Sera Prognostics (SERA) 10-Q 10 May 22 2022 Q1 Quarterly report Financial data

Cover

Cover - shares	3 Months Ended
	Mar. 31, 2022	May 06, 2022
Document Information [Line Items]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Mar. 31, 2022
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 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
Entity Shell Company	false
Entity Central Index Key	0001534969
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2022
Document Fiscal Period Focus	Q1
Amendment Flag	false
Class A common stock
Document Information [Line Items]
Entity Common Stock, Shares Outstanding (in shares)		29,529,296
Class B common stock
Document Information [Line Items]
Entity Common Stock, Shares Outstanding (in shares)		1,405,259

Condensed Balance Sheets (unaud

Condensed Balance Sheets (unaudited) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Current assets:
Cash and cash equivalents	$ 64,080	$ 58,932
Marketable securities	43,467	46,183
Accounts receivable	39	27
Other receivables	9	3,116
Prepaid expenses and other current assets	1,875	1,993
Total current assets	109,470	110,251
Property, plant, and equipment and finance lease right-of-use asset	2,571	1,773
Long-term marketable securities	22,337	34,848
Other assets	487	157
Total assets	134,865	147,029
Current liabilities:
Accounts payable	945	1,197
Accrued and other current liabilities	2,536	3,885
Deferred rent, current portion	0	139
Finance lease obligation, current portion	351
Finance lease obligation, current portion		74
Deferred revenue	3,112	3,116
Total current liabilities	6,944	8,411
Finance lease obligation, net of current portion	718
Finance lease obligation, net of current portion		54
Total liabilities	7,662	8,465
Commitments and Contingencies
Stockholders' equity:
Common stock, $0.0001 par value; 150,000,000 Class A shares authorized as of March 31, 2022 and December 31, 2021; 29,492,334 and 29,368,867 Class A shares issued and outstanding as of March 31, 2022 and December 31, 2021, respectively; 1,500,000 Class B shares authorized as of March 31, 2022 and December 31, 2021; 1,405,259 Class B shares issued and outstanding as of March 31, 2022 and December 31, 2021.	3	3
Additional paid-in capital	306,532	305,212
Accumulated other comprehensive loss	(656)	(183)
Accumulated deficit	(178,676)	(166,468)
Total stockholders' equity	127,203	138,564
Total liabilities and stockholders' equity	$ 134,865	$ 147,029

Condensed Balance Sheets (una_2

Condensed Balance Sheets (unaudited) (Parenthetical) - $ / shares	Mar. 31, 2022	Dec. 31, 2021
Class A common stock
Common stock, par value (in shares)	$ 0.0001	$ 0.0001
Common stock, shares authorized (in shares)	150,000,000	150,000,000
Common stock, shares issued (in shares)	29,492,334	29,368,867
Common stock, shares outstanding (in shares)	29,492,334	29,368,867
Class B common stock
Common stock, par value (in shares)	$ 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)	1,405,259	1,405,259

Condensed Statements of Operati

Condensed Statements of Operations and Comprehensive Loss (unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Income Statement [Abstract]
Revenue	$ 38	$ 13
Operating expenses:
Cost of revenue	20	5
Research and development	3,322	2,396
Selling and marketing	4,458	1,350
General and administrative	4,538	2,287
Total operating expenses	12,338	6,038
Loss from operations	(12,300)	(6,025)
Interest expense	(4)	(307)
Other income (expense), net	96	(27)
Net loss	$ (12,208)	$ (6,359)
Net loss per share, basic (in usd per share)	$ (0.40)	$ (3.55)
Net loss per share — diluted (in usd per share)	$ (0.40)	$ (3.55)
Weighted-average shares of common stock outstanding, basic (in shares)	30,801,579	1,791,841
Weighted-average shares of common stock outstanding, diluted (In shares)	30,801,579	1,791,841
Other comprehensive loss:
Unrealized loss on available-for-sale debt securities	$ (473)	$ 0
Total other comprehensive loss	(473)	0
Comprehensive loss	$ (12,681)	$ (6,359)

Condensed Statements of Convert

Condensed Statements of Convertible Preferred Stock and Stockholders’ Equity (Deficit) (unaudited) - USD ($) $ in Thousands	Total	Common Stock (Class A and B)	Additional Paid-In Capital	Accumulated Other Comprehensive Loss	Accumulated Deficit	Senior Convertible Preferred Stock	Junior Convertible Preferred Stock
Balance at the beginning (in shares) at Dec. 31, 2020						5,737,440	9,819,480
Balance at the beginning at Dec. 31, 2020						$ 50,192	$ 77,844
Increase (Decrease) in Temporary Equity [Roll Forward]
Issuance of Series E senior convertible preferred stock at $12.46 per share, net of issuance costs of $0.1 million (in shares)						4,938,482
Issuance of Series E senior convertible preferred stock at $12.46 per share, net of issuance costs of $0.1 million						$ 60,307
Balance at the ending (in shares) at Mar. 31, 2021						10,675,922	9,819,480
Balance at the ending at Mar. 31, 2021						$ 110,499	$ 77,844
Balance at the beginning (in shares) at Dec. 31, 2020		1,700,625
Balance at the beginning at Dec. 31, 2020	$ (125,570)	$ 0	$ 5,889	$ 0	$ (131,459)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Fair value of warrants to purchase common stock issued to Series E investor	1,071		1,071
Issuance of common stock upon exercise of stock options (in shares)		281,458
Issuance of common stock upon exercise of stock options	229		229
Stock-based compensation expense	239		239
Other comprehensive loss	0
Net loss	(6,359)				(6,359)
Balance at the ending (in shares) at Mar. 31, 2021		1,982,083
Balance at the ending at Mar. 31, 2021	(130,390)	$ 0	7,428	0	(137,818)
Balance at the beginning (in shares) at Dec. 31, 2021						0	0
Balance at the beginning at Dec. 31, 2021						$ 0	$ 0
Balance at the ending (in shares) at Mar. 31, 2022						0	0
Balance at the ending at Mar. 31, 2022						$ 0	$ 0
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)	123,467	123,467
Issuance of common stock upon exercise of stock options	$ 98		98
Stock-based compensation expense	1,222		1,222
Other comprehensive loss	(473)			(473)
Net loss	(12,208)				(12,208)
Balance at the ending (in shares) at Mar. 31, 2022		30,897,593
Balance at the ending at Mar. 31, 2022	$ 127,203	$ 3	$ 306,532	$ (656)	$ (178,676)

Condensed Statements of Conve_2

Condensed Statements of Convertible Preferred Stock and Stockholders’ Equity (Deficit) (unaudited) (Parenthetical) - Series E Senior Convertible Preferred Stock $ in Millions	3 Months Ended
	Mar. 31, 2021USD ($)$ / shares
Issue price per share (in usd per share) | $ / shares	$ 12.46
Stock issuance costs | $	$ 0.1

Condensed Statements of Cash Fl

Condensed Statements of Cash Flows (unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Cash flows from operating activities
Net loss	$ (12,208)	$ (6,359)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	165	201
Stock-based compensation	1,222	239
Non-cash interest expense	2	168
Other	36	19
Changes in operating assets and liabilities:
Accounts receivable	(12)	(6)
Other receivables	3,116	0
Prepaid expenses and other assets	320	(223)
Accounts payable	(252)	339
Accrued and other current liabilities	(1,942)	(1,297)
Deferred rent	0	(31)
Deferred revenue	(4)	0
Net cash used in operating activities	(9,557)	(6,950)
Cash flows from investing activities
Purchases of marketable securities	(6,614)	0
Proceeds from maturities and sales of marketable securities	21,252	0
Purchases of property and equipment	(7)	(41)
Proceeds from disposal of property and equipment	3	0
Net cash provided by (used in) investing activities	14,634	(41)
Cash flows from financing activities
Proceeds allocated to issuance of common stock warrants in connection with Series E	0	1,071
Proceeds from exercise of stock options	89	229
Payment of convertible note payable	0	(4,494)
Payment of loan payable	0	(3,100)
Finance lease principal payments	(18)	(17)
Payment of deferred offering costs	0	(630)
Net cash provided by financing activities	71	53,474
Net increase in cash and cash equivalents	5,148	46,483
Cash and cash equivalents at beginning of period	58,932	13,533
Cash and cash equivalents at end of period	64,080	60,016
Supplemental disclosure of cash flow information
Cash paid for interest	2	1,277
Supplemental disclosure of non-cash investing and financing information
Purchases of property and equipment in accounts payable and accruals	0	21
Series E senior convertible preferred stock offering costs included in accounts payable and accrued liabilities	0	82
Series E senior convertible preferred stock offering costs prepaid and deferred in prior period and reclassified to Series E senior convertible preferred stock	0	26
Deferred offering costs included in accounts payable and accrued liabilities	0	771
Series E Senior Convertible Preferred Stock
Cash flows from financing activities
Proceeds from issuance of Series E senior convertible preferred stock, net of issuance costs	$ 0	$ 60,415

Description of Business and Fin

Description of Business and Financial Condition	3 Months Ended
	Mar. 31, 2022
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, acquiring product rights, raising capital, establishing facilities, and organizing commercial operations to market the PreTRM test. Liquidity and Capital Resources The accompanying condensed 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 $178.7 million as of March 31, 2022. 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 commercialization activities for the PreTRM test, and to support additional clinical and preclinical trials and anticipated research and development 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 diagnostic products and could be required to delay, scale back, or abandon some or all of its development programs and other 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 successful commercial launch and market acceptance of the PreTRM test; (ii) the success of clinical trials and other research and development programs; (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. See Note 10—Capital Structure for additional details about the IPO. As of March 31, 2022, the Company had approximately $64.1 million in cash and cash equivalents and $65.8 million of marketable securities classified as available-for-sale. See Note 3—Cash, Cash Equivalents and Marketable Securities. The Company believes that its existing financial resources are sufficient to continue operating activities at least 12 months from the issuance date of these unaudited condensed financial statements.

