Surrozen (SRZN) 10-Q 15 Nov 21 2021 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2021	Nov. 10, 2021
Document Information [Line Items]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2021
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q3
Entity Registrant Name	Surrozen, Inc./DE
Entity Central Index Key	0001824893
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	true
Entity Ex Transition Period	false
Entity Common Stock, Shares Outstanding		35,027,407
Entity Current Reporting Status	Yes
Entity Shell Company	false
Entity File Number	001-39635
Entity Tax Identification Number	98-1556622
Entity Address, Address Line One	171 Oyster Point Blvd
Entity Address, Address Line Two	Suite 400
Entity Address, City or Town	South San Francisco
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	94080
City Area Code	650
Local Phone Number	489-9000
Entity Interactive Data Current	Yes
Entity Bankruptcy Proceedings, Reporting Current	false
Entity Incorporation, State or Country Code	DE
Document Quarterly Report	true
Document Transition Report	false
Common Stock [Member]
Document Information [Line Items]
Trading Symbol	SRZN
Title of 12(b) Security	Common Stock, $0.0001 par value per share
Security Exchange Name	NASDAQ
Redeemable Warrant [Member]
Document Information [Line Items]
Trading Symbol	SRZNW
Title of 12(b) Security	Redeemable warrants, each whole warrant exercisable for one share of Common Stock
Security Exchange Name	NASDAQ

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 61,096	$ 34,982
Prepaid expenses and other current assets	3,835	1,042
Short-term investments	49,071	14,200
Total current assets	114,002	50,224
Property and equipment, net	5,194	5,836
Operating lease right-of-use assets	4,855	5,556
Long-term investments	25,255	0
Other assets	925	39
Restricted cash	405	405
Total assets	150,636	62,060
Current liabilities:
Accounts payable	1,831	1,776
Accrued liabilities	8,495	3,394
Lease liabilities, current portion	2,215	2,108
Total current liabilities	12,541	7,278
Lease liabilities, noncurrent portion	6,056	7,489
Warrant liabilities	8,308	0
Total liabilities	26,905	14,767
Commitments and contingencies (Note 6 and Note 11)
Stockholders’ equity:
Preferred stock, $0.0001 par value, 10,000,000 shares authorized; no shares issued and outstanding as of September 30, 2021 and December 31, 2020
Common stock, $0.0001 par value, 500,000,000 shares authorized as of September 30, 2021 and December 31, 2020; [35,027,407] and 18,256,628 shares issued and outstanding as of September 30, 2021 and December 31, 2020, respectively	4	2
Additional paid-in-capital	251,438	135,292
Accumulated other comprehensive loss	(16)	0
Accumulated deficit	(127,695)	(88,001)
Total stockholders' equity	123,731	47,293
Total liabilities and stockholders’ equity	$ 150,636	$ 62,060

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Unaudited) (Parenthetical) - $ / shares	Sep. 30, 2021	Dec. 31, 2020
Statement Of Financial Position [Abstract]
Preferred stock par value	$ 0.0001	$ 0.0001
Preferred Stock, Shares Authorized	10,000,000	10,000,000
Preferred Stock, Shares Issued	0	0
Preferred Stock, Shares Outstanding	0	0
Common stock par value	$ 0.0001	$ 0.0001
Common Stock, Shares Authorized	500,000,000	500,000,000
Common Stock, Shares, Issued	35,027,407	18,256,628
Common Stock, Shares, Outstanding	35,027,407	18,256,628

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations and Comprehensive Loss (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Operating expenses:
Research and development	$ 10,418	$ 6,958	$ 29,284	$ 17,034
General and administrative	3,287	1,683	10,112	4,937
Total operating expenses	13,705	8,641	39,396	21,971
Loss from operations	(13,705)	(8,641)	(39,396)	(21,971)
Interest income	14	6	30	82
Other expense, net	(328)	0	(328)	0
Net loss	(14,019)	(8,635)	(39,694)	(21,889)
Unrealized loss on marketable securities	(16)	0	(16)	0
Comprehensive loss	$ (14,035)	$ (8,635)	$ (39,710)	$ (21,889)
Net loss per share attributable to common stockholders, basic and diluted	$ (0.51)	$ (0.47)	$ (1.86)	$ (1.43)
Weighted-average shares used in computing net loss per share attributable to common stockholders, basic and diluted	27,401,956	18,507,423	21,291,480	15,261,552

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Redeemable Convertible Preferred Stock and Shareholders' Equity (Unaudited) - USD ($) $ in Thousands	Total	Previously Reported	Revision of Prior Period, Reclassification, Adjustment	Common Stock	Common StockPreviously Reported	Common StockRevision of Prior Period, Reclassification, Adjustment	Common StockPIPE Investors	Additional Paid-in Capital	Additional Paid-in CapitalPreviously Reported	Additional Paid-in CapitalRevision of Prior Period, Reclassification, Adjustment	Accumulated Other Comprehensive (Loss)	Accumulated Other Comprehensive (Loss)Previously Reported	Accumulated Other Comprehensive (Loss)Revision of Prior Period, Reclassification, Adjustment	Accumulated Deficit	Accumulated DeficitPreviously Reported	Accumulated DeficitRevision of Prior Period, Reclassification, Adjustment	Redeemable Convertible Preferred Stock	Redeemable Convertible Preferred StockPreviously Reported	Redeemable Convertible Preferred StockRevision of Prior Period, Reclassification, Adjustment	Series C Redeemable Convertible Preferred Stock	Series C Redeemable Convertible Preferred StockAdditional Paid-in Capital
Temporary equity, Balance at the beginning at Dec. 31, 2019																		$ 83,211	$ (83,211)
Temporary equity, Balance at the beginning (in shares) at Dec. 31, 2019																	0	66,718,509	(66,718,509)
Balance at the beginning at Dec. 31, 2019	$ 29,386	$ (53,825)	$ 83,211	$ 1	$ 1			$ 84,670	$ 1,459	$ 83,211				$ (55,285)	$ (55,285)
Balance at the beginning (in shares) at Dec. 31, 2019				13,155,487	8,178,290	4,977,197
Issuance costs of series C redeemable convertible preferred stock																				$ (7)	$ (7)
Exercises of stock options	84							84
Exercises of stock options, shares				39,441
Restricted stock forfeited, shares				(5,123)
Reclassification to liability for early exercised stock options	(75)							(75)
Vesting of early exercised stock options	22							22
Stock-based compensation expense	180							180
Net loss	(6,287)													(6,287)
Balance at the end at Mar. 31, 2020	23,303			$ 1				84,874						(61,572)
Balance at the end (in shares) at Mar. 31, 2020				13,189,805
Temporary equity, Balance at the end at Mar. 31, 2020																	$ 0
Temporary equity, Balance at the end (in shares) at Mar. 31, 2020																	0
Temporary equity, Balance at the beginning at Dec. 31, 2019																		$ 83,211	$ (83,211)
Temporary equity, Balance at the beginning (in shares) at Dec. 31, 2019																	0	66,718,509	(66,718,509)
Balance at the beginning at Dec. 31, 2019	29,386	(53,825)	83,211	$ 1	$ 1			84,670	1,459	83,211				(55,285)	(55,285)
Balance at the beginning (in shares) at Dec. 31, 2019				13,155,487	8,178,290	4,977,197
Repurchase of early exercised stock options	0
Net loss	(21,889)
Balance at the end at Sep. 30, 2020	57,908			$ 2				135,080						(77,174)
Balance at the end (in shares) at Sep. 30, 2020				18,236,041
Temporary equity, Balance at the end at Sep. 30, 2020																	$ 0
Temporary equity, Balance at the end (in shares) at Sep. 30, 2020																	0
Temporary equity, Balance at the beginning at Mar. 31, 2020																	$ 0
Temporary equity, Balance at the beginning (in shares) at Mar. 31, 2020																	0
Balance at the beginning at Mar. 31, 2020	23,303			$ 1				84,874						(61,572)
Balance at the beginning (in shares) at Mar. 31, 2020				13,189,805
Issuance of Series C redeemable convertible preferred stock, net of issuance costs				$ 1																$ 49,893	$ 49,892
Issuance of Series C redeemable convertible preferred stock, net of issuance costs, shares				5,018,525
Exercises of stock options	8							8
Exercises of stock options, shares				6,498
Reclassification to liability for early exercised stock options	(3)							(3)
Vesting of early exercised stock options	20							20
Stock-based compensation expense	128							128
Net loss	(6,967)													(6,967)
Balance at the end at Jun. 30, 2020	66,382			$ 2				134,919						(68,539)
Balance at the end (in shares) at Jun. 30, 2020				18,214,828
Temporary equity, Balance at the end at Jun. 30, 2020																	$ 0
Temporary equity, Balance at the end (in shares) at Jun. 30, 2020																	0
Exercises of stock options	14							14
Exercises of stock options, shares				4,051
Restricted stock granted, shares				17,564
Reclassification to liability for early exercised stock options	(11)							(11)
Vesting of early exercised stock options	18							18
Repurchase of early exercised stock options, shares				(402)
Stock-based compensation expense	140							140
Net loss	(8,635)													(8,635)
Balance at the end at Sep. 30, 2020	57,908			$ 2				135,080						(77,174)
Balance at the end (in shares) at Sep. 30, 2020				18,236,041
Temporary equity, Balance at the end at Sep. 30, 2020																	$ 0
Temporary equity, Balance at the end (in shares) at Sep. 30, 2020																	0
Temporary equity, Balance at the beginning at Dec. 31, 2020																	$ 0	$ 133,097	$ (133,097)
Temporary equity, Balance at the beginning (in shares) at Dec. 31, 2020																	0	95,289,932	(95,289,932)
Balance at the beginning at Dec. 31, 2020	47,293	(85,804)	133,097	$ 2	$ 1	$ 1		135,292	2,196	133,096	$ 0	$ 0	$ 0	(88,001)	(88,001)
Balance at the beginning (in shares) at Dec. 31, 2020				18,256,628	8,648,718	9,607,910
Exercises of stock options	196							196
Exercises of stock options, shares				76,370
Restricted stock granted, shares				122,950
Reclassification to liability for early exercised stock options	(120)							(120)
Vesting of early exercised stock options	30							30
Stock-based compensation expense	475							475
Net loss	(13,022)													(13,022)
Balance at the end at Mar. 31, 2021	34,852			$ 2				135,873			0			(101,023)
Balance at the end (in shares) at Mar. 31, 2021				18,455,948
Temporary equity, Balance at the end at Mar. 31, 2021																	$ 0
Temporary equity, Balance at the end (in shares) at Mar. 31, 2021																	0
Temporary equity, Balance at the beginning at Dec. 31, 2020																	$ 0	$ 133,097	$ (133,097)
Temporary equity, Balance at the beginning (in shares) at Dec. 31, 2020																	0	95,289,932	(95,289,932)
Balance at the beginning at Dec. 31, 2020	$ 47,293	$ (85,804)	$ 133,097	$ 2	$ 1	$ 1		135,292	$ 2,196	$ 133,096	0	$ 0	$ 0	(88,001)	$ (88,001)
Balance at the beginning (in shares) at Dec. 31, 2020				18,256,628	8,648,718	9,607,910
Issuance of Series C redeemable convertible preferred stock, net of issuance costs, shares	12,020,000			12,020,000
Exercises of stock options, shares	154,427
Repurchase of early exercised stock options	$ 1
Net loss	(39,694)
Balance at the end at Sep. 30, 2021	$ 123,731			$ 4				251,438			(16)			(127,695)
Balance at the end (in shares) at Sep. 30, 2021				35,027,407
Temporary equity, Balance at the end at Sep. 30, 2021																	$ 0
Temporary equity, Balance at the end (in shares) at Sep. 30, 2021	0																0
Temporary equity, Balance at the beginning at Mar. 31, 2021																	$ 0
Temporary equity, Balance at the beginning (in shares) at Mar. 31, 2021																	0
Balance at the beginning at Mar. 31, 2021	$ 34,852			$ 2				135,873			0			(101,023)
Balance at the beginning (in shares) at Mar. 31, 2021				18,455,948
Exercises of stock options	109							109
Exercises of stock options, shares				50,179
Restricted stock granted, shares				70,258
Restricted stock forfeited, shares				(16,467)
Reclassification to liability for early exercised stock options	(65)							(65)
Vesting of early exercised stock options	47							47
Repurchase of early exercised stock options, shares				(1,142)
Stock-based compensation expense	532							532
Net loss	(12,653)													(12,653)
Balance at the end at Jun. 30, 2021	22,822			$ 2				136,496			0			(113,676)
Balance at the end (in shares) at Jun. 30, 2021				18,558,776
Temporary equity, Balance at the end at Jun. 30, 2021																	$ 0
Temporary equity, Balance at the end (in shares) at Jun. 30, 2021																	0
Issuance of common stock upon Business Combination and PIPE Financing, net of issuance costs and warrant liabilities	114,248			$ 2				114,246
Issuance of common stock upon Business Combination and PIPE Financing, net of issuance costs and warrant liabilities, shares				16,440,757
Exercises of stock options	72							72
Exercises of stock options, shares				0			27,874
Reclassification to liability for early exercised stock options	(40)							(40)
Vesting of early exercised stock options	48							48
Stock-based compensation expense	616							616
Other comprehensive loss	(16)										(16)
Net loss	(14,019)													(14,019)
Balance at the end at Sep. 30, 2021	$ 123,731			$ 4				$ 251,438			$ (16)			$ (127,695)
Balance at the end (in shares) at Sep. 30, 2021				35,027,407
Temporary equity, Balance at the end at Sep. 30, 2021																	$ 0
Temporary equity, Balance at the end (in shares) at Sep. 30, 2021	0																0

