Surrozen (SRZN) 10-K 28 Mar 22 2021 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Mar. 25, 2022	Jun. 30, 2021
Document Information [Line Items]
Document Type	10-K
Amendment Flag	false
Document Annual Report	true
Document Period End Date	Dec. 31, 2021
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	FY
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		35,126,654
Entity Public Float			$ 81.4
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
ICFR Auditor Attestation Flag	false
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 Incorporation, State or Country Code	DE
Document Transition Report	false
Auditor Firm ID	42
Auditor Location	San Francisco, California
Auditor Name	Ernst & Young LLP
Common Stock
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
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

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 33,091	$ 34,982
Short-term marketable securities	68,760	14,200
Prepaid expenses and other current assets	3,338	1,042
Total current assets	105,189	50,224
Property and equipment, net	4,794	5,836
Operating lease right-of-use assets	4,582	5,556
Long-term marketable securities	21,655	0
Restricted cash	405	405
Other assets	549	39
Total assets	137,174	62,060
Current liabilities:
Accounts payable	2,718	1,776
Accrued and other liabilities	8,662	3,394
Lease liabilities, current portion	2,193	2,108
Total current liabilities	13,573	7,278
Lease liabilities, noncurrent portion	5,600	7,489
Warrant liabilities	8,301	0
Total liabilities	27,474	14,767
Commitments and contingencies (Note 6 and Note 12)
Stockholders’ equity:
Preferred stock, $0.0001 par value, 10,000,000 shares authorized; no shares issued and outstanding as of December 31, 2021 and 2020	0	0
Common stock, $0.0001 par value, 500,000,000 shares authorized as of December 31, 2021 and 2020; 35,034,431 and 18,256,628 shares issued and outstanding as of December 31, 2021 and 2020, respectively	4	2
Additional paid-in-capital	252,464	135,292
Accumulated other comprehensive loss	(119)	0
Accumulated deficit	(142,649)	(88,001)
Total stockholders’ equity	109,700	47,293
Total liabilities and stockholders’ equity	$ 137,174	$ 62,060

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - $ / shares	Dec. 31, 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 shares, par value	$ 0.0001	$ 0.0001
Common shares, shares authorized	500,000,000	500,000,000
Common shares, shares issued	35,034,431	18,256,628
Common shares, shares outstanding	35,034,431	18,256,628

Consolidated Statements of Oper

Consolidated Statements of Operations and Comprehensive Loss - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Operating expenses:
Research and development	$ 40,177	$ 25,684
General and administrative	14,214	7,123
Total operating expenses	54,391	32,807
Loss from operations	(54,391)	(32,807)
Interest income	72	91
Other expense, net	(329)	0
Net loss	(54,648)	(32,716)
Unrealized loss on marketable securities, net of tax	(119)	0
Comprehensive loss	$ (54,767)	$ (32,716)
Net loss per share attributable to common stockholders, basic and diluted	$ (2.21)	$ (2.05)
Weighted-average shares used in computing net loss per share attributable to common stockholders, basic and diluted	24,689,339	15,972,348

Condensed Consolidated Statemen

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	Additional Paid-in Capital	Additional Paid-in CapitalPreviously Reported	Additional Paid-in CapitalRevision of Prior Period, Reclassification, Adjustment	Accumulated Other Comprehensive Income (Loss), Derivative Qualifying as Hedge, Excluded Component, Including Portion Attributable to Noncontrolling Interest	Retained Earnings	Retained EarningsPreviously Reported	Redeemable Convertible Preferred StockPreviously Reported	Redeemable Convertible Preferred StockRevision of Prior Period, Reclassification, Adjustment
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)
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													66,718,509	(66,718,509)
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	49,886			$ 1			49,885
Issuance of Series C redeemable convertible preferred stock, net of issuance costs, shares				5,018,525
Exercises of stock options	167						167
Exercises of stock options, shares				71,568
Reclassification to liability for early exercised stock options	(150)						(150)
Vesting of early exercised stock options	85						85
Repurchase of early exercised stock options, shares				(1,393)
Restricted stock granted, shares				17,564
Restricted stock forfeited, shares				(5,123)
Stock-based compensation expense	635						635
Net loss	(32,716)										(32,716)
Balance at the end at Dec. 31, 2020	$ 47,293			$ 2			135,292			$ 0	(88,001)
Balance at the end (in shares) at Dec. 31, 2020				18,256,628
Issuance of Series C redeemable convertible preferred stock, net of issuance costs, shares	12,020,000			12,020,000
Issuance of common stock upon Business Combination and PIPE Financing, net of transaction costs and warrant liabilities	$ 114,465			$ 2			114,463
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	$ 411						411
Exercises of stock options, shares	161,451			161,447
Reclassification to liability for early exercised stock options	$ (225)						(225)
Vesting of early exercised stock options	207						207
Repurchase of early exercised stock options, shares				1,142
Restricted stock granted, shares				(193,208)
Restricted stock forfeited, shares				(16,467)
Stock-based compensation expense	2,316						2,316
Other comprehensive loss	(119)									(119)
Net loss	(54,648)										(54,648)
Balance at the end at Dec. 31, 2021	$ 109,700			$ 4			$ 252,464			$ (119)	$ (142,649)
Temporary equity, Balance at the end (in shares) at Dec. 31, 2021	0
Balance at the end (in shares) at Dec. 31, 2021				35,034,431

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Redeemable Convertible Preferred Stock and Shareholders' Equity (Unaudited) (Parenthetical) $ in Thousands	12 Months Ended
	Dec. 31, 2020USD ($)
Series C Redeemable Convertible Preferred Stock
Adjustment to additional paid in capital stock issuance costs	$ 114

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Operating activities:
Net loss	$ (54,648)	$ (32,716)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation	2,066	1,937
Stock-based compensation	2,316	635
Non-cash operating lease expense	1,231	992
Amortization of premium on marketable securities, net	105	1
Change in fair value of warrant liabilities	(71)	0
Transaction costs allocated to warrants in connection with Business Combination	409	0
Changes in operating assets and liabilities:
Prepaid expenses and other current assets	(2,296)	(732)
Other assets	(510)	10
Accounts payable	857	537
Accrued and other liabilities	3,789	1,903
Operating lease liabilities	(2,061)	(1,666)
Net cash used in operating activities	(48,813)	(29,099)
Investing activities:
Purchases of property and equipment	(1,269)	(874)
Purchases of marketable securities	(91,739)	(14,201)
Proceeds from sales of marketable securities	1,100	0
Proceeds from maturities of marketable securities	14,200	0
Net cash used in investing activities	(77,708)	(15,075)
Financing activities:
Proceeds from issuance of common stock upon Business Combination and PIPE Financing, net of transaction costs	124,220	0
Proceeds from issuance of redeemable convertible preferred stock, net of issuance costs	0	49,886
Proceeds from exercise of stock options	411	167
Repurchase of early exercised stock options	(1)	(1)
Net cash provided by financing activities	124,630	50,052
Net (decrease) increase in cash, cash equivalents and restricted cash	(1,891)	5,878
Cash, cash equivalents and restricted cash at beginning of year	35,387	29,509
Cash, cash equivalents and restricted cash at end of year	33,496	35,387
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 accounts payable and accrued liabilities	1,792	0
Purchases of property and equipment included in accounts payable	22	267
Vesting of early exercises of stock options	207	85
Reclassification to liability for early exercised stock options	225	150
Increase in right-of-use assets and lease liabilities due to lease extension	257	0
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	33,091	34,982
Restricted cash	405	405
Cash, cash equivalents and restricted cash	$ 33,496	$ 35,387

Organization and Business

Organization and Business	12 Months Ended
	Dec. 31, 2021
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Organization and Business	Note 1. Orga nization 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., 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 the Company. 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 $ 128.8 million, after deducting the transaction fees incurred by Consonance. 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 years ended December 31, 2021 and 2020, the Company incurred a net loss of $ 54.6 million and $ 32.7 million, respectively. During the years ended December 31, 2021 and 2020, the Company used $ 48.8 million and $ 29.1 million of cash in operations. As of December 31, 2021, the Company had an accumulated deficit of approximately $ 142.6 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 December 31, 2021, the Company had cash, cash equivalents and marketable securities of $ 123.5 million . Given the cash proceeds from the Business Combination and the PIPE Financing, management believes that the existing cash, cash equivalents, and marketable securities are sufficient for the Company to continue operating activities for at least the next 12 months from the date of issuance of its 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. In February 2022, the Company entered into a purchase agreement and a registration rights agreement with Lincoln Park Capital Fund, LLC, or Lincoln Park, pursuant to which the Company has the right, but not the obligation, to sell to Lincoln Park, and Lincoln Park is obligated to purchase up to $ 50.0 million of the Company’s common stock from time to time over a 36-month period, subject to certain conditions and limitations (see Note 14). 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. Risks and Uncertainties The Company’s future results of operations involve a number of risks and uncertainties. Factors that could affect the Company’s future operating results and cause actual results to vary materially from expectations include, but are not limited to, uncertainty of results of clinical trials and reaching milestones, uncertainty of regulatory approval of the Company’s potential drug candidates, uncertainty of market acceptance of the Company’s products, competition from substitute products and larger companies, securing and protecting proprietary technology, strategic relationships and dependence on key individuals and sole source suppliers. Products developed by the Company require clearances from the U.S. Food and Drug Administration or other international regulatory agencies prior to commercial sales. There can be no assurance that the products will receive the necessary clearances. If the Company was denied clearance, clearance was delayed or the Company was unable to maintain clearance, it could have a materially adverse impact on the Company. The Company is subject to risks and uncertainties as a result of the COVID-19 pandemic. The Company is continuing to closely monitor the impact of the COVID-19 pandemic on its business and has taken and continues to take proactive efforts to protect the health and safety of its employees and to maintain business continuity. The extent of the impact of the COVID-19 pandemic on the Company's activities is highly uncertain and difficult to predict, as the response to the pandemic is ongoing and information continues to evolve. The severity of the impact of the COVID-19 pandemic on the Company's activities will depend on a number of factors, including, but not limited to, the duration and severity of the pandemic, including the severity of any additional periods of increases or spikes in the number of cases in the areas the Company and its suppliers operate and areas where the Company’s clinical trial sites are planned to be located. As a result, the Company's future results of operations and liquidity could be adversely impacted by delays in preclinical studies, delays in manufacturing activities and planned clinical trials, supply chain disruptions and the ongoing impact on its operating activities and employees. The extent and severity of the impact on the Company's future financial condition, liquidity or results of operations is highly uncertain and cannot be fully predicted as of the date of issuance of these consolidated financial statements.