Significant Accounting Policies

Significant Accounting Policies	3 Months Ended
	Mar. 31, 2022
Accounting Policies [Abstract]
Significant Accounting Policies	Significant Accounting Policies Basis of Presentation The accompanying unaudited condensed financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (“U.S. GAAP”) and applicable rules and regulations of the U.S. Securities and Exchange Commission (the "SEC") regarding interim financial reporting. Certain information and note disclosures normally included in the financial statements prepared in accordance with U.S. GAAP have been condensed or omitted pursuant to such rules and regulations. As such, these unaudited condensed financial statements should be read in conjunction with the audited financial statements and accompanying notes included in the Company's Annual Report on Form 10-K for the year ended December 31, 2021. The unaudited interim condensed financial statements have been prepared on a basis consistent with the audited annual financial statements as of and for the year ended December 31, 2021, and, in the opinion of the Company’s management, reflect all adjustments, consisting solely of normal recurring adjustments, necessary for the fair presentation of the Company’s financial results. The balance sheet as of December 31, 2021 has been derived from the audited financial statements at that date but does not include all information and footnotes required by GAAP for complete financial statements. The results of the three months ended March 31, 2022 are not necessarily indicative of the results to be expected for the full year ending December 31, 2022, or any other period. 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”). Reverse Stock Split On June 30, 2021, the Company’s board of directors (the “Board of Directors”) approved a 1-for-2.079 reverse stock split of the Company’s common stock and redeemable convertible preferred stock, which was effective by amendment to the Company’s charter on July 7, 2021. The par value and authorized shares of the common stock and redeemable convertible preferred stock were not adjusted as a result of the reverse stock split. All issued and outstanding common stock, warrants, options to purchase common stock and per share amounts contained in the financial statements have been retroactively adjusted to give effect to the reverse stock split for all periods presented. Leases The Company adopted ASU 2016-02, Leases, ("Topic 842") and its subsequent updates effective January 1, 2022. The Company adopted Topic 842 using a modified retrospective method. As such, comparative periods ending prior to January 1, 2022 are presented in accordance with ASC 840, Leases , and periods ending after January 1, 2022 are presented in accordance with Topic 842. There was no impact to the Company's accumulated deficit as a result of adopting Topic 842. The Company used the package of practical expedients permitted under Topic 842. As a result, the Company did not reassess its lease population, classifications of existing leases, or initial direct costs of existing leases as of the adoption date. 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. The Company also elected not to separate lease components from non-lease components for all classes of leased assets except for building leases. The adoption of Topic 842 resulted in a right-of-use asset of $0.5 million related to the Company's operating lease being recognized in other assets on the condensed balance sheets as of January 1, 2022. A corresponding lease liability of $0.6 million related to the Company's operating lease was recognized in accrued and other liabilities on the condensed balance sheets as of January 1, 2022. In addition, at January 1, 2022, approximately $0.1 million of lease-related liabilities were removed from deferred rent, current portion as a reduction to the initial operating lease right-of-use asset. As a result of adopting Topic 842, leases classified as capital leases under ASC 840 are now called finance leases. Accordingly, the condensed balance sheet items formerly captioned "Capital lease obligation, current portion" and "Capital lease obligation, net of current portion" will now be captioned "Finance lease obligation, current portion" and "Finance lease obligation, net of current portion", respectively, beginning in the current period. Amounts in these balance sheet items were capital leases under ASC 840 in periods ending prior to January 1, 2022, while amounts in these balance sheet items are finance leases under ASC 842 in periods ending subsequent to January 1, 2022. The Company's finance lease right-of-use asset and liability balances were not materially affected by the adoption of Topic 842. Use of Estimates The preparation of the condensed 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 condensed 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 COVID-19 pandemic and the evolving actions of governments, private sector participants and the public in an effort to contain the spread of the COVID-19 virus and address its impacts have intensified and have had significant direct and indirect effects on businesses and commerce. The extent to which the COVID-19 pandemic may impact the Company’s business, financial condition, cash flows, and results of operations, in particular, will depend on future developments that are highly uncertain, many of which are outside the Company’s control. Such developments include the availability and effectiveness of actions taken to contain or treat COVID-19, the ultimate geographic spread and duration of the pandemic, the extent and duration of a resurgence of the COVID-19 virus and variant strains thereof, new information concerning the severity of the COVID-19 virus, the effectiveness and intensity of measures to contain the COVID-19 virus and the economic impact of the pandemic and the reactions to it. Such developments, among others, depending on their nature, duration, and intensity, could have a significant adverse effect on the Company’s business, financial condition, cash flows, and results of operations. There were no significant estimates contained in the preparation of the Company’s condensed financial statements or impacts to the Company’s condensed financial statements for the three months ended March 31, 2022 that were a direct result of the COVID-19 pandemic. 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 the condensed financial statements. Recently Issued Accounting Pronouncements Not Yet Adopted In June 2016, the FASB issued ASU 2016-13, Financial Instruments—Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments. The objective of the standard is to provide information about expected credit losses on financial instruments at each reporting date and to change how other-than-temporary impairments on investment securities are recorded. The Company is currently an emerging growth company and has elected to use the extended transition period for complying with new or revised accounting standards that have different effective dates for public and private companies. As such, the guidance is effective for the Company beginning on January 1, 2023, with early adoption permitted. The Company is currently evaluating the impact the standard may have on its financial statements and related disclosures. Other recent accounting pronouncements issued by the FASB (including its Emerging Issues Task Force) and the SEC did not, or are not believed by the Company’s management to, have a material impact on the Company’s financial position, results of operations or cash flows.

Cash, Cash Equivalents and Mark

Cash, Cash Equivalents and Marketable Securities	3 Months Ended
	Mar. 31, 2022
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 March 31, 2022 and December 31, 2021 were as follows (in thousands): March 31, 2022 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Cash and cash equivalents: Cash $ 133 $ — $ — $ 133 Money market funds 2,342 — — 2,342 Commercial paper 61,610 — (5) 61,605 Total cash and cash equivalents 64,085 — (5) 64,080 Current marketable securities: Commercial paper 30,051 2 (69) 29,984 Corporate debt securities 1,962 — (15) 1,947 U.S. federal agency securities 7,687 — (94) 7,593 U.S. government securities 3,996 — (53) 3,943 Total current marketable securities 43,696 2 (231) 43,467 Long-term marketable securities: U.S. federal agency securities 18,060 — (322) 17,738 U.S. government securities 4,699 — (100) 4,599 Total long-term marketable securities 22,759 — (422) 22,337 Total cash, cash equivalents and marketable securities $ 130,540 $ 2 $ (658) $ 129,884 December 31, 2021 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Cash and cash equivalents: Cash $ 70 $ — $ — $ 70 Money market funds 4,021 — — 4,021 Commercial paper 54,843 — (2) 54,841 Total cash and cash equivalents 58,934 — (2) 58,932 Current marketable securities: Commercial paper 39,696 — (24) 39,672 Corporate debt securities 6,515 — (4) 6,511 Total current marketable securities 46,211 — (28) 46,183 Long-term marketable securities: U.S. federal agency securities 25,787 — (112) 25,675 U.S. government securities 8,694 — (38) 8,656 Corporate debt securities 520 — (3) 517 Total long-term marketable securities 35,001 — (153) 34,848 Total cash, cash equivalents and marketable securities $ 140,146 $ — $ (183) $ 139,963 As of March 31, 2022 and December 31, 2021, the Company had no available-for-sale debt securities that had been in a continuous unrealized loss position for a period greater than 12 months. The Company determined that no available-for-sale securities were other-than-temporarily impaired as of March 31, 2022 and December 31, 2021. 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. The Company's marketable securities classified by contractual maturities as of March 31, 2022 were as follows (in thousands): Amortized Cost Fair Value Due within one year $ 43,696 $ 43,467 Due after one year through five years 22,759 22,337 Total $ 66,455 $ 65,804

