Sera Prognostics (SERA) 10-K 20 Mar 24 2023 FY Annual report Financial data

Cover

Cover - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Mar. 15, 2024	Jun. 30, 2023
Document Information [Line Items]
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2023
Current Fiscal Year End Date	--12-31
Document Transition Report	false
Entity File Number	001-40606
Entity Registrant Name	SERA PROGNOSTICS, INC.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	26-1911522
Entity Address, Address Line One	2749 East Parleys Way
Entity Address, Address Line Two	Suite 200
Entity Address, City or Town	Salt Lake City
Entity Address, State or Province	UT
Entity Address, Postal Zip Code	84109
City Area Code	801
Local Phone Number	990-0520
Title of 12(b) Security	Class A Common Stock, $0.0001 par value per share
Trading Symbol	SERA
Security Exchange Name	NASDAQ
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	true
Entity Ex Transition Period	false
ICFR Auditor Attestation Flag	false
Entity Shell Company	false
Entity Public Float			$ 91.7
Documents Incorporated by Reference	Portions of the registrant’s definitive proxy statement relating to its 2024 annual meeting of stockholders (the “Proxy Statement”) are incorporated by reference into Part III of this Annual Report on Form 10-K where indicated. The Proxy Statement will be filed with the Securities and Exchange Commission within 120 days after the end of the registrant’s fiscal year ended December 31, 2023.
Entity Central Index Key	0001534969
Document Fiscal Year Focus	2023
Document Fiscal Period Focus	FY
Amendment Flag	false
Document Financial Statement Error Correction [Flag]	false
Class A common stock
Document Information [Line Items]
Entity Common Stock, Shares Outstanding (in shares)		31,457,902
Class B common stock
Document Information [Line Items]
Entity Common Stock, Shares Outstanding (in shares)		967,759

Audit Information

Audit Information	12 Months Ended
	Dec. 31, 2023
Auditor Information [Abstract]
Auditor Firm ID	42
Auditor Name	Ernst & Young LLP
Auditor Location	Salt Lake City, Utah

Balance Sheets (unaudited)

Balance Sheets (unaudited) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Current assets:
Cash and cash equivalents	$ 3,880	$ 29,878
Marketable securities	45,199	52,826
Accounts receivable	160	113
Other receivables	11,310	6,000
Prepaid expenses and other current assets	795	1,308
Total current assets	61,344	90,125
Property and equipment, net	1,999	3,059
Long-term marketable securities	30,841	21,329
Other assets	1,257	1,816
Total assets	95,441	116,329
Current liabilities:
Accounts payable	1,046	1,548
Accrued and other current liabilities	2,722	4,444
Finance lease obligation, current portion	440	464
Deferred revenue	20,235	9,082
Total current liabilities	24,443	15,538
Finance lease obligation, net of current portion	196	626
Operating lease obligation, net of current portion	644	1,222
Total liabilities	25,283	17,386
Commitments and Contingencies
Stockholders' equity:
Common stock, $0.0001 par value; 150,000,000 Class A shares authorized; 30,736,513 and 29,612,687 Class A shares issued and outstanding as of December 31, 2023 and 2022, respectively; 1,500,000 Class B shares authorized; 1,405,259 Class B shares issued as of December 31, 2023 and 2022; 967,759 and 1,405,259 Class B shares outstanding as of December 31, 2023 and 2022, respectively.	3	3
Additional paid-in capital	317,066	310,575
Accumulated other comprehensive loss	(15)	(981)
Accumulated deficit	(246,896)	(210,654)
Total stockholders' equity	70,158	98,943
Total liabilities and stockholders' equity	$ 95,441	$ 116,329

Balance Sheets (Parenthetical)

Balance Sheets (Parenthetical) - $ / shares	Dec. 31, 2023	Dec. 31, 2022
Class A common stock
Common stock, par value (in usd per share)	$ 0.0001	$ 0.0001
Common stock, shares authorized (in shares)	150,000,000	150,000,000
Common stock, shares issued (in shares)	30,736,513	29,612,687
Common stock, shares outstanding (in shares)	30,736,513	29,612,687
Class B common stock
Common stock, par value (in usd per share)	$ 0.0001	$ 0.0001
Common stock, shares authorized (in shares)	1,500,000	1,500,000
Common stock, shares issued (in shares)	1,405,259	1,405,259
Common stock, shares outstanding (in shares)	967,759	1,405,259

Statements of Operations and Co

Statements of Operations and Comprehensive Loss - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Income Statement [Abstract]
Revenue	$ 306	$ 268
Operating expenses:
Cost of revenue	210	193
Research and development	15,225	14,244
Selling and marketing	8,349	14,699
General and administrative	16,343	16,784
Total operating expenses	40,127	45,920
Loss from operations	(39,821)	(45,652)
Interest expense	(55)	(61)
Other income, net	3,634	1,527
Net loss	$ (36,242)	$ (44,186)
Net loss per share, diluted (in usd per share)	$ (1.16)	$ (1.43)
Net loss per share, basic (in usd per share)	$ (1.16)	$ (1.43)
Weighted-average shares of common stock outstanding, diluted (in shares)	31,200,652	30,943,426
Weighted-average shares of common stock outstanding, basic (in shares)	31,200,652	30,943,426
Other comprehensive income (loss):
Unrealized gain (loss) on available-for-sale debt securities	$ 966	$ (798)
Total other comprehensive income (loss)	966	(798)
Comprehensive loss	$ (35,276)	$ (44,984)

Statements of Convertible Prefe

Statements of Convertible Preferred Stock and Stockholders’ Equity (Deficit) - USD ($) $ in Thousands	Total	Common Stock (Class A and B)	Additional Paid-In Capital	Accumulated Other Comprehensive Loss	Accumulated Deficit
Balance at the beginning (in shares) at Dec. 31, 2021		30,774,126
Balance at the beginning at Dec. 31, 2021	$ 138,564	$ 3	$ 305,212	$ (183)	$ (166,468)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock upon exercise of stock options (in shares)		243,820
Issuance of common stock upon exercise of stock options	308		308
Stock-based compensation expense	5,055		5,055
Other comprehensive loss	(798)			(798)
Net loss	(44,186)				(44,186)
Balance at the ending (in shares) at Dec. 31, 2022		31,017,946
Balance at the ending at Dec. 31, 2022	$ 98,943	$ 3	310,575	(981)	(210,654)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock upon exercise of stock options (in shares)	593,091	593,091
Issuance of common stock upon exercise of stock options	$ 1,095		1,095
Stock Issued During Period, Value, Employee Stock Purchase Plan	123		123
Stock Issued During Period, Shares, Employee Stock Purchase Plans		93,235
Stock-based compensation expense	5,273		5,273
Other comprehensive loss	966			966
Net loss	(36,242)				(36,242)
Balance at the ending (in shares) at Dec. 31, 2023		31,704,272
Balance at the ending at Dec. 31, 2023	$ 70,158	$ 3	$ 317,066	$ (15)	$ (246,896)

Statements of Cash Flows

Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Cash flows from operating activities
Net loss	$ (36,242)	$ (44,186)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	900	756
Stock-based compensation	5,273	5,055
Operating Lease, Right-of-Use Asset, Amortization Expense	526	462
Non-cash interest expense	0	12
Non-cash investment income, net	(1,182)	(239)
Other	18	(22)
Changes in operating assets and liabilities:
Accounts receivable	(47)	(86)
Other receivables	(5,310)	(2,884)
Prepaid expenses and other assets	465	718
Accounts payable	(442)	352
Accrued and other current liabilities	(2,301)	(514)
Deferred revenue	11,154	5,966
Net cash used in operating activities	(27,188)	(34,610)
Cash flows from investing activities
Purchases of marketable securities	(54,143)	(48,073)
Proceeds from maturities and sales of marketable securities	54,398	54,399
Purchases of property and equipment	(128)	(791)
Proceeds from Sale of Property, Plant, and Equipment	311	16
Net cash provided by investing activities	438	5,551
Cash flows from financing activities
Proceeds from exercise of stock options	1,095	308
Proceeds, Issuance of Shares, Share-Based Payment Arrangement, Excluding Option Exercised	123	0
Finance Lease, Principal Payments	(466)	(303)
Net cash provided by financing activities	752	5
Net decrease in cash and cash equivalents	(25,998)	(29,054)
Cash and cash equivalents at beginning of period	29,878	58,932
Cash and cash equivalents at end of period	3,880	29,878
Supplemental disclosure of cash flow information
Cash paid for interest	55	48
Supplemental disclosure of non-cash investing and financing information
Purchases of property and equipment in accounts payable and accruals	$ 20	$ 0

Description of Business and Fin

Description of Business and Financial Condition	12 Months Ended
	Dec. 31, 2023
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Description of Business and Financial Condition	Description of Business and Financial Condition Sera Prognostics, Inc. (the “Company”) is a women’s health company utilizing its proprietary proteomics and bioinformatics platform to discover, develop, and commercialize biomarker tests with an initial focus on improving pregnancy outcomes. The Company was incorporated in the State of Delaware on January 17, 2008 and its operations are located in Salt Lake City, Utah, including a Clinical Laboratory Improvement Amendments (“CLIA”)-certified laboratory. Since its inception, the Company’s activities have consisted of performing research and development, conducting clinical studies for its pipeline products and services, acquiring product rights, raising capital, establishing facilities, and organizing commercial operations to market the PreTRM test. Liquidity and Capital Resources The accompanying financial statements have been prepared on a going concern basis, which contemplates the realization of assets and the satisfaction of liabilities and commitments in the normal course of business. The Company has incurred net losses and negative cash flows from operations since inception and had an accumulated deficit of $246.9 million as of December 31, 2023. The Company’s management expects the Company to incur significant additional operating losses and negative cash flows for the foreseeable future, principally as a result of the Company’s activities relating to the PreTRM test and the Company’s other pipeline products and services, including clinical and preclinical trials and anticipated research and development activities as well as commercialization activities. There can be no assurance that the Company will eventually achieve significant revenues or profitability to sustain operations, or if achieved, can sustain either on a continuing basis. If the Company is unable to achieve significant revenues or raise additional funds, when needed, it may not be able to continue the development or commercialization of its products and services and could be required to delay, scale back, or abandon some or all of its operations. No assurance can be given that the Company will be successful in raising the required capital on reasonable terms and at the required times, or at all. Any additional equity financing, if available to the Company, may not be available on favorable terms and may be dilutive to current stockholders, and any debt financing, if available, may involve restrictive covenants and dilutive financing instruments. The Company’s future operations are highly dependent on a combination of factors, including (i) the commercialization and market acceptance of the PreTRM test and the successful development, commercial launch, marketing, and distribution of other pipeline products and services; (ii) the success of scientific and clinical studies and other research and development programs that support current and future products and services; (iii) the development of competitive products by other biotechnology and laboratory companies; (iv) the Company’s ability to manage growth of the organization; (v) the Company’s ability to protect its intellectual property, technology, and products; and, ultimately (vi) the timely and successful completion of any additional financing. The principal sources of the Company’s working capital to date have been the proceeds from the sale and issuance of convertible preferred stock and convertible notes, bank loans, and the sale and issuance of Class A common stock in an initial public offering (“IPO”), which was completed in July 2021. As of December 31, 2023, the Company had aggregate cash, cash equivalents, and available-for-sale securities of approximately $79.9 million. See Note 3—Cash, Cash Equivalents and Marketable Securities. The Company evaluated that its existing financial resources are sufficient to continue operating activities at least 12 months from the issuance date of these financial statements.

