0000950170-23-040648 | 10-Q | XBRL Viewer

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Fair Value Measurement - Schedule of Financial Assets and Liabilities Measured at Fair Value on Recurring Basis (Parenthetical) (Details) $ in Millions	Jun. 30, 2023 USD ($)
Cash and Cash Equivalents [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets	$ 1.0
Short-Term Marketable Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets	$ 3.0

Commitments and Contingencies

6 Months Ended

Jun. 30, 2023

Commitments and Contingencies Disclosure [Abstract]

Commitments and Contingencies

Note 8. Commitments and Contingencies

Lease Agreement

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.

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 condensed consolidated balance sheets. On March 10, 2023, Silicon Valley Bank, or SVB, was closed by the California Department of Financial Protection and Innovation, which appointed the Federal Deposit Insurance Corporation, or FDIC, as a receiver. On March 27, 2023, First-Citizens Bank & Trust Company assumed all of SVB's customer deposits and certain other liabilities and acquired substantially all of SVB's loans and certain other assets from the FDIC. As required by the landlord, the Company is working on replacing the letter of credit issued by SVB with a letter of credit from a different financial institution.

The operating lease expense for the three and six months ended June 30, 2023 and 2022 was $0.4 million, $0.8 million, $0.5 million and $1.0 million, respectively.

Aggregate future minimum rental payments under the operating leases as of June 30, 2023, were as follows (in thousands):


Remaining six months ending December 31, 2023	$	1,311
Year ending December 31, 2024		2,670
Year ending December 31, 2025		891
Total lease payments		4,872
Less: Imputed interest		(344	)
Operating lease liabilities	$	4,528

Organization and Business	6 Months Ended
Jun. 30, 2023
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization and Business	Note 1. Organization and Business Organization Surrozen, Inc., or the Company, is a clinical 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. Surrozen Netherlands, B.V. was incorporated in May 2022 and located in Amsterdam, Netherlands as a wholly-owned subsidiary of the Company. Liquidity The Company has incurred net losses since inception. For the three and six months ended June 30, 2023, the Company incurred a net loss of $9.4 million and $23.7 million , respectively. For the three and six months ended June 30, 2022, the Company incurred a net loss of $13.9 million and $21.9 million, respectively. For the six months ended June 30, 2023 and 2022, the Company used $22.9 million and $29.8 million of cash in operations, respectively. As of June 30, 2023, the Company had cash, cash equivalents and marketable securities of $53.4 million and an accumulated deficit of approximately $202.3 million. The Company expects operating expenses to continue to be significant in connection with its ongoing clinical studies and anticipates the need to raise additional capital to continue to execute its long-range business plan. 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 unaudited consolidated financial statements. However, if the Company’s anticipated cash burn is greater than anticipated, the Company could use its capital resources sooner than expected which may result in the need to reduce future planned expenditures and/or raise additional capital to continue to fund the operations.

Organization and Business

6 Months Ended

Jun. 30, 2023

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Organization and Business

Note 1. Organization and Business

Organization

Surrozen, Inc., or the Company, is a clinical 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. Surrozen Netherlands, B.V. was incorporated in May 2022 and located in Amsterdam, Netherlands as a wholly-owned subsidiary of the Company.

Liquidity

The Company has incurred net losses since inception. For the three and six months ended June 30, 2023, the Company incurred a net loss of $9.4 million and $23.7 million , respectively. For the three and six months ended June 30, 2022, the Company incurred a net loss of $13.9 million and $21.9 million, respectively. For the six months ended June 30, 2023 and 2022, the Company used $22.9 million and $29.8 million of cash in operations, respectively. As of June 30, 2023, the Company had cash, cash equivalents and marketable securities of $53.4 million and an accumulated deficit of approximately $202.3 million. The Company expects operating expenses to continue to be significant in connection with its ongoing clinical studies and anticipates the need to raise additional capital to continue to execute its long-range business plan.

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 unaudited consolidated financial statements. However, if the Company’s anticipated cash burn is greater than anticipated, the Company could use its capital resources sooner than expected which may result in the need to reduce future planned expenditures and/or raise additional capital to continue to fund the operations.