Property and Equipment

Property and Equipment	3 Months Ended
	Mar. 31, 2022
Property, Plant and Equipment [Abstract]
Property and Equipment	Property and Equipment The following table presents the components of property and equipment, net, as of March 31, 2022 and December 31, 2021 (in thousands): March 31, December 31, Laboratory equipment $ 5,991 $ 5,033 Computer equipment 1,217 1,212 Leasehold improvements 710 710 Software 465 465 Furniture and fixtures 320 320 Total property and equipment 8,703 7,740 Less accumulated depreciation and amortization (6,132) (5,967) Property and equipment, net $ 2,571 $ 1,773

Accrued and Other Current Liabi

Accrued and Other Current Liabilities	3 Months Ended
	Mar. 31, 2022
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 March 31, 2022 and December 31, 2021 (in thousands): March 31, December 31, Accrued compensation $ 954 $ 2,498 Accrued paid time off 607 460 Operating lease liability, current portion 446 — Other current liabilities 529 927 Total accrued and other current liabilities $ 2,536 $ 3,885

Other Income (Expense), net

Other Income (Expense), net	3 Months Ended
	Mar. 31, 2022
Other Income and Expenses [Abstract]
Other Income (Expense), net	Other Income (Expense), net The following table presents the components of other income (expense), net, for the three months ended March 31, 2022 and 2021 (in thousands): Three Months Ended 2022 2021 Interest income $ 78 $ 2 Fair value remeasurements — (10) Other gains (losses), net 18 (19) Other income (expense), net $ 96 $ (27)

Loans and Convertible Promissor

Loans and Convertible Promissory Notes	3 Months Ended
	Mar. 31, 2022
Debt Disclosure [Abstract]
Loans and Convertible Promissory Notes	Loans and Convertible Promissory Notes Bank Loan In 2014, through a Loan and Security Agreement (the “Loan Agreement”) with a bank, the Company obtained a term loan for $10.0 million. The Loan Agreement, as amended, had a final repayment date of September 1, 2021. Repayment of amounts borrowed were paid in equal monthly installments of principal, plus all accrued interest. The loan bore interest, on the outstanding daily balance, equal to the greater of 1.0% above the Prime Rate then in effect, or 4.75%. In addition, the Loan Agreement required a Final Payment Fee (as defined in the Loan Agreement) equal to one-percent of the aggregate principal amount borrowed, or $0.1 million. In March 2021, the Company repaid the outstanding principal of $2.0 million, accrued interest of $6 thousand, and the Final Payment Fee of $0.1 million related to this loan. Convertible Promissory Note In February 2019, the Company authorized the issuance of a $6.4 million subordinated convertible promissory note (the “February 2019 Convertible Note”) to a current stockholder, bearing 12% interest and a maturity date of February 26, 2021, to provide liquidity and additional working capital. On February 15, 2021, the maturity date was extended to March 28, 2021. The February 2019 Convertible Note was convertible at the option of the holder into shares of Series D Convertible Preferred Stock at a conversion price equal to 80% of the issuance price of the Series D Convertible Preferred Stock of $9.03 per share. In July 2019, $1.9 million of the $6.4 million February 2019 Convertible Note’s principal and $0.1 million of accrued interest were converted into 277,507 shares of the Company’s Series D Preferred Stock. The conversion feature of the February 2019 Convertible Note met the requirements for separate accounting and was recognized as a liability at the measurement date fair value of $2.4 million, subject to remeasurement to fair value, with any changes in estimated fair value recognized as a component of other income (expense), net. A corresponding discount, which reduced the carrying value of the February 2019 Convertible Note, was also recorded. The unamortized discount was written off in proportion to the partial conversion, with the remaining discount accreted to interest expense until maturity. The Company recognized additional interest expense of $0.1 million from accretion of the discount during the three months ended March 31, 2021. On March 24, 2021, the Company repaid the outstanding principal of $4.5 million and accrued interest of $1.1 million related to the February 2019 Convertible Note. Paycheck Protection Loan

Fair Value Measurements

Fair Value Measurements	3 Months Ended
	Mar. 31, 2022
Fair Value Disclosures [Abstract]
Fair Value Measurements	Fair Value Measurements As of March 31, 2022 and December 31, 2021, 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. 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. Concurrent with the Company's IPO in July 2021, the outstanding preferred stock warrants were converted to common stock warrants. As such, there were no preferred stock warrants outstanding at March 31, 2022 and December 31, 2021. Immediately prior to the conversion, the Company adjusted the fair value of the preferred stock warrants using the Black-Scholes option pricing model based on the publicly available fair value of the Company's common stock on the pricing date of the Company's IPO along with other significant unobservable inputs. The fair value of the preferred stock warrant liability was then reclassified to equity upon conversion. In periods ending before the Company's IPO, including the three months ended March 31, 2021, the Company’s convertible preferred stock warrant liability was valued using Level 3 inputs in a Black-Scholes option pricing model (see Note 12 — Warrants). The Company, utilizing a third-party valuation firm to assist with the estimation of the fair value of common stock, employed a hybrid method of option-pricing model (OPM) and Probability-Weighted Expected Return Method (“PWERM”). Under the hybrid OPM and PWERM approach, the per share value calculated under OPM and PWERM were weighted based on expected exit outcomes and the quality of the information specific to each allocation methodology to arrive at a final estimated fair value per share of the common stock before a discount for lack of marketability was applied. This model also calculated the fair value of the other classes of equity, including preferred shares. This estimated preferred stock value, along with other significant unobservable inputs, was an input into a Black-Scholes option pricing model, which calculated the fair value of the preferred stock warrant liability. The other significant unobservable inputs in this calculation were the remaining expected term, which considered the timing of a liquidation event that would net settle the awards before their contractual term expired, and the expected equity volatility, which is a statistical measure of the dispersion of returns for a given security. Volatility was determined based on select comparable public guideline companies in the same business sector. Significant increases (decreases) in the term would have resulted in significantly higher (lower) fair value measurements. Significant increases (decreases) in the volatility would have resulted in significantly higher (lower) fair value measurements. 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 March 31, 2022: Level 1 Level 2 Level 3 Assets: Cash equivalents: Money market funds $ 2,342 $ — $ — Commercial paper — 61,605 — Marketable securities: Commercial paper — 29,984 — Corporate debt securities — 1,947 — U.S. federal agency securities — 25,331 — U.S. government securities — 8,542 — Total assets $ 2,342 $ 127,409 $ — 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, 2021: Level 1 Level 2 Level 3 Assets: Cash equivalents: Money market funds $ 4,021 $ — $ — Commercial paper — 54,841 — Marketable securities: Commercial paper — 39,672 — Corporate debt securities — 7,028 — U.S. federal agency securities — 25,675 — U.S. government securities — 8,656 — Total assets $ 4,021 $ 135,872 $ —

Related Party Transactions

Related Party Transactions	3 Months Ended
	Mar. 31, 2022
Related Party Transactions [Abstract]
Related Party Transactions	Related Party Transactions In July 2019, the Company entered into a consulting agreement with Blue Ox Healthcare Partners, LLC (“Blue Ox”) to advise the Company on development of strategies with the goal to obtain widespread insurance coverage for the PreTRM test. Contemporaneously with the consulting agreement, Blue Ox participated in the initial closing of the Series D Convertible Preferred Stock financing in July 2019. In October 2021, the Company entered into an additional consulting agreement with Blue Ox to advise the Company on development of strategies with the goal of increasing Medicaid coverage of the PreTRM test. Payments for this additional consulting agreement are based on the achievement of specific milestones. The Company paid fees related to these consulting agreements of $0.4 million and $0.1 million for the three months ended March 31, 2022 and 2021, respectively. In June 2019, the Company entered into a master services agreement with Healthcore Inc., a wholly-owned subsidiary of Anthem, Inc. (“Anthem”). This agreement covers a range of research projects, including Healthcore’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 $0.7 million and $0.2 million for the three months ended March 31, 2022 and 2021, respectively. In November 2020, the Company entered into a Laboratory Services Agreement with Anthem 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 $19 thousand and $9 thousand for the three months ended March 31, 2022 and 2021, respectively. In February 2021, the Company entered into a Commercial Collaboration Agreement with Anthem 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 Anthem’s network of covered members. Pursuant to the Commercial Collaboration Agreement, Anthem will purchase a certain minimum number of tests for each of the first three years of the term of the Commercial Collaboration Agreement. Additionally, Anthem has 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 $3.1 million during the three months ended March 31, 2022, which amount related to the minimum payments for the year ended December 31, 2021. Such minimum payments were initially recorded as deferred revenue at December 31, 2021. Deferred revenue is recognized as revenue when the Company delivers PreTRM test results to Anthem patients pursuant to the Commercial Collaboration Agreement. There were no cash receipts related to the Commercial Collaboration Agreement for the three months ended March 31, 2021. The Company has 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 Anthem. The Company and Anthem have agreed to form a Joint Operating Committee to oversee the relationship, comprised of two voting members each from Anthem and the Company. The Company will submit monthly invoices to Anthem for the sale of the PreTRM test at the negotiated rates. Anthem has been participating in the Company’s PRIME study and at the conclusion of the PRIME study, under the Commercial Collaboration Agreement, the parties have agreed to use commercially reasonable efforts to enter into Anthem'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 Anthem has purchased a fixed number of PreTRM tests as agreed by the parties. The Commercial Collaboration Agreement with Anthem 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 Anthem 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 Anthem are immaterial in the context of the Commercial Collaboration Agreement. There were no material revenues related to the Commercial Collaboration Agreement for the three months ended March 31, 2022 and 2021.