Significant Accounting Policies

Significant Accounting Policies	12 Months Ended
	Dec. 31, 2023
Accounting Policies [Abstract]
Significant Accounting Policies	Significant Accounting Policies Basis of Presentation The accompanying financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (“U.S. GAAP”). Any reference in these notes to applicable accounting guidance is meant to refer to the authoritative U.S. GAAP included in the Accounting Standards Codification (“ASC”), and Accounting Standards Updates (“ASU”) issued by the Financial Accounting Standards Board (“FASB”). Use of Estimates The preparation of the financial statements in conformity with U.S. GAAP requires the Company’s management to make estimates and assumptions that affect the amounts reported in the financial statements and accompanying notes. The Company evaluates these estimates on an ongoing basis. The Company bases these estimates on historical and anticipated results, trends, and various other assumptions that the Company believes are reasonable under the circumstances, including assumptions as to future events. Actual results could differ materially from those estimates. The Company’s financial statements as of and for the year ended December 31, 2023 reflect the Company’s estimates of the impact of the current macroeconomic environment, including the impact of inflation and higher interest rates. The extent to which these conditions will directly or indirectly impact the Company’s business, results of operations, and financial condition is uncertain. The Company is not aware of any specific event or circumstance that would require an update to its estimates, judgments, and assumptions or a revision of the carrying value of the Company’s assets or liabilities as of the date of this filing. Cash and cash equivalents The Company considers all highly liquid financial instruments with maturities of 90 days or less at the date of purchase to be cash equivalents. The carrying amounts reported in the balance sheets for cash and cash equivalents are valued at cost, which approximates their fair value. As of December 31, 2023 and 2022, cash and cash equivalents consisted of cash, money market funds, and commercial paper. Cash and cash equivalents are stated at fair value. Marketable Securities The Company has classified its marketable securities, all of which are debt securities, as available-for-sale securities. These securities are carried at estimated fair value. Available-for-sale debt securities with an estimated fair value below the amortized cost basis are assessed to determine what amount of that difference, if any, is attributable to expected credit losses. An allowance for credit losses on available-for-sale debt securities is recognized as a charge in other income, net on the Company’s statements of operations and comprehensive loss, and any remaining unrealized losses, net of the related tax effect, are included in accumulated other comprehensive loss in stockholders’ equity until realized. Gains and losses on marketable security transactions are reported on the specific-identification method. Concentration of credit risk Financial instruments that potentially subject the Company to concentrations of credit risk consist primarily of cash and cash equivalents and marketable securities. The Company maintains bank deposits in accounts at federally insured financial institutions and these deposits may exceed federally insured limits. The Company is exposed to credit risk in the event of default by the financial institution holding its cash to the extent recorded in the balance sheet. The Company has not experienced any losses on its deposits of cash. The Company’s cash equivalents consist of money market funds and investment grade commercial paper. Marketable securities consist of investments in U.S. government securities, U.S. federal agency securities, investment grade commercial paper, and investment grade corporate securities. The Company’s investment portfolio in corporate debt securities is highly liquid and diversified among individual issuers. The Company did not experience any credit losses related to its investment portfolio for the years ended December 31, 2023 and 2022. Property and Equipment Property and equipment are recorded at cost less accumulated depreciation and amortization. Depreciation and amortization are computed using the straight-line method over the shorter of estimated useful lives of the assets or the respective lease term. The estimated useful life of each asset category is as follows: Computer equipment 3 years Software 3 years Machinery and equipment 5 years Furniture and fixtures 5 years Leasehold improvements Shorter of useful life or remaining lease term Amortization expense of assets acquired through finance leases is included in depreciation and amortization expense in the accompanying statements of operations and comprehensive loss. Costs of repairs and maintenance that do not extend the useful life or improve the related assets are expensed as incurred. Costs of major replacements or improvements are capitalized. When assets are sold, or otherwise disposed of, the cost and related accumulated depreciation are removed from the accounts and any gain or loss is included in operating expense. Leases The Company’s operating lease relates to office and laboratory space at its headquarters. The Company’s finance leases are for certain equipment related to the Company’s information technology infrastructure and laboratory operations. The Company determines if an arrangement is a lease at inception. The Company has elected not to separate lease components from non-lease components for all classes of leased assets except for building leases. The Company elected to treat leases with lease terms of 12 months or less as short-term leases. No right-of-use assets or lease liabilities are recognized for short-term leases. For leases with a lease term greater than 12 months, right-of-use assets and lease liabilities are recognized on the balance sheets at the commencement date based on the present value of the remaining lease payments and includes only payments that are fixed and determinable at commencement. The Company’s lease terms may include options to extend or terminate when it is reasonably certain that the Company will exercise such options. To date, the rates implicit in the Company’s finance leases have been determinable, and the Company uses those rates to calculate the present value of its finance lease liabilities. The implicit rate in the Company’s operating lease is not readily determinable. As such, the Company uses its incremental borrowing rate to calculate the present value of its operating lease liabilities. Operating lease costs are recognized on a straight-line basis over the lease terms. Finance lease assets are amortized on a straight-line basis over the shorter of the estimated useful lives of the assets or the lease terms. Deferred Revenue The Company recognizes deferred revenue in accordance with ASC 606, Revenue from Contracts with Customers (“ASC 606”). Deferred revenue is recognized when a customer pays consideration, or the Company has a right to an amount of consideration that is unconditional before the Company transfers the good or service to the customer. The Company’s deferred revenue balance as of December 31, 2023 and 2022 relates to certain contractual minimum payments received by the Company as part of its commercial collaboration agreements. Deferred revenue is recognized as revenue when the Company delivers PreTRM test results to customers pursuant to its commercial collaboration agreements. Revenue Recognition Revenue is generated from the sale of PreTRM tests. The Company recognizes revenue based on accounting standards applied to determine the measurement of revenue and timing of when it is recognized. The Company applies the following five-step approach as set forth under ASC 606: (i) identify the contract(s) with a customer; (ii) identify the performance obligations in the contract (iii) determine the transaction price; (iv) allocate the transaction price to the performance obligations in the contract; and (v) recognize revenue when (or as) the Company satisfies a performance obligation. The Company applies the five-step model when it is probable that the Company will collect the consideration it is entitled to in exchange for fulfilling its performance obligation. The Company recognizes revenue upon delivery of test results, which it considers to be the only performance obligation, and allocates all of the transaction price to this performance obligation. In determining the transaction price, which is an estimate of the amount of variable consideration expected to be received, the Company uses the expected value method under ASC 606. The Company considers all reasonably available information to identify various possible consideration amounts and considers the probability of the variable consideration for each scenario. The Company’s estimate of transaction price does not include any estimated amount of variable consideration that is constrained. Significant judgments are required in determining the estimates for each transaction. These estimates include many assumptions, any of which, if incorrect, could result in significant differences between the estimated price and the amount ultimately collected for any given transaction. The Company applies this method consistently to portfolios of similar contracts when estimating the effect of any uncertainty on the amount of variable consideration to which it will be entitled. In the aggregate, across the numerous transactions within each portfolio, these differences can lead to material variances between estimated and actual revenue in any given period. The estimate of revenue is necessarily founded on assumptions of payer behavior such as changes in payer mix, payer collections, current customer contractual requirements, and experience with ultimate collection from third-party payers and patients. Each of these aspects of payer behavior (and various others) can change significantly from quarter to quarter, and the Company currently has limited experience with historical payment patterns. Each of these contributes to the potential variability between estimated transaction price and actual consideration received as discussed above, which is expected to be more pronounced early in the process of commercializing a diagnostic test. The Company makes its best efforts to continually refine its estimates of expected consideration as the Company gains additional experience with collections and historical payment patterns. Accordingly, the Company may update its estimate of the amount of revenue to be recognized for previously delivered tests. Cost of Revenue Cost of revenue reflects the aggregate costs incurred in delivering the proteomic testing results to clinicians and includes expenses for third-party specimen collection and shipping costs, as well as the Company’s lab personnel, materials and supplies, equipment and infrastructure expenses associated with clinical testing, and allocated overhead including rent and equipment depreciation. Costs associated with performing the Company’s tests are recorded as the tests are processed regardless of whether and when revenue is recognized with respect to such tests. Research and Development Expenses The Company expenses all research and development costs as they are incurred. Research and development expenses consist primarily of personnel costs, stock-based compensation charges, clinical trial costs, and third-party contracted services associated with research and development. The Company recognizes expense associated with third-party contracted services based on the completion of activities as specified in the applicable contracts. Costs incurred under contracts with clinical sites are generally accrued as patient encounters occur, consistent with the terms outlined in the associated contract. Upon termination of contracts with third parties, the Company’s obligations are limited to costs incurred or committed to date. As a result, accrued research and development expenses represent the estimated contractual liability to third parties at the reported period. Stock-based Compensation The Company recognizes stock-based compensation for all stock-based awards in accordance with ASC 718, C ompensation-Stock Compensation , which requires an entity to measure the cost of employee services received in exchange for an award of equity instruments based on the grant-date fair value of the award. The fair value of restricted stock units granted under the Company’s equity incentive plans is measured based on the grant-date fair value of the Company’s Class A common stock. The fair value of stock options granted under the Company’s equity incentive plans is estimated using the Black-Scholes option pricing model. Input assumptions used in calculating the fair value of stock options represent management’s estimates and involve inherent uncertainties and the application of management’s judgment. These input assumptions include the expected term of the awards, the expected common stock price volatility over the term of the awards, risk-free interest rates, and the expected dividend yield. The fair value of the Company’s Class A common stock is determined by using the closing price per share of the Company’s Class A common stock as reported on Nasdaq. The Company uses the simplified calculation of expected life since the Company does not have sufficient historical exercise data to estimate the expected term. Volatility is based on an average of the historical volatility of the Company’s common stock and the volatilities of the common stock of select comparable publicly-traded entities with characteristics similar to those of the Company. The risk-free rate is based on the U.S. Treasury yield curve in effect at the time of grant for periods corresponding with the expected life of the option. Forfeitures are estimated at the time of grant based on the Company’s historical experience and are adjusted as necessary. The fair value of equity awards is recognized as compensation cost on a straight-line basis by the Company over the participant’s requisite service period, which is the award’s vesting period. All stock-based compensation costs are classified in the statements of operations and comprehensive loss based upon the underlying participant’s role within the Company. Income Taxes The Company accounts for income taxes under the asset and liability method, which requires the recognition of deferred tax assets and liabilities for the expected future tax consequences of events that have been included in the financial statements. Under this method, deferred tax assets and liabilities are determined on the basis of the differences between the financial statement and tax bases of assets and liabilities using enacted tax rates in effect for the year in which the differences are expected to reverse. The effect of a change in tax rates on deferred tax assets and liabilities is recognized in income in the period that includes the enactment date. The Company recognizes deferred tax assets to the extent that it believes these assets are more likely than not to be realized. In making such a determination, the Company considers all available positive and negative evidence, including future reversals of existing taxable temporary differences, projected future taxable income, tax-planning strategies, and results of recent operations. If the Company determines that it would be able to realize its deferred tax assets in the future in excess of their net recorded amount, the Company would make an adjustment to the deferred tax asset valuation allowance, which would reduce the provision for income taxes. The Company records uncertain tax positions in accordance with ASC 740 on the basis of a two-step process whereby (1) it determines whether it is more likely than not that the tax positions will be sustained on the basis of the technical merits of the position and (2) for those tax positions that meet the more-likely-than-not recognition threshold, it recognizes the largest amount of tax benefit that is more than 50 percent likely to be realized upon ultimate settlement with the related tax authority. The Company recognizes interest and penalties related to unrecognized tax benefits within the income tax expense line in the accompanying statements of operations and comprehensive loss. Any accrued interest and penalties related to uncertain tax positions will be reflected as a liability in the balance sheets. Retirement Savings Plan The Company sponsors a safe harbor 401(k) plan that covers all of the Company’s eligible employees. The plan allows employees to make contributions up to a specified percentage of their compensation, subject to statutory limitations. The Company makes safe harbor matching contributions equal to 100% of the first 3% of a plan participant’s eligible compensation, plus 50% of the next 2% of a plan participant’s eligible compensation. The Company may also make an additional discretionary match or profit sharing contribution to the plan. The Company recorded expense related to its 401(k) plan of $0.6 million for the years ended December 31, 2023 and 2022. Segments The Company operates as one operating segment, which is developing and commercializing its medical diagnostic products and services. The Company’s chief operating decision maker, its chief executive officer, reviews financial information on an aggregate basis for making decisions regarding resource allocation and assessing performance. Comprehensive Loss Comprehensive loss consists of net loss and other gains and losses affecting stockholders’ equity that, under U.S. GAAP, are excluded from net loss. For the years ended December 31, 2023 and 2022, comprehensive loss includes unrealized gains (losses) on the Company’s available-for-sale debt securities. Net Loss per Share Basic net loss per share is calculated by dividing net loss by the weighted-average number of shares of common stock outstanding for the period, without consideration of potentially dilutive securities. Diluted net loss per share is computed by dividing net loss by the weighted-average number of shares of common stock and potentially dilutive securities outstanding for the period. For purposes of the diluted net loss per share calculation, stock options and warrants to purchase common stock are considered to be potentially dilutive securities. For periods in which the Company reports a net loss, all potentially dilutive shares are anti-dilutive and are therefore excluded from the calculation of diluted net loss per share. The Company has two classes of common stock and calculates net loss per share using the two-class method. The rights, including the liquidation and dividend rights, of the holders of the Company’s Class A and Class B common stock are identical, except with respect to voting and conversion. The undistributed earnings for each period are allocated based on the contractual participation rights of the Class A and Class B common shares as if the earnings for the period had been distributed. As the liquidation and dividend rights are identical, the undistributed earnings are allocated on a proportionate basis and the resulting amount per share for Class A and Class B common stock was the same for the years ended December 31, 2023 and 2022. Recently Issued Accounting Pronouncements Not Yet Adopted In December 2023, the FASB issued ASU 2023-09, Income Taxes (Topic 740): Improvements to Income Tax Disclosures , which is intended to improve the transparency of income tax disclosures by requiring consistent categories and greater disaggregation of information in the effective tax rate reconciliation and income taxes paid by jurisdiction. The ASU is effective for public business entities’ annual periods beginning after December 15, 2024, with early adoption permitted. The Company is currently evaluating the impact of adopting this guidance on its financial statements. In November 2023, the FASB issued ASU No. 2023-07, Improvements to Reportable Segments Disclosures. While ASU 2023-07 requires incremental disclosures, it does not change how an entity identifies its operating segments, aggregates those operating segments, or applies the quantitative thresholds to determine reportable segments. This ASU is effective for all public business entities for fiscal years beginning after December 15, 2023, and interim periods within fiscal years beginning after December 15, 2024. Entities must adopt the changes to the segment reporting guidance on a retrospective basis. The Company is currently evaluating the impact of adopting this guidance on its financial statements. Early adoption is permitted; however, the Company is not early adopting the standard. Emerging Growth Company Status The Company is an emerging growth company, as defined in the Jumpstart Our Business Startups Act of 2012 (the “JOBS Act”). Under the JOBS Act, emerging growth companies can delay adopting new or revised accounting standards until such time as those standards apply to private companies. The Company has elected to use this extended transition period for complying with new or revised accounting standards that have different effective dates for public and private companies until the earlier of the date that it is (a) no longer an emerging growth company or (b) affirmatively and irrevocably opt out of the extended transition period provided in the JOBS Act. As a result, these financial statements may not be comparable to companies that comply with the new or revised accounting pronouncements as of public company effective dates.