License Agreements - Additional Information (Details) - USD ($) $ in Thousands	1 Months Ended			3 Months Ended		6 Months Ended
	Jun. 30, 2018	Sep. 30, 2016	Mar. 31, 2016	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
License Agreements [Line Items]
Research and development expense				$ 6,937	$ 9,581	$ 15,023	$ 18,952
Stanford License Agreements [Member] \| Stanford [Member]
License Agreements [Line Items]
Payments for milestone agreement or earned royalties on achievement of milestones			$ 5,000
Payments for achievement of specified development and regulatory milestones	$ 400
Payments for milestone agreement on achievement of milestones						0
Stanford License Agreements [Member] \| Stanford [Member] \| Maximum
License Agreements [Line Items]
Payments for milestone agreement or earned royalties on achievement of milestones			$ 900
UCSF License And Option Agreements [Member] \| Stanford [Member]
License Agreements [Line Items]
Payments for milestone agreement on achievement of milestones						0
Distributed Bio Subscription Agreement [Member]
License Agreements [Line Items]
Payments for achievement of specified development and regulatory milestones		$ 5,900
Distributed Bio Subscription Agreement [Member] \| Stanford [Member]
License Agreements [Line Items]
Research and development expense				$ 100	$ 100	$ 100	$ 100

Fair Value Measurement - Additional Information (Details) $ / shares in Units, $ in Thousands	6 Months Ended
	Jun. 30, 2023 USD ($) $ / shares
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Other than temporary impairment losses \| $	$ 0
PIPE Warrants \| Maximum [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Stock price to redeem warrants	$ 18
PIPE Warrants \| Minimum [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Stock price to redeem warrants	$ 10
Measurement Input, Expected Dividend Rate \| PIPE Warrants
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Alternative Investment, Measurement Input	0

Restructuring (Additional Information) (Details) $ in Millions	6 Months Ended
	Jun. 30, 2023 USD ($)
Restructuring Reserve [Abstract]
Restructuring Charges	$ 1.2
Reduction in workforce	25.00%

Common Stock Warrants

6 Months Ended

Jun. 30, 2023

Equity [Abstract]

Common Stock Warrants

Note 10. Common Stock Warrants

The following table sets forth the common stock warrants outstanding as of June 30, 2023 and December 31, 2022 (in thousands, except exercise price per warrant):


Type	Classification	Expiration Date	Exercise Price		June 30, 2023		December 31, 2022
Public Warrants	Liability	August 12, 2026	$	11.50		2,733		2,733
PIPE Warrants	Liability	August 12, 2026		11.50		3,174		3,174
Total						5,907		5,907

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 shares issuable upon exercise of the Public Warrants may be adjusted in the event of a share dividend, extraordinary dividend or recapitalization, reorganization, merger or consolidation. The Company would not be obligated to deliver any shares of common stock pursuant to the exercise of a Public Warrant and would have no obligation to settle such Public Warrant exercise unless a registration statement under the Securities Act with respect to the common stock underlying the Public Warrants is then effective. If 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.

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 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.

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. At June 30, 2023, the PIPE Warrants are the same in all respects as the Public Warrants.

On March 31, 2023, the Company entered into an amended and restated warrant agreement with Continental Stock Transfer & Trust Company as warrant agent, or the PIPE Warrant Agreement. PIPE Warrants may be converted into Public Warrants on transfer pursuant to the terms of the PIPE Warrant Agreement. As of June 30, 2023, no PIPE Warrants were converted into Public Warrants.

Classification

The Public Warrants and PIPE Warrants are not considered indexed to the Company’s common stock as certain provisions of the warrant agreements could change the settlement amount of these warrants. As a result, they were classified as liabilities and recorded at fair value with subsequent change in their respective fair value recognized in other income (expense), net within the unaudited condensed consolidated statements of operations and comprehensive loss. See Note 3 for the discussion of warrant valuations.

Balance Sheet Components (Tables)

6 Months Ended

Jun. 30, 2023

Balance Sheet Related Disclosures [Abstract]

Schedule of Accrued Liabilities

Accrued and other liabilities consist of the following (in thousands):


	June 30,		December 31,
	2023		2022
Accrued payroll and related expenses	$	2,456	$	3,964
Accrued research and development expenses		944		1,665
Accrued professional service fees		289		638
Liability for early exercised stock options		29		89
Other		183		492
Accrued and other liabilities	$	3,901	$	6,848

Collaboration and License Agreements

6 Months Ended

Jun. 30, 2023

Business Combination and Asset Acquisition [Abstract]