Capital Structure

Capital Structure	3 Months Ended
	Mar. 31, 2022
Stockholders' Equity Note [Abstract]
Capital Structure	Capital StructureOn July 19, 2021, the Company completed its IPO and issued 4,687,500 shares of its Class A common stock at a price of $16.00 per share for net proceeds of approximately $66.6 million, after deducting underwriting discounts and commissions and offering expenses payable by the Company. In connection with the IPO, all shares of convertible preferred stock converted into 22,434,130 shares of Class A common stock and 1,405,259 shares of Class B common stock. 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. The following shares of Class A common stock were reserved for future issuance: March 31, December 31, 2021 Warrants to purchase Class A common stock 2,788,484 2,788,484 Options to purchase Class A common stock 8,016,915 6,287,126 Class A common stock available for future grants under the 2021 Equity Incentive Plan 2,458,235 3,136,737 Class A common stock available for future grants under the 2021 Employee Stock Purchase Plan 598,777 305,089 Total 13,862,411 12,517,436 As of December 31, 2021, all deferred offering costs related to the Company's IPO, totaling $3.1 million, had been reclassified to additional paid-in capital. Convertible Preferred Stock In connection with the IPO, all shares of convertible preferred stock converted into 22,434,130 shares of Class A common stock and 1,405,259 shares of Class B common stock. No new convertible preferred stock has been issued or authorized since the IPO, and as such, there was no convertible preferred stock outstanding as of March 31, 2022 and December 31, 2021. In connection with various preferred stock financings, the Company issued warrants to purchase common stock and warrants to purchase preferred stock. See Note 12 — Warrants for additional details.

Stock-Based Compensation

Stock-Based Compensation	3 Months Ended
	Mar. 31, 2022
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 restricted stock to employees, directors, and consultants of the Company. Options and restricted stock generally vest over a four-year period and options generally expire ten years from the date of grant. Options are exercisable only to the extent vested. 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 March 31, 2022, there were 2,458,235 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 March 31, 2022, no shares had been granted 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, 2021 6,287,126 $ 4.36 7.8 $ 20,095 Granted 1,918,637 4.30 Expired — — Cancelled (65,381) 6.94 Exercised (123,467) 0.80 Outstanding — March 31, 2022 8,016,915 $ 4.38 8.2 $ 7,047 Vested and expected to vest at March 31, 2022 7,488,330 $ 4.30 8.1 $ 6,931 Vested and exercisable at March 31, 2022 2,967,940 $ 2.51 6.4 $ 5,135 The following table presents the impact of stock-based compensation expense in the statements of operations for the periods indicated (in thousands): Three Months Ended 2022 2021 Research and development expense $ 383 $ 64 Sales and marketing expense 313 62 General and administrative expense 526 113 Total employee stock-based compensation $ 1,222 $ 239 At March 31, 2022, there was $15.3 million of unrecognized stock-based compensation cost related to unvested stock options, which is expected to be recognized over a weighted average period of 3.1 years.

Warrants

Warrants	3 Months Ended
	Mar. 31, 2022
Warrants and Rights Note Disclosure [Abstract]
Warrants	Warrants Warrants to purchase common stock 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 March 31, 2022 December 31, 2021 $ 5.20 15,979 15,979 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 2,788,484 2,788,484 There was no common stock warrant activity for the three months ended March 31, 2022. Warrants to purchase preferred stock Concurrent with the Company's IPO, all outstanding preferred stock warrants were converted to an equal number of Class A common stock warrants. Immediately prior to the conversion, the Company adjusted the preferred stock warrant liability to fair value. See Note 8—Fair Value Measurements. The fair value of the preferred stock warrant liability was then reclassified to equity upon conversion to common stock warrants. As such, there were no outstanding warrants to purchase convertible preferred stock as of March 31, 2022 and December 31, 2021, and no corresponding preferred stock warrant liability. In connection with the issuance of Series D Convertible Preferred Stock, the Company issued warrants to purchase shares of Series D Convertible Preferred Stock. These warrants were exercisable for cash immediately when granted, and had a ten-year expiration. The initial fair value of these warrants was calculated using the Black-Scholes option pricing model and recorded as a reduction to additional paid-in capital and a corresponding preferred stock warrant liability. During each reporting period in which this warrant liability was outstanding, any changes in the fair value of this warrant liability were recorded in other income (expense), net. Total adjustments to the fair value of this warrant liability resulted in other expense of $10 thousand during the three months ended March 31, 2021. No adjustments were required during the three months ended March 31, 2022 as this warrant liability was no longer outstanding.

Commitments and Contingences

Commitments and Contingences	3 Months Ended
	Mar. 31, 2022
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 significant 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 March 31, 2022 (in thousands): Lease-Related Assets and Liabilities Financial Statement Line Items March 31, 2022 Right-of-use assets: Operating leases Other assets $ 342 Finance leases Property and equipment, net 1,188 Total right-of-use assets $ 1,530 Lease liabilities: Operating leases Accrued and other current liabilities $ 446 Finance leases Finance lease obligation, current portion 351 Finance lease obligation, net of current portion 718 Total lease liabilities $ 1,515 Lease costs and other information consisted of the following (in thousands, except terms and rates): Three Months Ended March 31, 2022 Lease cost Finance lease cost: Amortization of right-of-use assets $ 16 Interest on lease liabilities 4 Operating lease cost 116 Total lease cost $ 136 Other information Finance leases: Operating cash outflows $ 2 Financing cash outflows $ 18 Right-of-use assets obtained in exchange for lease liabilities $ 958 Weighted-average remaining lease term (in years) 2.9 Weighted-average discount rate 6.3% Operating leases: Operating cash outflows $ 151 Right-of-use assets obtained in exchange for lease liabilities $ 453 Weighted-average remaining lease term (in years) 0.8 Weighted-average discount rate 4.5% Future minimum lease payments for the Company's leases as of March 31, 2022 were as follows (in thousands): Operating Leases Finance Leases Total 2022 $ 453 $ 295 $ 748 2023 — 407 407 2024 — 351 351 2025 — 117 117 2026 and thereafter — — — Total minimum lease payments 453 1,170 1,623 Less: imputed interest (7) (101) (108) Present value of future lease payments 446 1,069 1,515 Less: current portion 446 351 797 Long-term portion $ — $ 718 $ 718 Operating Leases The Company leases a total of approximately 24,100 square feet of office and laboratory space under a single non-cancelable operating lease with a termination date of December 31, 2022. Under the terms of the lease agreement, the Company has an option to renew the lease for one additional five-year rental period, which the Company is not reasonably certain it will exercise. The Company includes lease extension options in the right-of-use asset and lease liability when the Company is reasonably certain it will exercise the options. The rate implicit 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 March 31, 2022 and December 31, 2021. 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.