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2021
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Note 2. Summary of Significant Accounting Policies Basis of Presentation The Company’s 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 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 consolidated financial statements prior to the Business Combination represents the accounts of Legacy Surrozen at their historical cost as if Legacy Surrozen is the predecessor to the Company. The 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 consolidated financial statements for the periods presented prior to the Business Combination have been retroactively restated to reflect the exchange ratio established in the Business Combination. See Note 3 for additional details. Use of Estimates The preparation of 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 consolidated financial statements and the reported amounts of expenses during the reporting period. Significant estimates and assumptions made in the accompanying 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, initial fair value of warrants issued in connection with the PIPE Financing, income taxes and operating 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. Segment Reporting Operating segments are defined as components of an entity for which separate financial information is available and that is regularly reviewed by the Chief Operating Decision Maker, or CODM, in deciding how to allocate resources to an individual segment and in assessing performance. The Company’s CODM is its Chief Executive Officer. The Company has determined that it operates in one segment. Concentration of Credit Risk Financial instruments, which potentially subject the Company to significant concentration of credit risk, consist of cash, cash equivalents and marketable securities. The Company's cash is held by one financial institution that management believes is creditworthy . Such deposits held with the financial institution may at times exceed federally insured limits, however, its exposure to credit risk in the event of default by the financial institution is limited to the extent of amounts recorded on the consolidated balance sheets. The Company performs evaluations of the relative credit standing of these financial institutions to limit the amount of credit exposure. The Company's policy is to invest cash in institutional money market funds and marketable securities with high credit quality to limit the amount of credit exposure. The Company currently maintains a portfolio of cash equivalents and marketable securities in a variety of securities, including money market funds, U.S. government bonds, foreign bonds, commercial paper and corporate debt securities. The Company has not experienced any losses on its cash equivalents and marketable securities. Cash and Cash Equivalents Cash equivalents relate to securities having an original maturity of three months or less at the time of purchase. As of December 31, 2021, cash and cash equivalents consisted of bank deposits and money market funds. As of December 31, 2020, cash and cash equivalents consisted of bank deposits, money market funds and commercial paper. Restricted Cash As of each of December 31, 2021 and 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. Marketable Securities The Company invests its excess cash in marketable U.S. government bonds, foreign bonds, commercial paper and corporate debt securities. All marketable securities have been classified as available-for-sale and are carried at estimated fair value as determined based upon quoted market prices or pricing models for similar 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 marketable securities have maturities less than or equal to one year as of the balance sheet date. Long-term marketable securities 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 accumulated other comprehensive loss in stockholders’ equity until realized. Gains and losses on marketable security transactions are reported on the specific-identification method. Interest income is recognized in the consolidated statements of operations and comprehensive loss when earned. The Company periodically evaluates its available-for-sale marketable securities for impairment. Starting January 1, 2020, upon adoption of ASU 2016-13, when the fair value of a marketable security is below its amortized cost, the amortized cost is reduced to its fair value if it is more likely than not that the Company is required to sell the impaired security before recovery of its amortized cost basis, or the Company has the intention to sell the security. If neither of these conditions are met, the Company determines whether the impairment is due to credit losses by comparing the present value of the expected cash flows of the security with its amortized cost basis. The amount of impairment recognized is limited to the excess of the amortized cost over the fair value of the security. An allowance for credit losses for the excess of amortized cost over the expected cash flows is recorded in other expense, net on the consolidated statements of operations. Impairment losses that are not credit-related are included in accumulated other comprehensive loss in stockholders’ equity. Property and Equipment Property and equipment, including leasehold improvements, are recorded at cost net of accumulated depreciation. Property and equipment are depreciated using the straight-line method over the estimated useful lives of the assets as follows: Asset Estimated useful life Leasehold improvements Shorter of useful life of asset or lease term Computer equipment 3 years Furniture, fixtures and equipment 3 - 8 years Lab equipment 3 years When assets are retired or otherwise disposed of, the cost and related accumulated depreciation are removed from the consolidated balance sheet and the resulting gain or loss is recognized in the period realized. Maintenance and repairs are expensed as incurred. Leases The Company accounts for its leases under ASC 842, Leases . Material leases with a term longer than one year are recognized as right-of-use, or ROU, assets and lease liabilities in the Company's consolidated balance sheets. The Company determines the lease classification and measurement of its ROU assets and lease liabilities at the lease commencement date and thereafter if modified. The Company uses its incremental borrowing rate, based on the information available at the commencement date, to determine the present value of lease payments if the rate implicit in the lease is not readily available. The ROU asset is based on the measurement of the lease liability and is adjusted for lease incentives provided by the landlord. Lease expense for the Company’s operating leases is recognized on a straight-line basis over the lease term. The lease term includes any renewal options and termination options that the Company is reasonably assured to exercise. Impairment of Long-Lived Assets The Company reviews long-lived assets for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable. Recoverability is measured by comparing the carrying amount to the future net undiscounted cash flows which the assets are expected to generate. If such assets are considered to be impaired, the impairment to be recognized is measured by the amount by which the carrying amount of the assets exceeds the projected discounted future net cash flows arising from the asset. The Company has not identified any such impairment losses to date. Warrant Liabilities The Company's Public Warrants, Private Placement Warrants and PIPE Warrants are 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 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 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, bonus, payroll taxes, stock-based compensation, employee benefits, materials, supplies, depreciation on and maintenance of research equipment, and the allocated facility-related costs, 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 December 31, 2021, the Company received $ 1.0 million from the grant and $ 1.0 million was recognized as a reduction of research and development expenses during the year ended December 31, 2021. Accrued Research and Development Expenses The Company records accruals for estimated costs of research, preclinical, clinical, and manufacturing development, which are significant components of research and development expenses, within accrued and other liabilities in the accompanying consolidated balance sheets. A substantial portion of the Company’s ongoing research and development activities is conducted by third-party service providers. The Company accrues the costs incurred under agreements with these third parties based on estimates of actual work completed in accordance with the respective agreements. The Company determines the estimated costs through discussions with internal personnel and external service providers as to the progress, or stage of completion or actual timeline of the services and the agreed-upon fees to be paid for such services. Payments made to third parties under these arrangements in advance of the performance of the related services by the third parties are recorded as prepaid expenses until the services are rendered. For the years ended December 31, 2021 and 2020, the Company has not experienced any material differences between accrued costs and actual costs incurred. If the actual timing of the performance of services or the level of effort varies from the estimate, the Company adjusts accrued expenses or prepaid expenses accordingly, which impact research and development expenses. Although the Company does not expect its estimates to be materially different from amounts actually incurred, its understanding of the status and timing of services performed relative to the actual status and timing of services performed may vary and may result in reporting amounts that are too high or too low in any particular period. Stock-Based Compensation The Company recognizes stock-based compensation expense for all stock-based awards. Stock-based compensation cost is estimated at the grant date based on the fair value of the equity for financial reporting purposes and is recognized as expense on a straight-line basis over the requisite service period. Forfeitures are accounted for as they occur. The Company has elected to calculate the fair value of options based on the Black-Scholes option pricing model, or the Black-Scholes Model. The Black-Scholes Model requires the use of various assumptions including common stock valuation, expected option life and expected stock price volatility. The Company estimates the expected term for stock options using the simplified method as the midpoint between the vesting date and the contractual expiration date of the award. Due to the limited trading history of the Company’s stock, the Company estimates the volatility using volatilities of a group of public companies in a comparable industry, stage of life cycle, and size. The interest rate is derived from the U.S. Treasury instruments with maturities similar to the expected term of the options. The Company has not declared nor expects to declare dividends. Therefore, there is no dividend impact on the valuation of options. Prior to the Business Combination, the fair value of common stock was determined considering numerous objective and subjective factors and requires judgment. These objective and subjective factors include, but are not limited to: • relevant precedent transactions involving the Company’s capital stock; • contemporaneous valuations performed by third-party specialists; • rights, preferences, and privileges of the Company’s redeemable convertible preferred stock relative to those of the Company’s common stock; • actual operating and financial performance; • current business conditions and financial projections; • likelihood of achieving a liquidity event, such as an initial public offering or a sale of the Company’s business; • the lack of marketability of the Company’s common stock, and the illiquidity of stock-based awards involving securities in a private company; • market multiples of comparable publicly traded companies; • stage of development; • industry information such as market size and growth; and • U.S. and global capital and macroeconomic conditions. Following the closing of the Business Combination, the fair value of our common stock has been determined based on the quoted market price of our common stock. Comprehensive Loss The Company’s comprehensive loss consists of net loss and unrealized losses on available-for-sale securities. For the year ended December 31, 2020, the Company’s unrealized loss on available-for-sale securities was de minimis. 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 the 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: December 31, 2021 2020 Options outstanding 1,794,300 1,070,301 Unvested restricted stock 160,643 46,199 Unvested common stock subject to repurchase 74,840 103,790 Warrants to purchase common stock 7,217,974 — Total 9,247,757 1,220,290 Income Taxes The Company accounts for income taxes under the asset and liability method. Under this method, deferred tax assets and liabilities are determined based on the difference between the financial statement carrying amounts and tax bases of assets and liabilities using enacted tax rates expected to be in effect for the year in which the differences are expected to reverse. Valuation allowances are established when necessary to reduce deferred tax assets to the amounts more likely than not to be realized. The Company assesses all material positions taken in any income tax return, including all significant uncertain positions, in all tax years that are still subject to assessment or challenge by relevant taxing authorities. Assessing an uncertain tax position begins with the initial determination of the position’s sustainability and is measured at the largest amount of benefit that is more likely than not of being realized upon ultimate settlement. As of each balance sheet date, unresolved uncertain tax positions must be reassessed, and the Company will determine whether (i) the factors underlying the sustainability assertion have changed and (ii) the amount of the recognized tax benefit is still appropriate. The recognition and measurement of tax benefits require significant judgment. Judgments concerning the recognition and measurement of a tax benefit might change as new information becomes available. The Company’s policy is to recognize interest and penalties related to the underpayment of income taxes as a component of income tax expense or benefit. To date, there have been no interest or penalties charged in relation to unrecognized tax benefits. 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 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 November 2021, the FASB issued ASU No. 2021-10, Government Assistance (Topic 832): Disclosures by Business Entities about Government Assistance , which amends disclosures to increase transparency of government assistance, including (i) the types of assistance, (ii accounting for the assistance and (iii) the effect of the assistance on an entity’s financial statements. The standard is effective for all business entities for annual periods beginning after December 15, 2021. The Company adopted this guidance as of January 1, 2021 on a retrospective basis, with no material impact on the consolidated financial statements upon adoption. 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 consolidated financial statements upon adoption.