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Redeemable Convertible Preferred Stock and Shareholders' Equity (Unaudited) (Parenthetical) $ in Thousands	3 Months Ended
	Jun. 30, 2020USD ($)
Series C Redeemable Convertible Preferred Stock
Adjustment to additional paid in capital stock issuance costs	$ 106

Condensed Consolidated Statem_4

Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Operating activities:
Net loss	$ (39,694)	$ (21,889)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation	1,528	1,468
Stock-based compensation	1,623	448
Non-cash operating lease expense	958	693
Change in fair value of warrant liabilities	(64)	0
Transaction costs allocated to warrants in connection with Business Combination	392	0
Changes in operating assets and liabilities:
Prepaid expenses and other current assets	(2,793)	(399)
Other assets	(886)	(24)
Accounts payable	129	5
Accrued liabilities	3,120	1,105
Operating Lease liabilities	(1,583)	(1,169)
Net cash used in operating activities	(37,270)	(19,762)
Investing activities:
Purchases of property and equipment	(945)	(414)
Purchases of marketable securities	(74,342)	0
Sales of marketable securities	1,100	0
Maturities of marketable securities	13,100	0
Net cash used in investing activities	(61,087)	(414)
Financing activities:
Proceeds from issuance of common stock upon Business Combination and PIPE Financing, net of transaction costs	124,095	0
Proceeds from issuance of redeemable convertible preferred stock, net of issuance costs	0	49,886
Proceeds from exercise of stock options	377	106
Repurchase of early exercised stock options	(1)	0
Net cash provided by financing activities	124,471	49,992
Net increase in cash, cash equivalents and restricted cash	26,114	29,816
Cash, cash equivalents and restricted cash at beginning of period	35,387	29,509
Cash, cash equivalents and restricted cash at end of period	61,501	59,325
Supplemental disclosure of noncash investing and financing activities:
Conversion of redeemable convertible preferred stock into common stock	133,097	0
Assumption of warrant liabilities in Business Combination	8,372	0
Transaction costs in Business Combination included in accrued liabilities	1,867
Capital expenditures in accounts payable and accrued liabilities	208	82
Vesting of early exercises of stock options	125	60
Reclassification to liability for early exercised stock options	225	89
Increase In Right Of Use Assets And Lease Liabilities Due To Lease Extension	257
Right-of-use asset obtained in exchange for operating lease liabilities		563
Reconciliation Of Cash Cash Equivalents And Restricted Cash To Consolidated Balance Sheets Abstract
Cash and cash equivalents	61,096	58,920
Restricted cash	405	405
Cash, cash equivalents and restricted cash	$ 61,501	$ 59,325

Organization and Business

Organization and Business	9 Months Ended
	Sep. 30, 2021
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Organization and Business	Note 1. Organization and Business Organization Surrozen, Inc., or the Company, formerly known as Consonance-HFW Acquisition Corp., or Consonance, is a preclinical stage biotechnology company committed to discovering and developing drug candidates to selectively modulate the Wnt pathway, a critical mediator of tissue repair, in a broad range of organs and tissues. The Company, a Delaware corporation, is located in South San Francisco, California. Business Combination and Private Investment in Public Entity Financing Consonance was a blank check company incorporated as a Cayman Islands exempted company on August 21, 2020. It was formed for the purpose of effecting a merger, share exchange, asset acquisition, share purchase, reorganization or similar business combination with one or more businesses. On August 11, 2021, Consonance consummated a business combination, or the Business Combination, pursuant to the business combination agreement, or the Business Combination Agreement, entered into on April 15, 2021 among Consonance, Perseverance Merger Sub Inc., a subsidiary of Consonance, or Merger Sub, and Surrozen, Inc., or Legacy Surrozen, a Delaware company incorporated on August 12, 2015. Upon closing of the Business Combination, Consonance became a Delaware corporation and was renamed to Surrozen, Inc., or New Surrozen, Legacy Surrozen was renamed to Surrozen Operating, Inc., and Merger Sub merged with and into Legacy Surrozen, with Legacy Surrozen as the surviving company and, after giving effect to such merger, continuing as a wholly-owned subsidiary of New Surrozen. Immediately after the consummation of the Business Combination, certain investors subscribed for and purchased an aggregate of 12,020,000 units for a purchase price of $ 10.00 per unit through a private investment in public entity financing, or PIPE Financing. Each unit consists of one share of the Company’s common stock and one-third of one redeemable warrant for one share of the Company’s common stock exercisable at $ 11.50 per share. In connection with the consummation of the Business Combination and PIPE Financing, Legacy Surrozen received cash consideration of $ 128.3 million, after deducting the transaction fees incurred by Consonance. In general, under Section 382 of the Internal Revenue Code of 1986, as amended, or the Code, a corporation that undergoes an “ownership change” (as defined under Section 382 of the Code and applicable Treasury Regulations) is subject to limitations on its ability to utilize its pre-change net operating loss carryforwards, or NOLs, to offset future taxable income. The Company has not determined whether its NOLs are limited under Section 382 of the Code. As a result, there are uncertainties that the Business Combination may have triggered an ownership change. Prior to the Business Combination, Consonance’s units, public shares and public warrants were listed on the New York Stock Exchange under the symbols “CHFW.U,” “CHFW,” and “CHFW.W,” respectively. On August 12, 2021, the Company's common stock and public warrants began trading on the Nasdaq Capital Market under the symbols “SRZN” and “SRZNW,” respectively. See Note 3, " Recapitalization " for additional details. Liquidity The Company has incurred net operating losses each period since inception. During the three and nine months ended September 30, 2021, the Company incurred a net loss of $ 14.0 million and $ 39.7 million , respectively. During the nine months ended September 30, 2021, the Company used $ 37.3 million of cash in operations. As of September 30, 2021, the Company had an accumulated deficit of approximately $ 127.7 million . The Company expects operating losses to continue in the foreseeable future because of additional costs and expenses related to the research and development activities. As of September 30, 2021, the Company had cash, cash equivalents and investments of $ 135.4 million . Management believes that the existing cash, cash equivalents, and investments are sufficient for the Company to continue operating activities for at least the next 12 months from the date of issuance of its unaudited condensed consolidated financial statements. The Company plans to continue to fund its operations through public or private equity financings, debt financings or other capital sources, including government grants, potential collaborations with other companies or other strategic transactions. The Company’s ultimate success depends on the outcome of its research and development activities. Failure to generate sufficient cash flows from operations, raise additional capital and reduce discretionary spending could have a material adverse effect on the Company’s ability to achieve its intended business objectives. These factors would have a material adverse effect on the Company’s future financial results, financial position and cash flows. Impact of COVID-19 Pandemic The Company’s business has been and could continue to be adversely affected by the evolving Coronavirus Disease 2019 (COVID-19) pandemic. For example, the COVID-19 pandemic has resulted in and could result in delays to the Company’s preclinical studies of its product pipeline. At this time, the extent to which the COVID-19 pandemic impacts the Company’s business will depend on future developments, which are highly uncertain and cannot be predicted.

Summary of Significant Accounti

Summary of Significant Accounting Policies	9 Months Ended
	Sep. 30, 2021
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Note 2. Summary of Significant Accounting Policies Basis of Presentation The Company’s unaudited condensed consolidated financial statements and accompanying notes have been prepared in accordance with generally accepted accounting principles in the United States of America, or U.S. GAAP, as determined by the Financial Accounting Standards Board, or FASB, Accounting Standards Codification, or ASC, and pursuant to the regulations of the U.S. Securities and Exchange Commission, or SEC. The unaudited condensed consolidated financial statements include the accounts of the Company and its subsidiary. All intercompany transactions and balances have been eliminated. The Business Combination discussed in Note 1 was accounted for as a reverse recapitalization with Legacy Surrozen as the accounting acquirer and Consonance as the acquired company for accounting purposes. Accordingly, all historical financial information presented in the unaudited condensed consolidated financial statements represents the accounts of Legacy Surrozen at their historical cost as if Legacy Surrozen is the predecessor to the Company. The unaudited condensed consolidated financial statements following the closing of the Business Combination reflect the results of the combined entity’s operations. All issued and outstanding common stock, redeemable convertible preferred stock and stock awards of Legacy Surrozen and per share amounts contained in the unaudited condensed consolidated financial statements for the periods presented prior to the closing of the Business Combination have been retroactively restated to reflect the exchange ratio established in the Business Combination. See Note 3, " Recapitalization " for additional details. Use of Estimates The preparation of unaudited condensed consolidated financial statements in conformity with U.S. GAAP requires management to make judgments, estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities as of the date of the unaudited condensed consolidated financial statements and the reported amounts of expenses during the reporting period. Significant estimates and assumptions made in the accompanying unaudited condensed consolidated financial statements include, but are not limited to, certain accruals for research and development activities, the fair value of common stock prior to the Business Combination, stock-based compensation expense, fair value of warrants issued in connection with the PIPE Financing, uncertain tax positions and lease liabilities. Management bases its estimates on historical experience and on various other market-specific and relevant assumptions that are believed to be reasonable under the circumstances, the results of which form the basis for making judgments about the carrying value of assets and liabilities that are not readily apparent from other sources. Actual results could materially differ from those estimates. The extent to which the coronavirus 2019, or COVID-19, pandemic will ultimately impact the Company’s business, results of operations, financial conditions, or cash flows continues to be highly uncertain. The severity of the impact on the Company's business for the remainder of calendar year 2021 and beyond will depend on a number of factors, including, but not limited to, the duration and severity of the pandemic, and the impact of any variants of the virus, the extent and severity of the impact on the Company's customers and suppliers, the continued disruption to demand for the Company's products and services, and the impact of the global business and economic environment on liquidity and the availability of capital, all of which are uncertain and cannot be predicted. Unaudited Condensed Consolidated Financial Statements The accompanying unaudited condensed consolidated balance sheet as of September 30, 2021, the unaudited condensed consolidated statements of stockholders’ equity and the unaudited condensed consolidated statements of operations and comprehensive loss for the three and nine months ended September 30, 2021 and 2020, and the unaudited condensed consolidated statements of cash flows for the nine months ended September 30, 2021 and 2020 are unaudited. The unaudited condensed consolidated financial statements have been prepared in accordance with U.S. GAAP for interim financial information and in accordance with the instructions to Form 10-Q and Rule 10-01 of Regulation S-X of the Securities Act of 1933, as amended. Accordingly, they do not include all of the information and notes required by U.S. GAAP for complete financial statements. The unaudited condensed consolidated financial statements, in management’s opinion, include all adjustments consisting of only normal recurring adjustments necessary for the fair statement of the Company’s financial position as of September 30, 2021, its results of operations for the three and nine months ended September 30, 2021 and 2020, and its cash flows for the nine months ended September 30, 2021 and 2020. The financial data and the other financial information disclosed in the notes to these unaudited condensed consolidated financial statements related to the nine-month periods are also unaudited. The unaudited condensed consolidated balance sheet as of December 31, 2020 was derived from the audited financial statements as of that date. The results of operations for the three and nine months ended September 30, 2021 are not necessarily indicative of the results to be expected for the full fiscal year or any other period. These unaudited condensed consolidated financial statements should be read in conjunction with the Company’s audited financial statements and accompanying notes for the years ended December 31, 2020. Restricted Cash As of each of September 30, 2021 and December 31, 2020, the Company had $ 0.4 million of restricted cash in the form of a letter of credit for the Company’s facility lease. The restricted cash is classified as a noncurrent asset as the Company is required to maintain the letter of credit for the benefit of the landlord until the end of the lease term in April 2025. Concentration of Credit Risk Financial instruments, which potentially subject the Company to significant concentration of credit risk, consist of cash, cash equivalents, investments and restricted cash. The Company is exposed to credit risk in the event of default to the extent recorded in the unaudited condensed consolidated balance sheets. The Company has not experienced any losses in such accounts. Management believes that the Company is not exposed to significant credit risk due to the financial position of the depository institution in which its bank deposits are held. To manage credit risks related to investments, the Company invests in various highly rated commercial paper, government bonds, corporate bonds and foreign bonds. Investments The Company has investments in marketable securities. The Company’s investment policy is consistent with the definition of available-for-sale securities. The Company does not buy or hold securities principally for the purpose of selling them in the near future. The Company’s policy is focused on the preservation of capital, liquidity, and return. From time to time, the Company may sell certain securities, but the objectives are generally not to generate profits on short-term differences in price. Short-term investments have maturities less than or equal to one year as of the balance sheet date. Long-term investments have maturities greater than one year as of the balance sheet date. These marketable securities are carried at estimated fair value with unrealized holding gains and losses included in other comprehensive loss in stockholders’ equity until realized. Gains and losses on marketable security transactions are reported on the specific-identification method. Dividend and interest income are recognized in the unaudited condensed consolidated statements of operations and comprehensive loss when earned. Warrant Liabilities The Company's Public Warrants, Private Placement Warrants and PIPE Warrants were classified as liabilities (see Note 8). The transaction costs of $ 0.4 million that were incurred in connection with the Business Combination were allocated to the warrant liabilities and recognized in other expense, net within the unaudited condensed consolidated statements of operations and comprehensive loss. At the end of each reporting period, any change in fair value during the period are recognized in the other expense, net within the unaudited condensed consolidated statements of operations and comprehensive loss. The Company will continue to adjust the warrant liabilities for changes in the fair value until the earlier of a) the exercise or expiration of the warrants or b) the redemption of the warrants, at which time such warrants will be reclassified to additional paid-in capital. Research and Development Expenses Research and development costs are expensed as incurred. Research and development costs consist of external and internal expenses directly attributable to the conduct of research and development programs. The external expenses include the costs of services provided by outside contractors, clinical research organizations and contract manufacturing organizations. The internal expenses include the costs of salaries, payroll taxes, stock-based compensation, employee benefits, materials, supplies, depreciation on and maintenance of research equipment, and the facility costs for laboratory space used for research and development activities, such as rent, utilities, insurance, repairs and maintenance, and general support services. The Company has entered into and may continue to enter into licensing or subscription arrangements to access and utilize certain technology. In each case, the Company evaluates if the license agreement results in the acquisition of an asset or a business. To date, none of the Company’s license agreements have been considered an acquisition of a business. For asset acquisitions, the upfront payments to acquire such licenses, as well as any future milestone payments made before product approval that do not meet the definition of a derivative, are immediately recognized as research and development expense when they are paid or become payable, provided there is no alternative future use of the rights in other research and development projects. In September 2020, the Company was awarded a grant from the National Institute of Health, which would partially fund studies for SZN-043 in an amount up to $ 1.0 million through August 2021, with the possibility of an additional $ 2.0 million through August 2025, subject to the availability of funds and satisfactory progress of the project. The Company records the government grant received as a liability and ratably recognizes the amount as a reduction of research and development expenses when the costs related to the grant are incurred. As of September 30, 2021, the Company received $ 0.9 million from the grant. During the three and nine months ended September 30, 2021, $ 0.8 million was recognized as a reduction of research and development expenses. Net Loss Per Share Basic net loss per share is calculated by dividing the net loss attributable to common stock by the weighted-average number of shares of common stock outstanding for the period, without consideration for potential dilutive securities. Since the Company was in a loss position for the periods presented, basic net loss per share is the same as diluted net loss per share as the effects of potentially dilutive securities are antidilutive. The following table presents the potential common stock outstanding that were excluded from the computation of diluted net loss per share of common stock as of the periods presented because including them would have been antidilutive: September 30, 2021 2020 Options outstanding 1,700,513 890,239 Unvested restricted stock 178,208 54,157 Unvested common stock subject to repurchase 101,879 110,442 Warrants to purchase common stock 7,217,974 — Total 9,198,574 1,054,838 Emerging Growth Company Status The Company is an emerging growth company, as defined in the Jumpstart Our Business Startups Act of 2012, or the JOBS Act. Under the JOBS Act, emerging growth companies can delay adopting new or revised accounting standards issued subsequent to the enactment of the JOBS Act until such time as those standards apply to private companies. The Company has elected to use this extended transition period for complying with certain new or revised accounting standards that have different effective dates for public and private companies until the earlier of the date that it is (i) no longer an emerging growth company or (ii) affirmatively and irrevocably opt out of the extended transition period provided in the JOBS Act. As a result, these unaudited condensed consolidated financial statements may not be comparable to companies that comply with the new or revised accounting pronouncements as of public company effective dates. Recently Adopted Accounting Pronouncements In December 2019, the FASB issued ASU No. 2019-12, Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes, which amends the existing guidance relating to the accounting for income taxes. This standard is intended to simplify the accounting for income taxes by removing certain exceptions to the general principles of accounting for income taxes and to improve the consistent application of U.S. GAAP for other areas of accounting for income taxes by clarifying and amending existing guidance. The standard is effective for public business entities for fiscal years beginning after December 15, 2020 and interim periods within those fiscal years. The standard is effective for entities other than public business entities for fiscal years beginning after December 15, 2021. The Company early adopted this guidance as of January 1, 2021, with no material impact on the unaudited condensed consolidated financial statements upon adoption.