Cash, Cash Equivalents and Mark

Cash, Cash Equivalents and Marketable Securities	12 Months Ended
	Dec. 31, 2023
Cash and Cash Equivalents [Abstract]
Cash, Cash Equivalents and Marketable Securities	Cash, Cash Equivalents and Marketable Securities The Company has classified its marketable securities as available-for-sale. The Company’s cash, cash equivalents and marketable securities by major security type as of December 31, 2023 and 2022 were as follows (in thousands): December 31, 2023 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Cash and cash equivalents: Cash $ 2,608 $ — $ — $ 2,608 Money market funds 1,272 — — 1,272 Total cash and cash equivalents 3,880 — — 3,880 Current marketable securities: Commercial paper 11,769 6 (2) 11,773 Corporate debt securities 1,155 — (2) 1,153 U.S. federal agency securities 19,644 — (102) 19,542 U.S. government securities 12,812 — (81) 12,731 Total current marketable securities 45,380 6 (187) 45,199 Long-term marketable securities: U.S. federal agency securities 9,406 27 (17) 9,416 U.S. government securities 4,388 3 (5) 4,386 Corporate debt securities 16,880 159 — 17,039 Total long-term marketable securities 30,674 189 (22) 30,841 Total cash, cash equivalents and marketable securities $ 79,934 $ 195 $ (209) $ 79,920 December 31, 2022 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Cash and cash equivalents: Cash $ 913 $ — $ — $ 913 Money market funds 2,618 — — 2,618 Commercial paper 26,356 — (9) 26,347 Total cash and cash equivalents 29,887 — (9) 29,878 Current marketable securities: Commercial paper 15,219 2 (66) 15,155 Corporate debt securities 507 — (5) 502 U.S. federal agency securities 28,964 — (364) 28,600 U.S. government securities 8,702 — (133) 8,569 Total current marketable securities 53,392 2 (568) 52,826 Long-term marketable securities: U.S. federal agency securities 9,810 — (199) 9,611 U.S. government securities 10,770 — (208) 10,562 Corporate debt securities 1,156 — — 1,156 Total long-term marketable securities 21,736 — (407) 21,329 Total cash, cash equivalents and marketable securities $ 105,015 $ 2 $ (984) $ 104,033 The following tables summarize the Company’s available-for-sale debt securities and cash equivalents with unrealized losses as of December 31, 2023 and 2022, aggregated by major security type and the length of time that individual securities have been in a continuous loss position (in thousands): December 31, 2023 Less than 12 months 12 months or greater Total Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses Commercial paper $ 5,453 $ (2) $ — $ — $ 5,453 $ (2) Corporate debt securities 1,153 (2) — — 1,153 (2) U.S. federal agency securities 15,308 (52) 8,751 (67) 24,059 (119) U.S. government securities 4,769 (13) 10,895 (73) 15,664 (86) Total $ 26,683 $ (69) $ 19,646 $ (140) $ 46,329 $ (209) December 31, 2022 Less than 12 months 12 months or greater Total Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses Commercial paper $ 40,063 $ (75) $ — $ — $ 40,063 $ (75) Corporate debt securities 1,156 — 502 (5) 1,658 (5) U.S. federal agency securities 12,869 (228) 25,342 (335) 38,211 (563) U.S. government securities 10,562 (208) 8,569 (133) 19,131 (341) Total $ 64,650 $ (511) $ 34,413 $ (473) $ 99,063 $ (984) As of December 31, 2023 and 2022, the Company had not recorded any allowance for credit losses related to its available-for-sale securities. The Company attributes the declines in the fair value of its available-for-sale securities to normal market and interest rate fluctuations. The declines in fair value are not attributed to declines in credit quality. The Company does not intend to sell investments while they are in an unrealized loss position and does not believe that it is more likely than not that the Company will be required to sell the investments before recovery of their amortized cost basis, which may be maturity. All of the Company’s investments mature in less than two years. The Company’s marketable securities classified by contractual maturities as of December 31, 2023 were as follows (in thousands): Amortized Cost Fair Value Due within one year $ 45,380 $ 45,199 Due after one year through five years 30,674 30,841 Total $ 76,054 $ 76,040

Property and Equipment

Property and Equipment	12 Months Ended
	Dec. 31, 2023
Property, Plant and Equipment [Abstract]
Property and Equipment	Property and Equipment The following table presents the components of property and equipment, net, as of December 31, 2023 and 2022 (in thousands): December 31, 2023 2022 Laboratory equipment $ 5,734 $ 5,914 Computer equipment 1,054 1,230 Leasehold improvements 772 710 Software 1,141 1,141 Furniture and fixtures 320 320 Total property and equipment 9,021 9,315 Less accumulated depreciation and amortization (7,022) (6,256) Property and equipment, net $ 1,999 $ 3,059 Depreciation and amortization expense was $0.9 million and $0.8 million for the years ended December 31, 2023 and 2022, respectively.

Accrued and Other Current Liabi

Accrued and Other Current Liabilities	12 Months Ended
	Dec. 31, 2023
Accounts Payable and Accrued Liabilities, Current [Abstract]
Accrued and Other Current Liabilities	Accrued and Other Current Liabilities The following table presents the components of accrued and other current liabilities as of December 31, 2023 and 2022 (in thousands): December 31, 2023 2022 Accrued compensation $ 779 $ 2,290 Accrued vacation 365 430 Accrued 401(k) matching contributions 74 568 Operating lease liability, current portion 578 519 Other current liabilities 926 637 Total accrued and other current liabilities $ 2,722 $ 4,444

Other Income (Expense), net

Other Income (Expense), net	12 Months Ended
	Dec. 31, 2023
Other Income and Expenses [Abstract]
Other Income (Expense), net	Other Income, net The following table presents the components of other income, net, for the years ended December 31, 2023 and 2022 (in thousands): Year Ended 2023 2022 Interest income $ 1,640 $ 456 Investment income, net 1,994 1,071 Other income, net $ 3,634 $ 1,527

Fair Value Measurements

Fair Value Measurements	12 Months Ended
	Dec. 31, 2023
Fair Value Disclosures [Abstract]
Fair Value Measurements	Fair Value Measurements As of December 31, 2023 and 2022, the carrying amounts of the Company’s receivables, prepaid and other current assets, accounts payable, and accrued and other current liabilities approximate their fair values, principally due to the short-term nature of the assets and liabilities. The recorded values of the finance leases approximate fair value as the interest rates approximate market interest rates. Money market funds are highly liquid investments and are actively traded. The pricing information on money market funds is readily available and can be independently validated as of the measurement date. This approach results in the classification of these securities as Level 1 of the fair value hierarchy. U.S. government agency bonds, U.S. government bonds, commercial paper, and corporate debt securities are measured at fair value using Level 2 inputs. The Company reviews trading activity and pricing for these investments as of each measurement date. The Company follows a fair value hierarchy that prioritizes the inputs to valuation techniques used to measure fair value. 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. The three levels of the fair value hierarchy are as follows: Level 1 inputs are observable, quoted prices (unadjusted) in active markets for identical assets or liabilities that the Company can access at the measurement date. Level 2 inputs are observable inputs other than quoted prices included in Level 1 that are observable either directly or indirectly or 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 inputs are unobservable inputs in which there is little or no market data, which require the Company to develop its own assumptions. The following table shows the Company’s assets measured at fair value on a recurring basis by level within the fair value hierarchy (in thousands) as of December 31, 2023: Level 1 Level 2 Level 3 Assets: Cash equivalents: Money market funds $ 1,272 $ — $ — Marketable securities: Commercial paper — 11,773 — Corporate debt securities — 18,192 — U.S. federal agency securities — 28,958 — U.S. government securities — 17,117 — Total assets $ 1,272 $ 76,040 $ — The following table shows the Company’s assets and liabilities measured at fair value on a recurring basis by level within the fair value hierarchy (in thousands) as of December 31, 2022: Level 1 Level 2 Level 3 Assets: Cash equivalents: Money market funds $ 2,618 $ — $ — Commercial paper — 26,347 — Marketable securities: Commercial paper — 15,155 — Corporate debt securities — 1,658 — U.S. federal agency securities — 38,211 — U.S. government securities — 19,131 — Total assets $ 2,618 $ 100,502 $ —

Related Party Transactions

Related Party Transactions	12 Months Ended
	Dec. 31, 2023
Related Party Transactions [Abstract]
Related Party Transactions	Related Party Transactions In June 2019, the Company entered into a master services agreement with Carelon Research, a subsidiary of Elevance Health, Inc. (“Elevance Health”). This agreement covers a range of research projects, including Carelon Research’s role as a contract research organization for the P rematurity R isk Assessment Combined With Clinical I nterventions for Improving Neonatal outco ME s (“PRIME”) study. The Company paid fees related to this agreement of $4.0 million and $2.2 million for the years ended December 31, 2023 and 2022, respectively, which were recorded in research and development expenses in the Company’s statements of operations and comprehensive loss. In November 2020, the Company entered into a Laboratory Services Agreement with Elevance Health related to the PRIME study. This agreement provides a contracted rate for certain tests performed pursuant to the study. The Company recognized revenues related to this agreement of $61 thousand and $100 thousand for the years ended December 31, 2023 and 2022, respectively. In February 2021, the Company entered into a commercial collaboration agreement with Elevance Health and its affiliates (the “Commercial Collaboration Agreement”). The Commercial Collaboration Agreement provides defined payment within a defined period for use of the PreTRM test within Elevance Health’s network of covered members. Pursuant to the Commercial Collaboration Agreement, Elevance Health will purchase a certain minimum number of tests for each of the first three years of the term of the agreement. Additionally, Elevance Health agreed to pay a certain minimum amount per year for the first three years of the term of the Commercial Collaboration Agreement. The Company received $6.0 million during the year ended December 31, 2023, which amount related to the minimum payments for the year ended December 31, 2022. As of December 31, 2023, the Company recorded $11.2 million in other receivables related to the minimum payments for the year ended December 31, 2023, which was received in January 2024. Such minimum payments are initially recorded as deferred revenue. Deferred revenue is recognized as revenue when the Company delivers PreTRM test results to Elevance Health patients pursuant to the Commercial Collaboration Agreement. The Company also agreed to develop a sales, marketing, and customer service program, and to provide training and marketing to duly licensed physicians specializing in obstetrics and gynecology or family medicine, or licensed nurse midwives, at the reasonable request of Elevance Health. Elevance Health has been participating in the Company’s PRIME study and at the conclusion of the PRIME study, under the Commercial Collaboration Agreement, the parties agreed to use commercially reasonable efforts to enter into Elevance Health’s standard lab provider agreement. Unless earlier terminated due to breach, the Commercial Collaboration Agreement will remain in effect until the later of (a) the third anniversary of the effective date or (b) the date on which Elevance Health has purchased a fixed number of PreTRM tests as agreed by the parties. The Commercial Collaboration Agreement with Elevance Health is considered to be within the scope of ASC Topic 808, Collaborative Arrangements (“ASC 808”), as the parties are active participants and exposed to the risks and rewards of the collaborative activity. The Company determined the PreTRM tests to be a performance obligation for which Elevance Health is a customer and a unit of account within the scope of ASC 606. The associated transaction price is based on the contractual minimum number of tests and the agreed upon defined payment amount per test. The transaction price was allocated to this single performance obligation, which will be recognized upon delivery of test results expected to occur over the term of the agreement. All other items promised to Elevance Health are immaterial in the context of the Commercial Collaboration Agreement. There were no material revenues related to the Commercial Collaboration Agreement for the years ended December 31, 2023 and 2022.

Capital Structure

Capital Structure	12 Months Ended
	Dec. 31, 2023
Stockholders' Equity Note [Abstract]
Capital Structure	Capital Structure Common Stock The Company has two authorized classes of common stock, Class A and Class B. The rights of the holders of Class A and Class B common stock are identical, except with respect to voting and conversion. Each share of Class A common stock is entitled to one vote and shares of Class B common stock are non-voting. Each share of Class B common stock may be converted at any time to one share of Class A common stock at the option of its holder, subject to the ownership limitations provided for in the Company’s amended and restated certificate of incorporation. In September 2023, holders of Class B common stock converted 437,500 shares of Class B common stock to 437,500 shares of Class A common stock. The following shares of Class A common stock were reserved for future issuance: December 31, 2023 2022 Warrants to purchase Class A common stock 2,775,978 2,775,978 Options to purchase Class A common stock 7,251,663 8,428,441 Restricted stock units outstanding 2,692,459 — Class A common stock available for future grants under the 2021 Equity Incentive Plan 1,002,091 1,926,356 Class A common stock available for future grants under the 2021 Employee Stock Purchase Plan 801,668 598,777 Total 14,523,859 13,729,552 Preferred Stock The Company is authorized to issue up to 5,000,000 shares of preferred stock, par value $0.0001 per share. There were no preferred shares outstanding at December 31, 2023 and 2022.