Recapitalization

Recapitalization	12 Months Ended
	Dec. 31, 2021
Recapitalization Note [Abstract]
Recapitalization	Note 3. Recapitalization On August 11, 2021, Consonance consummated the Business Combination and PIPE Financing (see Note 1). Legacy Surrozen received the aggregate cash consideration of $ 128.8 million, after deducting the transaction fees incurred by Consonance. The cash consideration was comprised of $ 8.6 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 $ 6.3 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 $ 5.9 million were recorded as a reduction of additional paid-in capital in the 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 stockholders 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 , or the 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 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	12 Months Ended
	Dec. 31, 2021
Fair Value Disclosures [Abstract]
Fair Value Measurement	Note 4. Fair Value Measurement The Company’s financial instruments include cash, cash equivalents, marketable securities, restricted cash, accounts payable, accrued and other liabilities and warrant liabilities. The carrying amount of cash and cash equivalents, restricted cash, accounts payable, and accrued and other liabilities approximate their fair values due to their short-term maturities. The accounting guidance for fair value establishes a framework for measuring fair value and a fair value hierarchy that prioritizes the inputs used in valuation techniques. The fair value hierarchy is based on three levels of inputs that may be used to measure fair value as follows: Level 1—Observable inputs such as unadjusted, quoted prices in active markets for identical assets or liabilities at the measurement date. Level 2—Inputs (other than quoted prices included in Level 1) are either directly or indirectly observable for the asset or liability. These include quoted prices for similar assets or liabilities in active markets and quoted prices for identical or similar assets or liabilities in markets that are not active. Level 3—Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities. 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 December 31, 2021 Level 1 Level 2 Level 3 Total Assets: Money market funds (1) $ 32,310 $ — $ — $ 32,310 Commercial paper — 49,136 — 49,136 Corporate bonds — 19,480 — 19,480 Government bonds — 18,082 — 18,082 Foreign bonds — 3,717 — 3,717 Total financial assets measured at fair $ 32,310 $ 90,415 $ — $ 122,725 Liabilities (3) : Public Warrants $ 3,527 $ — $ — $ 3,527 Private Placement Warrants — 166 — 166 PIPE Warrants — 4,608 — 4,608 Total financial liabilities measured at $ 3,527 $ 4,774 $ — $ 8,301 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 consolidated balance sheets as of December 31, 2021 and 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 consolidated balance sheet. (3) See the definition and discussion of Public Warrants, Private Placement Warrants and PIPE Warrants in Note 8. 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 were initially recorded at fair value using a binomial lattice model. The PIPE Warrants were classified as Level 3 at issuance because the fair value was measured based on significant inputs that are unobservable in the market. 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 at the initial measurement were as follows: August 11, 2021 Expected term (in years) 5.01 Expected volatility 18.90 % Risk-free interest rate 0.81 % Dividend yield — Given the adequate history of the market data of the Public Warrants as of December 31, 2021, the PIPE Warrants were remeasured at December 31, 2021 based on the observable market quote of the Public Warrants and are classified as Level 2. The valuation technique was changed since the fair value of the Public Warrant is equally or more representative of the fair value of the PIPE Warrants. The fair value of each PIPE Warrant was determined to be consistent with that of a Public Warrant because the PIPE Warrants are also subject to the make-whole redemption feature, which allows the Company to redeem both types of warrants on similar terms. There were no other transfers of financial instruments between Level 1, Level 2, and Level 3, and there were no financial liabilities as of December 31, 2020. The following table sets forth a summary of the changes in the fair value of the Company’s warrant liabilities for the year ended December 31, 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) ( 30 ) ( 2 ) ( 39 ) ( 71 ) Balance, end of period $ 3,527 $ 166 $ 4,608 $ 8,301 (1) The change in fair value of the warrant liabilities was recognized in other expense, net within the consolidated statements of operations and comprehensive loss. The following tables provide the Company’s marketable securities by security type (in thousands): As of December 31, 2021 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Commercial paper $ 49,136 $ — $ — $ 49,136 Corporate bonds 15,920 4 ( 17 ) 15,907 Foreign bonds 3,725 — ( 8 ) 3,717 Total short-term marketable securities $ 68,781 $ 4 $ ( 25 ) $ 68,760 Government bonds $ 18,165 $ — $ ( 83 ) $ 18,082 Corporate bonds 3,588 — ( 15 ) 3,573 Total long-term marketable securities $ 21,753 $ — $ ( 98 ) $ 21,655 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 marketable securities $ 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 December 31, 2021 (dollars in thousands): Less Than 12 Months Number of Investments Fair Value Unrealized Losses Corporate bonds 5 $ 12,572 $ ( 32 ) Government bonds 3 18,082 ( 83 ) Foreign bonds 2 3,717 ( 8 ) 10 $ 34,371 $ ( 123 ) As of December 31, 2020, $ 14.2 million of marketable securities are included in short-term marketable securities. As of December 31, 2021 and 2020, all short-term marketable securities had maturities of one year or less. All long-term marketable securities as of December 31, 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 marketable securities during the years ended December 31, 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. The Company determined that the unrealized loss was primarily attributed to changes in current market interest rates and not to credit quality. The Company does not intend to sell the marketable securities that are in an unrealized loss position, nor is it more likely than not that the Company will be required to sell the marketable securities before the recovery of the amortized cost basis, which may be at maturity. As a result, the Company did no t recognize any other-than-temporary impairment losses as of December 31, 2021.

Balance Sheet Components

Balance Sheet Components	12 Months Ended
	Dec. 31, 2021
Balance Sheet Related Disclosures [Abstract]
Balance Sheet Components	Note 5. Balance Sheet Components Property and Equipment, Net Property and equipment, net, consists of the following (in thousands): December 31, 2021 2020 Leasehold improvements $ 7,052 $ 7,052 Lab equipment 6,881 6,084 Furniture and office equipment 309 310 Computer equipment 93 137 Total property and equipment 14,335 13,583 Less accumulated depreciation and amortization ( 9,541 ) ( 7,747 ) Property and equipment, net $ 4,794 $ 5,836 Depreciation expense for the years ended December 31, 2021 and 2020 was $ 2.1 million and $ 1.9 million, respectively. During the year ended December 31, 2021, the Company disposed fully depreciated equipment with the aggregate original costs of $ 0.3 million. Accrued and Other Liabilities Accrued and other liabilities consist of the following (in thousands): December 31, 2021 2020 Accrued payroll and related expenses $ 2,887 $ 1,673 Accrued research and development expenses 3,666 1,305 Accrued professional service fees 1,520 — Liability for early exercised stock options 205 188 Other 384 228 Accrued and other liabilities $ 8,662 $ 3,394

Leases

Leases	12 Months Ended
	Dec. 31, 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 in the 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 the 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 years ended December 31, 2021 and 2020 was $ 2.0 million and $ 1.8 million, respectively. Aggregate future minimum rental payments under the operating leases as of December 31, 2021, were as follows (in thousands): Year ending December 31, 2022 $ 2,743 Year ending December 31, 2023 2,596 Year ending December 31, 2024 2,670 Year ending December 31, 2025 891 Total lease payments 8,900 Less: Imputed interest ( 1,107 ) Operating lease liabilities $ 7,793 The following represents supplemental information related to the Company’s operating facility leases: December 31, 2021 2020 Cash paid for amounts included in the measurement of lease liabilities (in thousands) $ 2,856 $ 2,520 Weighted-average remaining lease term (in years) 3.25 4.19 Weighted-average discount rate 8.43 % 8.40 %

License Agreement

License Agreement	12 Months Ended
	Dec. 31, 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, 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 for 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 given by Stanford. For the years ended December 31, 2021 and 2020, the Company incurred research and development expenses of approximately $ 0.1 million, respectively, under the Stanford Agreements. No milestones have been achieved as of December 31, 2021. UCSF License and Option Agreements In September and October 2016, the Company entered into two separate license and option agreements with UCSF, 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 for 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 December 31, 2021, the Company has no t exercised the option. For the years ended December 31, 2021 and 2020, the Company incurred research and development expenses of $ 50,000 and $ 0.1 million under the UCSF Agreements. No milestones have been achieved as of December 31, 2021. Unless earlier terminated, each UCSF Agreement will continue until four years from its execution date and the Company may exercise the option to negotiate a commercial license at any time during that term. Additionally, the Company may extend each UCSF Agreements for any additional four years by paying UCSF a nominal term extension fee. The Company may terminate either UCSF Agreement at any time for any reason by providing at least 60 days’ written notice to UCSF. UCSF may terminate either UCSF Agreement if UCSF reasonably believes the Company is in material breach of such UCSF Agreement and the Company fails to remedy such breach within 60 days after written notice of such breach given 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 years ended December 31, 2021 and 2020, the Company incurred research and development expenses of $ 0.3 million and $ 0.2 million under 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 December 31, 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	12 Months Ended
	Dec. 31, 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 Consonance’s 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 December 31, 2021, the following common stock warrants were outstanding: Type Classification Expiration Date Exercise Price per Share December 31, 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. The registration statement on Form S-1 to register for resale under the Securities Act of 1933, as amended, was effective in November 2021. The Company shall use its efforts to maintain the effectiveness of the registration statement until the expiration or redemption of the Public Warrants. If the Company fails to have maintained an effective registration statement, 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 Consonance’s 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 Consonance’s 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 are classified as liabilities and recorded at fair value with subsequent change in their respective fair value recognized in other expense, net within the 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	12 Months Ended
	Dec. 31, 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 December 31, 2021, no shares of redeemable convertible preferred stock were outstanding.