Recapitalization

Recapitalization	9 Months Ended
	Sep. 30, 2021
Recapitalization Note [Abstract]
Recapitalization	Note 3. Recapitalization On August 11, 2021, Consonance consummated the Business Combination and PIPE Financing (see Note 1), and Legacy Surrozen received cash consideration of $ 128.3 million, after deducting the transaction fees incurred by Consonance. The cash consideration was comprised of $ 8.1 million in proceeds from issuance of common stock upon the closing of the Business Combination and $ 120.2 million in proceeds from the PIPE Financing. The Company incurred transaction costs of $ 6.0 million, consisting of legal, accounting and other professional services directly related to the Business Combination, $ 0.4 million of which were allocated to the warrant liabilities assumed and recognized as other expenses when incurred. The remaining $ 5.6 million were recorded as a reduction of additional paid-in capital in the unaudited condensed consolidated balance sheet. Legacy Surrozen was deemed the accounting acquirer in the Business Combination and the Business Combination was accounted for as a reverse recapitalization based on the following predominant factors:  Legacy Surrozen’s shareholders have the greatest voting interest in the Company;  The Company’s board and senior management are primarily composed of individuals associated with Legacy Surrozen; and  Legacy Surrozen is the larger entity based on historical operating activity and has the larger employee base at the time of the Business Combination. Accordingly, for accounting purposes, the reverse recapitalization was treated as the equivalent of Legacy Surrozen issuing stock for the net assets of Consonance, accompanied by a recapitalization. Consonance had 4,420,757 shares of common stock outstanding prior to the Business Combination and issued 12,020,000 shares of the Company's common stock in connection with the PIPE Financing, representing the total of 16,440,757 shares issued by Legacy Surrozen in the reverse recapitalization. The net assets of Consonance are stated at historical cost, with no goodwill or other intangible assets recorded. Pursuant to the Business Combination Agreement, upon the closing of the Business Combination, (i) each share of redeemable convertible preferred stock of Legacy Surrozen (on an as converted to common stock basis) and each share of common stock of Legacy Surrozen, whether vested or unvested, was converted into 0.175648535 shares of the Company’s common stock and (ii) each outstanding option to purchase common stock of Legacy Surrozen was converted into an option to purchase shares of the Company’s common stock based on an exchange ratio of 0.175648535 (“Exchange Ratio”), with corresponding adjustments to the exercise price. All issued and outstanding common stock, preferred stock and stock awards of Legacy Surrozen and corresponding capital amounts contained in the unaudited condensed consolidated financial statements for the periods presented prior to the closing of the Business Combination have been retroactively restated to reflect the conversion.

Fair Value Measurement

Fair Value Measurement	9 Months Ended
	Sep. 30, 2021
Fair Value Disclosures [Abstract]
Fair Value Measurement	Note 4. Fair Value Measurement The following tables summarize the Company’s financial assets and liabilities that are measured at fair value on a recurring basis (in thousands): As of September 30, 2021 Level 1 Level 2 Level 3 Total Assets: Money market funds (1) $ 55,606 $ — $ — $ 55,606 Commercial paper — 39,739 — 39,739 Government bonds — 18,191 — 18,191 Corporate bonds — 12,652 — 12,652 Foreign bonds — 3,744 — 3,744 Total financial assets measured at fair $ 55,606 $ 74,326 $ — $ 129,932 Liabilities: Public Warrants $ 3,496 $ — $ — $ 3,496 Private Placement Warrants — 165 — 165 PIPE Warrants — — 4,647 4,647 Total financial liabilities measured at $ 3,496 $ 165 $ 4,647 $ 8,308 As of December 31, 2020 Level 1 Level 2 Level 3 Total Assets: Money market funds (1) $ 31,896 $ — $ — $ 31,896 Corporate bonds — 1,115 — 1,115 Commercial paper (2) — 15,285 — 15,285 Total financial assets measured at $ 31,896 $ 16,400 $ — $ 48,296 (1) Money market funds are included in cash and cash equivalents on the unaudited condensed consolidated balance sheet as of September 30, 2021 and December 31, 2020. (2) As of December 31, 2020, marketable securities with original maturities of three months or less, in the amount of $ 2.2 million, are included in cash and cash equivalents on the unaudited condensed consolidated balance sheet. There have been no changes to the valuation methods utilized during the nine months ended September 30, 2021. The Company’s financial instruments include cash, cash equivalents, investments, restricted cash, accounts payable, accrued liabilities and warrant liabilities. The carrying amount of cash and cash equivalents, restricted cash, accounts payable, and accrued liabilities approximate their fair values due to their short-term maturities. There were no transfers of financial instruments between Level 1, Level 2, and Level 3 during the periods presented. Investments in corporate bonds, commercial paper, foreign bonds and government bonds are classified as Level 2 as they were valued based upon quoted market prices for similar instruments in active markets, quoted prices for identical or similar instruments in markets that are not active, and model-based valuation techniques for which all significant inputs are observable in the market or can be corroborated by observable market data for substantially the full term of the assets. The Public Warrants are classified as Level 1 due to the use of an observable market quote in an active market. The Private Placement Warrants are classified as Level 2 due to the use of observable market data for identical or similar liabilities. The fair value of each Private Placement Warrant was determined to be consistent with that of a Public Warrant because the Private Warrants are also subject to the make-whole redemption feature, which allows the Company to redeem both types of warrants on similar terms when the stock price is in the range of $ 10 to $ 18 per share. The PIPE Warrants are classified as Level 3 because the fair value was measured based on significant inputs that are unobservable in the market. See the definition and discussion of Public Warrants, Private Placement Warrants and PIPE Warrants in Note 8. The PIPE Warrants were initially recorded at fair value and subsequently remeasured at each reporting period using a binomial lattice model. The significant unobservable input used in the fair value measurement of the PIPE Warrants is the expected volatility. The expected volatility was implied from the market price of the Company’s Public Warrants. The expected term was based on the remaining contractual term of the PIPE Warrants, and the risk-free interest rate was based on the implied yield available on U.S. Treasury Securities with a maturity equivalent to the expected term. The dividend rate is based on the historical rate, which the Company anticipated remaining at zero. The key inputs into the binomial lattice model for the PIPE Warrants were as follows at the initial measurement and September 30, 2021: August 11, September 30, 2021 2021 Expected term (in years) 5.01 4.87 Expected volatility 18.90 % 37.80 % Risk-free interest rate 0.81 % 0.95 % Dividend yield — — The following table set forth a summary of the change in the fair value of the Company’s warrant liabilities for the three and nine months ended September 30, 2021 (in thousands): Public Warrants Private Placement Warrants PIPE Warrants Total Warrant Liabilities Balance, beginning of period $ — $ — $ — $ — Assumption in Business Combination 3,557 168 4,647 8,372 Change in fair value upon (1) ( 61 ) ( 3 ) — ( 64 ) Balance, end of period $ 3,496 $ 165 $ 4,647 $ 8,308 (1) Change in fair value of the warrant liabilities was recognized in other expense, net within the unaudited condensed consolidated statements of operations and comprehensive loss. The following tables provide the Company’s investments by security type (in thousands): As of September 30, 2021 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Commercial paper $ 39,739 $ — $ — $ 39,739 Corporate bonds 5,591 — ( 3 ) 5,588 Foreign bonds 3,745 — ( 1 ) 3,744 Total short-term investments $ 49,075 $ — $ ( 4 ) $ 49,071 Government bonds $ 18,202 $ — $ ( 11 ) $ 18,191 Corporate bonds 7,065 1 ( 2 ) 7,064 Total long-term investments $ 25,267 $ 1 $ ( 13 ) $ 25,255 As of December 31, 2020 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Corporate bonds $ 1,115 $ — $ — $ 1,115 Commercial paper 15,285 — — 15,285 Total short-term investments $ 16,400 $ — $ — $ 16,400 The following table indicates the length of the time that individual securities have been in a continuous unrealized loss position as of September 30, 2021: Less Than 12 Months Number of Investments Fair Value Unrealized Losses Government bonds 3 $ 18,191 $ ( 11 ) Corporate bonds 3 9,197 ( 5 ) Foreign bonds 2 3,744 ( 1 ) 8 $ 31,132 $ ( 17 ) As of December 31, 2020, $ 14.2 million of marketable securities are included in short-term investments. As of September 30, 2021 and December 31, 2020, all short-term investments had maturities of one year or less. All long-term investments as of September 30, 2021 had maturities of greater than one year but less than two years. There have been no significant realized gains or losses on the short-term and long-term investments during the three and nine months ended September 30, 2021 and 2020. The Company periodically reviews the available-for-sale investments for other-than-temporary impairment loss. All investments with unrealized losses have been in a loss position for less than 12 months. As a result, the Company did no t recognize any other-than-temporary impairment losses as of September 30, 2021.