Stock-Based Compensation

Stock-Based Compensation	12 Months Ended
	Dec. 31, 2023
Share-Based Payment Arrangement [Abstract]
Stock-Based Compensation	Stock-Based Compensation Equity Incentive Plans In November 2011, the Company established the 2011 Employee, Director and Consultant Equity Incentive Plan (the “2011 Plan”) and reserved shares of the Company’s common stock for sale and issuance under the 2011 Plan. Options granted under the 2011 Plan generally vest over a four-year period and generally expire ten years from the date of grant. Options are exercisable only to the extent vested. The 2011 Plan terminated in November 2021, and accordingly, no additional shares are available for grant under the 2011 Plan. The 2011 Plan continues to govern outstanding awards granted under the 2011 Plan. The 2021 Equity Incentive Plan (the “2021 Plan”) was established in July 2021. The 2021 Plan provides for the grant of incentive and non-statutory stock options as well as other stock rights to employees, directors and consultants of the Company. Options generally vest over a four-year period, are exercisable only to the extent vested, and generally expire ten years from the date of grant. Restricted stock units (“RSUs”) generally vest over either a two-year or four-year period. The 2021 Plan includes provisions for annual automatic increases to the number of shares of Class A common stock reserved for issuance under the 2021 Plan. In addition, any shares that otherwise would be returned to the 2011 Plan as a result of the expiration or cancellation of stock options may be added to the 2021 Plan. As of December 31, 2023, there were 1,002,091 shares of the Company’s Class A common stock that were available for future grants under the 2021 Plan. The 2021 Employee Stock Purchase Plan (the “2021 ESPP”) was established in July 2021. The 2021 ESPP includes provisions for annual automatic increases to the number of shares of Class A common stock reserved for issuance under the 2021 ESPP. As of December 31, 2023, there were 801,668 shares of the Company’s Class A common stock that were available for future grants under the 2021 ESPP. Stock Options Unless otherwise noted, references to “options” in the subsequent disclosures, refers to the combined incentive and non-statutory stock options issued as employee and non-employee stock-based compensation, and authorized under the 2011 Plan and the 2021 Plan. The following table summarizes information about these options granted and outstanding: Number of Weighted- Weighted- Aggregate Intrinsic Value (In Thousands) Outstanding — December 31, 2022 8,428,441 $ 3.65 7.7 $ 115 Granted 991,866 3.49 Expired (14,430) 0.75 Cancelled (1,561,123) 4.25 Exercised (593,091) 1.85 Outstanding — December 31, 2023 7,251,663 $ 3.66 6.9 $ 20,014 Vested and expected to vest at December 31, 2023 7,120,916 $ 3.64 6.9 $ 19,763 Vested and exercisable at December 31, 2023 5,477,835 $ 3.28 6.5 $ 16,856 The weighted-average grant date fair value of options granted during the years ended December 31, 2023 and 2022 was $2.28 and $1.92 per share, respectively. The total aggregate intrinsic value of options exercised during the years ended December 31, 2023 and 2022 was $1.4 million and $0.5 million, respectively. The total fair value of options vested for the years ended December 31, 2023 and 2022 was $4.8 million and $5.8 million, respectively. The fair values calculated using the Black-Scholes option pricing model were estimated on each grant date using the following assumptions: Year Ended December 31, 2023 2022 Expected volatility 70.1% - 72.4% 63.7% - 69.1% Risk-free interest rate 3.7% - 4.2% 1.7% - 4.3% Expected term (in years) 5.3 - 7.0 5.3 - 7.0 Expected dividend yield — % — % RSUs The following table summarizes information about RSUs granted and outstanding under the 2021 Plan: Number of Awards Weighted-Average Grant Date Fair Value Outstanding — December 31, 2022 — $ — Granted 2,827,824 2.10 Forfeited (135,365) 3.76 Vested — — Outstanding — December 31, 2023 2,692,459 $ 2.01 Stock-Based Compensation Expense The following table presents the impact of stock-based compensation expense in the statements of operations for the periods indicated (in thousands): Year Ended 2023 2022 Research and development expense $ 1,574 $ 1,671 Sales and marketing expense 657 590 General and administrative expense 3,042 2,794 Total employee stock-based compensation $ 5,273 $ 5,055 The information about unrecognized stock-based compensation expense for outstanding unvested stock options and RSUs as of December 31, 2023 was as follows (in thousands, except years): Unrecognized Stock-Based Compensation Expense Weighted-Average Period of Recognition (in years) Stock Options $ 5,035 1.6 RSUs 3,942 2.7 Total unrecognized stock-based compensation expense $ 8,977

Warrants

Warrants	12 Months Ended
	Dec. 31, 2023
Warrants and Rights Note Disclosure [Abstract]
Warrants	Warrants All outstanding common stock warrants were exercisable immediately when granted. All outstanding common stock warrants are exercisable for shares of Class A common stock. The Company’s common stock warrants outstanding were as follows: Number of Warrants Outstanding as of: Exercise Price December 31, 2023 December 31, 2022 $ 5.20 3,473 3,473 9.03 1,032,404 1,032,404 10.84 1,009,795 1,009,795 12.38 8,083 8,083 20.77 722,223 722,223 2,775,978 2,775,978

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2023
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingences	Commitments and Contingencies Leases The Company is the lessee in all of its lease arrangements. The Company did not enter into any leases with related parties during the presented periods. The Company makes assumptions and judgments when assessing contracts for lease components, determining lease classifications, and calculating right-of-use asset and lease liability values. These assumptions and judgments may include the useful lives and fair values of the leased assets, the implicit rate underlying the Company’s leases, the Company’s incremental borrowing rate or the Company’s intent to exercise or not exercise options available in lease contracts. The following table shows right-of-use assets and lease liabilities, and the associated financial statement line items as of December 31, 2023 and 2022 (in thousands): December 31, Lease-Related Assets and Liabilities Financial Statement Line Items 2023 2022 Right-of-use assets: Operating leases Other assets $ 1,180 $ 1,707 Finance leases Property and equipment, net 1,008 1,317 Total right-of-use assets $ 2,188 $ 3,024 Lease liabilities: Operating leases Accrued and other current liabilities $ 578 $ 519 Operating lease obligation, net of current portion 644 1,222 Finance leases Finance lease obligation, current portion 440 464 Finance lease obligation, net of current portion 196 626 Total lease liabilities $ 1,858 $ 2,831 Lease costs and other information consisted of the following (in thousands, except terms and rates): Year Ended December 31, 2023 2022 Lease cost Finance lease cost: Amortization of right-of-use assets $ 312 $ 280 Interest on lease liabilities 55 61 Operating lease cost 636 504 Total lease cost $ 1,003 $ 845 Other information Finance leases: Operating cash outflows $ 55 $ 48 Financing cash outflows $ 466 $ 303 Right-of-use assets obtained in exchange for lease liabilities $ 18 $ 1,253 Weighted-average remaining lease term (in years) 1.4 2.3 Weighted-average discount rate 6.5% 6.4% Operating leases: Operating cash outflows $ 628 $ 609 Right-of-use assets obtained in exchange for lease liabilities $ — $ 2,169 Weighted-average remaining lease term (in years) 2.0 3.0 Weighted-average discount rate 7.5% 7.5% Future minimum lease payments for the Company’s leases as of December 31, 2023 were as follows (in thousands): Operating Leases Finance Leases Total 2024 $ 646 $ 467 $ 1,113 2025 666 197 863 2026 — 2 2 2027 and thereafter — — — Total minimum lease payments 1,312 666 1,978 Less: imputed interest (90) (30) (120) Present value of future lease payments 1,222 636 1,858 Less: current portion 578 440 1,018 Long-term portion $ 644 $ 196 $ 840 Operating Leases The Company leases a total of approximately 24,300 square feet of office and laboratory space under a single non-cancelable operating lease with a termination date of December 31, 2025 (as amended, the “Office Lease”). The Office Lease includes an early termination right which termination would occur under certain circumstances, as provided in the amended Office Lease, after July 1, 2024 if exercised. The Company is not currently reasonably certain it will exercise the termination right. The implicit rate provided in the Company’s operating lease is not readily determinable. As such, the Company uses its incremental borrowing rate to calculate the present value of its operating lease liabilities. Finance Leases The Company leases certain equipment related to its information technology infrastructure and laboratory operations. All of the Company’s current finance leases include bargain purchase options that the Company is reasonably certain to exercise. The Company has elected not to separate lease and non-lease components for its equipment leases. The rates implicit in the Company’s finance leases are determinable, and the Company uses those rates to calculate the present value of its finance lease liabilities. Indemnification The Company has agreed to indemnify its officers and directors for certain events or occurrences, while the officer or director is or was serving at the Company’s request in such capacity. The maximum amount of potential future indemnification is unlimited; however, the Company purchases director and officer insurance coverage that provides for corporate reimbursements of covered obligations that limits the Company’s exposure and enables it to recover a portion of potential future amounts paid. The Company is unable to reasonably estimate the maximum amount that could be payable under these arrangements since these obligations are not capped but are conditional to the unique facts and circumstances involved. Accordingly, the Company has no liabilities recorded for these agreements as of December 31, 2023 and 2022. The Company has never incurred costs to defend lawsuits or settle claims related to these indemnification agreements. Employee Agreements The Company has signed various employment agreements with key executives pursuant to which if their employment is terminated by the Company without cause or by the employees for good reason, or following a change of control of the Company, the employees are entitled to receive certain benefits, including severance payments, accelerated vesting of stock and stock options, and certain insurance benefits. Legal Matters The Company is not currently a party to any material litigation or other material legal proceedings. The Company may, from time to time, be involved in various legal proceedings arising from the normal course of business activities, and an unfavorable resolution of any of these matters could materially affect the Company’s future results of operations, cash flows, or financial position.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2023
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes The Company has not recorded any income tax expense for the years ended December 31, 2023 and 2022 due to its history of operating losses. The provision for income taxes includes the following components for the years ended December 31, 2023 and 2022 (in thousands): Year Ended 2023 2022 Current: Federal $ — $ — State — — Total current benefit (provision) $ — $ — Deferred: Federal $ 8,178 $ 9,400 State 2,198 1,951 Change in valuation allowance (10,376) (11,351) Total deferred benefit (provision) $ — $ — Total income tax benefit (provision) $ — $ — The benefit (provision) for income taxes differs from the amount computed at federal statutory rates as follows (in thousands): Year Ended December 31, 2023 2022 Computed Federal income tax benefit (expense) at the statutory rate $ 7,602 21.00 % $ 9,278 21.00 % R&D credits 698 1.93 % 566 1.28 % Equity-based expenses (63) (0.17) % (325) (0.74) % State income taxes, net of federal benefit 1,783 4.92 % 1,771 4.01 % State net operating loss carryforward true up 154 0.42 % (8) (0.02) % Change in statutory rates 163 0.45 % 78 0.18 % Other 39 0.11 % (9) (0.02) % Valuation allowance (10,376) (28.66) % (11,351) (25.69) % Income tax benefit (provision) $ — — % $ — — % Significant components of the Company’s net deferred income tax assets (liabilities) are as follows (in thousands): December 31, 2023 2022 Deferred tax assets: Net operating loss carryforwards $ 53,072 $ 46,674 R&D credits 3,856 3,038 R&E expenses 5,219 2,644 Accruals and reserves 278 635 Equity-based compensation 2,440 1,496 Depreciation and amortization — 5 Lease liability 317 438 Other 7 3 Total deferred tax asset before allowance 65,189 54,933 Less: valuation allowance (64,879) (54,504) Total deferred tax asset 310 429 Deferred tax liabilities: Right-of-use asset (306) (429) Depreciation and amortization (4) — Net deferred tax assets $ — $ — Management assesses the available positive and negative evidence to estimate if sufficient future taxable income will be generated to use the existing deferred tax assets. A significant piece of objective negative evidence evaluated is the cumulative loss incurred since inception. Such objective evidence limits the ability to consider other subjective evidence such as the Company’s projections for future growth. On the basis of this evaluation, a full valuation allowance of $64.9 million and $54.5 million has been recorded as of December 31, 2023 and 2022, respectively, as it is more likely than not that the deferred tax assets will not be realized. The valuation allowance increased by $10.4 million and $11.4 million for the years ended December 31, 2023 and 2022, respectively, and there is no tax benefit presented in the accompanying financial statements. The Company is subject to minimum taxes in several of the state jurisdictions where it files income tax returns. The amounts paid are immaterial and not presented above as a component of the current state tax provision. As of December 31, 2023, the Company had U.S. federal and state net operating loss carryforwards of approximately $211.6 million and $143.7 million, respectively. Of the federal amount, $141.3 million can be carried forward indefinitely, while the remainder begins to expire after 2028, if not utilized. The state amounts begin to expire at various dates after 2030. Because of the change of ownership provisions of the Tax Reform Act of 1986, use of a portion of the Company’s NOL and tax credit carryforwards may be limited in future periods. Further, a portion of the carryforwards may expire before being applied to reduce future income tax liabilities. There are currently no federal or state tax audits in progress. All prior tax years remain subject to examination by Federal and State of Utah authorities due to the existence of net operating loss carryforwards. The Company recognizes the tax benefit of an uncertain tax position only if it is more likely than not that a tax position will be sustained upon examination by the appropriate taxing authorities, based on technical merits. The reversal of the uncertain tax positions would not affect the Company’s effective tax rate to the extent that it continues to maintain a full valuation allowance against its deferred tax assets. As of December 31, 2023 and 2022, the Company did not record any material interest expense or penalties related to uncertain tax positions or the settlement of audits for prior periods. The Company does not expect a significant increase or decrease in its uncertain tax positions within the next 12 months. A reconciliation of the beginning and ending amount of uncertain tax positions (in thousands): Year Ended 2023 2022 Balance at the beginning of the year $ 2,025 $ 1,648 Gross increases—prior period 80 — Gross increases—current period 465 377 Balance at the end of the year $ 2,570 $ 2,025

Net Loss Per Share

Net Loss Per Share	12 Months Ended
	Dec. 31, 2023
Earnings Per Share [Abstract]
Net Loss Per Share	Net loss per share The Company calculates net loss per share of Class A and Class B common stock using the two-class method. For periods in which the Company reports a net loss, all potentially dilutive shares are anti-dilutive and are therefore excluded from the calculation of diluted net loss per share. For the years ended December 31, 2023 and 2022, the Company reported net losses and as such, basic and diluted net loss per share are the same. As the liquidation and dividend rights are identical for Class A and Class B common shares, the undistributed earnings are allocated on a proportionate basis and the resulting amount per share for Class A and Class B common stock was the same for the years ended December 31, 2023 and 2022. The Company excluded the following potentially dilutive securities, presented based on amounts outstanding at each period end, from the computation of diluted net loss per share for the periods indicated because their impact would have been anti-dilutive: December 31, 2023 2022 Warrants to purchase Class A common stock 2,775,978 2,775,978 Options to purchase Class A common stock 7,251,663 8,428,441 Restricted stock units outstanding 2,692,459 — Total 12,720,100 11,204,419