Net Loss Per Share

Net Loss Per Share	3 Months Ended
	Mar. 31, 2022
Earnings Per Share [Abstract]
Net Loss Per Share	Net loss per share For the three months ended March 31, 2022, the Company calculated 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 three months ended March 31, 2022, the Company reported a net loss and as such, basic and diluted net loss per share are the same. 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 three months ended March 31, 2022. The Company issued certain shares of convertible preferred stock that were outstanding until the Company's IPO and were concluded to be participating securities. For the three months ended March 31, 2021, there was only one class of common stock outstanding. Due to the presence of participating securities, the Company calculated net loss per share for the three months ending March 31, 2021 using the more dilutive of the treasury stock or the two-class method. For periods presented in which the Company reports a net loss, the losses are not allocated to the participating securities. As the Company reported a net loss during the three months ending March 31, 2021, diluted net loss per share was the same as basic net loss per share, since dilutive common shares are not assumed to have been issued if their effect is anti-dilutive. The preferred stock converted to common stock in July 2021 as part of the Company's IPO. See Note 10—Capital Structure for additional details. The following table sets forth the computation of basic and diluted net loss per share of Class A and Class B common stock during 2022 (in thousands, except share and per share amounts): Three Months Ended Class A Class B Net loss $ (11,651) $ (557) Weighted average common stock outstanding, basic and diluted 29,396,320 1,405,259 Net loss per share — basic and diluted $ (0.40) $ (0.40) The following table sets forth the computation of the basic and diluted net loss per share during 2021 (in thousands, except share and per share amounts): Three Months Ended Net loss $ (6,359) Weighted average common stock outstanding, basic and diluted 1,791,841 Net loss per share — basic and diluted $ (3.55) 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: March 31, 2022 2021 Junior convertible preferred stock — 9,819,480 Senior convertible preferred stock — 10,675,922 Warrants to purchase convertible preferred stock — 81,543 Warrants to purchase Class A common stock 2,788,484 2,741,813 Options to purchase Class A common stock 8,016,915 4,958,194 Total 10,805,399 28,276,952

Significant Accounting Polici_2

Significant Accounting Policies (Policies)	3 Months Ended
	Mar. 31, 2022
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The accompanying unaudited condensed financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (“U.S. GAAP”) and applicable rules and regulations of the U.S. Securities and Exchange Commission (the "SEC") regarding interim financial reporting. Certain information and note disclosures normally included in the financial statements prepared in accordance with U.S. GAAP have been condensed or omitted pursuant to such rules and regulations. As such, these unaudited condensed financial statements should be read in conjunction with the audited financial statements and accompanying notes included in the Company's Annual Report on Form 10-K for the year ended December 31, 2021. The unaudited interim condensed financial statements have been prepared on a basis consistent with the audited annual financial statements as of and for the year ended December 31, 2021, and, in the opinion of the Company’s management, reflect all adjustments, consisting solely of normal recurring adjustments, necessary for the fair presentation of the Company’s financial results. The balance sheet as of December 31, 2021 has been derived from the audited financial statements at that date but does not include all information and footnotes required by GAAP for complete financial statements. The results of the three months ended March 31, 2022 are not necessarily indicative of the results to be expected for the full year ending December 31, 2022, or any other period. 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”).
Reverse Stock Split	Reverse Stock Split On June 30, 2021, the Company’s board of directors (the “Board of Directors”) approved a 1-for-2.079 reverse stock split of the Company’s common stock and redeemable convertible preferred stock, which was effective by amendment to the Company’s charter on July 7, 2021. The par value and authorized shares of the common stock and redeemable convertible preferred stock were not adjusted as a result of the reverse stock split. All issued and outstanding common stock, warrants, options to purchase common stock and per share amounts contained in the financial statements have been retroactively adjusted to give effect to the reverse stock split for all periods presented.
Leases	Leases The Company adopted ASU 2016-02, Leases, ("Topic 842") and its subsequent updates effective January 1, 2022. The Company adopted Topic 842 using a modified retrospective method. As such, comparative periods ending prior to January 1, 2022 are presented in accordance with ASC 840, Leases , and periods ending after January 1, 2022 are presented in accordance with Topic 842. There was no impact to the Company's accumulated deficit as a result of adopting Topic 842. The Company used the package of practical expedients permitted under Topic 842. As a result, the Company did not reassess its lease population, classifications of existing leases, or initial direct costs of existing leases as of the adoption date. 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. The Company also elected not to separate lease components from non-lease components for all classes of leased assets except for building leases. The adoption of Topic 842 resulted in a right-of-use asset of $0.5 million related to the Company's operating lease being recognized in other assets on the condensed balance sheets as of January 1, 2022. A corresponding lease liability of $0.6 million related to the Company's operating lease was recognized in accrued and other liabilities on the condensed balance sheets as of January 1, 2022. In addition, at January 1, 2022, approximately $0.1 million of lease-related liabilities were removed from deferred rent, current portion as a reduction to the initial operating lease right-of-use asset.
Use of Estimates	Use of Estimates The preparation of the condensed 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 condensed 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 COVID-19 pandemic and the evolving actions of governments, private sector participants and the public in an effort to contain the spread of the COVID-19 virus and address its impacts have intensified and have had significant direct and indirect effects on businesses and commerce. The extent to which the COVID-19 pandemic may impact the Company’s business, financial condition, cash flows, and results of operations, in particular, will depend on future developments that are highly uncertain, many of which are outside the Company’s control. Such developments include the availability and effectiveness of actions taken to contain or treat COVID-19, the ultimate geographic spread and duration of the pandemic, the extent and duration of a resurgence of the COVID-19 virus and variant strains thereof, new information concerning the severity of the COVID-19 virus, the effectiveness and intensity of measures to contain the COVID-19 virus and the economic impact of the pandemic and the reactions to it. Such developments, among others, depending on their nature, duration, and intensity, could have a significant adverse effect on the Company’s business, financial condition, cash flows, and results of operations. There were no significant estimates contained in the preparation of the Company’s condensed financial statements or impacts to the Company’s condensed financial statements for the three months ended March 31, 2022 that were a direct result of the COVID-19 pandemic. 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 the condensed financial statements.
Recently Issued Accounting Pronouncements Not Yet Adopted	Recently Issued Accounting Pronouncements Not Yet Adopted In June 2016, the FASB issued ASU 2016-13, Financial Instruments—Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments. The objective of the standard is to provide information about expected credit losses on financial instruments at each reporting date and to change how other-than-temporary impairments on investment securities are recorded. The Company is currently an emerging growth company and has elected to use the extended transition period for complying with new or revised accounting standards that have different effective dates for public and private companies. As such, the guidance is effective for the Company beginning on January 1, 2023, with early adoption permitted. The Company is currently evaluating the impact the standard may have on its financial statements and related disclosures. Other recent accounting pronouncements issued by the FASB (including its Emerging Issues Task Force) and the SEC did not, or are not believed by the Company’s management to, have a material impact on the Company’s financial position, results of operations or cash flows.

Cash, Cash Equivalents and Ma_2

Cash, Cash Equivalents and Marketable Securities (Tables)	3 Months Ended
	Mar. 31, 2022
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 March 31, 2022 and December 31, 2021 were as follows (in thousands): March 31, 2022 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Cash and cash equivalents: Cash $ 133 $ — $ — $ 133 Money market funds 2,342 — — 2,342 Commercial paper 61,610 — (5) 61,605 Total cash and cash equivalents 64,085 — (5) 64,080 Current marketable securities: Commercial paper 30,051 2 (69) 29,984 Corporate debt securities 1,962 — (15) 1,947 U.S. federal agency securities 7,687 — (94) 7,593 U.S. government securities 3,996 — (53) 3,943 Total current marketable securities 43,696 2 (231) 43,467 Long-term marketable securities: U.S. federal agency securities 18,060 — (322) 17,738 U.S. government securities 4,699 — (100) 4,599 Total long-term marketable securities 22,759 — (422) 22,337 Total cash, cash equivalents and marketable securities $ 130,540 $ 2 $ (658) $ 129,884 December 31, 2021 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Cash and cash equivalents: Cash $ 70 $ — $ — $ 70 Money market funds 4,021 — — 4,021 Commercial paper 54,843 — (2) 54,841 Total cash and cash equivalents 58,934 — (2) 58,932 Current marketable securities: Commercial paper 39,696 — (24) 39,672 Corporate debt securities 6,515 — (4) 6,511 Total current marketable securities 46,211 — (28) 46,183 Long-term marketable securities: U.S. federal agency securities 25,787 — (112) 25,675 U.S. government securities 8,694 — (38) 8,656 Corporate debt securities 520 — (3) 517 Total long-term marketable securities 35,001 — (153) 34,848 Total cash, cash equivalents and marketable securities $ 140,146 $ — $ (183) $ 139,963
Schedule of Marketable Securities Classified by Contractual Maturities	The Company's marketable securities classified by contractual maturities as of March 31, 2022 were as follows (in thousands): Amortized Cost Fair Value Due within one year $ 43,696 $ 43,467 Due after one year through five years 22,759 22,337 Total $ 66,455 $ 65,804

Property and Equipment (Tables)

Property and Equipment (Tables)	3 Months Ended
	Mar. 31, 2022
Property, Plant and Equipment [Abstract]
Schedule of Components of Property and Equipment, Net	The following table presents the components of property and equipment, net, as of March 31, 2022 and December 31, 2021 (in thousands): March 31, December 31, Laboratory equipment $ 5,991 $ 5,033 Computer equipment 1,217 1,212 Leasehold improvements 710 710 Software 465 465 Furniture and fixtures 320 320 Total property and equipment 8,703 7,740 Less accumulated depreciation and amortization (6,132) (5,967) Property and equipment, net $ 2,571 $ 1,773

Accrued and Other Current Lia_2

Accrued and Other Current Liabilities (Tables)	3 Months Ended
	Mar. 31, 2022
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 March 31, 2022 and December 31, 2021 (in thousands): March 31, December 31, Accrued compensation $ 954 $ 2,498 Accrued paid time off 607 460 Operating lease liability, current portion 446 — Other current liabilities 529 927 Total accrued and other current liabilities $ 2,536 $ 3,885