Stock Based Compensation Plan

Stock Based Compensation Plan	12 Months Ended
	Dec. 31, 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. Following the adoption of the 2021 Plan, no additional stock awards will be issued under the 2015 Plan. As of December 31, 2021, the Company had 4,344,699 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 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 945,526 10.13 Exercised ( 161,451 ) 2.47 Cancelled ( 60,076 ) 4.54 Outstanding – 1,794,300 6.31 8.43 $ 3,663 Options outstanding and 655,238 3.06 7.31 2,687 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 December 31, 2021. The intrinsic value of options exercised during the years ended December 31, 2021 and 2020 was $ 1.2 million and $ 0.2 million, respectively. During the years ended December 31, 2021 and 2020, the Company granted options with a weighted-average grant-date fair value of $ 6.36 per share and $ 0.74 per share, respectively. 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, as previously 263,022 $ 0.69 Retroactive application of recapitalization ( 216,823 ) RSAs, unvested at December 31, 2020, after effect of 46,199 3.96 Granted 193,208 9.95 Vested ( 62,297 ) 7.00 Forfeited ( 16,467 ) 9.76 RSAs, unvested at December 31, 2021 160,643 9.39 The fair value of RSAs vested during the years ended December 31, 2021 and 2020 was $ 0.6 million and $ 0.3 million, respectively. (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: Year Ended December 31, 2021 2020 Expected term (in years) 6.01 6.03 Expected volatility 71.23 % 61.41 % Risk-free rate 0.89 % 0.80 % Dividend yield — — (b) Stock-Based Compensation Total stock-based compensation recorded in the consolidated statements of operations and comprehensive loss related to options and RSAs was as follows (in thousands): Year Ended December 31, 2021 2020 Research and development $ 736 $ 423 General and administrative 1,580 212 Total stock-based compensation expense $ 2,316 $ 635 As of December 31, 2021, there was approximately $ 7.8 million of stock-based compensation expense to be recognized over a weighted-average period of approximately 3.11 years. (c) Early Exercise of Stock Options Unvested options granted under the 2015 Plan were exercisable 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 December 31, 2021, there were 74,840 shares of common stock outstanding, subject to the Company’s right of repurchase at a weighted average exercise price of $ 2.73 per share.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2021
Income Tax Disclosure [Abstract]
Income Taxes	Note 11. Income Taxes No provision for income taxes was recorded for the years ended December 31, 2021 and 2020. The Company has incurred net operating losses for all the periods presented. The Company accounts for income taxes in accordance with the asset and liability method, which requires that the tax benefit of net operating losses, temporary differences and credit carryforwards be recorded as an asset to the extent that management assesses that realization is “more likely than not.” Realization of the future tax benefits is dependent on the Company’s ability to generate sufficient taxable income within the carryforward period. Because of the Company’s recent history of operating losses, management believes that recognition of the deferred tax assets arising from the above-mentioned future tax benefits is not likely to be realized and, accordingly, has provided a full valuation allowance. Significant components of the Company’s net deferred tax assets consist of the following (in thousands): December 31, 2021 2020 Deferred tax assets Net operating loss carryforwards $ 31,826 $ 22,585 Research and development credits 2,392 2,166 Lease liabilities 1,521 2,487 Accrual and reserves 590 457 Employee retention credits 284 — Capitalized intangible costs 122 156 Stock-based compensation 129 2 Other 3 5 Gross deferred tax assets 36,867 27,858 Less valuation allowance ( 35,665 ) ( 25,941 ) Deferred tax assets, net of valuation allowance 1,202 1,917 Deferred tax liabilities Right-of-use assets ( 962 ) ( 1,555 ) Fixed assets ( 101 ) ( 340 ) Other ( 139 ) ( 22 ) Gross deferred tax liabilities ( 1,202 ) ( 1,917 ) Total net deferred tax assets $ — $ — The net valuation allowance increased by $ 9.7 million and $ 9.6 million for the years ended December 31, 2021 and 2020, respectively. As of December 31, 2021, the Company had net operating loss, or NOL, carryforwards of approximately $ 133.9 million and $ 53.0 million available to reduce future taxable income, if any, for federal and California state income tax purposes, respectively. NOL carryforwards generated after 2018 for federal tax reporting purposes of $ 121.5 million have an indefinite carryforward period. The remaining federal and state net operating loss carryforwards begin expiring in 2036 . As of December 31, 2021, the Company had research and development credit carryforwards of approximately $ 1.0 million and $ 2.8 million available to reduce future taxable income, if any, for federal and California state income tax purposes, respectively. The federal credit carryforwards begin expiring in 2036 and the state credits carry forward indefinitely . Federal and state laws impose substantial restrictions on the utilization of net operating loss and tax credit carryforwards in the event of an ownership change for tax purposes, as defined in Section 382 of the Internal Revenue Code. As a result of such ownership changes, the Company’s ability to realize the potential future benefit of tax losses and tax credits that existed at the time of the ownership change may be limited and may expire unutilized. Such impairment of tax losses and tax credits would reduce the deferred tax asset and corresponding valuation allowance, as a result of the limitation. The Company completed an assessment of the available NOLs under Section 382 and determined that the Company underwent an ownership change in September 2020. As a result of the annual limitations caused by the ownership change, it was estimated the approximately $ 1.3 million of federal tax credit and $ 27.4 million of California NOL will expire unrealized for income tax purposes, and such amounts are excluded from the carryforward balances as of December 31, 2021. The Company recognizes uncertain income tax positions at the largest amount that is more likely than not to be sustained upon audit by the relevant taxing authority. An uncertain income tax position will not be recognized if it has less than a 50% likelihood of being sustained. The unrecognized tax benefits, if recognized, would not have an impact on the Company’s effective tax rate assuming the Company continues to maintain a full valuation allowance position. The Company does not expect its unrecognized tax benefits to change significantly over the next 12 months. A reconciliation of the Company’s unrecognized tax benefits is as follows (in thousands): December 31, 2021 2020 Balance at beginning of the year $ 921 $ 673 Additions based on tax positions related to current year 480 248 Reductions based on tax positions of prior year ( 427 ) — Balance at end of the year $ 974 $ 921 The Company files income tax returns in the U.S. federal and California tax jurisdictions. As of the date these financial statements were issued, the Company is not under examination by any income tax authority. The federal and state income tax returns from December 31, 2016 to December 31, 2020 remain subject to examination. A reconciliation of the statutory U.S. federal tax rate to the Company’s effective tax rate is as follows: December 31, 2021 2020 Statutory rate 21.00 % 21.00 % State tax ( 2.78 ) 7.96 Tax credits 1.70 0.84 Change in valuation allowance ( 16.92 ) ( 29.43 ) NOL and tax credits limited under 382 ( 2.43 ) — Other ( 0.57 ) ( 0.37 ) Total 0.00 % 0.00 % On March 27, 2020, the Coronavirus Aid, Relief and Economic Securities Act, or CARES Act, was enacted and signed into law in response to the COVID-19 pandemic. The CARES Act, among other things, permits NOL carryovers and carrybacks to offset 100 % of taxable income for taxable years beginning before 2021. In addition, the CARES Act allows NOLs incurred in 2018, 2019 and 2020 to be carried back to each of the five preceding taxable years to generate a refund of previously paid income taxes. Other provisions include increased limits on the deduction of interest expense from 30 % to 50 % of adjusted taxable income for tax years beginning in 2019 and 2020, increased limits on 2020 charitable contribution deductions from 10 % to 25 % of taxable income and accelerated refunds of alternative minimum tax credits. The provisions of the CARES Act did not have a material impact for the year ended December 31, 2021. On December 21, 2020, the Consolidated Appropriations Act, 2021, or the Appropriations Act, was signed into law which expanded and extended some of CARES Act provisions, including the expansion of the employee retention credits. The Company will claim employee retention credits of $ 1.0 million for the 2021 tax year. The Company will recognize the benefit of those credits as the refunds are received.

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2021
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	Note 12. 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 consolidated financial statements were issued, the Company has not incurred any material costs or accrued any liabilities in the 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.

401(K) Plan

401(K) Plan	12 Months Ended
	Dec. 31, 2021
Compensation And Retirement Disclosure [Abstract]
401(K) Plan	Note 13. 401(k) Plan Effective January 1, 2016, the Company established a 401(k) retirement savings plan, or the 401(k) Plan, for the exclusive benefit of all eligible employees and their beneficiaries with the intention to provide a measure of retirement security. The 401(k) Plan is intended to qualify as a tax-qualified plan under Section 401(k) of the Internal Revenue Code so that contributions to the 401(k) Plan and income earned on such contributions are not taxable to participants until withdrawn or distributed from the 401(k) Plan. The 401(k) Plan provides that each participant may contribute up to 100 % of his or her pre-tax compensation, up to annual statutory limits. Under the 401(k) Plan, each employee is fully vested in his or her deferred salary contributions. Employee contributions are held and invested by the plan’s trustee. The 401(k) Plan also permits the Company to make discretionary and matching contributions, subject to established limits and a vesting schedule. Each year, at the discretion of the Company, employer’s match may be a discretionary percentage allocated proportionate to salary deferral, as the Company elects each year. The employer matching contributions in 2021 and 2020 were nominal.