Significant Accounting Polici_2

Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2023
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The accompanying financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (“U.S. GAAP”). Any reference in these notes to applicable accounting guidance is meant to refer to the authoritative U.S. GAAP included in the Accounting Standards Codification (“ASC”), and Accounting Standards Updates (“ASU”) issued by the Financial Accounting Standards Board (“FASB”).
Use of Estimates	Use of Estimates The preparation of the financial statements in conformity with U.S. GAAP requires the Company’s management to make estimates and assumptions that affect the amounts reported in the financial statements and accompanying notes. The Company evaluates these estimates on an ongoing basis. The Company bases these estimates on historical and anticipated results, trends, and various other assumptions that the Company believes are reasonable under the circumstances, including assumptions as to future events. Actual results could differ materially from those estimates.
Cash and Cash Equivalents	Cash and cash equivalents
Marketable Securities	Marketable Securities
Concentration of Credit Risk	Concentration of credit risk Financial instruments that potentially subject the Company to concentrations of credit risk consist primarily of cash and cash equivalents and marketable securities. The Company maintains bank deposits in accounts at federally insured financial institutions and these deposits may exceed federally insured limits. The Company is exposed to credit risk in the event of default by the financial institution holding its cash to the extent recorded in the balance sheet. The Company has not experienced any losses on its deposits of cash. The Company’s cash equivalents consist of money market funds and investment grade commercial paper. Marketable securities consist of investments in U.S. government securities, U.S. federal agency securities, investment grade commercial paper, and investment grade corporate securities. The Company’s investment portfolio in corporate debt securities is highly liquid and diversified among individual issuers. The Company did not experience any credit losses related to its investment portfolio for the years ended December 31, 2023 and 2022.
Property and Equipment	Property and Equipment Property and equipment are recorded at cost less accumulated depreciation and amortization. Depreciation and amortization are computed using the straight-line method over the shorter of estimated useful lives of the assets or the respective lease term. The estimated useful life of each asset category is as follows: Computer equipment 3 years Software 3 years Machinery and equipment 5 years Furniture and fixtures 5 years Leasehold improvements Shorter of useful life or remaining lease term
Leases	Leases The Company’s operating lease relates to office and laboratory space at its headquarters. The Company’s finance leases are for certain equipment related to the Company’s information technology infrastructure and laboratory operations. The Company determines if an arrangement is a lease at inception. The Company has elected not to separate lease components from non-lease components for all classes of leased assets except for building leases. The Company elected to treat leases with lease terms of 12 months or less as short-term leases. No right-of-use assets or lease liabilities are recognized for short-term leases. For leases with a lease term greater than 12 months, right-of-use assets and lease liabilities are recognized on the balance sheets at the commencement date based on the present value of the remaining lease payments and includes only payments that are fixed and determinable at commencement. The Company’s lease terms may include options to extend or terminate when it is reasonably certain that the Company will exercise such options. To date, the rates implicit in the Company’s finance leases have been determinable, and the Company uses those rates to calculate the present value of its finance lease liabilities. The implicit rate in the Company’s operating lease is not readily determinable. As such, the Company uses its incremental borrowing rate to calculate the present value of its operating lease liabilities.
Revenue	Deferred Revenue The Company recognizes deferred revenue in accordance with ASC 606, Revenue from Contracts with Customers (“ASC 606”). Deferred revenue is recognized when a customer pays consideration, or the Company has a right to an amount of consideration that is unconditional before the Company transfers the good or service to the customer. The Company’s deferred revenue balance as of December 31, 2023 and 2022 relates to certain contractual minimum payments received by the Company as part of its commercial collaboration agreements. Deferred revenue is recognized as revenue when the Company delivers PreTRM test results to customers pursuant to its commercial collaboration agreements. Revenue Recognition Revenue is generated from the sale of PreTRM tests. The Company recognizes revenue based on accounting standards applied to determine the measurement of revenue and timing of when it is recognized. The Company applies the following five-step approach as set forth under ASC 606: (i) identify the contract(s) with a customer; (ii) identify the performance obligations in the contract (iii) determine the transaction price; (iv) allocate the transaction price to the performance obligations in the contract; and (v) recognize revenue when (or as) the Company satisfies a performance obligation. The Company applies the five-step model when it is probable that the Company will collect the consideration it is entitled to in exchange for fulfilling its performance obligation. The Company recognizes revenue upon delivery of test results, which it considers to be the only performance obligation, and allocates all of the transaction price to this performance obligation. In determining the transaction price, which is an estimate of the amount of variable consideration expected to be received, the Company uses the expected value method under ASC 606. The Company considers all reasonably available information to identify various possible consideration amounts and considers the probability of the variable consideration for each scenario. The Company’s estimate of transaction price does not include any estimated amount of variable consideration that is constrained. Significant judgments are required in determining the estimates for each transaction. These estimates include many assumptions, any of which, if incorrect, could result in significant differences between the estimated price and the amount ultimately collected for any given transaction. The Company applies this method consistently to portfolios of similar contracts when estimating the effect of any uncertainty on the amount of variable consideration to which it will be entitled. In the aggregate, across the numerous transactions within each portfolio, these differences can lead to material variances between estimated and actual revenue in any given period. The estimate of revenue is necessarily founded on assumptions of payer behavior such as changes in payer mix, payer collections, current customer contractual requirements, and experience with ultimate collection from third-party payers and patients. Each of these aspects of payer behavior (and various others) can change significantly from quarter to quarter, and the Company currently has limited experience with historical payment patterns. Each of these contributes to the potential variability between estimated transaction price and actual consideration received as discussed above, which is expected to be more pronounced early in the process of commercializing a diagnostic test. The Company makes its best efforts to continually refine its estimates of expected consideration as the Company gains additional experience with collections and historical payment patterns. Accordingly, the Company may update its estimate of the amount of revenue to be recognized for previously delivered tests. Cost of Revenue Cost of revenue reflects the aggregate costs incurred in delivering the proteomic testing results to clinicians and includes expenses for third-party specimen collection and shipping costs, as well as the Company’s lab personnel, materials and supplies, equipment and infrastructure expenses associated with clinical testing, and allocated overhead including rent and equipment depreciation. Costs associated with performing the Company’s tests are recorded as the tests are processed regardless of whether and when revenue is recognized with respect to such tests.
Research and Development Expense	Research and Development Expenses The Company expenses all research and development costs as they are incurred. Research and development expenses consist primarily of personnel costs, stock-based compensation charges, clinical trial costs, and third-party contracted services associated with research and development. The Company recognizes expense associated with third-party contracted services based on the completion of activities as specified in the applicable contracts. Costs incurred under contracts with clinical sites are generally accrued as patient encounters occur, consistent with the terms outlined in the associated contract. Upon termination of contracts with third parties, the Company’s obligations are limited to costs incurred or committed to date. As a result, accrued research and development expenses represent the estimated contractual liability to third parties at the reported period.
Share-based Compensation	Stock-based Compensation The Company recognizes stock-based compensation for all stock-based awards in accordance with ASC 718, C ompensation-Stock Compensation , which requires an entity to measure the cost of employee services received in exchange for an award of equity instruments based on the grant-date fair value of the award. The fair value of restricted stock units granted under the Company’s equity incentive plans is measured based on the grant-date fair value of the Company’s Class A common stock. The fair value of stock options granted under the Company’s equity incentive plans is estimated using the Black-Scholes option pricing model. Input assumptions used in calculating the fair value of stock options represent management’s estimates and involve inherent uncertainties and the application of management’s judgment. These input assumptions include the expected term of the awards, the expected common stock price volatility over the term of the awards, risk-free interest rates, and the expected dividend yield. The fair value of the Company’s Class A common stock is determined by using the closing price per share of the Company’s Class A common stock as reported on Nasdaq. The Company uses the simplified calculation of expected life since the Company does not have sufficient historical exercise data to estimate the expected term. Volatility is based on an average of the historical volatility of the Company’s common stock and the volatilities of the common stock of select comparable publicly-traded entities with characteristics similar to those of the Company. The risk-free rate is based on the U.S. Treasury yield curve in effect at the time of grant for periods corresponding with the expected life of the option. Forfeitures are estimated at the time of grant based on the Company’s historical experience and are adjusted as necessary. The fair value of equity awards is recognized as compensation cost on a straight-line basis by the Company over the participant’s requisite service period, which is the award’s vesting period. All stock-based compensation costs are classified in the statements of operations and comprehensive loss based upon the underlying participant’s role within the Company.
Income Taxes	Income Taxes The Company accounts for income taxes under the asset and liability method, which requires the recognition of deferred tax assets and liabilities for the expected future tax consequences of events that have been included in the financial statements. Under this method, deferred tax assets and liabilities are determined on the basis of the differences between the financial statement and tax bases of assets and liabilities using enacted tax rates in effect for the year in which the differences are expected to reverse. The effect of a change in tax rates on deferred tax assets and liabilities is recognized in income in the period that includes the enactment date. The Company recognizes deferred tax assets to the extent that it believes these assets are more likely than not to be realized. In making such a determination, the Company considers all available positive and negative evidence, including future reversals of existing taxable temporary differences, projected future taxable income, tax-planning strategies, and results of recent operations. If the Company determines that it would be able to realize its deferred tax assets in the future in excess of their net recorded amount, the Company would make an adjustment to the deferred tax asset valuation allowance, which would reduce the provision for income taxes. The Company records uncertain tax positions in accordance with ASC 740 on the basis of a two-step process whereby (1) it determines whether it is more likely than not that the tax positions will be sustained on the basis of the technical merits of the position and (2) for those tax positions that meet the more-likely-than-not recognition threshold, it recognizes the largest amount of tax benefit that is more than 50 percent likely to be realized upon ultimate settlement with the related tax authority. The Company recognizes interest and penalties related to unrecognized tax benefits within the income tax expense line in the accompanying statements of operations and comprehensive loss. Any accrued interest and penalties related to uncertain tax positions will be reflected as a liability in the balance sheets.
Postemployment Benefit Plans, Policy	Retirement Savings Plan
Segments	Segments The Company operates as one operating segment, which is developing and commercializing its medical diagnostic products and services. The Company’s chief operating decision maker, its chief executive officer, reviews financial information on an aggregate basis for making decisions regarding resource allocation and assessing performance.
Comprehensive Loss	Comprehensive Loss
Net Loss per Share	Net Loss per Share Basic net loss per share is calculated by dividing net loss by the weighted-average number of shares of common stock outstanding for the period, without consideration of potentially dilutive securities. Diluted net loss per share is computed by dividing net loss by the weighted-average number of shares of common stock and potentially dilutive securities outstanding for the period. For purposes of the diluted net loss per share calculation, stock options and warrants to purchase common stock are considered to be potentially dilutive securities. For periods in which the Company reports a net loss, all potentially dilutive shares are anti-dilutive and are therefore excluded from the calculation of diluted net loss per share.
Recently Issued Accounting Pronouncements Not Yet Adopted	Recently Issued Accounting Pronouncements Not Yet Adopted In December 2023, the FASB issued ASU 2023-09, Income Taxes (Topic 740): Improvements to Income Tax Disclosures , which is intended to improve the transparency of income tax disclosures by requiring consistent categories and greater disaggregation of information in the effective tax rate reconciliation and income taxes paid by jurisdiction. The ASU is effective for public business entities’ annual periods beginning after December 15, 2024, with early adoption permitted. The Company is currently evaluating the impact of adopting this guidance on its financial statements. In November 2023, the FASB issued ASU No. 2023-07, Improvements to Reportable Segments Disclosures. While ASU 2023-07 requires incremental disclosures, it does not change how an entity identifies its operating segments, aggregates those operating segments, or applies the quantitative thresholds to determine reportable segments. This ASU is effective for all public business entities for fiscal years beginning after December 15, 2023, and interim periods within fiscal years beginning after December 15, 2024. Entities must adopt the changes to the segment reporting guidance on a retrospective basis. The Company is currently evaluating the impact of adopting this guidance on its financial statements. Early adoption is permitted; however, the Company is not early adopting the standard.