Other Income (Expense), net (Ta

Other Income (Expense), net (Tables)	3 Months Ended
	Mar. 31, 2022
Other Income and Expenses [Abstract]
Schedule of Components of Other Income (Expense), Net	The following table presents the components of other income (expense), net, for the three months ended March 31, 2022 and 2021 (in thousands): Three Months Ended 2022 2021 Interest income $ 78 $ 2 Fair value remeasurements — (10) Other gains (losses), net 18 (19) Other income (expense), net $ 96 $ (27)

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	3 Months Ended
	Mar. 31, 2022
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 March 31, 2022: Level 1 Level 2 Level 3 Assets: Cash equivalents: Money market funds $ 2,342 $ — $ — Commercial paper — 61,605 — Marketable securities: Commercial paper — 29,984 — Corporate debt securities — 1,947 — U.S. federal agency securities — 25,331 — U.S. government securities — 8,542 — Total assets $ 2,342 $ 127,409 $ — 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, 2021: Level 1 Level 2 Level 3 Assets: Cash equivalents: Money market funds $ 4,021 $ — $ — Commercial paper — 54,841 — Marketable securities: Commercial paper — 39,672 — Corporate debt securities — 7,028 — U.S. federal agency securities — 25,675 — U.S. government securities — 8,656 — Total assets $ 4,021 $ 135,872 $ —

Capital Structure (Tables)

Capital Structure (Tables)	3 Months Ended
	Mar. 31, 2022
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: March 31, December 31, 2021 Warrants to purchase Class A common stock 2,788,484 2,788,484 Options to purchase Class A common stock 8,016,915 6,287,126 Class A common stock available for future grants under the 2021 Equity Incentive Plan 2,458,235 3,136,737 Class A common stock available for future grants under the 2021 Employee Stock Purchase Plan 598,777 305,089 Total 13,862,411 12,517,436

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	3 Months Ended
	Mar. 31, 2022
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, 2021 6,287,126 $ 4.36 7.8 $ 20,095 Granted 1,918,637 4.30 Expired — — Cancelled (65,381) 6.94 Exercised (123,467) 0.80 Outstanding — March 31, 2022 8,016,915 $ 4.38 8.2 $ 7,047 Vested and expected to vest at March 31, 2022 7,488,330 $ 4.30 8.1 $ 6,931 Vested and exercisable at March 31, 2022 2,967,940 $ 2.51 6.4 $ 5,135
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): Three Months Ended 2022 2021 Research and development expense $ 383 $ 64 Sales and marketing expense 313 62 General and administrative expense 526 113 Total employee stock-based compensation $ 1,222 $ 239

Warrants (Tables)

Warrants (Tables)	3 Months Ended
	Mar. 31, 2022
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 March 31, 2022 December 31, 2021 $ 5.20 15,979 15,979 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 2,788,484 2,788,484

Commitment and Contingencies (T

Commitment and Contingencies (Tables)	3 Months Ended
	Mar. 31, 2022
Commitments and Contingencies Disclosure [Abstract]
Schedule of Leases in Financial Statement	The following table shows right-of-use assets and lease liabilities, and the associated financial statement line items as of March 31, 2022 (in thousands): Lease-Related Assets and Liabilities Financial Statement Line Items March 31, 2022 Right-of-use assets: Operating leases Other assets $ 342 Finance leases Property and equipment, net 1,188 Total right-of-use assets $ 1,530 Lease liabilities: Operating leases Accrued and other current liabilities $ 446 Finance leases Finance lease obligation, current portion 351 Finance lease obligation, net of current portion 718 Total lease liabilities $ 1,515
Schedule of Lease Cost and Other Information	Lease costs and other information consisted of the following (in thousands, except terms and rates): Three Months Ended March 31, 2022 Lease cost Finance lease cost: Amortization of right-of-use assets $ 16 Interest on lease liabilities 4 Operating lease cost 116 Total lease cost $ 136 Other information Finance leases: Operating cash outflows $ 2 Financing cash outflows $ 18 Right-of-use assets obtained in exchange for lease liabilities $ 958 Weighted-average remaining lease term (in years) 2.9 Weighted-average discount rate 6.3% Operating leases: Operating cash outflows $ 151 Right-of-use assets obtained in exchange for lease liabilities $ 453 Weighted-average remaining lease term (in years) 0.8 Weighted-average discount rate 4.5%
Schedule of Future Minimum Lease Payments	Future minimum lease payments for the Company's leases as of March 31, 2022 were as follows (in thousands): Operating Leases Finance Leases Total 2022 $ 453 $ 295 $ 748 2023 — 407 407 2024 — 351 351 2025 — 117 117 2026 and thereafter — — — Total minimum lease payments 453 1,170 1,623 Less: imputed interest (7) (101) (108) Present value of future lease payments 446 1,069 1,515 Less: current portion 446 351 797 Long-term portion $ — $ 718 $ 718
Schedule of Future Minimum Lease Payments	Future minimum lease payments for the Company's leases as of March 31, 2022 were as follows (in thousands): Operating Leases Finance Leases Total 2022 $ 453 $ 295 $ 748 2023 — 407 407 2024 — 351 351 2025 — 117 117 2026 and thereafter — — — Total minimum lease payments 453 1,170 1,623 Less: imputed interest (7) (101) (108) Present value of future lease payments 446 1,069 1,515 Less: current portion 446 351 797 Long-term portion $ — $ 718 $ 718

Net Loss Per Share (Tables)

Net Loss Per Share (Tables)	3 Months Ended
	Mar. 31, 2022
Earnings Per Share [Abstract]
Schedule of Computation of Basic and Diluted Net Loss per Share	The following table sets forth the computation of basic and diluted net loss per share of Class A and Class B common stock during 2022 (in thousands, except share and per share amounts): Three Months Ended Class A Class B Net loss $ (11,651) $ (557) Weighted average common stock outstanding, basic and diluted 29,396,320 1,405,259 Net loss per share — basic and diluted $ (0.40) $ (0.40) The following table sets forth the computation of the basic and diluted net loss per share during 2021 (in thousands, except share and per share amounts): Three Months Ended Net loss $ (6,359) Weighted average common stock outstanding, basic and diluted 1,791,841 Net loss per share — basic and diluted $ (3.55)
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: March 31, 2022 2021 Junior convertible preferred stock — 9,819,480 Senior convertible preferred stock — 10,675,922 Warrants to purchase convertible preferred stock — 81,543 Warrants to purchase Class A common stock 2,788,484 2,741,813 Options to purchase Class A common stock 8,016,915 4,958,194 Total 10,805,399 28,276,952

Description of Business and F_2

Description of Business and Financial Condition (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Accumulated deficit	$ (178,676)	$ (166,468)
Cash and cash equivalents	64,080	$ 58,932
Available-for-sale securities	$ 65,804

Significant Accounting Polici_3

Significant Accounting Policies (Details) $ in Thousands	Jul. 07, 2021	Mar. 31, 2022USD ($)	Jan. 01, 2022USD ($)
Lessee, Lease, Description [Line Items]
Reverse stock split conversion ratio	0.481000
Right-of-use assets		$ 342
Lease liability		$ 446
Accounting Standards Update 2016-02
Lessee, Lease, Description [Line Items]
Right-of-use assets			$ 500
Lease liability			600
Lease-related liabilities removed from deferred rent			$ 100

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	Mar. 31, 2022	Dec. 31, 2021
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	$ 66,455
Fair Value	65,804
Amortized Cost	130,540	$ 140,146
Gross Unrealized Gains	2	0
Gross Unrealized Losses	(658)	(183)
Fair Value	129,884	139,963
Cash and cash equivalents:
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	64,085	58,934
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(5)	(2)
Cash equivalents:	64,080	58,932
Cash and cash equivalents: | Cash
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	133	70
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Cash equivalents:	133	70
Cash and cash equivalents: | Money market funds
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	2,342	4,021
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Cash equivalents:	2,342	4,021
Cash and cash equivalents: | Commercial paper
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	61,610	54,843
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(5)	(2)
Cash equivalents:	61,605	54,841
Current marketable securities:
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	43,696	46,211
Gross Unrealized Gains	2	0
Gross Unrealized Losses	(231)	(28)
Fair Value	43,467	46,183
Current marketable securities: | Commercial paper
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	30,051	39,696
Gross Unrealized Gains	2	0
Gross Unrealized Losses	(69)	(24)
Fair Value	29,984	39,672
Current marketable securities: | Corporate debt securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	1,962	6,515
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(15)	(4)
Fair Value	1,947	6,511
Current marketable securities: | U.S. federal agency securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	7,687
Gross Unrealized Gains	0
Gross Unrealized Losses	(94)
Fair Value	7,593
Current marketable securities: | U.S. government securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	3,996
Gross Unrealized Gains	0
Gross Unrealized Losses	(53)
Fair Value	3,943
Long-term marketable securities:
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	22,759	35,001
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(422)	(153)
Fair Value	22,337	34,848
Long-term marketable securities: | Corporate debt securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost		520
Gross Unrealized Gains		0
Gross Unrealized Losses		(3)
Fair Value		517
Long-term marketable securities: | U.S. federal agency securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	18,060	25,787
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(322)	(112)
Fair Value	17,738	25,675
Long-term marketable securities: | U.S. government securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	4,699	8,694
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(100)	(38)
Fair Value	$ 4,599	$ 8,656