Subsequent Events

Subsequent Events	12 Months Ended
	Dec. 31, 2021
Subsequent Events [Abstract]
Subsequent Events	Note 14. Subsequent Events In February 2022, the Company entered into a purchase agreement and a registration rights agreement with Lincoln Park, pursuant to which the Company has the right, but not the obligation, to sell to Lincoln Park, and Lincoln Park is obligated to purchase up to $ 50.0 million of the Company’s common stock. Such sales of common stock by the Company, if any, will be subject to certain limitations, and may occur from time to time, at the Company’s sole discretion over a 36-month period. Upon execution of the purchase agreement, the Company issued 100,000 shares of common stock to Lincoln Park with the fair value of $ 0.3 million as consideration for Lincoln Park's commitment to purchase the Company's common stock. In the event that the Company sells its common stock under the purchase agreement for an aggregate price equal to or greater than $ 30.0 million, the Company shall pay the additional commitment fee of $ 0.1 million to Lincoln Park. The Company does not have the right to commence any sales until all of the conditions set forth in the purchase agreement have been satisfied, including, but not limited to, a registration statement being declared effective by the SEC.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2021
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The Company’s 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 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 consolidated financial statements prior to the Business Combination represents the accounts of Legacy Surrozen at their historical cost as if Legacy Surrozen is the predecessor to the Company. The 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 consolidated financial statements for the periods presented prior to the Business Combination have been retroactively restated to reflect the exchange ratio established in the Business Combination. See Note 3 for additional details.
Use of Estimates	Use of Estimates The preparation of 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 consolidated financial statements and the reported amounts of expenses during the reporting period. Significant estimates and assumptions made in the accompanying 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, initial fair value of warrants issued in connection with the PIPE Financing, income taxes and operating 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.
Segment Reporting	Segment Reporting Operating segments are defined as components of an entity for which separate financial information is available and that is regularly reviewed by the Chief Operating Decision Maker, or CODM, in deciding how to allocate resources to an individual segment and in assessing performance. The Company’s CODM is its Chief Executive Officer. The Company has determined that it operates in one segment.
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 and marketable securities. The Company's cash is held by one financial institution that management believes is creditworthy . Such deposits held with the financial institution may at times exceed federally insured limits, however, its exposure to credit risk in the event of default by the financial institution is limited to the extent of amounts recorded on the consolidated balance sheets. The Company performs evaluations of the relative credit standing of these financial institutions to limit the amount of credit exposure. The Company's policy is to invest cash in institutional money market funds and marketable securities with high credit quality to limit the amount of credit exposure. The Company currently maintains a portfolio of cash equivalents and marketable securities in a variety of securities, including money market funds, U.S. government bonds, foreign bonds, commercial paper and corporate debt securities. The Company has not experienced any losses on its cash equivalents and marketable securities.
Cash and Cash Equivalents	Cash and Cash Equivalents Cash equivalents relate to securities having an original maturity of three months or less at the time of purchase. As of December 31, 2021, cash and cash equivalents consisted of bank deposits and money market funds. As of December 31, 2020, cash and cash equivalents consisted of bank deposits, money market funds and commercial paper.
Restricted Cash	Restricted Cash As of each of December 31, 2021 and 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.
Marketable Securities	Marketable Securities The Company invests its excess cash in marketable U.S. government bonds, foreign bonds, commercial paper and corporate debt securities. All marketable securities have been classified as available-for-sale and are carried at estimated fair value as determined based upon quoted market prices or pricing models for similar 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 marketable securities have maturities less than or equal to one year as of the balance sheet date. Long-term marketable securities 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 accumulated other comprehensive loss in stockholders’ equity until realized. Gains and losses on marketable security transactions are reported on the specific-identification method. Interest income is recognized in the consolidated statements of operations and comprehensive loss when earned. The Company periodically evaluates its available-for-sale marketable securities for impairment. Starting January 1, 2020, upon adoption of ASU 2016-13, when the fair value of a marketable security is below its amortized cost, the amortized cost is reduced to its fair value if it is more likely than not that the Company is required to sell the impaired security before recovery of its amortized cost basis, or the Company has the intention to sell the security. If neither of these conditions are met, the Company determines whether the impairment is due to credit losses by comparing the present value of the expected cash flows of the security with its amortized cost basis. The amount of impairment recognized is limited to the excess of the amortized cost over the fair value of the security. An allowance for credit losses for the excess of amortized cost over the expected cash flows is recorded in other expense, net on the consolidated statements of operations. Impairment losses that are not credit-related are included in accumulated other comprehensive loss in stockholders’ equity.
Property and Equipment	Property and Equipment Property and equipment, including leasehold improvements, are recorded at cost net of accumulated depreciation. Property and equipment are depreciated using the straight-line method over the estimated useful lives of the assets as follows: Asset Estimated useful life Leasehold improvements Shorter of useful life of asset or lease term Computer equipment 3 years Furniture, fixtures and equipment 3 - 8 years Lab equipment 3 years When assets are retired or otherwise disposed of, the cost and related accumulated depreciation are removed from the consolidated balance sheet and the resulting gain or loss is recognized in the period realized. Maintenance and repairs are expensed as incurred.
Leases	Leases The Company accounts for its leases under ASC 842, Leases . Material leases with a term longer than one year are recognized as right-of-use, or ROU, assets and lease liabilities in the Company's consolidated balance sheets. The Company determines the lease classification and measurement of its ROU assets and lease liabilities at the lease commencement date and thereafter if modified. The Company uses its incremental borrowing rate, based on the information available at the commencement date, to determine the present value of lease payments if the rate implicit in the lease is not readily available. The ROU asset is based on the measurement of the lease liability and is adjusted for lease incentives provided by the landlord. Lease expense for the Company’s operating leases is recognized on a straight-line basis over the lease term. The lease term includes any renewal options and termination options that the Company is reasonably assured to exercise.
Impairment of Long-Lived Assets	Impairment of Long-Lived Assets The Company reviews long-lived assets for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable. Recoverability is measured by comparing the carrying amount to the future net undiscounted cash flows which the assets are expected to generate. If such assets are considered to be impaired, the impairment to be recognized is measured by the amount by which the carrying amount of the assets exceeds the projected discounted future net cash flows arising from the asset. The Company has not identified any such impairment losses to date.
Warrant Liabilities	Warrant Liabilities The Company's Public Warrants, Private Placement Warrants and PIPE Warrants are 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 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 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, bonus, payroll taxes, stock-based compensation, employee benefits, materials, supplies, depreciation on and maintenance of research equipment, and the allocated facility-related costs, 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 December 31, 2021, the Company received $ 1.0 million from the grant and $ 1.0 million was recognized as a reduction of research and development expenses during the year ended December 31, 2021.
Accrued Research and Development Expenses	Accrued Research and Development Expenses The Company records accruals for estimated costs of research, preclinical, clinical, and manufacturing development, which are significant components of research and development expenses, within accrued and other liabilities in the accompanying consolidated balance sheets. A substantial portion of the Company’s ongoing research and development activities is conducted by third-party service providers. The Company accrues the costs incurred under agreements with these third parties based on estimates of actual work completed in accordance with the respective agreements. The Company determines the estimated costs through discussions with internal personnel and external service providers as to the progress, or stage of completion or actual timeline of the services and the agreed-upon fees to be paid for such services. Payments made to third parties under these arrangements in advance of the performance of the related services by the third parties are recorded as prepaid expenses until the services are rendered. For the years ended December 31, 2021 and 2020, the Company has not experienced any material differences between accrued costs and actual costs incurred. If the actual timing of the performance of services or the level of effort varies from the estimate, the Company adjusts accrued expenses or prepaid expenses accordingly, which impact research and development expenses. Although the Company does not expect its estimates to be materially different from amounts actually incurred, its understanding of the status and timing of services performed relative to the actual status and timing of services performed may vary and may result in reporting amounts that are too high or too low in any particular period.
Stock-Based Compensation	Stock-Based Compensation The Company recognizes stock-based compensation expense for all stock-based awards. Stock-based compensation cost is estimated at the grant date based on the fair value of the equity for financial reporting purposes and is recognized as expense on a straight-line basis over the requisite service period. Forfeitures are accounted for as they occur. The Company has elected to calculate the fair value of options based on the Black-Scholes option pricing model, or the Black-Scholes Model. The Black-Scholes Model requires the use of various assumptions including common stock valuation, expected option life and expected stock price volatility. The Company estimates the expected term for stock options using the simplified method as the midpoint between the vesting date and the contractual expiration date of the award. Due to the limited trading history of the Company’s stock, the Company estimates the volatility using volatilities of a group of public companies in a comparable industry, stage of life cycle, and size. The interest rate is derived from the U.S. Treasury instruments with maturities similar to the expected term of the options. The Company has not declared nor expects to declare dividends. Therefore, there is no dividend impact on the valuation of options. Prior to the Business Combination, the fair value of common stock was determined considering numerous objective and subjective factors and requires judgment. These objective and subjective factors include, but are not limited to: • relevant precedent transactions involving the Company’s capital stock; • contemporaneous valuations performed by third-party specialists; • rights, preferences, and privileges of the Company’s redeemable convertible preferred stock relative to those of the Company’s common stock; • actual operating and financial performance; • current business conditions and financial projections; • likelihood of achieving a liquidity event, such as an initial public offering or a sale of the Company’s business; • the lack of marketability of the Company’s common stock, and the illiquidity of stock-based awards involving securities in a private company; • market multiples of comparable publicly traded companies; • stage of development; • industry information such as market size and growth; and • U.S. and global capital and macroeconomic conditions. Following the closing of the Business Combination, the fair value of our common stock has been determined based on the quoted market price of our common stock.
Comprehensive Loss	Comprehensive Loss The Company’s comprehensive loss consists of net loss and unrealized losses on available-for-sale securities. For the year ended December 31, 2020, the Company’s unrealized loss on available-for-sale securities was de minimis.
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 the 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: December 31, 2021 2020 Options outstanding 1,794,300 1,070,301 Unvested restricted stock 160,643 46,199 Unvested common stock subject to repurchase 74,840 103,790 Warrants to purchase common stock 7,217,974 — Total 9,247,757 1,220,290
Income Taxes	Income Taxes The Company accounts for income taxes under the asset and liability method. Under this method, deferred tax assets and liabilities are determined based on the difference between the financial statement carrying amounts and tax bases of assets and liabilities using enacted tax rates expected to be in effect for the year in which the differences are expected to reverse. Valuation allowances are established when necessary to reduce deferred tax assets to the amounts more likely than not to be realized. The Company assesses all material positions taken in any income tax return, including all significant uncertain positions, in all tax years that are still subject to assessment or challenge by relevant taxing authorities. Assessing an uncertain tax position begins with the initial determination of the position’s sustainability and is measured at the largest amount of benefit that is more likely than not of being realized upon ultimate settlement. As of each balance sheet date, unresolved uncertain tax positions must be reassessed, and the Company will determine whether (i) the factors underlying the sustainability assertion have changed and (ii) the amount of the recognized tax benefit is still appropriate. The recognition and measurement of tax benefits require significant judgment. Judgments concerning the recognition and measurement of a tax benefit might change as new information becomes available. The Company’s policy is to recognize interest and penalties related to the underpayment of income taxes as a component of income tax expense or benefit. To date, there have been no interest or penalties charged in relation to unrecognized tax benefits.
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 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 November 2021, the FASB issued ASU No. 2021-10, Government Assistance (Topic 832): Disclosures by Business Entities about Government Assistance , which amends disclosures to increase transparency of government assistance, including (i) the types of assistance, (ii accounting for the assistance and (iii) the effect of the assistance on an entity’s financial statements. The standard is effective for all business entities for annual periods beginning after December 15, 2021. The Company adopted this guidance as of January 1, 2021 on a retrospective basis, with no material impact on the consolidated financial statements upon adoption. 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 consolidated financial statements upon adoption.

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2021
Accounting Policies [Abstract]
Summary of Property and Equipment Useful Lives	Property and equipment, including leasehold improvements, are recorded at cost net of accumulated depreciation. Property and equipment are depreciated using the straight-line method over the estimated useful lives of the assets as follows: Asset Estimated useful life Leasehold improvements Shorter of useful life of asset or lease term Computer equipment 3 years Furniture, fixtures and equipment 3 - 8 years Lab equipment 3 years
Schedule of Antidilutive 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: December 31, 2021 2020 Options outstanding 1,794,300 1,070,301 Unvested restricted stock 160,643 46,199 Unvested common stock subject to repurchase 74,840 103,790 Warrants to purchase common stock 7,217,974 — Total 9,247,757 1,220,290

Fair Value Measurement (Tables)

Fair Value Measurement (Tables)	12 Months Ended
	Dec. 31, 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 December 31, 2021 Level 1 Level 2 Level 3 Total Assets: Money market funds (1) $ 32,310 $ — $ — $ 32,310 Commercial paper — 49,136 — 49,136 Corporate bonds — 19,480 — 19,480 Government bonds — 18,082 — 18,082 Foreign bonds — 3,717 — 3,717 Total financial assets measured at fair $ 32,310 $ 90,415 $ — $ 122,725 Liabilities (3) : Public Warrants $ 3,527 $ — $ — $ 3,527 Private Placement Warrants — 166 — 166 PIPE Warrants — 4,608 — 4,608 Total financial liabilities measured at $ 3,527 $ 4,774 $ — $ 8,301 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 consolidated balance sheets as of December 31, 2021 and 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 consolidated balance sheet. (3) See the definition and discussion of Public Warrants, Private Placement Warrants and PIPE Warrants in Note 8.
Schedule of Measurement of PIPE Warrants with Binomial Lattice Model	The key inputs into the binomial lattice model for the PIPE Warrants at the initial measurement were as follows: August 11, 2021 Expected term (in years) 5.01 Expected volatility 18.90 % Risk-free interest rate 0.81 % Dividend yield —
Summary of Changes in Fair Value of Warrant Liabilities	The following table sets forth a summary of the changes in the fair value of the Company’s warrant liabilities for the year ended December 31, 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) ( 30 ) ( 2 ) ( 39 ) ( 71 ) Balance, end of period $ 3,527 $ 166 $ 4,608 $ 8,301 (1) The change in fair value of the warrant liabilities was recognized in other expense, net within the consolidated statements of operations and comprehensive loss.
Schedule of Marketable Securities by Security Type	The following tables provide the Company’s marketable securities by security type (in thousands): As of December 31, 2021 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Commercial paper $ 49,136 $ — $ — $ 49,136 Corporate bonds 15,920 4 ( 17 ) 15,907 Foreign bonds 3,725 — ( 8 ) 3,717 Total short-term marketable securities $ 68,781 $ 4 $ ( 25 ) $ 68,760 Government bonds $ 18,165 $ — $ ( 83 ) $ 18,082 Corporate bonds 3,588 — ( 15 ) 3,573 Total long-term marketable securities $ 21,753 $ — $ ( 98 ) $ 21,655 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 marketable securities $ 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 December 31, 2021 (dollars in thousands): Less Than 12 Months Number of Investments Fair Value Unrealized Losses Corporate bonds 5 $ 12,572 $ ( 32 ) Government bonds 3 18,082 ( 83 ) Foreign bonds 2 3,717 ( 8 ) 10 $ 34,371 $ ( 123 )