Balance Sheet Components

Balance Sheet Components	9 Months Ended
	Sep. 30, 2021
Balance Sheet Related Disclosures [Abstract]
Balance Sheet Components	Note 5. Balance Sheet Components Prepaid Expenses and Other Current Assets Prepaid expenses and other current assets consist of the following (in thousands): September 30, 2021 December 31, 2020 Prepaid insurance $ 2,211 $ 2 Prepaid research and development expenses 618 256 Prepaid rent 330 322 Other 676 462 Prepaid expenses and other current assets $ 3,835 $ 1,042 Accrued Liabilities Accrued liabilities consist of the following (in thousands): September 30, 2021 December 31, 2020 Accrued payroll and related expenses $ 2,109 $ 1,673 Accrued research and development expenses 3,805 1,305 Accrued professional service fees 1,850 — Liability for early exercised stock options 287 188 Other accrued expenses 444 228 Accrued liabilities $ 8,495 $ 3,394 Other Assets Other assets consist of the following (in thousands): September 30, 2021 December 31, 2020 Prepaid insurance $ 848 $ — Other 77 39 Other assets $ 925 $ 39

Leases

Leases	9 Months Ended
	Sep. 30, 2021
Leases [Abstract]
Leases	Note 6. Leases In August 2016, the Company entered into a lease agreement for office and lab space, which consists of approximately 32,813 square feet of rental space in South San Francisco, California. The office space lease is classified as an operating lease. The initial lease term commenced in May 2017 and ends in April 2025 , with rent payments escalating each year. The Company has options to extend the lease for additional years, but the exercise of the option was not reasonably certain. The landlord provided the Company with a tenant improvement allowance of up to $ 4.6 million. In connection with the lease, the Company maintains a letter of credit for the benefit of the landlord in the amount of $ 0.4 million, which is recorded as restricted cash on the unaudited condensed consolidated balance sheets. In January 2020, the Company entered into a lease agreement for a term of 18 months for approximately 6,478 square feet of office space. The new office space lease is classified as an operating lease. The new lease commenced in June 2020 and rent payments escalate after 14 months. In September 2021, the Company amended the lease to extend the lease term until June 2022 . The extended lease is on the same terms and conditions as those in the initial agreement, including the monthly rent payment. The modification did not change the lease classification and it resulted in an increase of $ 0.3 million in right-of-use assets and lease liabilities. Operating lease expense during the three and nine months ended September 30, 2021 and 2020 was $ 0.5 million, $ 1.5 million, $ 0.5 million and $ 1.3 million, respectively. Aggregate future minimum rental payments under the operating leases as of September 30, 2021, were as follows (in thousands): Remaining three months ending December 31, 2021 $ 722 Year ending December 31, 2022 2,713 Year ending December 31, 2023 2,564 Year ending December 31, 2024 2,646 Year ending December 31, 2025 891 Total lease payments 9,536 Less: Imputed interest ( 1,265 ) Operating lease liabilities $ 8,271

License Agreements

License Agreements	9 Months Ended
	Sep. 30, 2021
License Agreements [Abstract]
License Agreements	Note 7. License Agreements Stanford License Agreements In March 2016, the Company entered into a license agreement with Stanford University, or the 2016 Stanford Agreement, which was amended in July 2016, October 2016 and January 2021, pursuant to which the Company obtained from Stanford a worldwide, exclusive, sublicensable license under certain patents, rights, or licensed patents and technology related to its engineered Wnt surrogate molecules to make, use, import, offer to sell and sell products that are claimed by the licensed patents or that use or incorporate such technology, or licensed products, for the treatment, diagnosis and prevention of human and veterinary diseases. In consideration for this license, the Company paid Stanford a nominal upfront fee and issued an aggregate of 42,451 shares of our common stock to Stanford, the University of Washington and two co-inventors of the licensed patents. In addition, the Company agreed to pay Stanford nominal annual license maintenance fees which are creditable against earned royalties owed to Stanford for the same year, an aggregate of up to $ 0.9 million for the achievement of specified development and regulatory milestones, and an aggregate of up to $ 5.0 million for achievement of specified sales milestones. Stanford is also entitled to receive royalties from the Company equal to a very low single digit percentage of the Company’s and its sublicensees’ net sales of licensed products that are covered by a valid claim of a licensed patent. Additionally, the Company agreed to pay Stanford a sub-teen double digit percentage of certain consideration the Company receives as a result of granting sublicenses to the licensed patents and, if the Company is acquired, a one-time change of control fee in the low six figures. Stanford retains the right under the 2016 Stanford Agreement, on behalf of itself, Stanford Hospital and Clinics, the University of Washington and all other non-profit research institutions, to practice the licensed patents and technology for any non-profit purpose. The licensed patents and technology are additionally subject to a non-exclusive, irrevocable, worldwide license held by the Howard Hughes Medical Institute to practice the licensed patents and technology for its research purposes, but with no right to assign or sublicense. In June 2018, the Company entered into another license agreement with Stanford, or the 2018 Stanford Agreement, pursuant to which the Company obtained from Stanford a worldwide, exclusive, sublicensable license under certain patent rights related to its surrogate R-spondin proteins, or the licensed patents, to make, use, import, offer to sell and sell products that are claimed by the licensed patents, or licensed products, for the treatment, diagnosis and prevention of human and veterinary diseases, or the exclusive field. Additionally, Stanford granted the Company a worldwide, non- exclusive, sublicensable license under the licensed patents to make and use licensed products for research and development purposes in furtherance of the exclusive field and a worldwide, non-exclusive license to make, use and import, but not to offer to sell or sell, licensed products in any other field of use. In consideration of these licenses, the Company paid Stanford a nominal upfront fee. The Company also agreed to pay Stanford nominal annual license maintenance fees which are creditable against earned royalties owed to Stanford for the same year, and an aggregate of up to $ 0.425 million for the achievement of specified development and regulatory milestones. Stanford is also entitled to receive royalties from the Company equal to a sub-single digit percentage of the Company’s and its sublicensees’ net sales of licensed products. Additionally, the Company agreed to pay Stanford a one-time payment in the low six figures for each sublicense of the licensed patents that the Company grants to a third party and, if the Company is acquired, a one-time nominal change of control fee. Stanford retains the right under the 2018 Stanford Agreement, on behalf of itself, Stanford Health Care, Lucile Packard Children’s Hospital at Stanford and all other non-profit research institutions, to practice the licensed patents for any non-profit purpose. The licensed patents are additionally subject to a non-exclusive, irrevocable, worldwide license held by the Howard Hughes Medical Institute to exercise any intellectual property rights with respect to the licensed patents for research purposes, including the right to sublicense to non-profit and governmental entities but with no other rights to assign or sublicense. Under each of the 2016 Stanford Agreement and the 2018 Stanford Agreement, or Stanford Agreements, the Company agreed to use commercially reasonable efforts to develop and commercialize licensed products and the Company agreed to achieve certain funding and development milestones by certain dates. Unless earlier terminated, each Stanford Agreement will continue until the expiration of the patents licensed under such Stanford Agreement. The Company may terminate either Stanford Agreement at any time for any reason by providing at least 30 days’ written notice to Stanford. Stanford may terminate either Stanford Agreement if the Company breaches certain provisions of that Stanford Agreement and fail to remedy such breach within 90 days after written notice of the breach by Stanford. For the nine months ended September 30, 2021 and 2020, the Company paid approximately $ 50,000 and $ 40,000 research and development expenses related to the Stanford Agreements, respectively. For the three months ended September 30, 2021 and 2020, the amount paid by the Company was de minimis. No milestones have been achieved as of September 30, 2021. UCSF License and Option Agreements In September and October 2016, the Company entered into two separate license and option agreements with The Regents of the University of California, or the UCSF Agreements, pursuant to which the Company obtained exclusive licenses from UCSF for internal research and antibody discovery purposes and an option to negotiate with UCSF to obtain an exclusive license under UCSF’s rights in the applicable library to make, use, sell, offer for sale and import products incorporating antibodies identified or resulting from the Company’s use of such library, or licensed products. In consideration of the license and option rights under the UCSF Agreements, the Company paid UCSF a nominal option issue fee and agreed to pay UCSF a nominal annual option maintenance fee. In January 2020, the Company amended and restated the UCSF Agreements to provide non-exclusive licenses to make and use a certain human Fab naïve phage display library and to make and use a certain phage display llama VHH single domain antibody library for internal research and antibody discovery purposes and an option to negotiate with UCSF to obtain a non-exclusive license under UCSF’s rights in the applicable library to make, use, sell, offer for sale and import products incorporating antibodies identified or resulting from the Company’s use of such library, or licensed products. If the Company exercises the option under the UCSF Agreements, the Company and UCSF will negotiate in good faith the terms of a non-exclusive commercial license agreement in addition to the pre-agreed terms which include payment to UCSF of a nominal license issue fee, nominal annual license maintenance fees, nominal to low six figure milestone payments for the achievement of a specified regulatory milestone event for each licensed product, nominal annual minimum royalties, which are creditable against earned royalties for the same year, and earned royalties equal to a sub-single digit percentage of the Company’s and the Company’s sublicensees’ net sales of licensed products. As of September 30, 2021, the Company has no t exercised the option. For each of the three and nine months ended September 30, 2021, the Company paid $ 25,000 for the annual license maintenance fee. No annual license maintenance fee was paid for the three and nine months ended September 30, 2020. For both the nine months ended September 30, 2021 and 2020, the Company paid no research and development expenses related to the UCSF Agreements. No milestones have been achieved as of September 30, 2021. Unless earlier terminated, the UCSF Agreements will continue until four years from its effective date, and the Company may exercise the option to negotiate a commercial license at any time during that term. Additionally, the Company may extend the UCSF Agreements for any additional four years by paying UCSF a nominal term extension fee. The Company may terminate the UCSF Agreements at any time for any reason by providing at least 60 days’ written notice to UCSF. UCSF may terminate the UCSF Agreements if UCSF reasonably believes the Company is in material breach of the UCSF Agreements and the Company fails to remedy such breach within 60 days after written notice of such breach by UCSF. Additionally, the UCSF Agreements will automatically terminate in the event of the Company’s bankruptcy. Distributed Bio Subscription Agreement In September 2016, the Company entered into, and in January 2019 the Company amended, an antibody library subscription agreement with Charles River Laboratories International, Inc., formerly known as Distributed Bio, or the Distributed Bio Agreement, in which the Company obtained from Distributed Bio a non-exclusive license to use Distributed Bio’s antibody library to identify antibodies directed to an unlimited number of the Company’s proprietary targets and to make, use, sell, offer for sale, import and exploit products incorporating the antibodies that the Company identifies, or licensed products. In consideration for the rights granted to the Company under the Distributed Bio Agreement, the Company paid Distributed Bio a nominal upfront fee and an additional nominal fee upon entering into the amendment. The Company agreed to pay Distributed Bio an annual fee in the low six figures after the first three years. Additionally, the Company agreed to pay Distributed Bio an aggregate of $ 5.9 million for each licensed product that achieves specified development, regulatory and commercial milestones and royalties equal to a very low single digit percentage of the Company’s and its sublicensees’ net sales of licensed products. The Company’s obligation to pay royalties will end for each licensed product ten years after its first commercial sale. For the three and nine months ended September 30, 2021 and 2020, the Company did no t make any payments related to the Distributed Bio Agreement. In September 2021, the Company achieved the first milestone and recorded the related milestone payment of $ 50,000 as research and development expense. No other milestones have been achieved as of September 30, 2021. Unless earlier terminated, the Distributed Bio Agreement will continue for an initial four-year term and will thereafter automatically renew for additional one-year terms. The Company may terminate the Distributed Bio Agreement for convenience at any time by providing written notice to Distributed Bio. The Company and Distributed Bio may terminate the Distributed Bio Agreement for the other party’s material breach and failure to cure such breach within 60 days after notice of such breach.