Collaboration and License Agreements

Note 5. Collaboration and License Agreements

Collaboration and License Agreement with Boehringer Ingelheim International GmbH

In October 2022, the Company executed the CLA with BI to research, develop and commercialize Fzd4 bi-specific antibodies designed using the Company’s SWAP technology, including SZN-413. The Company and BI are conducting partnership research focused on SZN-413 during a one-year period, which BI has the right to extend by up to six months. The Company granted BI an exclusive, royalty-bearing, worldwide, sublicensable license, under the applicable patents and know-how, to develop, manufacture and commercialize, for all uses, one lead and two back-up Fzd4 bi-specific antibodies selected by BI. After an initial period of joint research, BI shall be responsible for all further research, preclinical and clinical development, manufacturing, regulatory approvals, and commercialization of licensed products at its expense. Unless terminated earlier, the CLA will remain effective, on a country-by-country and product-by-product basis, until the expiration of BI's royalty obligations. BI has the right to terminate the CLA for any reason after a specified notice period. Each party has the right to terminate the CLA on account of the other party’s bankruptcy or material, uncured breach.

Under the terms of the CLA, BI agreed to pay a non-refundable upfront payment of $12.5 million less any applicable withholding tax, success-based milestone payments up to a total of $587.0 million and mid-single digit to low-double digit royalties on net sales of the licensed products should any reach commercialization. The royalty payments will be subject to reduction due to patent expiration, generic competition and payments made under certain licenses for third-party intellectual property. The Company received $10.5 million of the upfront payment from BI in November 2022. The associated withholding tax of $2.0 million is expected to be refunded to the Company in 2023.

The Company determined that the CLA is within the scope of ASC 606. The Company evaluated the promised goods and services and determined that the license to the Company's intellectual property granted to BI represented one performance obligation for the purposes of conducting the partnership research and further development on SZN-413. The transaction price was determined to be $12.5 million,

which is the non-refundable upfront payment. Variable consideration related to future milestones was fully constrained because the Company cannot conclude that it is probable that a significant reversal in the amount of cumulative revenue recognized will not occur, given the inherent uncertainty of success with these future milestones. For sales-based royalties, the Company determined that the license is the predominant item to which the royalties relate to. Accordingly, the Company will recognize revenue at the later of (i) when the related sales occur, or (ii) when the performance obligation to which some or all the royalty has been allocated has been satisfied (or partially satisfied). The Company will re-evaluate the transaction price in each reporting period and as uncertain events are resolved or other changes in circumstances occur. The Company recognized the non-refundable upfront payment of $12.5 million as collaboration and license revenue at a point in time upon delivery of the license in the fourth quarter of 2022. The associated withholding tax of $2.0 million to be refunded was recognized as accounts receivable on the condensed consolidated balance sheets as of June 30, 2023 and December 31, 2022.

Stock Based Compensation Plan - Summary of RSA Activity (Details) - RSA shares in Thousands	6 Months Ended
	Jun. 30, 2023 $ / shares shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of Shares RSAs, unvested, Beginning Balance \| shares	105
Number of Shares RSAs, Vested \| shares	(24)
Number of Shares RSAs, unvested, Ending Balance \| shares	81
Weighted Average Grant Date Fair Value RSAs, Unvested Beginning Balance \| $ / shares	$ 9.74
Weighted Average Grant Date Fair Value RSAs, Vested \| $ / shares	9.68
Weighted Average Grant Date Fair Value RSAs, Unvested Ending Balance \| $ / shares	$ 9.76

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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+ Details

Stock Based Compensation Plan - Additional Information (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Weighted average grant date fair value/shares	$ 0.63	$ 2.34
Unrecognized stock based compensation expense	$ 7.6
Weighted-average period	2 years 1 month 28 days
RSA
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Fair value of RSAs vested	$ 0.1	$ 0.1
2021 Stock Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares reserved for future issuance	4.4
Options \| 2021 Stock Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Description of modification of options	Options under the 2021 Plan generally vest over four years.
Options \| Maximum \| 2021 Stock Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expiration period	10 years
Employee Stock Purchase Plan [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares reserved for future issuance	0.5
Shares Issued under ESPP	0.5
Percentage of discount payroll deductions	15.00%
Common Stock Trading Discription	The eligible employees are able to purchase shares at 85% of the lower of the fair market value of the Company’s common stock on the first trading day of the offering period or on the purchase day

Balance Sheet Components

6 Months Ended

Jun. 30, 2023

Balance Sheet Related Disclosures [Abstract]

Balance Sheet Components

Note 4. Balance Sheet Components

Accrued and Other Liabilities

Accrued and other liabilities consist of the following (in thousands):


	June 30,		December 31,
	2023		2022
Accrued payroll and related expenses	$	2,456	$	3,964
Accrued research and development expenses		944		1,665
Accrued professional service fees		289		638
Liability for early exercised stock options		29		89
Other		183		492
Accrued and other liabilities	$	3,901	$	6,848