Balance Sheet Components (Table

Balance Sheet Components (Tables)	12 Months Ended
	Dec. 31, 2021
Balance Sheet Related Disclosures [Abstract]
Schedule of Property and Equipment, Net	Property and equipment, net, consists of the following (in thousands): December 31, 2021 2020 Leasehold improvements $ 7,052 $ 7,052 Lab equipment 6,881 6,084 Furniture and office equipment 309 310 Computer equipment 93 137 Total property and equipment 14,335 13,583 Less accumulated depreciation and amortization ( 9,541 ) ( 7,747 ) Property and equipment, net $ 4,794 $ 5,836
Schedule of Accrued and Other Liabilities	Accrued and other liabilities consist of the following (in thousands): December 31, 2021 2020 Accrued payroll and related expenses $ 2,887 $ 1,673 Accrued research and development expenses 3,666 1,305 Accrued professional service fees 1,520 — Liability for early exercised stock options 205 188 Other 384 228 Accrued and other liabilities $ 8,662 $ 3,394

Leases (Tables)

Leases (Tables)	12 Months Ended
	Dec. 31, 2021
Leases [Abstract]
Summary of Lessee, Operating Lease, Liability, Maturity	Aggregate future minimum rental payments under the operating leases as of December 31, 2021, were as follows (in thousands): Year ending December 31, 2022 $ 2,743 Year ending December 31, 2023 2,596 Year ending December 31, 2024 2,670 Year ending December 31, 2025 891 Total lease payments 8,900 Less: Imputed interest ( 1,107 ) Operating lease liabilities $ 7,793
Schedule of Supplemental Information Related to Operating Leases	The following represents supplemental information related to the Company’s operating facility leases: December 31, 2021 2020 Cash paid for amounts included in the measurement of lease liabilities (in thousands) $ 2,856 $ 2,520 Weighted-average remaining lease term (in years) 3.25 4.19 Weighted-average discount rate 8.43 % 8.40 %

Common Stock Warrants (Tables)

Common Stock Warrants (Tables)	12 Months Ended
	Dec. 31, 2021
Equity [Abstract]
Schedule of Common Stock Warrants Outstanding	As of December 31, 2021, the following common stock warrants were outstanding: Type Classification Expiration Date Exercise Price per Share December 31, 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)	12 Months Ended
	Dec. 31, 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 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 945,526 10.13 Exercised ( 161,451 ) 2.47 Cancelled ( 60,076 ) 4.54 Outstanding – 1,794,300 6.31 8.43 $ 3,663 Options outstanding and 655,238 3.06 7.31 2,687
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, as previously 263,022 $ 0.69 Retroactive application of recapitalization ( 216,823 ) RSAs, unvested at December 31, 2020, after effect of 46,199 3.96 Granted 193,208 9.95 Vested ( 62,297 ) 7.00 Forfeited ( 16,467 ) 9.76 RSAs, unvested at December 31, 2021 160,643 9.39
Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions	The fair value of options is estimated at the grant date using the Black-Scholes option pricing model with the following weighted-average assumptions: Year Ended December 31, 2021 2020 Expected term (in years) 6.01 6.03 Expected volatility 71.23 % 61.41 % Risk-free rate 0.89 % 0.80 % Dividend yield — —
Schedule of Stock-Based Compensation Expense	Total stock-based compensation recorded in the consolidated statements of operations and comprehensive loss related to options and RSAs was as follows (in thousands): Year Ended December 31, 2021 2020 Research and development $ 736 $ 423 General and administrative 1,580 212 Total stock-based compensation expense $ 2,316 $ 635

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2021
Income Tax Disclosure [Abstract]
Summary of Net Deferred Tax Assets	Significant components of the Company’s net deferred tax assets consist of the following (in thousands): December 31, 2021 2020 Deferred tax assets Net operating loss carryforwards $ 31,826 $ 22,585 Research and development credits 2,392 2,166 Lease liabilities 1,521 2,487 Accrual and reserves 590 457 Employee retention credits 284 — Capitalized intangible costs 122 156 Stock-based compensation 129 2 Other 3 5 Gross deferred tax assets 36,867 27,858 Less valuation allowance ( 35,665 ) ( 25,941 ) Deferred tax assets, net of valuation allowance 1,202 1,917 Deferred tax liabilities Right-of-use assets ( 962 ) ( 1,555 ) Fixed assets ( 101 ) ( 340 ) Other ( 139 ) ( 22 ) Gross deferred tax liabilities ( 1,202 ) ( 1,917 ) Total net deferred tax assets $ — $ —
Summary of Tax Benefits	A reconciliation of the Company’s unrecognized tax benefits is as follows (in thousands): December 31, 2021 2020 Balance at beginning of the year $ 921 $ 673 Additions based on tax positions related to current year 480 248 Reductions based on tax positions of prior year ( 427 ) — Balance at end of the year $ 974 $ 921
Schedule of Reconciliation of U.S. Federal Statutory Income Tax Rate TO Effective Income Tax Rate	A reconciliation of the statutory U.S. federal tax rate to the Company’s effective tax rate is as follows: December 31, 2021 2020 Statutory rate 21.00 % 21.00 % State tax ( 2.78 ) 7.96 Tax credits 1.70 0.84 Change in valuation allowance ( 16.92 ) ( 29.43 ) NOL and tax credits limited under 382 ( 2.43 ) — Other ( 0.57 ) ( 0.37 ) Total 0.00 % 0.00 %

Organization and Business - Add

Organization and Business - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands	Apr. 15, 2021	Dec. 31, 2021	Dec. 31, 2020
Subsidiary Sale Of Stock [Line Items]
Issuance of Series C redeemable convertible preferred stock, net of issuance costs, shares		12,020,000
Common stock warrants exercise price per share		$ 11.50
Proceeds from divestiture of businesses		$ 50,000
Net loss		(54,648)	$ (32,716)
Net cash used in Operation		48,813	29,099
Accumulated deficit		(142,649)	$ (88,001)
Cash, cash equivalents and marketable securities		123,500
Surrozen Inc
Subsidiary Sale Of Stock [Line Items]
Proceeds From business combination		$ 128,800
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]
Description of stock issuance after business combination	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.
Issuance of Series C redeemable convertible preferred stock, net of issuance costs, shares	12,020,000
Shares issued, price per share	$ 10

Summary of Significant Accoun_4

Summary of Significant Accounting Policies - Additional Information (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2021USD ($)	Aug. 31, 2025USD ($)	Aug. 31, 2021USD ($)	Dec. 31, 2020USD ($)
Number of Operating Segments	1
Restricted cash	$ 33,496			$ 35,387
Transaction costs			$ 400
Recognized of reduction for research and development expenses	1,000
National Institute Of Health
Award Granted	1,000	$ 2,000	$ 1,000
Letter of Credit
Restricted cash	$ 400			$ 400

Summary of Significant Accoun_5

Summary of Significant Accounting Policies - Summary of Property and Equipment Useful Lives (Details)	12 Months Ended
	Dec. 31, 2021
Leasehold Improvements [Member]
Property, Plant and Equipment, Estimated Useful Lives	Shorter of useful life of asset or lease term
Computer Equipment [Member]
Property, Plant and Equipment, Estimated Useful Lives	3 years
Furniture Fixtures And Equipment [Member] | Minimum [Member]
Property, Plant and Equipment, Estimated Useful Lives	3
Furniture Fixtures And Equipment [Member] | Maximum [Member]
Property, Plant and Equipment, Estimated Useful Lives	8 years
Lab Equipment [Member]
Property, Plant and Equipment, Estimated Useful Lives	3 years

Summary of Significant Accoun_6

Summary of Significant Accounting Policies - Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share (Details) - shares	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Accounting Policies [Line Items]
Antidilutive securities excluded from computation of diluted net loss per share	9,247,757	1,220,290
Options Outstanding [Member]
Accounting Policies [Line Items]
Antidilutive securities excluded from computation of diluted net loss per share	1,794,300	1,070,301
Unvested restricted stock [Member]
Accounting Policies [Line Items]
Antidilutive securities excluded from computation of diluted net loss per share	160,643	46,199
Unvested common stock subject to repurchase [Member]
Accounting Policies [Line Items]
Antidilutive securities excluded from computation of diluted net loss per share	74,840	103,790
Warrants To Purchase Common Stock [Member]
Accounting Policies [Line Items]
Antidilutive securities excluded from computation of diluted net loss per share	7,217,974	0