Common Stock Warrants

Common Stock Warrants	9 Months Ended
	Sep. 30, 2021
Equity [Abstract]
Common Stock Warrants	Note 8. Common Stock Warrants In connection with the Business Combination, Legacy Surrozen, as the accounting acquirer, was deemed to assume 3,066,651 warrants held by Consonance’s stockholders, or the Public Warrants, and 144,666 warrants held by the Sponsor, or the Private Placement Warrants. In addition, immediately after the consummation of the Business Combination, certain investors subscribed for and purchased an aggregate of 12,020,000 units in the PIPE Financing, consisting of 12,020,000 shares of the Company’s common stock and 4,006,657 warrants, or the PIPE Warrants. As of September 30, 2021, the following common stock warrants were outstanding: Type Classification Expiration Date Exercise Price per Share September 30, 2021 Public Warrants Liability August 12, 2026 $ 11.50 3,066,651 Private Placement Warrants Liability August 12, 2026 11.50 144,666 PIPE Warrants Liability August 12, 2026 11.50 4,006,657 Total 7,217,974 Public Warrants Each whole Public Warrant entitles the holder to purchase one share of the Company’s common stock at a price of $ 11.50 per share, at any time commencing on November 23, 2021 and terminating at the earlier of August 12, 2026 or upon redemption or liquidation. The exercise price and number of ordinary shares issuable upon exercise of the Public Warrants may be adjusted in the event of a share dividend, extraordinary dividend or recapitalization, reorganization, merger or consolidation. The Company would not be obligated to deliver any shares of common stock pursuant to the exercise of a Public Warrant and would have no obligation to settle such Public Warrant exercise unless a registration statement under the Securities Act with respect to the common stock underlying the Public Warrants is then effective. If such registration statement has not been declared effective by the 60 th day after the closing of the Business Combination, the Public Warrant holders have the right to exercise the Public Warrants on a cashless basis until such time as there is an effective registration statement. Once the Public Warrants become exercisable, the Company may redeem the outstanding Public Warrants at a price of $ 0.01 per warrant if the closing price of common stock equals or exceeds $ 18.00 per share (as adjusted for share sub-divisions, share capitalizations, reorganizations, recapitalizations and similar transaction). Additionally, the Company may redeem the outstanding Public Warrants, once they become exercisable, at a price of $ 0.10 per warrant if the closing price of common stock equals or exceeds $ 10.00 per share (as adjusted for share sub-divisions, share capitalizations, reorganizations, recapitalizations and similar transaction). Notice of redemption shall be mailed to the Public Warrant holders no less than 30 days prior to the redemption date, or the Redemption Period. If the closing price of common stock equals or exceeds $ 10.00 per share and is less than $ 18.00 per share, during the Redemption Period, the Public Warrant holders may elect to exercise their Public Warrants on a cashless basis based on a make-whole table. In no event will the Company be required to net cash settle the Public Warrants. The Public Warrant holders do not have the rights or privileges of common stockholders and any voting rights until they exercise their Public Warrants and receive common stock. Private Placement Warrants The Private Placement Warrants have terms and provisions that are identical to those of the Public Warrants, except that so long as they are held by the Sponsor or any of its permitted transferees, the Private Placement Warrants: (i) may be exercised for cash or on a cashless basis, (ii) may not be transferred, assigned or sold until 30 days after the completion of the Business Combination, (iii) shall not be redeemable by the Company if the closing price of common stock equals or exceeds $ 18.00 per share (as adjusted for share sub-divisions, share capitalizations, reorganizations, recapitalizations and similar transaction) and (iv) shall only be redeemable if the closing price of common stock is less than $ 18.00 per share (as adjusted for share sub-divisions, share capitalizations, reorganizations, recapitalizations and similar transaction). If the Private Placement Warrants are held by holders other than the Sponsor or its permitted transferees, the Private Placement Warrants will be redeemable by the Company in all redemption scenarios and exercisable by the holders on the same basis as the Public Warrants. PIPE Warrants Each whole PIPE Warrant entitles the holder to purchase one share of the Company’s common stock at a price of $ 11.50 per share, at any time commencing on November 23, 2021 and terminating on August 12, 2026 . The PIPE Warrants are the same in all respects as the Public Warrants except that the PIPE Warrants are not redeemable before August 12, 2022. Classification The Public Warrants, Private Placement Warrants and PIPE Warrants are not considered indexed to the Company’s common stock as certain provisions of the warrant agreements could change the settlement amount of these warrants. As a result, they were classified as liabilities and recorded at fair value with subsequent change in their respective fair value recognized in the other expense, net within the unaudited condensed consolidated statements of operations and comprehensive loss at each reporting date. See Note 4 for the discussion of warrant valuations.

Redeemable Convertible Preferre

Redeemable Convertible Preferred stock	9 Months Ended
	Sep. 30, 2021
Temporary Equity [Abstract]
Redeemable Convertible Preferred Stock	Note 9. Redeemable Convertible Preferred Stock Immediately prior to the closing of the Business Combination, all 95,289,932 issued and outstanding shares of the redeemable convertible preferred stock of Legacy Surrozen were converted into Legacy Surrozen’s common stock, on a one-for-one basis , and then converted into 16,737,520 shares of the Company’s common stock based on the Exchange Ratio established in the Business Combination . As of September 30, 2021, no shares of redeemable convertible preferred stock were outstanding.

Stock Based Compensation Plan

Stock Based Compensation Plan	9 Months Ended
	Sep. 30, 2021
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Stock Based Compensation Plan	Note 10. Stock-Based Compensation Plan Prior to the Business Combination, Legacy Surrozen maintained the 2015 Stock Plan, or the 2015 Plan, which provided for the granting of options to purchase shares of common stock to officers, employees, directors, consultants and key persons who provide services to the Company. Options under the 2015 Plan have a term of 10 years and generally vest over a four-year period with one-year cliff vesting. In conjunction with the Business Combination, options and the corresponding exercise price under the 2015 Plan were converted into the awards under the 2021 Equity Incentive Plan based on the Exchange Ratio. Each converted option is subject to the same terms and conditions as were applicable to the corresponding options under 2015 Plan. In August 2021, the Company adopted 2021 Equity Incentive Plan, or the 2021 Plan, which provides for the granting of options to employees, directors and consultants. Options granted under the 2021 Plan may be either incentive stock options, or ISOs, or nonqualified stock options, or NSOs. The 2021 Plan also allows for the grant of restricted stock awards, or RSAs, restricted stock units, performance awards and other awards. Options granted under the 2021 Plan expire no later than 10 years from the date of grant. The exercise price of each option may not be less than 100 % of the fair market value of the common stock at the date of grant. Options may be granted to stockholders possessing more than 10 % of the total combined voting power of all classes of stocks of the Company at an exercise price at least 110 % of the fair value of the common stock at the date of grant and the options are not exercisable after the expiration of 5 years from the date of grant. Options under the 2021 Plan generally vest 25 % upon one year of continued service to the Company, with the remainder in monthly increments over three additional years. Upon adoption of the 2021 Plan, no additional stock awards will be issued under the 2015 Plan. As of September 30, 2021, the Company had 4,450,253 shares of common stock available for issuance under the 2021 Plan. A summary of stock option activity under the plans is set forth below: Options outstanding Weighted Weighted Average Aggregate Average Remaining Intrinsic Number of Exercise Contractual Life Value Options Price (In years) (In thousands) Outstanding – 6,093,611 $ 0.40 8.43 Retroactive application of ( 5,023,310 ) Outstanding – 1,070,301 2.26 8.43 Granted 839,972 10.45 Exercised ( 154,427 ) 2.36 Cancelled ( 55,333 ) 4.60 Outstanding – 1,700,513 6.23 8.59 $ 4,262 Options outstanding and 539,783 2.56 7.33 2,715 Options vested and expect to vest 1,700,513 6.23 8.59 4,262 The aggregate intrinsic values of options outstanding, exercisable, vested and expected to vest is the difference between the exercise price of the options and the fair value of the Company’s common stock at September 30, 2021. The intrinsic value of options exercised during the nine months ended September 30, 2021 was $ 1.0 million. During the nine months ended September 30, 2021, the Company granted options with a weighted-average grant-date fair value of $ 6.51 per share. The Company’s Board of Directors granted equity awards in the form of RSAs for certain of the Company’s employees and directors under the 2015 Plan. The Company’s outstanding RSAs began vesting one month after the grant date and vest 1/48 th per month over four years . The following table summarizes the Company’s RSA activity: Weighted Average Number of Grant Date Shares Fair Value RSAs, unvested at December 31, 2020, 263,022 $ 0.69 Retroactive application of ( 216,823 ) RSAs, unvested at December 31, 2020, 46,199 3.96 Granted 193,208 9.95 Vested ( 44,732 ) 6.83 Forfeited ( 16,467 ) 9.76 RSAs, unvested at September 30, 2021 178,208 9.19 The fair value of RSAs vested during the nine months ended September 30, 2021 was $ 0.4 million. (a) Fair Value of Options The fair value of options is estimated at the grant date using the Black-Scholes option-pricing model with the following weighted-average assumptions: Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 Expected term (in years) 6.08 6.04 6.00 6.00 Expected volatility 81.99 % 62.30 % 69.98 % 60.17 % Risk-free rate 0.99 % 0.33 % 0.85 % 1.05 % Dividend yield — — — - — (b) Stock-Based Compensation Total stock-based compensation recorded in the unaudited condensed consolidated statements of operations and comprehensive loss related to options and RSAs was as follows (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 Research and development $ 187 $ 103 $ 534 $ 304 General and administrative 429 37 1,089 144 Total stock-based $ 616 $ 140 $ 1,623 $ 448 As of September 30, 2021, there was approximately $ 8.2 million of stock-based compensation expense to be recognized over a weighted-average period of approximately 3.32 years. (c) Early Exercise of Stock Options Unvested options granted under the 2015 Plan may be early exercised prior to the closing of the Business Combination. Shares issued as a result of early exercise that have not vested are subject to repurchase by the Company upon termination of the purchaser’s employment or services, at the price paid by the purchaser. The proceeds initially were recorded in a liability for early exercised options and are reclassified to common stock and additional paid-in capital as the Company’s repurchase right lapses. As of September 30, 2021, there were 101,879 shares of common stock outstanding, subject to the Company’s right of repurchase at a weighted average exercise price of $ 2.82 per share.