Cash, Cash Equivalents and Ma_4

Cash, Cash Equivalents and Marketable Securities - Narrative (Details) - USD ($)	Mar. 31, 2022	Dec. 31, 2021
Cash and Cash Equivalents [Abstract]
Debt securities, available-for-sale, continuous unrealized loss position, 12 months or longer	$ 0	$ 0
Debt securities, available-for-sale, other than temporary impairment	$ 0	$ 0

Cash, Cash Equivalents and Ma_5

Cash, Cash Equivalents and Marketable Securities - Marketable Securities Classified by Contractual Maturities (Details) $ in Thousands	Mar. 31, 2022USD ($)
Amortized Cost
Due within one year	$ 43,696
Due after one year through five years	22,759
Amortized Cost	66,455
Fair Value
Due within one year	43,467
Due after one year through five years	22,337
Fair Value	$ 65,804

Property and Equipment - Compon

Property and Equipment - Components of Property and Equipment, Net (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Property, Plant and Equipment [Line Items]
Property, plant, and equipment and finance lease right-of-use asset, gross	$ 8,703	$ 7,740
Less accumulated depreciation and amortization	(6,132)	(5,967)
Property, plant, and equipment and finance lease right-of-use asset, net	2,571	1,773
Laboratory equipment
Property, Plant and Equipment [Line Items]
Property, plant, and equipment and finance lease right-of-use asset, gross	5,991	5,033
Computer equipment
Property, Plant and Equipment [Line Items]
Property, plant, and equipment and finance lease right-of-use asset, gross	1,217	1,212
Leasehold improvements
Property, Plant and Equipment [Line Items]
Property, plant, and equipment and finance lease right-of-use asset, gross	710	710
Software
Property, Plant and Equipment [Line Items]
Property, plant, and equipment and finance lease right-of-use asset, gross	465	465
Furniture and fixtures
Property, Plant and Equipment [Line Items]
Property, plant, and equipment and finance lease right-of-use asset, gross	$ 320	$ 320

Property and Equipment - Narrat

Property and Equipment - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Property, Plant and Equipment [Abstract]
Depreciation and amortization	$ 165	$ 201

Accrued and Other Current Lia_3

Accrued and Other Current Liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Accounts Payable and Accrued Liabilities, Current [Abstract]
Accrued compensation	$ 954	$ 2,498
Accrued paid time off	607	460
Operating lease liability, current portion	446	0
Other current liabilities	529	927
Total accrued and other current liabilities	$ 2,536	$ 3,885

Other Income (Expense), net (De

Other Income (Expense), net (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Other Income and Expenses [Abstract]
Interest income	$ 78	$ 2
Fair value remeasurements	0	(10)
Other gains (losses), net	18	(19)
Other income (expense), net	$ 96	$ (27)

Loans and Convertible Promiss_2

Loans and Convertible Promissory Notes - Bank Loan (Details) - Loan and Security Agreement - USD ($) $ in Thousands	1 Months Ended	12 Months Ended
	Mar. 31, 2021	Dec. 31, 2014
Debt Instrument [Line Items]
Term loan		$ 10,000
Long term debt, Interest rate		4.75%
Percentage of amount borrowed from bank loan		1.00%
Final payment fee	$ 100	$ 100
Repayment of outstanding principal	2,000
Repayment of accrued interest	$ 6
Prime Rate
Debt Instrument [Line Items]
Long term debt, spread on base interest rate		1.00%

Loans and Convertible Promiss_3

Loans and Convertible Promissory Notes - Convertible Promissory Notes (Details) - February 2019 Convertible Note $ / shares in Units, $ in Millions	Mar. 24, 2021USD ($)	Jul. 31, 2019USD ($)shares	Feb. 28, 2019USD ($)$ / shares	Mar. 31, 2021USD ($)
Debt Instrument [Line Items]
Aggregate principal amount			$ 6.4
Debt instrument, stated interest rate			12.00%
Debt instrument, convertible, conversion price (in usd per share) | $ / shares			$ 9.03
Liability at the measurement date fair value			$ 2.4
Accretion of discount				$ 0.1
Repayment of outstanding principal	$ 4.5
Repayment of accrued interest	$ 1.1
Series D Convertible Preferred Stock
Debt Instrument [Line Items]
Debt instrument, conversion price percentage			0.80
Amount of original debt converted		$ 1.9
Interest expense		$ 0.1
Debt conversion, converted instrument, shares issued (in shares) | shares		277,507

Loans and Convertible Promiss_4

Loans and Convertible Promissory Notes - Paycheck Protection Loan (Details) - Paycheck Protection Program Loan - USD ($) $ in Millions	1 Months Ended
	Jun. 30, 2021	Apr. 30, 2020
Debt Instrument [Line Items]
Aggregate principal amount		$ 1.1
Amount of debt outstanding	$ 1.1

Fair Value Measurements - Narra

Fair Value Measurements - Narrative (Details) - shares	Mar. 31, 2022	Dec. 31, 2021
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Number of warrants outstanding (in shares)	2,788,484	2,788,484
Preferred Stock
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Number of warrants outstanding (in shares)	0	0

Fair Value Measurements - Finan

Fair Value Measurements - Financial Assets that are Measured at Fair Value on a Recurring Basis (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Assets:
Marketable securities:	$ 65,804
Level 1 | Recurring
Assets:
Total assets	2,342	$ 4,021
Level 1 | Recurring | Commercial paper
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 equivalents:	2,342	4,021
Level 1 | Recurring | Commercial paper
Assets:
Cash equivalents:	0	0
Level 2 | Recurring
Assets:
Total assets	127,409	135,872
Level 2 | Recurring | Commercial paper
Assets:
Marketable securities:	29,984	39,672
Level 2 | Recurring | Corporate debt securities
Assets:
Marketable securities:	1,947	7,028
Level 2 | Recurring | U.S. federal agency securities
Assets:
Marketable securities:	25,331	25,675
Level 2 | Recurring | U.S. government securities
Assets:
Marketable securities:	8,542	8,656
Level 2 | Recurring | Money market funds
Assets:
Cash equivalents:	0	0
Level 2 | Recurring | Commercial paper
Assets:
Cash equivalents:	61,605	54,841
Level 3 | Recurring
Assets:
Total assets	0	0
Level 3 | Recurring | Commercial paper
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 equivalents:	0	0
Level 3 | Recurring | Commercial paper
Assets:
Cash equivalents:	$ 0	$ 0

Related Party Transactions (Det

Related Party Transactions (Details)	1 Months Ended	3 Months Ended
	Feb. 28, 2021	Mar. 31, 2022USD ($)voting_member	Mar. 31, 2021USD ($)
Commercial Collaboration Agreement
Related Party Transaction [Line Items]
Number of voting members from each party | voting_member		2
Blue Ox | Consulting agreement
Related Party Transaction [Line Items]
Fees paid		$ 400,000	$ 100,000
Healthcore Inc | Master services agreement
Related Party Transaction [Line Items]
Fees paid		700,000	200,000
Anthem | Laboratory Services Agreement
Related Party Transaction [Line Items]
Recognized revenue		19,000	9,000
Anthem | Commercial Collaboration Agreement
Related Party Transaction [Line Items]
Term of agreement	3 years
Cash receipts		$ 3,100,000	$ 0

Capital Structure - Narrative (

Capital Structure - Narrative (Details) $ / shares in Units, $ in Millions	Jul. 19, 2021USD ($)$ / sharesshares	Mar. 31, 2022common_stock_classvoteshares	Dec. 31, 2021USD ($)shares	Jul. 20, 2021shares
Class of Stock [Line Items]
Number of common stock classes authorized | common_stock_class		2
Common stock, conversion ratio		1
Deferred offering costs related to an equity offering | $			$ 3.1
Initial Public Offering
Class of Stock [Line Items]
Issue price per share (in usd per share) | $ / shares	$ 16
Net proceeds from issuance of common stock | $	$ 66.6
Class A common stock
Class of Stock [Line Items]
Common stock issued from conversion of convertible securities (in shares)	22,434,130
Number of votes per share | vote		1
Class A common stock | Initial Public Offering
Class of Stock [Line Items]
Number of shares of common stock issued (in shares)	4,687,500
Class B common stock
Class of Stock [Line Items]
Common stock issued from conversion of convertible securities (in shares)	1,405,259
Convertible Preferred Stock
Class of Stock [Line Items]
Preferred stock issued (in shares)				0
Preferred stock, additional shares authorized (in shares)		0
Preferred stock outstanding (in shares)		0	0