Recapitalization - Additional I

Recapitalization - Additional Information (Details) $ in Thousands	1 Months Ended	12 Months Ended
	Aug. 31, 2021USD ($)shares	Dec. 31, 2021USD ($)shares	Dec. 31, 2020USD ($)shares
Subsidiary Sale Of Stock [Line Items]
Proceeds from issuance of common stock upon Business Combination and PIPE Financing, net of transaction costs		$ 124,220	$ 0
Transaction costs	$ 400
Reduction Of Additional Paid In Capital	$ 5,900
Common shares, shares outstanding | shares		35,034,431	18,256,628
Common shares, shares issued | shares		35,034,431	18,256,628
Exchange ratio	0.175648535	0.175648535
Surrozen Inc
Subsidiary Sale Of Stock [Line Items]
Common shares, shares outstanding | shares	4,420,757
Common shares, shares issued | shares	16,440,757
Goodwill	$ 0
Private Investment In Public Entity Offering
Subsidiary Sale Of Stock [Line Items]
Proceeds from cash acquired through acquisition and PIPE offering	128,800
Proceeds from issuance of common stock upon Business Combination and PIPE Financing, net of transaction costs	8,600
Proceeds from issuance of units upon PIPE Financing	120,200
Transaction costs	$ 6,300
Private Investment In Public Entity Offering | Surrozen Inc
Subsidiary Sale Of Stock [Line Items]
Common shares, 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 - USD ($) $ in Thousands		Dec. 31, 2021	Dec. 31, 2020
Assets:
Assets		$ 122,725	$ 48,296
Liabilities(3):
Liabilities	[1]	8,301
Money Market Funds
Assets:
Assets	[2]	32,310	31,896
Commercial Paper
Assets:
Assets		49,136	15,285	[3]
Corporate Bond
Assets:
Assets		19,480	1,115
Government Bonds
Assets:
Assets		18,082
Foreign Bonds
Assets:
Assets		3,717
Public Warrants
Liabilities(3):
Liabilities	[1]	3,527
Private Placement Warrants
Liabilities(3):
Liabilities	[1]	166
P I P E Warrants
Liabilities(3):
Liabilities	[1]	4,608
Level 1
Assets:
Assets		32,310	31,896
Liabilities(3):
Liabilities	[1]	3,527
Level 1 | Money Market Funds
Assets:
Assets	[2]	32,310	31,896
Level 1 | Commercial Paper
Assets:
Assets
Level 1 | Corporate Bond
Assets:
Assets
Level 1 | Government Bonds
Assets:
Assets
Level 1 | Foreign Bonds
Assets:
Assets
Level 1 | Public Warrants
Liabilities(3):
Liabilities	[1]	3,527
Level 1 | Private Placement Warrants
Liabilities(3):
Liabilities
Level 1 | P I P E Warrants
Liabilities(3):
Liabilities
Level 2
Assets:
Assets		90,415	16,400
Liabilities(3):
Liabilities	[1]	4,774
Level 2 | Money Market Funds
Assets:
Assets
Level 2 | Commercial Paper
Assets:
Assets		49,136	15,285	[3]
Level 2 | Corporate Bond
Assets:
Assets		19,480	1,115
Level 2 | Government Bonds
Assets:
Assets		18,082
Level 2 | Foreign Bonds
Assets:
Assets		3,717
Level 2 | Public Warrants
Liabilities(3):
Liabilities
Level 2 | Private Placement Warrants
Liabilities(3):
Liabilities	[1]	166
Level 2 | P I P E Warrants
Liabilities(3):
Liabilities	[1]	4,608
Level 3
Assets:
Assets		0
Liabilities(3):
Liabilities		0
Level 3 | Money Market Funds
Assets:
Assets		0
Level 3 | Commercial Paper
Assets:
Assets		0
Level 3 | Corporate Bond
Assets:
Assets		0
Level 3 | Government Bonds
Assets:
Assets		0
Level 3 | Foreign Bonds
Assets:
Assets		0
Level 3 | Public Warrants
Liabilities(3):
Liabilities		0
Level 3 | Private Placement Warrants
Liabilities(3):
Liabilities		0
Level 3 | P I P E Warrants
Liabilities(3):
Liabilities		$ 0
[1]	See the definition and discussion of Public Warrants, Private Placement Warrants and PIPE Warrants in Note 8.
[2]	Money market funds are included in cash and cash equivalents on the consolidated balance sheets as of December 31, 2021 and 2020.
[3]	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 consolidated balance sheet.

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) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Short-term marketable securities	$ 68,760	$ 14,200
Change in fair value of the public warrant, valuation technique amount	(71)	0
Financial liabilities		0
Transfers of financial instruments		$ 0
Other-than-temporary Impairment Loss, Debt Securities, Available-for-sale	$ 0
Minimum [Member] | P I P E Warrants
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Stock price to redeem warrants	$ 10
Maximum [Member] | P I P E Warrants
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Stock price to redeem warrants	$ 18

Fair Value Measurement - Sche_3

Fair Value Measurement - Schedule of Measurement of PIPE Warrants with Binomial Lattice Model (Details)	Aug. 11, 2021yr
Expected Term (Years)
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Warrants, Measurement Input	5.01
Expected Volatility
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Warrants, Measurement Input	0.1890
Risk-free Interest Rate
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Warrants, Measurement Input	0.0081
Dividend Yield
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Warrants, Measurement Input	0

Fair Value Measurement - Summar

Fair Value Measurement - Summary of Changes in Fair Value of Warrant Liabilities (Details) $ in Thousands	12 Months Ended
	Dec. 31, 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	(71)	[1]
Balance, end of period	8,301
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	(30)	[1]
Balance, end of period	3,527
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	(2)	[1]
Balance, end of period	166
P I P E 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	(39)	[1]
Balance, end of period	$ 4,608
[1]	The change in fair value of the warrant liabilities was recognized in other expense, net within the consolidated statements of operations and comprehensive loss.

Fair Value Measurement - Sche_4

Fair Value Measurement - Schedule of Marketable Securities by Security Type (Details) $ in Thousands	Dec. 31, 2021USD ($)Investments	Dec. 31, 2020USD ($)
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Amortized Cost Current	$ 68,781	$ 16,400
Amortized Cost, Non-current	21,753
Gross Unrealized Gains, Current	4	0
Gross Unrealized Gains, Non-current	0
Gross Unrealized Losses, Current	(25)	0
Gross Unrealized Gains, Non-current	(98)
Fair Value, Current	68,760	16,400
Fair Value, Non-current	$ 21,655
Number Of Positions | Investments	10
Less then 12 Months, Fair Value	$ 34,371
Less then 12 Months, Unrealized Losses	(123)
Commercial Paper
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Amortized Cost Current	49,136	15,285
Gross Unrealized Gains, Current		0
Gross Unrealized Losses, Current		0
Fair Value, Current	49,136	15,285
Corporate Bond
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Amortized Cost Current	15,920	1,115
Amortized Cost, Non-current	3,588
Gross Unrealized Gains, Current	4	0
Gross Unrealized Gains, Non-current	0
Gross Unrealized Losses, Current	(17)	0
Gross Unrealized Gains, Non-current	(15)
Fair Value, Current	15,907	$ 1,115
Fair Value, Non-current	$ 3,573
Number Of Positions | Investments	5
Less then 12 Months, Fair Value	$ 12,572
Less then 12 Months, Unrealized Losses	(32)
Foreign Bonds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Amortized Cost Current	3,725
Gross Unrealized Gains, Current
Gross Unrealized Losses, Current	(8)
Fair Value, Current	$ 3,717
Number Of Positions | Investments	2
Less then 12 Months, Fair Value	$ 3,717
Less then 12 Months, Unrealized Losses	(8)
Government Bonds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Amortized Cost, Non-current	18,165
Gross Unrealized Gains, Non-current	0
Gross Unrealized Gains, Non-current	(83)
Fair Value, Non-current	$ 18,082
Number Of Positions | Investments	3
Less then 12 Months, Fair Value	$ 18,082
Less then 12 Months, Unrealized Losses	$ (83)

Balance Sheet Components - Sche

Balance Sheet Components - Schedule of Property and Equipment, Net (Detail) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Property Plant And Equipment [Line Items]
Property and equipment	$ 14,335	$ 13,583
Less accumulated depreciation and amortization	(9,541)	(7,747)
Property and equipment, net	4,794	5,836
Leasehold Improvements [Member]
Property Plant And Equipment [Line Items]
Property and equipment	7,052	7,052
Lab Equipment [Member]
Property Plant And Equipment [Line Items]
Property and equipment	6,881	6,084
Furniture And Equipment [Member]
Property Plant And Equipment [Line Items]
Property and equipment	309	310
Computer Equipment [Member]
Property Plant And Equipment [Line Items]
Property and equipment	$ 93	$ 137

Balance Sheet Components - Addi

Balance Sheet Components - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Balance Sheet Related Disclosures [Abstract]
Depreciation	$ 2,066	$ 1,937
Aggregate original costs	$ 300

Balance Sheet Components - Sc_2

Balance Sheet Components - Schedule of Accrued Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Balance Sheet Related Disclosures [Abstract]
Accrued payroll and related expenses	$ 2,887	$ 1,673
Accrued research and development expenses	3,666	1,305
Accrued professional service fees	1,520
Liability for early exercised stock options	205	188
Other	384	228
Accrued and other liabilities	$ 8,662	$ 3,394

Leases - Additional Information

Leases - Additional Information (Details) $ in Thousands	1 Months Ended	12 Months Ended
	Sep. 30, 2021USD ($)	Dec. 31, 2021USD ($)ft²	Dec. 31, 2020USD ($)	Aug. 31, 2016ft²
Lessee Lease Description [Line Items]
Operating lease month of expiry of lease	2022-06
Restricted cash		$ 405	$ 405
Right-of-use asset obtained in exchange for operating lease liabilities	$ 300		563
Operating Lease, Expense		$ 2,000	$ 1,800
Eighteen Months [Member]
Lessee Lease Description [Line Items]
Area of real estate property | ft²		6,478
Operating lease term		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
Restricted cash		$ 400

Leases - Summary Of Lessee, Ope

Leases - Summary Of Lessee, Operating Lease, Liability, Maturity (Details) $ in Thousands	Dec. 31, 2021USD ($)
Leases [Abstract]
2022	$ 2,743
2023	2,596
2024	2,670
2025	891
Total lease payments	8,900
Less: Imputed interest	(1,107)
Operating lease liabilities	$ 7,793

Leases - Schedule of Supplement

Leases - Schedule of Supplemental Information Related to Operating Leases (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Leases [Abstract]
Cash paid for amounts included in the measurement of lease liabilities (in thousands)	$ 2,856	$ 2,520
Weighted-average remaining lease term (in years)	3 years 3 months	4 years 2 months 8 days
Weighted-average discount rate	8.43%	8.40%

License Agreements - Additional

License Agreements - Additional Information (Details) - USD ($) $ in Thousands	1 Months Ended				12 Months Ended
	Sep. 30, 2021	Jun. 30, 2018	Sep. 30, 2016	Mar. 31, 2016	Dec. 31, 2021	Dec. 31, 2020
Stock issued during period, shares, issued for services				42,451
Written Notice					60 days
Payments for milestone agreement or earned royalties on achievement of milestones					$ 0
Research and development					40,177	$ 25,684
Stanford License Agreements [Member] | Stanford [Member]
Payments for milestone agreement or earned royalties on achievement of milestones				$ 5,000
Payments for achievement of specified development and regulatory milestones		$ 425
Research and development					100	100
Payments for milestone agreement on achievement of milestones					$ 0
U C S F License And Option Agreements [Member]
Right to negotiate new agreement exercised option					no
U C S F License And Option Agreements [Member] | Stanford [Member]
Research and development					$ 50,000	100
Payments for milestone agreement on achievement of milestones					0
Distributed Bio Subscription Agreement [Member]
Payments for achievement of specified development and regulatory milestones			$ 5,900
Distributed Bio Subscription Agreement [Member] | Stanford [Member]
Research and development	$ 50,000					$ 200
Payments for milestone agreement on achievement of milestones					$ 300
Maximum [Member] | Stanford License Agreements [Member] | Stanford [Member]
Payments for milestone agreement or earned royalties on achievement of milestones				$ 900