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2021
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	Note 11. Commitments and Contingencies Indemnification From time to time, the Company enters into certain types of contracts that contingently require the Company to indemnify various parties against claims from third parties. These contracts primarily relate to (i) the Company’s bylaws, under which the Company must indemnify directors and executive officers, and may indemnify other officers and employees, for liabilities arising out of their relationship with the Company, (ii) contracts under which the Company must indemnify directors and certain officers for liabilities arising out of their relationship with the Company, (iii) contracts under which the Company may be required to indemnify customers or partners against certain claims, including claims from third parties asserting, among other things, infringement of their intellectual property rights and (iv) procurement, consulting, or license agreements under which the Company may be required to indemnify vendors, consultants or licensors for certain claims, including claims that may be brought against them arising from acts or omissions with respect to the supplied products, technology or services. From time to time, the Company may receive indemnification claims under these contracts in the normal course of business. In addition, under these contracts the Company may have to modify the accused infringing intellectual property and/or refund amounts received. In the event that one or more of these matters were to result in a claim against the Company, an adverse outcome, including a judgment or settlement, may cause a material adverse effect on the Company’s future business, operating results or financial condition. It is not possible to determine the maximum potential amount under these contracts due to the limited history of prior indemnification claims and the unique facts and circumstances involved in each particular agreement. The Company maintains director and officer insurance, which may cover certain liabilities arising from the Company’s obligation to indemnify its directors and certain officers. To the date of the unaudited condensed consolidated financial statements were issued, the Company has not incurred any material costs or accrued any liabilities in the unaudited condensed consolidated financial statements as a result of these provisions. Litigation The Company’s industry is characterized by frequent claims and litigation, including claims regarding intellectual property. As a result, the Company may be subject to various legal proceedings from time to time. The results of any future litigation cannot be predicted with certainty, and regardless of the outcome, litigation can have an adverse impact on the Company because of defense and settlement costs, diversion of management resources and other factors. Management is not aware of any pending or threatened litigation.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2021
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The Company’s unaudited condensed consolidated financial statements and accompanying notes have been prepared in accordance with generally accepted accounting principles in the United States of America, or U.S. GAAP, as determined by the Financial Accounting Standards Board, or FASB, Accounting Standards Codification, or ASC, and pursuant to the regulations of the U.S. Securities and Exchange Commission, or SEC. The unaudited condensed consolidated financial statements include the accounts of the Company and its subsidiary. All intercompany transactions and balances have been eliminated. The Business Combination discussed in Note 1 was accounted for as a reverse recapitalization with Legacy Surrozen as the accounting acquirer and Consonance as the acquired company for accounting purposes. Accordingly, all historical financial information presented in the unaudited condensed consolidated financial statements represents the accounts of Legacy Surrozen at their historical cost as if Legacy Surrozen is the predecessor to the Company. The unaudited condensed consolidated financial statements following the closing of the Business Combination reflect the results of the combined entity’s operations. All issued and outstanding common stock, redeemable convertible preferred stock and stock awards of Legacy Surrozen and per share amounts contained in the unaudited condensed consolidated financial statements for the periods presented prior to the closing of the Business Combination have been retroactively restated to reflect the exchange ratio established in the Business Combination. See Note 3, " Recapitalization " for additional details.
Use of Estimates	Use of Estimates The preparation of unaudited condensed consolidated financial statements in conformity with U.S. GAAP requires management to make judgments, estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities as of the date of the unaudited condensed consolidated financial statements and the reported amounts of expenses during the reporting period. Significant estimates and assumptions made in the accompanying unaudited condensed consolidated financial statements include, but are not limited to, certain accruals for research and development activities, the fair value of common stock prior to the Business Combination, stock-based compensation expense, fair value of warrants issued in connection with the PIPE Financing, uncertain tax positions and lease liabilities. Management bases its estimates on historical experience and on various other market-specific and relevant assumptions that are believed to be reasonable under the circumstances, the results of which form the basis for making judgments about the carrying value of assets and liabilities that are not readily apparent from other sources. Actual results could materially differ from those estimates. The extent to which the coronavirus 2019, or COVID-19, pandemic will ultimately impact the Company’s business, results of operations, financial conditions, or cash flows continues to be highly uncertain. The severity of the impact on the Company's business for the remainder of calendar year 2021 and beyond will depend on a number of factors, including, but not limited to, the duration and severity of the pandemic, and the impact of any variants of the virus, the extent and severity of the impact on the Company's customers and suppliers, the continued disruption to demand for the Company's products and services, and the impact of the global business and economic environment on liquidity and the availability of capital, all of which are uncertain and cannot be predicted.
Unaudited Condensed Consolidated Financial Statements	Unaudited Condensed Consolidated Financial Statements The accompanying unaudited condensed consolidated balance sheet as of September 30, 2021, the unaudited condensed consolidated statements of stockholders’ equity and the unaudited condensed consolidated statements of operations and comprehensive loss for the three and nine months ended September 30, 2021 and 2020, and the unaudited condensed consolidated statements of cash flows for the nine months ended September 30, 2021 and 2020 are unaudited. The unaudited condensed consolidated financial statements have been prepared in accordance with U.S. GAAP for interim financial information and in accordance with the instructions to Form 10-Q and Rule 10-01 of Regulation S-X of the Securities Act of 1933, as amended. Accordingly, they do not include all of the information and notes required by U.S. GAAP for complete financial statements. The unaudited condensed consolidated financial statements, in management’s opinion, include all adjustments consisting of only normal recurring adjustments necessary for the fair statement of the Company’s financial position as of September 30, 2021, its results of operations for the three and nine months ended September 30, 2021 and 2020, and its cash flows for the nine months ended September 30, 2021 and 2020. The financial data and the other financial information disclosed in the notes to these unaudited condensed consolidated financial statements related to the nine-month periods are also unaudited. The unaudited condensed consolidated balance sheet as of December 31, 2020 was derived from the audited financial statements as of that date. The results of operations for the three and nine months ended September 30, 2021 are not necessarily indicative of the results to be expected for the full fiscal year or any other period. These unaudited condensed consolidated financial statements should be read in conjunction with the Company’s audited financial statements and accompanying notes for the years ended December 31, 2020.
Restricted Cash	Restricted Cash As of each of September 30, 2021 and December 31, 2020, the Company had $ 0.4 million of restricted cash in the form of a letter of credit for the Company’s facility lease. The restricted cash is classified as a noncurrent asset as the Company is required to maintain the letter of credit for the benefit of the landlord until the end of the lease term in April 2025.
Concentration of Credit Risk	Concentration of Credit Risk Financial instruments, which potentially subject the Company to significant concentration of credit risk, consist of cash, cash equivalents, investments and restricted cash. The Company is exposed to credit risk in the event of default to the extent recorded in the unaudited condensed consolidated balance sheets. The Company has not experienced any losses in such accounts. Management believes that the Company is not exposed to significant credit risk due to the financial position of the depository institution in which its bank deposits are held. To manage credit risks related to investments, the Company invests in various highly rated commercial paper, government bonds, corporate bonds and foreign bonds.
Investments	Investments The Company has investments in marketable securities. The Company’s investment policy is consistent with the definition of available-for-sale securities. The Company does not buy or hold securities principally for the purpose of selling them in the near future. The Company’s policy is focused on the preservation of capital, liquidity, and return. From time to time, the Company may sell certain securities, but the objectives are generally not to generate profits on short-term differences in price. Short-term investments have maturities less than or equal to one year as of the balance sheet date. Long-term investments have maturities greater than one year as of the balance sheet date. These marketable securities are carried at estimated fair value with unrealized holding gains and losses included in other comprehensive loss in stockholders’ equity until realized. Gains and losses on marketable security transactions are reported on the specific-identification method. Dividend and interest income are recognized in the unaudited condensed consolidated statements of operations and comprehensive loss when earned.
Warrant Liabilities	Warrant Liabilities The Company's Public Warrants, Private Placement Warrants and PIPE Warrants were classified as liabilities (see Note 8). The transaction costs of $ 0.4 million that were incurred in connection with the Business Combination were allocated to the warrant liabilities and recognized in other expense, net within the unaudited condensed consolidated statements of operations and comprehensive loss. At the end of each reporting period, any change in fair value during the period are recognized in the other expense, net within the unaudited condensed consolidated statements of operations and comprehensive loss. The Company will continue to adjust the warrant liabilities for changes in the fair value until the earlier of a) the exercise or expiration of the warrants or b) the redemption of the warrants, at which time such warrants will be reclassified to additional paid-in capital.
Research and Development Expenses	Research and Development Expenses Research and development costs are expensed as incurred. Research and development costs consist of external and internal expenses directly attributable to the conduct of research and development programs. The external expenses include the costs of services provided by outside contractors, clinical research organizations and contract manufacturing organizations. The internal expenses include the costs of salaries, payroll taxes, stock-based compensation, employee benefits, materials, supplies, depreciation on and maintenance of research equipment, and the facility costs for laboratory space used for research and development activities, such as rent, utilities, insurance, repairs and maintenance, and general support services. The Company has entered into and may continue to enter into licensing or subscription arrangements to access and utilize certain technology. In each case, the Company evaluates if the license agreement results in the acquisition of an asset or a business. To date, none of the Company’s license agreements have been considered an acquisition of a business. For asset acquisitions, the upfront payments to acquire such licenses, as well as any future milestone payments made before product approval that do not meet the definition of a derivative, are immediately recognized as research and development expense when they are paid or become payable, provided there is no alternative future use of the rights in other research and development projects. In September 2020, the Company was awarded a grant from the National Institute of Health, which would partially fund studies for SZN-043 in an amount up to $ 1.0 million through August 2021, with the possibility of an additional $ 2.0 million through August 2025, subject to the availability of funds and satisfactory progress of the project. The Company records the government grant received as a liability and ratably recognizes the amount as a reduction of research and development expenses when the costs related to the grant are incurred. As of September 30, 2021, the Company received $ 0.9 million from the grant. During the three and nine months ended September 30, 2021, $ 0.8 million was recognized as a reduction of research and development expenses.
Net Loss Per Share	Net Loss Per Share Basic net loss per share is calculated by dividing the net loss attributable to common stock by the weighted-average number of shares of common stock outstanding for the period, without consideration for potential dilutive securities. Since the Company was in a loss position for the periods presented, basic net loss per share is the same as diluted net loss per share as the effects of potentially dilutive securities are antidilutive. The following table presents the potential common stock outstanding that were excluded from the computation of diluted net loss per share of common stock as of the periods presented because including them would have been antidilutive: September 30, 2021 2020 Options outstanding 1,700,513 890,239 Unvested restricted stock 178,208 54,157 Unvested common stock subject to repurchase 101,879 110,442 Warrants to purchase common stock 7,217,974 — Total 9,198,574 1,054,838
Emerging Growth Company Status	Emerging Growth Company Status The Company is an emerging growth company, as defined in the Jumpstart Our Business Startups Act of 2012, or the JOBS Act. Under the JOBS Act, emerging growth companies can delay adopting new or revised accounting standards issued subsequent to the enactment of the JOBS Act until such time as those standards apply to private companies. The Company has elected to use this extended transition period for complying with certain new or revised accounting standards that have different effective dates for public and private companies until the earlier of the date that it is (i) no longer an emerging growth company or (ii) affirmatively and irrevocably opt out of the extended transition period provided in the JOBS Act. As a result, these unaudited condensed consolidated financial statements may not be comparable to companies that comply with the new or revised accounting pronouncements as of public company effective dates.
Recently Adopted Accounting Pronouncements	Recently Adopted Accounting Pronouncements In December 2019, the FASB issued ASU No. 2019-12, Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes, which amends the existing guidance relating to the accounting for income taxes. This standard is intended to simplify the accounting for income taxes by removing certain exceptions to the general principles of accounting for income taxes and to improve the consistent application of U.S. GAAP for other areas of accounting for income taxes by clarifying and amending existing guidance. The standard is effective for public business entities for fiscal years beginning after December 15, 2020 and interim periods within those fiscal years. The standard is effective for entities other than public business entities for fiscal years beginning after December 15, 2021. The Company early adopted this guidance as of January 1, 2021, with no material impact on the unaudited condensed consolidated financial statements upon adoption.

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Tables)	9 Months Ended
	Sep. 30, 2021
Accounting Policies [Abstract]
Schedule of Anti-dilutive Securities Excluded from Computation of Earnings Per Share	The following table presents the potential common stock outstanding that were excluded from the computation of diluted net loss per share of common stock as of the periods presented because including them would have been antidilutive: September 30, 2021 2020 Options outstanding 1,700,513 890,239 Unvested restricted stock 178,208 54,157 Unvested common stock subject to repurchase 101,879 110,442 Warrants to purchase common stock 7,217,974 — Total 9,198,574 1,054,838

Fair Value Measurement (Tables)

Fair Value Measurement (Tables)	9 Months Ended
	Sep. 30, 2021
Fair Value Disclosures [Abstract]
Schedule of Financial Assets and Liabilities Measured at Fair Value on Recurring Basis	The following tables summarize the Company’s financial assets and liabilities that are measured at fair value on a recurring basis (in thousands): As of September 30, 2021 Level 1 Level 2 Level 3 Total Assets: Money market funds (1) $ 55,606 $ — $ — $ 55,606 Commercial paper — 39,739 — 39,739 Government bonds — 18,191 — 18,191 Corporate bonds — 12,652 — 12,652 Foreign bonds — 3,744 — 3,744 Total financial assets measured at fair $ 55,606 $ 74,326 $ — $ 129,932 Liabilities: Public Warrants $ 3,496 $ — $ — $ 3,496 Private Placement Warrants — 165 — 165 PIPE Warrants — — 4,647 4,647 Total financial liabilities measured at $ 3,496 $ 165 $ 4,647 $ 8,308 As of December 31, 2020 Level 1 Level 2 Level 3 Total Assets: Money market funds (1) $ 31,896 $ — $ — $ 31,896 Corporate bonds — 1,115 — 1,115 Commercial paper (2) — 15,285 — 15,285 Total financial assets measured at $ 31,896 $ 16,400 $ — $ 48,296 (1) Money market funds are included in cash and cash equivalents on the unaudited condensed consolidated balance sheet as of September 30, 2021 and December 31, 2020. (2) As of December 31, 2020, marketable securities with original maturities of three months or less, in the amount of $ 2.2 million, are included in cash and cash equivalents on the unaudited condensed consolidated balance sheet.
Schedule of Measurement of PIPE Warrants with Binomial Lattice Model	The key inputs into the binomial lattice model for the PIPE Warrants were as follows at the initial measurement and September 30, 2021: August 11, September 30, 2021 2021 Expected term (in years) 5.01 4.87 Expected volatility 18.90 % 37.80 % Risk-free interest rate 0.81 % 0.95 % Dividend yield — —
Summary of Changes in Fair Value of Warrant Liabilities	The following table set forth a summary of the change in the fair value of the Company’s warrant liabilities for the three and nine months ended September 30, 2021 (in thousands): Public Warrants Private Placement Warrants PIPE Warrants Total Warrant Liabilities Balance, beginning of period $ — $ — $ — $ — Assumption in Business Combination 3,557 168 4,647 8,372 Change in fair value upon (1) ( 61 ) ( 3 ) — ( 64 ) Balance, end of period $ 3,496 $ 165 $ 4,647 $ 8,308 Change in fair value of the warrant liabilities was recognized in other expense, net within the unaudited condensed consolidated statements of operations and comprehensive loss.
Schedule of Investments by Security Type	The following tables provide the Company’s investments by security type (in thousands): As of September 30, 2021 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Commercial paper $ 39,739 $ — $ — $ 39,739 Corporate bonds 5,591 — ( 3 ) 5,588 Foreign bonds 3,745 — ( 1 ) 3,744 Total short-term investments $ 49,075 $ — $ ( 4 ) $ 49,071 Government bonds $ 18,202 $ — $ ( 11 ) $ 18,191 Corporate bonds 7,065 1 ( 2 ) 7,064 Total long-term investments $ 25,267 $ 1 $ ( 13 ) $ 25,255 As of December 31, 2020 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Corporate bonds $ 1,115 $ — $ — $ 1,115 Commercial paper 15,285 — — 15,285 Total short-term investments $ 16,400 $ — $ — $ 16,400
Schedule Of Unrealized Loss On Investments	The following table indicates the length of the time that individual securities have been in a continuous unrealized loss position as of September 30, 2021: Less Than 12 Months Number of Investments Fair Value Unrealized Losses Government bonds 3 $ 18,191 $ ( 11 ) Corporate bonds 3 9,197 ( 5 ) Foreign bonds 2 3,744 ( 1 ) 8 $ 31,132 $ ( 17 )

Balance Sheet Components (Table

Balance Sheet Components (Tables)	9 Months Ended
	Sep. 30, 2021
Balance Sheet Related Disclosures [Abstract]
Schedule of Prepaid Expense and Other Current Assets	Prepaid expenses and other current assets consist of the following (in thousands): September 30, 2021 December 31, 2020 Prepaid insurance $ 2,211 $ 2 Prepaid research and development expenses 618 256 Prepaid rent 330 322 Other 676 462 Prepaid expenses and other current assets $ 3,835 $ 1,042
Schedule of Accrued Liabilities	Accrued liabilities consist of the following (in thousands): September 30, 2021 December 31, 2020 Accrued payroll and related expenses $ 2,109 $ 1,673 Accrued research and development expenses 3,805 1,305 Accrued professional service fees 1,850 — Liability for early exercised stock options 287 188 Other accrued expenses 444 228 Accrued liabilities $ 8,495 $ 3,394
Schedule of Other Assets	Other assets consist of the following (in thousands): September 30, 2021 December 31, 2020 Prepaid insurance $ 848 $ — Other 77 39 Other assets $ 925 $ 39

Leases (Tables)

Leases (Tables)	9 Months Ended
	Sep. 30, 2021
Leases [Abstract]
Summary of Lessee, Operating Lease, Liability, Maturity	Aggregate future minimum rental payments under the operating leases as of September 30, 2021, were as follows (in thousands): Remaining three months ending December 31, 2021 $ 722 Year ending December 31, 2022 2,713 Year ending December 31, 2023 2,564 Year ending December 31, 2024 2,646 Year ending December 31, 2025 891 Total lease payments 9,536 Less: Imputed interest ( 1,265 ) Operating lease liabilities $ 8,271

Common Stock Warrants Outstandi

Common Stock Warrants Outstanding (Tables)	9 Months Ended
	Sep. 30, 2021
Equity [Abstract]
Schedule of Common Stock Warrants Outstanding	As of September 30, 2021, the following common stock warrants were outstanding: Type Classification Expiration Date Exercise Price per Share September 30, 2021 Public Warrants Liability August 12, 2026 $ 11.50 3,066,651 Private Placement Warrants Liability August 12, 2026 11.50 144,666 PIPE Warrants Liability August 12, 2026 11.50 4,006,657 Total 7,217,974