Capital Structure - Common Stoc

Capital Structure - Common Stock (Details) - Class A common stock - shares	Mar. 31, 2022	Dec. 31, 2021
Class of Stock [Line Items]
Shares reserved for future issuance (in shares)	13,862,411	12,517,436
Warrants to purchase Class A common stock
Class of Stock [Line Items]
Shares reserved for future issuance (in shares)	2,788,484	2,788,484
Options to purchase Class A common stock
Class of Stock [Line Items]
Shares reserved for future issuance (in shares)	8,016,915	6,287,126
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)	2,458,235	3,136,737
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)	598,777	305,089

Stock-Based Compensation - Narr

Stock-Based Compensation - Narrative (Details) - USD ($) $ in Millions	1 Months Ended	3 Months Ended
	Nov. 30, 2011	Mar. 31, 2022	Dec. 31, 2021
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unamortized stock-based compensation cost		$ 15.3
Unamortized stock-based compensation cost expected to be recognized over a weighted average period		3 years 1 month 6 days
Class A common stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares available for future issuance (in shares)		13,862,411	12,517,436
2011 Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	4 years
Expiration term	10 years
2021 Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	4 years
Expiration term	10 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)		2,458,235
2021 ESPP
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares granted (in shares)		0

Stock-Based Compensation - Stoc

Stock-Based Compensation - Stock Options (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2022	Dec. 31, 2021
Number of Shares Subject to Options Outstanding
Outstanding at the beginning (in shares)	6,287,126
Granted (in shares)	1,918,637
Expired (in shares)	0
Cancelled (in shares)	(65,381)
Exercised (in shares)	(123,467)
Outstanding at the end (in shares)	8,016,915	6,287,126
Number of shares subject to options outstanding, vested and expected to vest at the end (in shares)	7,488,330
Number of shares subject to options outstanding, vested and exercisable at the end	2,967,940
Weighted- Average Exercise Price Per Share
Outstanding at the beginning (in usd per share)	$ 4.36
Granted (in usd per share)	4.30
Expired (in usd per share)	0
Cancelled (in usd per share)	6.94
Exercised (in usd per share)	0.80
Outstanding at the end (in usd per share)	4.38	$ 4.36
Weighted average exercise price per share, vested and expected to vest at the end (in usd per share)	4.30
Weighted average exercise price per share, vested and exercisable at the end (in usd per share)	$ 2.51
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Weighted average remaining contractual life, outstanding	8 years 2 months 12 days	7 years 9 months 18 days
Weighted average remaining contractual life, vested and expected to vest at the end	8 years 1 month 6 days
Weighted average remaining contractual life, vested and exercisable at the end	6 years 4 months 24 days
Aggregate intrinsic value, outstanding	$ 7,047	$ 20,095
Aggregate intrinsic value, vested and expected to vest at the end	6,931
Aggregate intrinsic value, vested and exercisable at the end	$ 5,135

Stock-Based Compensation - Expe

Stock-Based Compensation - Expense (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total employee stock-based compensation	$ 1,222	$ 239
Research and development expense
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total employee stock-based compensation	383	64
Sales and marketing expense
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total employee stock-based compensation	313	62
General and administrative expense
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total employee stock-based compensation	$ 526	$ 113

Warrants - Common Stock Warrant

Warrants - Common Stock Warrants Outstanding (Details) - $ / shares	Mar. 31, 2022	Dec. 31, 2021
Class of Warrant or Right [Line Items]
Number of warrants outstanding (in shares)	2,788,484	2,788,484
5.20
Class of Warrant or Right [Line Items]
Exercise price (in usd per share)	$ 5.20
Number of warrants outstanding (in shares)	15,979	15,979
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

Warrants - Narrative (Details)

Warrants - Narrative (Details) - USD ($)	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2021
Class of Warrant or Right [Line Items]
Warrants outstanding	$ 0		$ 0
Other expense	96,000	$ (27,000)
Interest expense	$ 4,000	307,000
2019 Warrant
Class of Warrant or Right [Line Items]
Warrant term	10 years
Warrant to purchase convertible preferred stock | Loan Agreement
Class of Warrant or Right [Line Items]
Warrant term	10 years
Interest expense	$ 0	10,000
Series D Convertible Preferred Stock | 2019 Warrant
Class of Warrant or Right [Line Items]
Other expense	$ 0	$ (10,000)

Commitments and Contingences -

Commitments and Contingences - Leases in Financial Statement (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Right-of-use assets:
Operating leases	$ 342
Finance leases	1,188
Total right-of-use assets	1,530
Lease liabilities:
Operating leases	446	$ 0
Finance lease obligation, current portion	351
Finance lease obligation, net of current portion	718
Total lease liabilities	$ 1,515
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, plant, and equipment and finance lease right-of-use asset	Property, plant, and equipment and finance lease right-of-use asset
Operating Lease, Liability, Current, Statement of Financial Position [Extensible Enumeration]	Accrued Liabilities and Other Liabilities	Accrued Liabilities and Other Liabilities

Commitments and Contingences _2

Commitments and Contingences - Lease Cost and Other Information (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Lease cost
Amortization of right-of-use assets	$ 16
Interest on lease liabilities	4
Operating lease cost	116
Total lease cost	136
Finance leases:
Operating cash outflows	2
Financing cash outflows	18	$ 17
Right-of-use assets obtained in exchange for lease liabilities	$ 958
Weighted-average remaining lease term (in years)	2 years 10 months 24 days
Weighted-average discount rate	6.30%
Operating leases:
Operating cash outflows	$ 151
Right-of-use assets obtained in exchange for lease liabilities	$ 453
Weighted-average remaining lease term (in years)	9 months 18 days
Weighted-average discount rate	4.50%

Commitments and Contingences _3

Commitments and Contingences - Future Minimum Lease Payments (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Operating Leases
2022	$ 453
2023	0
2024	0
2025	0
2026 and thereafter	0
Total minimum lease payments	453
Less: imputed interest	(7)
Present value of future lease payments	446
Less: current portion	446	$ 0
Long-term portion	0
Finance Leases
2022	295
2023	407
2024	351
2025	117
2026 and thereafter	0
Total minimum lease payments	1,170
Less: imputed interest	(101)
Present value of future lease payments	1,069
Less: current portion	351
Long-term portion	718
Total
2022	748
2023	407
2024	351
2025	117
2026 and thereafter	0
Total minimum lease payments	1,623
Less: imputed interest	(108)
Total lease liabilities	1,515
Less: current portion	797
Long-term portion	$ 718

Commitments and Contingences _4

Commitments and Contingences - Narrative (Details)	Mar. 31, 2022USD ($)ft²	Dec. 31, 2021USD ($)
Commitments And Contingencies [Line Items]
Renewal period of lease	5 years
Indemnification liability | $	$ 0	$ 0
Office and laboratory space
Commitments And Contingencies [Line Items]
Number of square feet under lease | ft²	24,100

Net Loss Per Share - Computatio

Net Loss Per Share - Computation of the Basic and Diluted Net Loss Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Impairment Effects on Earnings Per Share [Line Items]
Net loss	$ (12,208)	$ (6,359)
Weighted average common stock outstanding, basic (in shares)	30,801,579	1,791,841
Weighted average common stock outstanding, diluted (in shares)	30,801,579	1,791,841
Net loss per share — basic (in usd per share)	$ (0.40)	$ (3.55)
Net loss per share — diluted (in usd per share)	$ (0.40)	$ (3.55)
Class A common stock
Impairment Effects on Earnings Per Share [Line Items]
Net loss	$ (11,651)
Weighted average common stock outstanding, basic (in shares)	29,396,320
Weighted average common stock outstanding, diluted (in shares)	29,396,320
Net loss per share — basic (in usd per share)	$ (0.40)
Net loss per share — diluted (in usd per share)	$ (0.40)
Class B common stock
Impairment Effects on Earnings Per Share [Line Items]
Net loss	$ (557)
Weighted average common stock outstanding, basic (in shares)	1,405,259
Weighted average common stock outstanding, diluted (in shares)	1,405,259
Net loss per share — basic (in usd per share)	$ (0.40)
Net loss per share — diluted (in usd per share)	$ (0.40)

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	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from the computation of earnings per share (in shares)	10,805,399	28,276,952
Junior Convertible Preferred 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)	0	9,819,480
Senior Convertible Preferred 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)	0	10,675,922
Warrants to purchase convertible preferred 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)	0	81,543
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)	2,788,484	2,741,813
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)	8,016,915	4,958,194