Common Stock Warrants - Additio

Common Stock Warrants - Additional Information (Details) - $ / shares	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Common Stock Warrants Outstanding	7,217,974
Stock issued during period shares new shares	12,020,000
Common Stock Warrants Expiration Date	Aug. 12, 2026
Warrant Redemption Condition Minimum Share Price Scenario Two	$ 18
Class Of Warrant Or Right Exercise Price Of Warrants Or Rights1	$ 11.50
Common Stock
Stock issued during period shares new shares	12,020,000	5,018,525
Public Warrants
Common Stock Warrants Outstanding	3,066,651
Common Stock Warrants Expiration Date	Aug. 12, 2026
Warrant Redemption Period	30 days
Warrant Redemption Condition Minimum Share Price Scenario One	$ 10
Class Of Warrant Or Right Exercise Price Of Warrants Or Rights1	11.50
Public Warrants | Common Stock, Closing Price equals or Exceeds $18 Per Share [Member]
Redemption Price Per Public Warrant	0.01
Closing Price of Common Stock	18
Public Warrants | Common Stock, Closing Price equals or Exceeds $10 Per Share [Member]
Redemption Price Per Public Warrant	0.10
Closing Price of Common Stock	$ 10
Private Placement Warrants
Common Stock Warrants Outstanding	144,666
Common Stock Warrants Expiration Date	Aug. 12, 2026
Lock-In period for Transfer, Assignment or Sale of Warrants	30 days
Class Of Warrant Or Right Exercise Price Of Warrants Or Rights1	$ 11.50
Private Placement Warrants | Common Stock, Closing Price equals or Exceeds $18 Per Share [Member]
Closing Price of Common Stock	18
Private Placement Warrants | Common Stock, Closing Price equals or Exceeds $10 Per Share [Member]
Closing Price of Common Stock	$ 18
P I P E Warrants
Common Stock Warrants Outstanding	4,006,657
Common Stock Warrants Expiration Date	Aug. 12, 2026
Class Of Warrant Or Right Exercise Price Of Warrants Or Rights1	$ 11.50

Common Stock Warrants - (Detail

Common Stock Warrants - (Details)	12 Months Ended
	Dec. 31, 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
P I P E 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) - shares	12 Months Ended
	Dec. 31, 2021	Aug. 11, 2021
Temporary equity shares outstanding	0
Conversion basis	one-for-one basis
Convertible preferred stock shares issued upon conversion	16,737,520
Redeemable Convertible Preferred Stock [Member]
Temporary equity shares outstanding		95,289,932

Stock Based Compensation Plan -

Stock Based Compensation Plan - Additional Information (Details) - USD ($) $ / shares in Units, $ in Millions	1 Months Ended	12 Months Ended
	Aug. 31, 2021	Dec. 31, 2021	Dec. 31, 2020
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Intrinsic value of options exercised		$ 1.2	$ 0.2
Weighted average grant date fair value/shares		$ 6.36	$ 0.74
Fair value of RSAs vested		$ 0.6	$ 0.3
Unrecognized stock based compensation expense		$ 7.8
Weighted-average period		3 years 1 month 9 days
Early exercises of options outstanding		74,840
Repurchase price per share		$ 2.73
RSA [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vesting Period		4 years
Employee Stock | Minimum [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Percentage of stockholders	10.00%
2015 stock plan [Member]
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
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Intrinsic Value		The Company’s outstanding RSAs began vesting one month after the grant date and vest 1/48th per month over four years.
2021 Stock Plan [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares reserved for future issuance		4,344,699
2021 Stock Plan [Member] | Employee Stock
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	110.00%
Exercisable period	5 years
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.
2021 Stock Plan [Member] | Employee Stock | Maximum [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expiration period		10 years
2021 Stock Plan [Member] | Employee Stock | Minimum [Member]
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) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of options recapitalization	(5,023,310)
Number of Options Granted	945,526
Number of Options Exercised	(161,451)
Number of Options Cancelled	(60,076)
Number of Options Outstanding Ending Balance	1,794,300
Number of Options outstanding and exercisable	655,238
Weighted Average Exercise Price Outstanding, Beginning Balance | $ / shares	$ 0.40
Weighted Average Exercise Price Outstanding Recapitalization | $ / shares	2.26
Weighted Average Exercise Price Granted	10.13
Weighted Average Exercise Price Exercised	2.47
Weighted Average Exercise Price Cancelled	4.54
Weighted Average Exercise Price Outstanding, Ending Balance	6.31	$ 0.40
Weighted Average Exercise Price Options outstanding and exercisable	$ 3.06
Weighted Average Remaining Contractual Life (In Years)	8 years 5 months 4 days	8 years 5 months 4 days
Weighted Average Remaining Contractual Life, exercisable (In Years)	7 years 3 months 21 days
Aggregate Intrinsic Value	$ 3,663
Aggregate Intrinsic Value Options outstanding and exercisable	$ 2,687
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
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

Stock Based Compensation Plan_3

Stock Based Compensation Plan - Summary of RSA Activity (Details) - RSA [Member] - $ / shares	12 Months Ended
	Dec. 31, 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	(62,297)
Number of Shares RSAs, Forfeited	(16,467)
Number of Shares RSAs, unvested, Ending Balance	160,643
Weighted Average Grant Date Fair Value RSAs, Granted	$ 9.95
Weighted Average Grant Date Fair Value RSAs, Vested	7
Weighted Average Grant Date Fair Value RSAs, Forfeited	9.76
Weighted Average Grant Date Fair Value RSAs, Unvested Ending Balance	$ 9.39
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)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected term (in years)	6 years 3 days	6 years 10 days
Expected volatility	71.23%	61.41%
Risk-free rate	0.89%	0.80%
Dividend yield	0.00%	0.00%

Stock Based Compensation Plan_4

Stock Based Compensation Plan - Schedule of Stock-Based Compensation Expenses (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
General and administrative	$ 14,214	$ 7,123
Total stock-based compensation expense	2,316	635
Research and Development Expense
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Research and development	736	423
General and Administrative Expense
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
General and administrative	$ 1,580	$ 212

Income Taxes - Additional Infor

Income Taxes - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Operating Loss Carryforwards [Line Items]
Research and development credit carryforwards	$ 2,392,000	$ 2,166,000
Tax credit carry forwards expiration start year	2036
Uncertain income tax position, Description	An uncertain income tax position will not be recognized if it has less than a 50% likelihood of being sustained.
Unrecognized Tax Benefits	$ 974,000	$ 921,000	$ 673,000
Percentage of net operating loss carryforward to offset taxable income	100.00%
Maximum limit of business interest expense percent		50.00%	30.00%
Maximum limit of charitable contribution deductions percent	25.00%	10.00%
Income tax expense (benefit)	$ 0	$ 0
Net valuation allowance increased	9,700,000	$ 9,600,000
Employee retention credits amount	1,000,000
Domestic Tax Authority [Member]
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards	133,900,000
Tax credit carry forward	1,300,000
Domestic Tax Authority [Member] | Research Tax Credit Carryforward [Member]
Operating Loss Carryforwards [Line Items]
Research and development credit carryforwards	$ 1,000,000
Tax credit carry forwards expiration start year	2036
Domestic Tax Authority [Member] | Indefinite Tax Year [Member]
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards	$ 121,500,000
State and Local Jurisdiction [Member]
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards	53,000,000
Research and development credit carryforwards	2,800,000
Tax credit carry forward	$ 27,400,000
State and Local Jurisdiction [Member] | Research Tax Credit Carryforward [Member]
Operating Loss Carryforwards [Line Items]
Tax credit carry forwards expiration start year	indefinitely

Income Taxes - Summary of Net D

Income Taxes - Summary of Net Deferred Tax Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Deferred tax assets
Net operating loss carryforwards	$ 31,826	$ 22,585
Research and development credits	2,392	2,166
Lease liabilities	1,521	2,487
Accrual and reserves	590	457
Employee retention credits	284	0
Capitalized intangible costs	122	156
Stock-based compensation	129	2
Other	3	5
Gross deferred tax assets	36,867	27,858
Less valuation allowance	(35,665)	(25,941)
Deferred tax assets, net of valuation allowance	1,202	1,917
Deferred tax liabilities
Right-of-use assets	(962)	(1,555)
Fixed assets	(101)	(340)
Other	(139)	(22)
Gross deferred tax liabilities	(1,202)	(1,917)
Total net deferred tax assets	$ 0	$ 0

Income Taxes - Summary of Tax B

Income Taxes - Summary of Tax Benefits (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Income Tax Disclosure [Abstract]
Balance at beginning of the year	$ 921	$ 673
Additions based on tax positions related to current year	480	248
Reductions based on tax positions of prior year	(427)	0
Balance at end of the year	$ 974	$ 921

Income Taxes - Schedule of Reco

Income Taxes - Schedule of Reconciliation of U.S. Federal Statutory Income Tax Rate TO Effective Income Tax Rate (Detail)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Income Tax Disclosure [Abstract]
Statutory rate	21.00%	21.00%
State tax	(2.78%)	7.96%
Tax credits	1.70%	0.84%
Change in valuation allowance	(16.92%)	(29.43%)
NOL and tax credits limited under 382	(2.43%)
Other	0.57%	(0.37%)
Effective Income Tax Rate Reconciliation, Percent, Total	0.00%	0.00%

401(K) Plan Additional Informat

401(K) Plan Additional Information (Details)	12 Months Ended
	Dec. 31, 2021
Compensation And Retirement Disclosure [Abstract]
Maximum annual contribution per employee	100.00%

Subsequent Events (Additional I

Subsequent Events (Additional Information) (Details) - USD ($) $ in Millions	1 Months Ended
	Feb. 28, 2022	Dec. 31, 2021	Dec. 31, 2020
Subsequent Event [Line Items]
Common shares, shares issued		35,034,431	18,256,628
Lincoln Park | Maximum [Member]
Subsequent Event [Line Items]
Stock Issuance period	36 months
Subsequent Events
Subsequent Event [Line Items]
Sale of Stock, Consideration Received on Transaction	$ 30
Subsequent Events | Maximum [Member]
Subsequent Event [Line Items]
Sale of Stock, Consideration Received on Transaction	50
Subsequent Events | Lincoln Park
Subsequent Event [Line Items]
Common stock purchase commitment	$ 0.1
Common shares, shares issued	100,000
Common stock with the fair value	$ 0.3