Stock Based Compensation Plan (

Stock Based Compensation Plan (Tables)	9 Months Ended
	Sep. 30, 2021
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Summary of Stock Option Activity	A summary of stock option activity under the plans is set forth below: Options outstanding Weighted Weighted Average Aggregate Average Remaining Intrinsic Number of Exercise Contractual Life Value Options Price (In years) (In thousands) Outstanding – 6,093,611 $ 0.40 8.43 Retroactive application of ( 5,023,310 ) Outstanding – 1,070,301 2.26 8.43 Granted 839,972 10.45 Exercised ( 154,427 ) 2.36 Cancelled ( 55,333 ) 4.60 Outstanding – 1,700,513 6.23 8.59 $ 4,262 Options outstanding and 539,783 2.56 7.33 2,715 Options vested and expect to vest 1,700,513 6.23 8.59 4,262
Summary of RSA Activity	The following table summarizes the Company’s RSA activity: Weighted Average Number of Grant Date Shares Fair Value RSAs, unvested at December 31, 2020, 263,022 $ 0.69 Retroactive application of ( 216,823 ) RSAs, unvested at December 31, 2020, 46,199 3.96 Granted 193,208 9.95 Vested ( 44,732 ) 6.83 Forfeited ( 16,467 ) 9.76 RSAs, unvested at September 30, 2021 178,208 9.19
Schedule of Weighted Average Assumptions Used to Estimate Fair Value of Options	The fair value of options is estimated at the grant date using the Black-Scholes option-pricing model with the following weighted-average assumptions: Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 Expected term (in years) 6.08 6.04 6.00 6.00 Expected volatility 81.99 % 62.30 % 69.98 % 60.17 % Risk-free rate 0.99 % 0.33 % 0.85 % 1.05 % Dividend yield — — — - —
Schedule of Stock-Based Compensation Expense	Total stock-based compensation recorded in the unaudited condensed consolidated statements of operations and comprehensive loss related to options and RSAs was as follows (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 Research and development $ 187 $ 103 $ 534 $ 304 General and administrative 429 37 1,089 144 Total stock-based $ 616 $ 140 $ 1,623 $ 448

Organization and Business - Add

Organization and Business - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands	Apr. 15, 2021	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Aug. 31, 2021	Dec. 31, 2020
Subsidiary Sale Of Stock [Line Items]
Stock issued during period shares new shares				12,020,000
Common stock warrants exercise price per share		$ 11.50		$ 11.50
Transaction costs						$ 400
Net loss		$ (14,019)	$ (8,635)	$ (39,694)	$ (21,889)
Loss from operations		(13,705)	$ (8,641)	(39,396)	(21,971)
Net cash used in Operation				(37,270)	$ (19,762)
Accumulated deficit		(127,695)		(127,695)			$ (88,001)
Cash, cash equivalents and investments		$ 135,400		135,400
Surrozen Inc
Subsidiary Sale Of Stock [Line Items]
Common stock, conversion basis	purchased an aggregate of 12,020,000 units for a purchase price of $10.00 per unit through a private investment in public entity financing, or PIPE Financing. Each unit consists of one share of the Company’s common stock and one-third of one redeemable warrant for one share of the Company’s common stock exercisable at $11.50 per share.
Proceeds from divestiture of businesses				$ 128,300
Surrozen Inc | Private Placement
Subsidiary Sale Of Stock [Line Items]
Common stock warrants exercise price per share	$ 11.50
Surrozen Inc | Unit | Private Placement
Subsidiary Sale Of Stock [Line Items]
Stock issued during period shares new shares	12,020,000
Shares issued, price per share	$ 10

Summary of Significant Accoun_4

Summary of Significant Accounting Policies - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2021	Aug. 31, 2025	Aug. 31, 2021	Dec. 31, 2020	Sep. 30, 2020
Accounting Policies [Line Items]
Restricted cash	$ 61,501	$ 61,501				$ 59,325
Transaction costs				$ 400
Recognized of reduction for research and development expenses	800	800
National Institute Of Health
Accounting Policies [Line Items]
Award Granted	900	900	$ 2,000	$ 1,000
Letter of Credit
Accounting Policies [Line Items]
Restricted cash	$ 400	$ 400			$ 400

Summary of Significant Accoun_5

Summary of Significant Accounting Policies - Schedule of Anti-dilutive Securities Excluded from Computation of Earnings Per Share (Details) - shares	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Accounting Policies [Line Items]
Antidilutive securities excluded from computation of diluted net loss per share	9,198,574	1,054,838
Options Outstanding [Member]
Accounting Policies [Line Items]
Antidilutive securities excluded from computation of diluted net loss per share	1,700,513	890,239
Unvested Restricted Stock
Accounting Policies [Line Items]
Antidilutive securities excluded from computation of diluted net loss per share	178,208	54,157
Unvested Common Stock Subject To Repurchase
Accounting Policies [Line Items]
Antidilutive securities excluded from computation of diluted net loss per share	101,879	110,442
Warrants To Purchase Common Stock
Accounting Policies [Line Items]
Antidilutive securities excluded from computation of diluted net loss per share	7,217,974

Recapitalization - Additional I

Recapitalization - Additional Information (Details) $ in Thousands	1 Months Ended	9 Months Ended
	Aug. 31, 2021USD ($)shares	Sep. 30, 2021USD ($)shares	Sep. 30, 2020USD ($)	Dec. 31, 2020shares
Subsidiary Sale Of Stock [Line Items]
Proceeds from issuance of common stock upon Business Combination and PIPE Financing, net of issuance costs		$ 124,095	$ 0
Transaction costs	$ 400
Reduction Of Additional Paid In Capital	$ 5,600
Common Stock, Shares, Outstanding | shares		35,027,407		18,256,628
Common Stock, Shares, Issued | shares		35,027,407		18,256,628
Exchange ratio	0.175648535	0.175648535
Surrozen Inc
Subsidiary Sale Of Stock [Line Items]
Common Stock, Shares, Outstanding | shares	4,420,757
Common Stock, Shares, Issued | shares	16,440,757
Other intangible assets	$ 0
Goodwill	0
Private Investment In Public Entity Offering [Member]
Subsidiary Sale Of Stock [Line Items]
Proceeds from cash acquired through acquisition and PIPE offering	128,300
Proceeds from issuance of common stock upon Business Combination and PIPE Financing, net of issuance costs	8,100
Proceeds from issuance of units upon PIPE Financing	120,200
Transaction costs	$ 6,000
Private Investment In Public Entity Offering [Member] | Surrozen Inc
Subsidiary Sale Of Stock [Line Items]
Common Stock, Shares, Issued | shares	12,020,000

Fair Value Measurement - Schedu

Fair Value Measurement - Schedule of Financial Assets and Liabilities Measured at Fair Value on Recurring Basis (Details) - Fair Value, Recurring [Member] - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets	$ 129,932	$ 48,296
Liabilities	8,308
Money Market Funds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets	55,606	31,896
Commercial Paper
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets	39,739	15,285
Government bonds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets	18,191
Corporate Bonds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets	12,652	1,115
Foreign bonds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets	3,744
Public Warrants
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Liabilities	3,496
Private Placement Warrants
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Liabilities	165
PIPE Warrants
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Liabilities	4,647
Level 1
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets	55,606	31,896
Liabilities	3,496
Level 1 | Money Market Funds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets	55,606	31,896
Level 1 | Commercial Paper
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets
Level 1 | Government bonds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets
Level 1 | Corporate Bonds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets	0
Level 1 | Foreign bonds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets
Level 1 | Public Warrants
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Liabilities	3,496
Level 1 | Private Placement Warrants
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Liabilities	0
Level 1 | PIPE Warrants
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Liabilities
Level 2
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets	74,326	16,400
Liabilities	165
Level 2 | Money Market Funds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets
Level 2 | Commercial Paper
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets	39,739	15,285
Level 2 | Government bonds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets	18,191
Level 2 | Corporate Bonds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets	12,652	1,115
Level 2 | Foreign bonds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets	3,744
Level 2 | Public Warrants
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Liabilities	0
Level 2 | Private Placement Warrants
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Liabilities	165
Level 2 | PIPE Warrants
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Liabilities
Level 3
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets
Liabilities	4,647
Level 3 | Money Market Funds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets	0
Level 3 | Commercial Paper
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets	0
Level 3 | Government bonds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets	0
Level 3 | Corporate Bonds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets	0
Level 3 | Foreign bonds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets
Level 3 | Public Warrants
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Liabilities	0
Level 3 | Private Placement Warrants
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Liabilities	0
Level 3 | PIPE Warrants
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Liabilities	$ 4,647

Fair Value Measurement - Sche_2

Fair Value Measurement - Schedule of Financial Assets and Liabilities Measured at Fair Value on Recurring Basis (Parenthetical) (Details) $ in Millions	Dec. 31, 2020USD ($)
Fair Value Disclosures [Abstract]
Marketable securities at fair value	$ 2.2

Fair Value Measurement - Additi

Fair Value Measurement - Additional Information (Details) $ / shares in Units, $ in Thousands	9 Months Ended
	Sep. 30, 2021USD ($)$ / shares	Dec. 31, 2020USD ($)
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Short-term investments | $	$ 49,071	$ 14,200
Other than temporary impairment losses | $	$ 0
PIPE Warrants | Maximum [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Stock price to redeem warrants | $ / shares	$ 18
PIPE Warrants | Minimum [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Stock price to redeem warrants | $ / shares	$ 10
Measurement Input, Expected Dividend Rate | PIPE Warrants
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Alternative Investment, Measurement Input	0

Fair Value Measurement - Sche_3

Fair Value Measurement - Schedule of Measurement of PIPE Warrants with Binomial Lattice Model (Details)	Sep. 30, 2021yr	Aug. 11, 2021yr
Expected Term (Years)
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Warrants, Measurement Input	4.87	5.01
Expected Volatility
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Warrants, Measurement Input	37.80	18.90
Risk-free Interest Rate
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Warrants, Measurement Input	0.95	0.81
Measurement Input, Expected Dividend Rate
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Warrants, Measurement Input	0	0

Fair Value Measurement - Summar

Fair Value Measurement - Summary of Changes in Fair Value of Warrant Liabilities (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2021USD ($)
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Balance, beginning of period	$ 0
Assumption in Business Combination	8,372
Change in fair value upon remeasurement	(64)
Balance, ending of period	8,308
Public Warrants
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Balance, beginning of period	0
Assumption in Business Combination	3,557
Change in fair value upon remeasurement	(61)
Balance, ending of period	3,496
Private Placement Warrants
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Balance, beginning of period	0
Assumption in Business Combination	168
Change in fair value upon remeasurement	(3)
Balance, ending of period	165
PIPE Warrants
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Balance, beginning of period	0
Assumption in Business Combination	4,647
Change in fair value upon remeasurement	0
Balance, ending of period	$ 4,647

Fair Value Measurement - Sche_4

Fair Value Measurement - Schedule of Investments by Security Type (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Amortized Cost Current	$ 49,075	$ 16,400
Amortized Cost, Non-current	25,267
Gross Unrealized Gains, Current	0	0
Gross Unrealized Gains, Non-current	1
Gross Unrealized Losses, Current	(4)	0
Gross Unrealized Losses, Non-current	13
Fair Value, Current	49,071	16,400
Fair Value, Non-current	25,255
Corporate Bonds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Amortized Cost Current	5,591	1,115
Amortized Cost, Non-current	7,065
Gross Unrealized Gains, Current	0	0
Gross Unrealized Gains, Non-current	1
Gross Unrealized Losses, Current	(3)	0
Gross Unrealized Losses, Non-current	2
Fair Value, Current	5,588	1,115
Fair Value, Non-current	7,064
Commercial Paper
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Amortized Cost Current	39,739	15,285
Gross Unrealized Gains, Current	0	0
Gross Unrealized Losses, Current		0
Fair Value, Current	39,739	$ 15,285
Foreign bonds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Amortized Cost Current	3,745
Gross Unrealized Gains, Current	0
Gross Unrealized Losses, Current	(1)
Fair Value, Current	3,744
Government bonds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Amortized Cost, Non-current	18,202
Gross Unrealized Gains, Non-current
Gross Unrealized Losses, Non-current	11
Fair Value, Non-current	$ 18,191

Fair Value Measurement - Sche_5

Fair Value Measurement - Schedule Of Unrealized Loss On Investments (Details) $ in Thousands	Sep. 30, 2021USD ($)Investments
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Number Of Positions | Investments	8
Less then 12 Months, Fair Value	$ 31,132
Less then 12 Months, Unrealized Losses	$ 17
Corporate Bonds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Number Of Positions | Investments	3
Less then 12 Months, Fair Value	$ 9,197
Less then 12 Months, Unrealized Losses	$ 5
Government bonds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Number Of Positions | Investments	3
Less then 12 Months, Fair Value	$ 18,191
Less then 12 Months, Unrealized Losses	$ 11
Foreign bonds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Number Of Positions | Investments	2
Less then 12 Months, Fair Value	$ 3,744
Less then 12 Months, Unrealized Losses	$ 1