Accounting Policies (Tables)

Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2023
Accounting Policies [Abstract]
Schedule of Property and Equipment, Useful Life	The estimated useful life of each asset category is as follows: Computer equipment 3 years Software 3 years Machinery and equipment 5 years Furniture and fixtures 5 years Leasehold improvements Shorter of useful life or remaining lease term The following table presents the components of property and equipment, net, as of December 31, 2023 and 2022 (in thousands): December 31, 2023 2022 Laboratory equipment $ 5,734 $ 5,914 Computer equipment 1,054 1,230 Leasehold improvements 772 710 Software 1,141 1,141 Furniture and fixtures 320 320 Total property and equipment 9,021 9,315 Less accumulated depreciation and amortization (7,022) (6,256) Property and equipment, net $ 1,999 $ 3,059

Cash, Cash Equivalents and Ma_2

Cash, Cash Equivalents and Marketable Securities (Tables)	12 Months Ended
	Dec. 31, 2023
Cash and Cash Equivalents [Abstract]
Schedule of Cash, Cash Equivalents and Marketable Securities by Major Security Type	The Company’s cash, cash equivalents and marketable securities by major security type as of December 31, 2023 and 2022 were as follows (in thousands): December 31, 2023 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Cash and cash equivalents: Cash $ 2,608 $ — $ — $ 2,608 Money market funds 1,272 — — 1,272 Total cash and cash equivalents 3,880 — — 3,880 Current marketable securities: Commercial paper 11,769 6 (2) 11,773 Corporate debt securities 1,155 — (2) 1,153 U.S. federal agency securities 19,644 — (102) 19,542 U.S. government securities 12,812 — (81) 12,731 Total current marketable securities 45,380 6 (187) 45,199 Long-term marketable securities: U.S. federal agency securities 9,406 27 (17) 9,416 U.S. government securities 4,388 3 (5) 4,386 Corporate debt securities 16,880 159 — 17,039 Total long-term marketable securities 30,674 189 (22) 30,841 Total cash, cash equivalents and marketable securities $ 79,934 $ 195 $ (209) $ 79,920 December 31, 2022 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Cash and cash equivalents: Cash $ 913 $ — $ — $ 913 Money market funds 2,618 — — 2,618 Commercial paper 26,356 — (9) 26,347 Total cash and cash equivalents 29,887 — (9) 29,878 Current marketable securities: Commercial paper 15,219 2 (66) 15,155 Corporate debt securities 507 — (5) 502 U.S. federal agency securities 28,964 — (364) 28,600 U.S. government securities 8,702 — (133) 8,569 Total current marketable securities 53,392 2 (568) 52,826 Long-term marketable securities: U.S. federal agency securities 9,810 — (199) 9,611 U.S. government securities 10,770 — (208) 10,562 Corporate debt securities 1,156 — — 1,156 Total long-term marketable securities 21,736 — (407) 21,329 Total cash, cash equivalents and marketable securities $ 105,015 $ 2 $ (984) $ 104,033
Schedule of Marketable Securities and Cash Equivalents in Unrealized Loss Positions	The following tables summarize the Company’s available-for-sale debt securities and cash equivalents with unrealized losses as of December 31, 2023 and 2022, aggregated by major security type and the length of time that individual securities have been in a continuous loss position (in thousands): December 31, 2023 Less than 12 months 12 months or greater Total Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses Commercial paper $ 5,453 $ (2) $ — $ — $ 5,453 $ (2) Corporate debt securities 1,153 (2) — — 1,153 (2) U.S. federal agency securities 15,308 (52) 8,751 (67) 24,059 (119) U.S. government securities 4,769 (13) 10,895 (73) 15,664 (86) Total $ 26,683 $ (69) $ 19,646 $ (140) $ 46,329 $ (209) December 31, 2022 Less than 12 months 12 months or greater Total Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses Commercial paper $ 40,063 $ (75) $ — $ — $ 40,063 $ (75) Corporate debt securities 1,156 — 502 (5) 1,658 (5) U.S. federal agency securities 12,869 (228) 25,342 (335) 38,211 (563) U.S. government securities 10,562 (208) 8,569 (133) 19,131 (341) Total $ 64,650 $ (511) $ 34,413 $ (473) $ 99,063 $ (984) As of December 31, 2023 and 2022, the Company had not recorded any allowance for credit losses related to its available-for-sale securities. The Company attributes the declines in the fair value of its available-for-sale securities to normal market and interest rate fluctuations. The declines in fair value are not attributed to declines in credit quality. The Company does not intend to sell investments while they are in an unrealized loss position and does not believe that it is more likely than not that the Company will be required to sell the investments before recovery of their amortized cost basis, which may be maturity. All of the Company’s investments mature in less than two years.
Schedule of Marketable Securities Classified by Contractual Maturities	The Company’s marketable securities classified by contractual maturities as of December 31, 2023 were as follows (in thousands): Amortized Cost Fair Value Due within one year $ 45,380 $ 45,199 Due after one year through five years 30,674 30,841 Total $ 76,054 $ 76,040

Property and Equipment (Tables)

Property and Equipment (Tables)	12 Months Ended
	Dec. 31, 2023
Property, Plant and Equipment [Abstract]
Schedule of Components of Property and Equipment, Net	The estimated useful life of each asset category is as follows: Computer equipment 3 years Software 3 years Machinery and equipment 5 years Furniture and fixtures 5 years Leasehold improvements Shorter of useful life or remaining lease term The following table presents the components of property and equipment, net, as of December 31, 2023 and 2022 (in thousands): December 31, 2023 2022 Laboratory equipment $ 5,734 $ 5,914 Computer equipment 1,054 1,230 Leasehold improvements 772 710 Software 1,141 1,141 Furniture and fixtures 320 320 Total property and equipment 9,021 9,315 Less accumulated depreciation and amortization (7,022) (6,256) Property and equipment, net $ 1,999 $ 3,059

Accrued and Other Current Lia_2

Accrued and Other Current Liabilities (Tables)	12 Months Ended
	Dec. 31, 2023
Accounts Payable and Accrued Liabilities, Current [Abstract]
Schedule of Components of Accrued and Other Current Liabilities	The following table presents the components of accrued and other current liabilities as of December 31, 2023 and 2022 (in thousands): December 31, 2023 2022 Accrued compensation $ 779 $ 2,290 Accrued vacation 365 430 Accrued 401(k) matching contributions 74 568 Operating lease liability, current portion 578 519 Other current liabilities 926 637 Total accrued and other current liabilities $ 2,722 $ 4,444

Other Income (Expense), net (Ta

Other Income (Expense), net (Tables)	12 Months Ended
	Dec. 31, 2023
Other Income and Expenses [Abstract]
Schedule of Components of Other Income (Expense), Net	The following table presents the components of other income, net, for the years ended December 31, 2023 and 2022 (in thousands): Year Ended 2023 2022 Interest income $ 1,640 $ 456 Investment income, net 1,994 1,071 Other income, net $ 3,634 $ 1,527

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2023
Fair Value Disclosures [Abstract]
Schedule of Financial Assets that are Measured at Fair Value on a Recurring basis	The following table shows the Company’s assets measured at fair value on a recurring basis by level within the fair value hierarchy (in thousands) as of December 31, 2023: Level 1 Level 2 Level 3 Assets: Cash equivalents: Money market funds $ 1,272 $ — $ — Marketable securities: Commercial paper — 11,773 — Corporate debt securities — 18,192 — U.S. federal agency securities — 28,958 — U.S. government securities — 17,117 — Total assets $ 1,272 $ 76,040 $ — The following table shows the Company’s assets and liabilities measured at fair value on a recurring basis by level within the fair value hierarchy (in thousands) as of December 31, 2022: Level 1 Level 2 Level 3 Assets: Cash equivalents: Money market funds $ 2,618 $ — $ — Commercial paper — 26,347 — Marketable securities: Commercial paper — 15,155 — Corporate debt securities — 1,658 — U.S. federal agency securities — 38,211 — U.S. government securities — 19,131 — Total assets $ 2,618 $ 100,502 $ —

Capital Structure (Tables)

Capital Structure (Tables)	12 Months Ended
	Dec. 31, 2023
Stockholders' Equity Note [Abstract]
Schedule of Common Stock Reserved for Future Issuance	The following shares of Class A common stock were reserved for future issuance: December 31, 2023 2022 Warrants to purchase Class A common stock 2,775,978 2,775,978 Options to purchase Class A common stock 7,251,663 8,428,441 Restricted stock units outstanding 2,692,459 — Class A common stock available for future grants under the 2021 Equity Incentive Plan 1,002,091 1,926,356 Class A common stock available for future grants under the 2021 Employee Stock Purchase Plan 801,668 598,777 Total 14,523,859 13,729,552

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	12 Months Ended
	Dec. 31, 2023
Share-Based Payment Arrangement [Abstract]
Summary of Options Granted and Outstanding	The following table summarizes information about these options granted and outstanding: Number of Weighted- Weighted- Aggregate Intrinsic Value (In Thousands) Outstanding — December 31, 2022 8,428,441 $ 3.65 7.7 $ 115 Granted 991,866 3.49 Expired (14,430) 0.75 Cancelled (1,561,123) 4.25 Exercised (593,091) 1.85 Outstanding — December 31, 2023 7,251,663 $ 3.66 6.9 $ 20,014 Vested and expected to vest at December 31, 2023 7,120,916 $ 3.64 6.9 $ 19,763 Vested and exercisable at December 31, 2023 5,477,835 $ 3.28 6.5 $ 16,856
Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions Using the Black-Scholes Method	The fair values calculated using the Black-Scholes option pricing model were estimated on each grant date using the following assumptions: Year Ended December 31, 2023 2022 Expected volatility 70.1% - 72.4% 63.7% - 69.1% Risk-free interest rate 3.7% - 4.2% 1.7% - 4.3% Expected term (in years) 5.3 - 7.0 5.3 - 7.0 Expected dividend yield — % — %
Schedule of Impact of Stock-based Compensation Expense in the Statements of Operations	The following table presents the impact of stock-based compensation expense in the statements of operations for the periods indicated (in thousands): Year Ended 2023 2022 Research and development expense $ 1,574 $ 1,671 Sales and marketing expense 657 590 General and administrative expense 3,042 2,794 Total employee stock-based compensation $ 5,273 $ 5,055
Share-Based Payment Arrangement, Restricted Stock and Restricted Stock Unit, Activity	The following table summarizes information about RSUs granted and outstanding under the 2021 Plan: Number of Awards Weighted-Average Grant Date Fair Value Outstanding — December 31, 2022 — $ — Granted 2,827,824 2.10 Forfeited (135,365) 3.76 Vested — — Outstanding — December 31, 2023 2,692,459 $ 2.01
Share-Based Payment Arrangement, Nonvested Award, Cost	The information about unrecognized stock-based compensation expense for outstanding unvested stock options and RSUs as of December 31, 2023 was as follows (in thousands, except years): Unrecognized Stock-Based Compensation Expense Weighted-Average Period of Recognition (in years) Stock Options $ 5,035 1.6 RSUs 3,942 2.7 Total unrecognized stock-based compensation expense $ 8,977

Warrants (Tables)

Warrants (Tables)	12 Months Ended
	Dec. 31, 2023
Warrants and Rights Note Disclosure [Abstract]
Schedule of Warrants or Rights	The Company’s common stock warrants outstanding were as follows: Number of Warrants Outstanding as of: Exercise Price December 31, 2023 December 31, 2022 $ 5.20 3,473 3,473 9.03 1,032,404 1,032,404 10.84 1,009,795 1,009,795 12.38 8,083 8,083 20.77 722,223 722,223 2,775,978 2,775,978

Commitment and Contingencies (T

Commitment and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2023
Commitments and Contingencies Disclosure [Abstract]
Schedule Of Leases In Statement of Financial Position	The following table shows right-of-use assets and lease liabilities, and the associated financial statement line items as of December 31, 2023 and 2022 (in thousands): December 31, Lease-Related Assets and Liabilities Financial Statement Line Items 2023 2022 Right-of-use assets: Operating leases Other assets $ 1,180 $ 1,707 Finance leases Property and equipment, net 1,008 1,317 Total right-of-use assets $ 2,188 $ 3,024 Lease liabilities: Operating leases Accrued and other current liabilities $ 578 $ 519 Operating lease obligation, net of current portion 644 1,222 Finance leases Finance lease obligation, current portion 440 464 Finance lease obligation, net of current portion 196 626 Total lease liabilities $ 1,858 $ 2,831
Schedule of Lease Cost and Other Information	Lease costs and other information consisted of the following (in thousands, except terms and rates): Year Ended December 31, 2023 2022 Lease cost Finance lease cost: Amortization of right-of-use assets $ 312 $ 280 Interest on lease liabilities 55 61 Operating lease cost 636 504 Total lease cost $ 1,003 $ 845 Other information Finance leases: Operating cash outflows $ 55 $ 48 Financing cash outflows $ 466 $ 303 Right-of-use assets obtained in exchange for lease liabilities $ 18 $ 1,253 Weighted-average remaining lease term (in years) 1.4 2.3 Weighted-average discount rate 6.5% 6.4% Operating leases: Operating cash outflows $ 628 $ 609 Right-of-use assets obtained in exchange for lease liabilities $ — $ 2,169 Weighted-average remaining lease term (in years) 2.0 3.0 Weighted-average discount rate 7.5% 7.5%
Finance Lease, Liability, Fiscal Year Maturity	Future minimum lease payments for the Company’s leases as of December 31, 2023 were as follows (in thousands): Operating Leases Finance Leases Total 2024 $ 646 $ 467 $ 1,113 2025 666 197 863 2026 — 2 2 2027 and thereafter — — — Total minimum lease payments 1,312 666 1,978 Less: imputed interest (90) (30) (120) Present value of future lease payments 1,222 636 1,858 Less: current portion 578 440 1,018 Long-term portion $ 644 $ 196 $ 840
Lessee, Operating Lease, Liability, Maturity	Future minimum lease payments for the Company’s leases as of December 31, 2023 were as follows (in thousands): Operating Leases Finance Leases Total 2024 $ 646 $ 467 $ 1,113 2025 666 197 863 2026 — 2 2 2027 and thereafter — — — Total minimum lease payments 1,312 666 1,978 Less: imputed interest (90) (30) (120) Present value of future lease payments 1,222 636 1,858 Less: current portion 578 440 1,018 Long-term portion $ 644 $ 196 $ 840

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2023
Income Tax Disclosure [Abstract]
Schedule of Components of Income Tax Benefit (Provision)	The provision for income taxes includes the following components for the years ended December 31, 2023 and 2022 (in thousands): Year Ended 2023 2022 Current: Federal $ — $ — State — — Total current benefit (provision) $ — $ — Deferred: Federal $ 8,178 $ 9,400 State 2,198 1,951 Change in valuation allowance (10,376) (11,351) Total deferred benefit (provision) $ — $ — Total income tax benefit (provision) $ — $ —
Schedule of Effective Income Tax Rate Reconciliation	The benefit (provision) for income taxes differs from the amount computed at federal statutory rates as follows (in thousands): Year Ended December 31, 2023 2022 Computed Federal income tax benefit (expense) at the statutory rate $ 7,602 21.00 % $ 9,278 21.00 % R&D credits 698 1.93 % 566 1.28 % Equity-based expenses (63) (0.17) % (325) (0.74) % State income taxes, net of federal benefit 1,783 4.92 % 1,771 4.01 % State net operating loss carryforward true up 154 0.42 % (8) (0.02) % Change in statutory rates 163 0.45 % 78 0.18 % Other 39 0.11 % (9) (0.02) % Valuation allowance (10,376) (28.66) % (11,351) (25.69) % Income tax benefit (provision) $ — — % $ — — %
Schedule of Deferred Tax Assets and Liabilities	Significant components of the Company’s net deferred income tax assets (liabilities) are as follows (in thousands): December 31, 2023 2022 Deferred tax assets: Net operating loss carryforwards $ 53,072 $ 46,674 R&D credits 3,856 3,038 R&E expenses 5,219 2,644 Accruals and reserves 278 635 Equity-based compensation 2,440 1,496 Depreciation and amortization — 5 Lease liability 317 438 Other 7 3 Total deferred tax asset before allowance 65,189 54,933 Less: valuation allowance (64,879) (54,504) Total deferred tax asset 310 429 Deferred tax liabilities: Right-of-use asset (306) (429) Depreciation and amortization (4) — Net deferred tax assets $ — $ —
Schedule of Uncertain Tax Positions Roll Forward	A reconciliation of the beginning and ending amount of uncertain tax positions (in thousands): Year Ended 2023 2022 Balance at the beginning of the year $ 2,025 $ 1,648 Gross increases—prior period 80 — Gross increases—current period 465 377 Balance at the end of the year $ 2,570 $ 2,025

