested restricted common stock shares par value							$ 0.0001
Transition Services Agreement
Related Party Transaction [Line Items]
Payment for terms of agreement			$ 900	$ 1,600
Transition Services Agreement | PLI Spinoff
Related Party Transaction [Line Items]
Initial term of agreement					1 year

401(K) Plan - Additional Inform

401(K) Plan - Additional Information (Details) - USD ($)	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Compensation And Retirement Disclosure [Abstract]
Company contribution to 401(k) plan	$ 400,000	$ 43,000

Subsequent Events - Additional

Subsequent Events - Additional Information (Details) $ / shares in Units, $ in Thousands	May 10, 2022USD ($)$ / sharesshares	Apr. 01, 2022USD ($)	Mar. 31, 2022USD ($)	Dec. 31, 2021USD ($)
Subsequent Event [Line Items]
Common stock—$0.0001 par value; 400,000,000 shares authorized as of March 31, 2022 and December 31, 2021; 39,103,107 shares and 38,960,716 shares issued at March 31, 2022 and December 31, 2021, respectively; 39,089,812 shares and 38,943,110 shares outstanding at March 31, 2022 and December 31, 2021, respectively;			$ 4	$ 4
Subsequent Event | Sale Agreement
Subsequent Event [Line Items]
Issuance of shares of common stock in initial public offering for cash, net of issuance costs, shares | shares	69,870
Common stock price per share | $ / shares	$ 36.14
Gross proceeds	$ 2,500
PLI | Subsequent Event | Sale Agreement | Agent
Subsequent Event [Line Items]
Percentage of commission from sale of common stock		3
Maximum | PLI | Subsequent Event | Sale Agreement | Agent
Subsequent Event [Line Items]
Common stock—$0.0001 par value; 400,000,000 shares authorized as of March 31, 2022 and December 31, 2021; 39,103,107 shares and 38,960,716 shares issued at March 31, 2022 and December 31, 2021, respectively; 39,089,812 shares and 38,943,110 shares outstanding at March 31, 2022 and December 31, 2021, respectively;		$ 150,000