Balance Sheet Components- Sched

Balance Sheet Components- Schedule of Prepaid Expenses and Other Current Assets (Detail) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Balance Sheet Related Disclosures [Abstract]
Prepaid insurance	$ 2,211	$ 2
Prepaid research and development expenses	618	256
Prepaid rent	330	322
Others	676	462
Prepaid expenses and other current assets	$ 3,835	$ 1,042

Balance Sheet Components - Sche

Balance Sheet Components - Schedule of Accrued Liabilities (Detail) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Balance Sheet Related Disclosures [Abstract]
Accrued payroll and related expenses	$ 2,109	$ 1,673
Accrued research and development expenses	3,805	1,305
Accrued professional service fees	1,850
Liability for early exercised stock options	287	188
Other accrued expenses	444	228
Accrued liabilities	$ 8,495	$ 3,394

Balance Sheet Components - Sc_2

Balance Sheet Components - Schedule of Other Assets (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Prepaid insurance	$ 2,211	$ 2
Others	676	462
Other assets	925	39
Other Assets [Member]
Prepaid insurance	848
Others	$ 77	$ 39

Leases - Additional Information

Leases - Additional Information (Details) $ in Thousands	1 Months Ended	3 Months Ended		9 Months Ended
	Sep. 30, 2021USD ($)	Sep. 30, 2021USD ($)	Sep. 30, 2020USD ($)	Sep. 30, 2021USD ($)	Sep. 30, 2020USD ($)	Dec. 31, 2020USD ($)	Jan. 31, 2020ft²	Aug. 31, 2016ft²
Lessee, Lease, Description [Line Items]
Operating lease month of expiry of lease	2022-06
Restricted cash	$ 405	$ 405		$ 405		$ 405
Right-of-use asset obtained in exchange for operating lease liabilities	$ 300				$ 563
Operating Lease, Expense		$ 500	$ 500	$ 1,500	$ 1,300
Eighteen Months [Member]
Lessee, Lease, Description [Line Items]
Area of Real Estate Property | ft²							6,478
Operating lease term	18 months	18 months		18 months
CALIFORNIA | Eight Years [Member]
Lessee, Lease, Description [Line Items]
Area of Real Estate Property | ft²								32,813
Operating lease month of expiry of lease				2025-04
Lease incentive from lessor	$ 4,600	$ 4,600		$ 4,600
Restricted cash	$ 400	$ 400		$ 400

Leases - Summary Of Lessee, Ope

Leases - Summary Of Lessee, Operating Lease, Liability, Maturity (Detail) $ in Thousands	Sep. 30, 2021USD ($)
Leases [Abstract]
2021	$ 722
2022	2,713
2023	2,564
2024	2,646
2025	891
Total lease payments	9,536
Less: Imputed interest	(1,265)
Operating lease liabilities	$ 8,271

License Agreements - Additional

License Agreements - Additional Information (Details) - USD ($)	1 Months Ended		3 Months Ended		9 Months Ended
	Jun. 30, 2018	Mar. 31, 2016	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
License Agreements [Line Items]
Stock issued during period, shares, issued for services		42,451
Research and development			$ 10,418,000	$ 6,958,000	$ 29,284,000	$ 17,034,000
Exercises of stock options, shares					154,427
Stanford License Agreements [Member] | Stanford [Member]
License Agreements [Line Items]
Payments for milestone agreement or earned royalties on achievement of milestones		$ 5,000,000
Payments for achievement of specified development and regulatory milestones	$ 425,000
Research and development					$ 50,000	40,000
Payments for milestone agreement on achievement of milestones					$ 0
Stanford License Agreements [Member] | Stanford [Member] | Maximum
License Agreements [Line Items]
Payments for milestone agreement or earned royalties on achievement of milestones		$ 900,000
UCSF License And Option Agreements [Member]
License Agreements [Line Items]
Right to negotiate new agreement exercised option					no
UCSF License And Option Agreements [Member] | Stanford [Member]
License Agreements [Line Items]
Research and development			0	0	$ 0	0
Annual License Maintenance Fee			25,000	0	25,000	0
Payments for milestone agreement on achievement of milestones					0
Distributed Bio Subscription Agreement [Member]
License Agreements [Line Items]
Payments for achievement of specified development and regulatory milestones					5,900,000
Distributed Bio Subscription Agreement [Member] | Stanford [Member]
License Agreements [Line Items]
Research and development					50,000,000
Payments for milestone agreement on achievement of milestones			$ 0	$ 0	$ 0	$ 0

Common Stock Warrants - Additio

Common Stock Warrants - Additional Information (Details) - $ / shares	3 Months Ended	9 Months Ended
	Jun. 30, 2020	Sep. 30, 2021
Common Stock Warrants Outstanding		7,217,974
Stock issued during period shares new shares		12,020,000
Common stock warrants exercise price per share		$ 11.50
Common Stock Warrants Expiration Date		Aug. 12, 2026
Warrant Redemption Condition Minimum Share Price Scenario Two		$ 18
Common Stock
Stock issued during period shares new shares	5,018,525	12,020,000
Public Warrants
Common Stock Warrants Outstanding		3,066,651
Common stock warrants exercise price per share		$ 11.50
Common Stock Warrants Expiration Date		Aug. 12, 2026
Warrant Redemption Period		30 days
Warrant redemption condition minimum share price scenario one		$ 10
Public Warrants | Common Stock, Closing Price equals or Exceeds $18 Per Share [Member]
Redemption Price Per Public Warrant		0.01
Issuance of common stock Per Share		18
Public Warrants | Common Stock, Closing Price equals or Exceeds $10 Per Share [Member]
Redemption Price Per Public Warrant		0.10
Issuance of common stock Per Share		$ 10
Private Placement Warrants
Common Stock Warrants Outstanding		144,666
Common stock warrants exercise price per share		$ 11.50
Common Stock Warrants Expiration Date		Aug. 12, 2026
Lock-In period for Transfer, Assignment or Sale of Warrants		30 days
Private Placement Warrants | Common Stock, Closing Price equals or Exceeds $18 Per Share [Member]
Issuance of common stock Per Share		$ 18
Private Placement Warrants | Common Stock, Closing Price equals or Exceeds $10 Per Share [Member]
Issuance of common stock Per Share		$ 18
PIPE Warrants
Common Stock Warrants Outstanding		4,006,657
Common stock warrants exercise price per share		$ 11.50
Common Stock Warrants Expiration Date		Aug. 12, 2026

Common Stock Warrants - (Detail

Common Stock Warrants - (Details)	9 Months Ended
	Sep. 30, 2021$ / sharesshares
Class Of Warrant Or Right [Line Items]
Common Stock Warrants Expiration Date	Aug. 12, 2026
Common stock warrants exercise price per share | $ / shares	$ 11.50
Common Stock Warrants Outstanding | shares	7,217,974
Public Warrants
Class Of Warrant Or Right [Line Items]
Common Stock Warrant Classification	Liability
Common Stock Warrants Expiration Date	Aug. 12, 2026
Common stock warrants exercise price per share | $ / shares	$ 11.50
Common Stock Warrants Outstanding | shares	3,066,651
Private Placement Warrants
Class Of Warrant Or Right [Line Items]
Common Stock Warrant Classification	Liability
Common Stock Warrants Expiration Date	Aug. 12, 2026
Common stock warrants exercise price per share | $ / shares	$ 11.50
Common Stock Warrants Outstanding | shares	144,666
PIPE Warrants
Class Of Warrant Or Right [Line Items]
Common Stock Warrant Classification	Liability
Common Stock Warrants Expiration Date	Aug. 12, 2026
Common stock warrants exercise price per share | $ / shares	$ 11.50
Common Stock Warrants Outstanding | shares	4,006,657

Redeemable Convertible Prefer_2

Redeemable Convertible Preferred Stock - Additional Information (Details)	9 Months Ended
	Sep. 30, 2021shares
Redeemable convertible preferred stock converted into common stock	one-for-one basis
Temporary equity shares outstanding	0
Convertible preferred stock shares issued upon conversion	16,737,520
Redeemable Convertible Preferred Stock [Member]
Temporary equity shares issued	95,289,932
Temporary equity shares outstanding	95,289,932

Stock Based Compensation Plan -

Stock Based Compensation Plan - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended	9 Months Ended
	Aug. 31, 2021	Sep. 30, 2021
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Intrinsic value of options exercised		$ 1,000
Intrinsic value of options exercised		$ 4,262
Weighted average grant date fair value/shares		$ 6.51
Fair value of RSAs vested		$ 400
Unrecognized stock based compensation expense		$ 8,200
Weighted-average period		3 years 3 months 25 days
Early exercises of options outstanding		101,879
Repurchase price per share		$ 2.82
RSA
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vesting Period		4 years
2021 Stock Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares reserved for future issuance		4,450,253
2015 stock plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expiration period		10 years
Vesting Period		4 years
Cliff vesting period		1 year
Additional stock awards issued under plan		0
Award vesting rights, description		The Company’s outstanding RSAs began vesting one month after the grant date and vest 1/48th per month over four years.
Options | 2021 Stock Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Exercisable period	5 years
Share-based Compensation Arrangement by Share-based Payment Award, Purchase Price of Common Stock, Percent	110.00%
percentage of vesting	25.00%
Description of modification of options	Options under the 2021 Plan generally vest 25% upon one year of continued service to the Company, with the remainder in monthly increments over three additional years.
Options | Maximum | 2021 Stock Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expiration period	10 years
Options | Minimum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Percentage of stockholders	10.00%
Options | Minimum | 2021 Stock Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Purchase Price of Common Stock, Percent	100.00%

Stock Based Compensation Plan_2

Stock Based Compensation Plan - Summary of Stock Option Activity for Company's Stock Option Plans (Details) $ / shares in Units, $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2021USD ($)$ / sharesshares	Dec. 31, 2020$ / sharesshares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of options recapitalization	(5,023,310)
Number of Options Granted	839,972
Number of Options Exercised	(154,427)
Number of Options Cancelled	(55,333)
Number of Options Outstanding Ending Balance	1,700,513
Number of Options outstanding and exercisable	539,783
Number of Options vested and expect to vest	1,700,513
Weighted Average Exercise Price Outstanding, Beginning Balance | $ / shares	$ 0.40
Weighted Average Exercise Price Outstanding Recapitalization | $ / shares	2.26
Weighted Average Exercise Price Granted | $ / shares	10.45
Weighted Average Exercise Price Exercised | $ / shares	2.36
Weighted Average Exercise Price Cancelled | $ / shares	4.60
Weighted Average Exercise Price Outstanding, Ending Balance | $ / shares	6.23	$ 0.40
Weighted Average Exercise Price Options outstanding and exercisable | $ / shares	2.56
Weighted Average Exercise Price Options vested and expect to vest | $ / shares	$ 6.23
Weighted Average Remaining Contractual Life (In Years)	8 years 7 months 2 days	8 years 5 months 4 days
Weighted Average Remaining Contractual Life, exercisable (In Years)	7 years 3 months 29 days
Weighted Average Remaining Contractual Life, vested and expect to vest (In Years)	8 years 7 months 2 days
Aggregate Intrinsic Value | $	$ 4,262
Aggregate Intrinsic Value Options outstanding and exercisable | $	2,715
Aggregate Intrinsic Value Options vested and expect to vest | $	$ 4,262
Previously Reported
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of Options Outstanding Beginning Balance	6,093,611
Number of Options Outstanding Ending Balance		6,093,611
After Business Combination
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of Options Outstanding Beginning Balance	1,070,301
Number of Options Outstanding Ending Balance		1,070,301

Stock Based Compensation Plan_3

Stock Based Compensation Plan - Summary of RSA Activity (Details) - RSA - $ / shares	9 Months Ended
	Sep. 30, 2021	Dec. 31, 2020
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Weighted Average Grant Date Fair Value, Recapitalization		(216,823)
Number of Shares RSAs, Granted	193,208
Number of Shares RSAs, Vested	(44,732)
Number of Shares RSAs, Forfeited	(16,467)
Number of Shares RSAs, unvested, Ending Balance	178,208
Weighted Average Grant Date Fair Value RSAs, Granted	$ 9.95
Weighted Average Grant Date Fair Value RSAs, Vested	6.83
Weighted Average Grant Date Fair Value RSAs, Forfeited	9.76
Weighted Average Grant Date Fair Value RSAs, Unvested Ending Balance	$ 9.19
Previously Reported
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number, Beginning Balance	263,022
Weighted Average Grant Date Fair Value RSAs, Unvested Beginning Balance	$ 0.69
After Business Combination
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number, Beginning Balance	46,199
Weighted Average Grant Date Fair Value RSAs, Recapitalization		$ 3.96

Stock Based Compensation Plan-

Stock Based Compensation Plan- Schedule of Weighted Average Assumptions Used to Estimate Fair Value of Options (Details)	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Expected term (in years)	6 years 29 days	6 years 14 days	6 years	6 years
Expected volatility	81.99%	62.30%	69.98%	60.17%
Risk-free rate	0.99%	0.33%	0.85%	1.05%
Dividend yield	0.00%	0.00%	0.00%	0.00%

Stock Based Compensation Plan_4

Stock Based Compensation Plan - Schedule of Stock-Based Compensation Expenses (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
General and administrative	$ 3,287	$ 1,683	$ 10,112	$ 4,937
Total stock-based compensation expense	616	140	1,623	448
Research and Development Expense
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Research and development	187	103	534	304
General and Administrative Expense
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
General and administrative	$ 429	$ 37	$ 1,089	$ 144