Net Loss Per Share (Tables)

Net Loss Per Share (Tables)	12 Months Ended
	Dec. 31, 2023
Earnings Per Share [Abstract]
Schedule of Anti-dilutive Securities Excluded from the Computation of Earnings per Share	The Company excluded the following potentially dilutive securities, presented based on amounts outstanding at each period end, from the computation of diluted net loss per share for the periods indicated because their impact would have been anti-dilutive: December 31, 2023 2022 Warrants to purchase Class A common stock 2,775,978 2,775,978 Options to purchase Class A common stock 7,251,663 8,428,441 Restricted stock units outstanding 2,692,459 — Total 12,720,100 11,204,419

Description of Business and F_2

Description of Business and Financial Condition (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Accumulated deficit	$ (246,896)	$ (210,654)
Fair Value	$ 79,920	$ 104,033

Significant Accounting Polici_3

Significant Accounting Policies - Narrative (Details) $ in Millions	12 Months Ended
	Dec. 31, 2023 USD ($) segment	Dec. 31, 2022 USD ($)
Defined Contribution Plan Disclosure [Line Items]
Defined Contribution Plan, Cost | $	$ 0.6	$ 0.6
Number of operating segments | segment	1
Defined Contribution Plan, Employer Matching Contribution, Second Tier
Defined Contribution Plan Disclosure [Line Items]
Defined Contribution Plan, Employer Matching Contribution, Percent of Employees' Gross Pay	2%
Defined Contribution Plan, Employer Matching Contribution, Percent of Match	50%
Defined Contribution Plan, Employer Matching Contribution, First Tier
Defined Contribution Plan Disclosure [Line Items]
Defined Contribution Plan, Employer Matching Contribution, Percent of Employees' Gross Pay	3%
Defined Contribution Plan, Employer Matching Contribution, Percent of Match	100%

Significant Accounting Polici_4

Significant Accounting Policies - Property and Equipment (Details)	Dec. 31, 2023
Computer equipment
Property, Plant and Equipment [Line Items]
Property and equipment, useful life	3 years
Software
Property, Plant and Equipment [Line Items]
Property and equipment, useful life	3 years
Machinery and equipment
Property, Plant and Equipment [Line Items]
Property and equipment, useful life	5 years
Furniture and fixtures
Property, Plant and Equipment [Line Items]
Property and equipment, useful life	5 years

Cash, Cash Equivalents and Ma_3

Cash, Cash Equivalents and Marketable Securities - Cash, Cash Equivalents and Marketable Securities by Major Security Type (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	$ 76,054
Fair Value	76,040
Amortized Cost	79,934	$ 105,015
Gross Unrealized Gains	195	2
Gross Unrealized Losses	(209)	(984)
Fair Value	79,920	104,033
Cash and cash equivalents:
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	3,880	29,887
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	(9)
Fair Value	3,880	29,878
Cash and cash equivalents: | Cash
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	2,608	913
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Fair Value	2,608	913
Cash and cash equivalents: | Money market funds
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	1,272	2,618
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Fair Value	1,272	2,618
Cash and cash equivalents: | Commercial Paper [Member]
Debt Securities, Available-for-sale [Line Items]
Amortized Cost		26,356
Gross Unrealized Gains		0
Gross Unrealized Losses		(9)
Fair Value		26,347
Current marketable securities:
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	45,380	53,392
Gross Unrealized Gains	6	2
Gross Unrealized Losses	(187)	(568)
Fair Value	45,199	52,826
Current marketable securities: | Commercial Paper [Member]
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	11,769	15,219
Gross Unrealized Gains	6	2
Gross Unrealized Losses	(2)	(66)
Fair Value	11,773	15,155
Current marketable securities: | U.S. federal agency securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	19,644	28,964
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(102)	(364)
Fair Value	19,542	28,600
Current marketable securities: | U.S. government securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	12,812	8,702
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(81)	(133)
Fair Value	12,731	8,569
Current marketable securities: | Corporate debt securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	1,155	507
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(2)	(5)
Fair Value	1,153	502
Long-term marketable securities:
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	30,674	21,736
Gross Unrealized Gains	189	0
Gross Unrealized Losses	(22)	(407)
Fair Value	30,841	21,329
Long-term marketable securities: | U.S. federal agency securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	9,406	9,810
Gross Unrealized Gains	27	0
Gross Unrealized Losses	(17)	(199)
Fair Value	9,416	9,611
Long-term marketable securities: | U.S. government securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	4,388	10,770
Gross Unrealized Gains	3	0
Gross Unrealized Losses	(5)	(208)
Fair Value	4,386	10,562
Long-term marketable securities: | Corporate debt securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	16,880	1,156
Gross Unrealized Gains	159	0
Gross Unrealized Losses	0	0
Fair Value	$ 17,039	$ 1,156

Cash, Cash Equivalents and Ma_4

Cash, Cash Equivalents and Marketable Securities - Marketable Securities and Cash Equivalents in Unrealized Loss Positions (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Debt Securities, Available-for-Sale, Unrealized Loss Position [Line Items]
Fair Value	$ 26,683	$ 64,650
Unrealized Losses	69	511
Fair Value	19,646	34,413
Unrealized Losses	140	473
Fair Value	46,329	99,063
Unrealized Losses	209	984
Commercial Paper [Member]
Debt Securities, Available-for-Sale, Unrealized Loss Position [Line Items]
Fair Value	5,453	40,063
Unrealized Losses	2	75
Fair Value	0	0
Unrealized Losses	0	0
Fair Value	5,453	40,063
Unrealized Losses	2	75
Corporate debt securities
Debt Securities, Available-for-Sale, Unrealized Loss Position [Line Items]
Fair Value	1,153	1,156
Unrealized Losses	2	0
Fair Value	0	502
Unrealized Losses	0	5
Fair Value	1,153	1,658
Unrealized Losses	2	5
U.S. federal agency securities
Debt Securities, Available-for-Sale, Unrealized Loss Position [Line Items]
Fair Value	15,308	12,869
Unrealized Losses	52	228
Fair Value	8,751	25,342
Unrealized Losses	67	335
Fair Value	24,059	38,211
Unrealized Losses	119	563
U.S. government securities
Debt Securities, Available-for-Sale, Unrealized Loss Position [Line Items]
Fair Value	4,769	10,562
Unrealized Losses	13	208
Fair Value	10,895	8,569
Unrealized Losses	73	133
Fair Value	15,664	19,131
Unrealized Losses	$ 86	$ 341

Cash, Cash Equivalents and Ma_5

Cash, Cash Equivalents and Marketable Securities - Narrative (Details) - USD ($)	Dec. 31, 2023	Dec. 31, 2022
Cash and Cash Equivalents [Abstract]
Amortized Cost	$ 76,054,000
Fair Value	19,646,000	$ 34,413,000
Debt Securities, Available-for-Sale, Allowance for Credit Loss	$ 0	$ 0

Cash, Cash Equivalents and Ma_6

Cash, Cash Equivalents and Marketable Securities - Marketable Securities Classified by Contractual Maturities (Details) $ in Thousands	Dec. 31, 2023 USD ($)
Amortized Cost
Due within one year	$ 45,380
Due after one year through five years	30,674
Amortized Cost	76,054
Fair Value
Due within one year	45,199
Due after one year through five years	30,841
Fair Value	$ 76,040

Property and Equipment (Details

Property and Equipment (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Property, Plant and Equipment [Line Items]
Total property and equipment	$ 9,021	$ 9,315
Less accumulated depreciation and amortization	(7,022)	(6,256)
Property and equipment, net	1,999	3,059
Laboratory equipment
Property, Plant and Equipment [Line Items]
Total property and equipment	5,734	5,914
Computer equipment
Property, Plant and Equipment [Line Items]
Total property and equipment	1,054	1,230
Leasehold improvements
Property, Plant and Equipment [Line Items]
Total property and equipment	772	710
Software
Property, Plant and Equipment [Line Items]
Total property and equipment	1,141	1,141
Furniture and fixtures
Property, Plant and Equipment [Line Items]
Total property and equipment	$ 320	$ 320

Property and Equipment - Additi

Property and Equipment - Additional Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Property, Plant and Equipment [Line Items]
Depreciation and amortization	$ 900	$ 756

Accrued and Other Current Lia_3

Accrued and Other Current Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Accounts Payable and Accrued Liabilities, Current [Abstract]
Accrued compensation	$ 779	$ 2,290
Accrued vacation	365	430
Accrued 401(k) matching contributions	74	568
Operating lease liability, current portion	578	519
Other current liabilities	926	637
Total accrued and other current liabilities	$ 2,722	$ 4,444

Other Income (Expense), net (De

Other Income (Expense), net (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Other Income and Expenses [Abstract]
Interest income	$ 1,640	$ 456
Investment income, net	1,994	1,071
Other income, net	$ 3,634	$ 1,527

Fair Value Measurements - Narra

Fair Value Measurements - Narrative (Details) - shares	Dec. 31, 2023	Dec. 31, 2022
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Number of warrants outstanding (in shares)	2,775,978	2,775,978

Fair Value Measurements - Finan

Fair Value Measurements - Financial Assets that are Measured at Fair Value on a Recurring Basis (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Assets:
Marketable securities:	$ 76,040
Level 1 | Recurring
Assets:
Total assets	1,272	$ 2,618
Level 1 | Recurring | Commercial Paper [Member]
Assets:
Marketable securities:	0	0
Level 1 | Recurring | Corporate debt securities
Assets:
Marketable securities:	0	0
Level 1 | Recurring | U.S. federal agency securities
Assets:
Marketable securities:	0	0
Level 1 | Recurring | U.S. government securities
Assets:
Marketable securities:	0	0
Level 1 | Recurring | Money market funds
Assets:
Cash and Cash Equivalents, Fair Value Disclosure	1,272	2,618
Level 1 | Recurring | Commercial Paper [Member]
Assets:
Cash and Cash Equivalents, Fair Value Disclosure		0
Level 2 | Recurring
Assets:
Total assets	76,040	100,502
Level 2 | Recurring | Commercial Paper [Member]
Assets:
Marketable securities:	11,773	15,155
Level 2 | Recurring | Corporate debt securities
Assets:
Marketable securities:	18,192	1,658
Level 2 | Recurring | U.S. federal agency securities
Assets:
Marketable securities:	28,958	38,211
Level 2 | Recurring | U.S. government securities
Assets:
Marketable securities:	17,117	19,131
Level 2 | Recurring | Money market funds
Assets:
Cash and Cash Equivalents, Fair Value Disclosure	0	0
Level 2 | Recurring | Commercial Paper [Member]
Assets:
Cash and Cash Equivalents, Fair Value Disclosure		26,347
Level 3 | Recurring
Assets:
Total assets	0	0
Level 3 | Recurring | Commercial Paper [Member]
Assets:
Marketable securities:	0	0
Level 3 | Recurring | Corporate debt securities
Assets:
Marketable securities:	0	0
Level 3 | Recurring | U.S. federal agency securities
Assets:
Marketable securities:	0	0
Level 3 | Recurring | U.S. government securities
Assets:
Marketable securities:	0	0
Level 3 | Recurring | Money market funds
Assets:
Cash and Cash Equivalents, Fair Value Disclosure	$ 0	0
Level 3 | Recurring | Commercial Paper [Member]
Assets:
Cash and Cash Equivalents, Fair Value Disclosure		$ 0

Related Party Transactions (Det

Related Party Transactions (Details) - USD ($) $ in Thousands	1 Months Ended	12 Months Ended
	Feb. 28, 2021	Dec. 31, 2023	Dec. 31, 2022
Related Party Transaction [Line Items]
Operating Expenses		$ 40,127	$ 45,920
Revenue		$ 306	268
Common Stock, Shares Converted		437,500
Investor | Master services agreement | Healthcore Inc
Related Party Transaction [Line Items]
Operating Expenses		$ 4,000	2,200
Investor | Laboratory Services Agreement | Elevance Health, Inc
Related Party Transaction [Line Items]
Revenue		61	$ 100
Investor | Commercial Collaboration Agreement | Elevance Health, Inc
Related Party Transaction [Line Items]
Term of agreement	3 years
Other receivables related to minimum payments		11,200
Related Party Transaction, Cash Received From Related Party		$ 6,000

Capital Structure - Narrative (

Capital Structure - Narrative (Details)	12 Months Ended
	Dec. 31, 2023 common_stock_class vote $ / shares shares	Dec. 31, 2022 $ / shares shares
Class of Stock [Line Items]
Number of common stock classes authorized | common_stock_class	2
Common stock, conversion ratio	1
Common Stock, Shares Converted	437,500
Class A common stock
Class of Stock [Line Items]
Number of votes per share | vote	1
Common stock, shares authorized (in shares)	150,000,000	150,000,000
Common stock, par value (in usd per share) | $ / shares	$ 0.0001	$ 0.0001
Common stock, shares issued (in shares)	30,736,513	29,612,687
Common stock, shares outstanding (in shares)	30,736,513	29,612,687
Class B common stock
Class of Stock [Line Items]
Common stock, shares authorized (in shares)	1,500,000	1,500,000
Common stock, par value (in usd per share) | $ / shares	$ 0.0001	$ 0.0001
Common stock, shares issued (in shares)	1,405,259	1,405,259
Common stock, shares outstanding (in shares)	967,759	1,405,259
Preferred Stock
Class of Stock [Line Items]
Preferred stock outstanding (in shares)	0	0
Preferred stock, authorized (in shares)	5,000,000
Preferred stock, par value (in usd per share) | $ / shares	$ 0.0001

Capital Structure - Common Stoc

Capital Structure - Common Stock (Details) - Class A common stock - shares	Dec. 31, 2023	Dec. 31, 2022
Class of Stock [Line Items]
Shares reserved for future issuance (in shares)	14,523,859	13,729,552
Warrants to purchase Class A common stock
Class of Stock [Line Items]
Shares reserved for future issuance (in shares)	2,775,978	2,775,978
Options to purchase Class A common stock
Class of Stock [Line Items]
Shares reserved for future issuance (in shares)	7,251,663	8,428,441
Class A common stock available for future grants under the 2021 Equity Incentive Plan
Class of Stock [Line Items]
Shares reserved for future issuance (in shares)	1,002,091	1,926,356
Class A common stock available for future grants under the 2021 Employee Stock Purchase Plan
Class of Stock [Line Items]
Shares reserved for future issuance (in shares)	801,668	598,777
Restricted Stock Units (RSUs)
Class of Stock [Line Items]
Shares reserved for future issuance (in shares)	2,692,459	0

Stock-Based Compensation - Narr

Stock-Based Compensation - Narrative (Details) - USD ($) $ / shares in Units, $ in Thousands		1 Months Ended		12 Months Ended
	Jul. 19, 2021	Jul. 31, 2021	Nov. 30, 2011	Dec. 31, 2023	Dec. 31, 2022
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted-average grant date fair value of options granted (in usd per share)				$ 2.28	$ 1.92
Aggregate intrinsic value of options exercised				$ 1,400	$ 500
Fair value of options vested				4,800	$ 5,800
Unamortized stock-based compensation cost				$ 5,035
Unamortized stock-based compensation cost expected to be recognized over a weighted average period				1 year 7 months 6 days
Class A common stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares available for future issuance (in shares)				14,523,859	13,729,552
2011 Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period			4 years
Expiration term			10 years
Shares available for grant				0
2021 Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expiration term	10 years
2021 Plan | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period		2 years
2021 Plan | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period		4 years
2021 Plan | Class A common stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares available for future issuance (in shares)				1,002,091
2021 ESPP | Class A common stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares available for future issuance (in shares)				801,668

Stock-Based Compensation - Stoc

Stock-Based Compensation - Stock Options (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Number of Shares Subject to Options Outstanding
Outstanding at the beginning (in shares)	8,428,441
Granted (in shares)	991,866
Expired (in shares)	(14,430)
Cancelled (in shares)	(1,561,123)
Exercised (in shares)	(593,091)
Outstanding at the end (in shares)	7,251,663	8,428,441
Number of shares subject to options outstanding, vested and expected to vest at the end (in shares)	7,120,916
Number of shares subject to options outstanding, vested and exercisable at the end	5,477,835
Weighted- Average Exercise Price Per Share
Outstanding at the beginning (in usd per share)	$ 3.65
Granted (in usd per share)	3.49
Expired (in usd per share)	0.75
Cancelled (in usd per share)	4.25
Exercised (in usd per share)	1.85
Outstanding at the end (in usd per share)	3.66	$ 3.65
Weighted average exercise price per share, vested and expected to vest at the end (in usd per share)	3.64
Weighted average exercise price per share, vested and exercisable at the end (in usd per share)	$ 3.28
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Weighted average remaining contractual life, outstanding	6 years 10 months 24 days	7 years 8 months 12 days
Weighted average remaining contractual life, vested and expected to vest at the end	6 years 10 months 24 days
Weighted average remaining contractual life, vested and exercisable at the end	6 years 6 months
Aggregate intrinsic value, outstanding	$ 20,014	$ 115
Aggregate intrinsic value, vested and expected to vest at the end	19,763
Aggregate intrinsic value, vested and exercisable at the end	$ 16,856

Stock-Based Compensation - Weig

Stock-Based Compensation - Weighted-Average Assumptions (Details) - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected volatility	70.10%	63.70%
Expected volatility	72.40%	69.10%
Risk-free interest rate	3.70%	1.70%
Risk-free interest rate	4.20%	4.30%
Expected dividend yield	$ 0	$ 0
Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term (in years)	5 years 3 months 18 days	5 years 3 months 18 days
Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term (in years)	7 years	7 years

Stock-Based Compensation - Expe

Stock-Based Compensation - Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total employee stock-based compensation	$ 5,273	$ 5,055
Research and development expense
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total employee stock-based compensation	1,574	1,671
Sales and marketing expense
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total employee stock-based compensation	657	590
General and administrative expense
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total employee stock-based compensation	$ 3,042	$ 2,794

Stock-Based Compensation - Rest

Stock-Based Compensation - Restricted Stock Units (Details) - Restricted Stock Units (RSUs) - $ / shares	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Nonvested, Number	2,692,459	0
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value	$ 2.01	$ 0
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Grants in Period	2,827,824
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value	$ 2.10
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Forfeited in Period	(135,365)
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Forfeitures, Weighted Average Grant Date Fair Value	$ 3.76
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Vested in Period	0
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Vested in Period, Weighted Average Grant Date Fair Value	$ 0

Stock-Based Compensation - Unre

Stock-Based Compensation - Unrecognized Cost (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2023 USD ($)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unamortized stock-based compensation cost	$ 5,035
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition	1 year 7 months 6 days
Share-Based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount	$ 8,977
Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition	2 years 8 months 12 days
Share-Based Payment Arrangement, Nonvested Award, Excluding Option, Cost Not yet Recognized, Amount	$ 3,942

Warrants - Common Stock Warrant

Warrants - Common Stock Warrants Outstanding (Details) - $ / shares	Dec. 31, 2023	Dec. 31, 2022
Class of Warrant or Right [Line Items]
Number of warrants outstanding (in shares)	2,775,978	2,775,978
5.2
Class of Warrant or Right [Line Items]
Exercise price (in usd per share)	$ 5.20
Number of warrants outstanding (in shares)	3,473	3,473
9.03
Class of Warrant or Right [Line Items]
Exercise price (in usd per share)	$ 9.03
Number of warrants outstanding (in shares)	1,032,404	1,032,404
10.84
Class of Warrant or Right [Line Items]
Exercise price (in usd per share)	$ 10.84
Number of warrants outstanding (in shares)	1,009,795	1,009,795
12.38
Class of Warrant or Right [Line Items]
Exercise price (in usd per share)	$ 12.38
Number of warrants outstanding (in shares)	8,083	8,083
20.77
Class of Warrant or Right [Line Items]
Exercise price (in usd per share)	$ 20.77
Number of warrants outstanding (in shares)	722,223	722,223

Commitments and Contingencies -

Commitments and Contingencies - Leases in Financial Statement (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Right-of-use assets:
Operating leases	$ 1,180	$ 1,707
Finance leases	1,008	1,317
Total right-of-use assets	2,188	3,024
Lease liabilities:
Operating leases	578	519
Operating lease obligation, net of current portion	644	1,222
Finance lease obligation, current portion	440	464
Finance lease obligation, net of current portion	196	626
Total lease liabilities	$ 1,858	$ 2,831
Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration]	Other assets	Other assets
Finance Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration]	Property and equipment, net	Property and equipment, net
Operating Lease, Liability, Current, Statement of Financial Position [Extensible Enumeration]	Accrued Liabilities and Other Liabilities	Accrued Liabilities and Other Liabilities

Commitments and Contingencies_2

Commitments and Contingencies - Lease Cost and Other Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Lease cost
Amortization of right-of-use assets	$ 312	$ 280
Interest on lease liabilities	55	61
Operating lease cost	636	504
Total lease cost	1,003	845
Finance leases:
Operating cash outflows	55	48
Financing cash outflows	466	303
Right-of-use assets obtained in exchange for lease liabilities	$ 18	$ 1,253
Weighted-average remaining lease term (in years)	1 year 4 months 24 days	2 years 3 months 18 days
Weighted-average discount rate	650%	640%
Operating leases:
Operating cash outflows	$ 628	$ 609
Right-of-use assets obtained in exchange for lease liabilities	$ 0	$ 2,169
Weighted-average remaining lease term (in years)	2 years	3 years
Weighted-average discount rate	750%	750%

Commitments and Contingencies_3

Commitments and Contingencies - Future Minimum Lease Payments (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Operating Leases
2024	$ 646
2025	666
2026	0
2027 and thereafter	0
Total minimum lease payments	1,312
Less: imputed interest	(90)
Present value of future lease payments	1,222
Less: current portion	578	$ 519
Operating lease obligation, net of current portion	644	1,222
Finance Leases
2024	467
2025	197
2026	2
2027 and thereafter	0
Total minimum lease payments	666
Less: imputed interest	(30)
Present value of future lease payments	636
Less: current portion	440	464
Long-term portion	196	626
Total
2024	1,113
2025	863
2026	2
2027 and thereafter	0
Total minimum lease payments	1,978
Less: imputed interest	(120)
Total lease liabilities	1,858	$ 2,831
Less: current portion	1,018
Long-term portion	$ 840

Commitments and Contingencies_4

Commitments and Contingencies - Narrative (Details)	Dec. 31, 2023 USD ($) ft²	Dec. 31, 2022 USD ($)
Commitments And Contingencies [Line Items]
Indemnification liability | $	$ 0	$ 0
Office and laboratory space
Commitments And Contingencies [Line Items]
Number of square feet under lease | ft²	24,300

Income Taxes - Narrative (Detai

Income Taxes - Narrative (Details) - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Income Tax Contingency [Line Items]
Income tax expense	$ 0	$ 0
Valuation allowance	64,879,000	54,504,000
Increase in valuation allowance	10,376,000	$ 11,351,000
Operating loss carryforwards	141,300,000
U.S Federal
Income Tax Contingency [Line Items]
Operating loss carryforwards	211,600,000
State
Income Tax Contingency [Line Items]
Operating loss carryforwards	$ 143,700,000

Income Taxes - Schedule of Comp

Income Taxes - Schedule of Components of Income Tax Provision (Details) - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Current:
Federal	$ 0	$ 0
State	0	0
Total current benefit (provision)	0	0
Deferred:
Federal	8,178,000	9,400,000
State	2,198,000	1,951,000
Change in valuation allowance	(10,376,000)	(11,351,000)
Total deferred benefit (provision)	0	0
Total income tax benefit (provision)	$ 0	$ 0

Income Taxes - Effective Tax Ra

Income Taxes - Effective Tax Rate Reconciliation (Details) - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Effective Income Tax Rate Reconciliation, Amount [Abstract]
Computed Federal income tax benefit (expense) at the statutory rate	$ 7,602,000	$ 9,278,000
R&D credits	698,000	566,000
Equity-based expenses	(63,000)	(325,000)
State income taxes, net of federal benefit	1,783,000	1,771,000
State net operating loss carryforward true up	154,000	(8,000)
Change in statutory rates	163,000	78,000
Other	39,000	(9,000)
Valuation allowance	(10,376,000)	(11,351,000)
Total income tax benefit (provision)	$ 0	$ 0
Effective Income Tax Rate Reconciliation, Percent [Abstract]
Computed Federal income tax benefit (expense) at the statutory rate	21%	21%
R&D credits	1.93%	1.28%
Equity-based expenses	(0.17%)	(0.74%)
State income taxes, net of federal benefit	4.92%	4.01%
State net operating loss carryforward true up	0.42%	(0.02%)
Change in statutory rates	0.45%	0.18%
Other	0.11%	(0.02%)
Valuation allowance	(28.66%)	(25.69%)
Income tax benefit (provision)	0%	0%

Income Taxes - Deferred Tax Ass

Income Taxes - Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Deferred tax assets:
Net operating loss carryforwards	$ 53,072	$ 46,674
Deferred Tax Assets, Tax Credit Carryforwards, Research	3,856	3,038
R&D credits	5,219	2,644
Accruals and reserves	278	635
Equity-based compensation	2,440	1,496
Depreciation and amortization	0	5
Other	7	3
Total deferred tax asset before allowance	65,189	54,933
Less: valuation allowance	(64,879)	(54,504)
Total deferred tax asset	310	429
Deferred Tax Liabilities, Right Of Use Assets	306	429
Right-of-use asset	(4)	0
Deferred tax liabilities:
Net deferred tax assets	0	0
Deferred Tax Assets Lease Liabilities	$ 317	$ 438

Income Taxes - Unrecognized Tax

Income Taxes - Unrecognized Tax Positions (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Balance at the beginning of the year	$ 2,025	$ 1,648
Gross increases—prior period	80	0
Gross increases—prior period	465	377
Balance at the beginning of the year	$ 2,570	$ 2,025

Net Loss Per Share - Anti-Dilut

Net Loss Per Share - Anti-Dilutive Securities Excluded from the Computation of Diluted Net Loss Per Share (Details) - shares	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from the computation of earnings per share (in shares)	12,720,100	11,204,419
Warrants to purchase Class A common stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from the computation of earnings per share (in shares)	2,775,978	2,775,978
Options to purchase Class A common stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from the computation of earnings per share (in shares)	7,251,663	8,428,441
Restricted Stock Units (RSUs)
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from the computation of earnings per share (in shares)	2,692,459	0