Recapitalization - Additional Information (Details) - shares	Jun. 30, 2023	Dec. 31, 2022
Subsidiary Sale Of Stock [Line Items]
Common shares, shares outstanding	30,571,000	30,088,000
Common shares, shares issued	30,571,000	30,088,000

Summary of Significant Accounting Policies

6 Months Ended

Jun. 30, 2023

Accounting Policies [Abstract]

Summary of Significant Accounting Policies

Note 2. Summary of Significant Accounting Policies

Basis of Presentation

The Company’s unaudited condensed consolidated financial statements and accompanying notes have been prepared in accordance with generally accepted accounting principles in the United States of America, or GAAP, and pursuant to the regulations of the U.S. Securities and Exchange Commission, or SEC. As permitted under those rules, certain notes or other financial information that are normally required by GAAP have been condensed or omitted and accordingly, the consolidated balance sheet as of December 31, 2022 has been derived from the Company’s audited consolidated financial statements at that date but does not include all of the information required by GAAP for complete consolidated financial statements. These unaudited condensed consolidated financial statements have been prepared on the same basis as the Company’s annual consolidated financial statements and, in the opinion of management, reflect all adjustments (consisting of normal recurring adjustments) that are necessary for a fair presentation of the Company’s consolidated financial statements. The results of operations for the three and six months ended June 30, 2023 are not necessarily indicative of the results to be expected for the year ended December 31, 2023 or for any other interim period or future year.

The unaudited condensed consolidated financial statements include the accounts of the Company and its subsidiaries. All intercompany transactions and balances have been eliminated.

The accompanying condensed consolidated financial statements and related financial information should be read in conjunction with the audited consolidated financial statements and the related notes thereto for the year ended December 31, 2022 included in the Company’s Annual Report on Form 10-K, filed with the SEC on March 31, 2023.

Use of Estimates

The preparation of unaudited condensed consolidated financial statements in conformity with GAAP requires management to make judgments, estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities as of the date of the unaudited condensed consolidated financial statements and the reported amounts of expenses during the reporting periods. Significant estimates and assumptions made in the accompanying unaudited condensed consolidated financial statements include but are not limited to certain accrued expenses for research and development activities and stock-based compensation expense. 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.

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 may at times exceed federally insured limits. However, the Company’s exposure to credit risk in the event of default by the financial institution is limited to the extent of amounts recorded on the unaudited condensed consolidated balance sheets. The Company believes it is not exposed to significant credit risk on cash. 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, commercial paper and corporate debt securities. The Company has not experienced any losses on its cash equivalents and marketable securities.

Marketable Securities

The Company invests its excess cash in U.S. government bonds, commercial paper and 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. These marketable securities are carried at estimated fair value with unrealized holding gains or losses included in accumulated other comprehensive income (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 unaudited condensed consolidated statements of operations and comprehensive loss when earned.

The Company periodically evaluates its available-for-sale marketable securities for impairment. When the fair value of a marketable security is below its amortized cost basis, 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, 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 basis over the fair value of the security. An allowance for credit losses for the excess of amortized cost basis over the expected cash flows, if any, is recorded in other income (expense), net on the unaudited condensed consolidated statements of operations. Impairment losses that are not credit-related are included in accumulated other comprehensive income (loss) in stockholders’ equity.

Warrant Liabilities

The Company's warrants are classified as liabilities. At the end of each reporting period, any changes in fair value during the period are recognized in other income (expense), net within the unaudited condensed consolidated statements of operations and comprehensive loss. The Company will continue to adjust the warrant liabilities for changes in the fair value until the earlier of a) the exercise or expiration of the warrants or b) the redemption of the warrants, at which time such warrants will be reclassified to additional paid-in capital.

Revenue Recognition

The Company records accounts receivable for amounts billed to the customer for which the Company has an unconditional right to consideration. The Company assesses accounts receivable for impairment and, to date, no impairment losses have been recorded.

The Company executed a Collaboration and Licensing Agreement, or CLA, with Boehringer Ingelheim International GmbH, or BI, in October 2022 to which the Company licensed certain rights to its intellectual property that is determined within the scope of ASC 606. The terms of the CLA include payment to the Company of a non-refundable upfront payment, development, regulatory and commercial milestone payments and royalties on net sales of licensed products.

The Company determined that the Company's intellectual property granted to BI represented one performance obligation for the purposes of conducting the partnership research and further development on SZN-413. The transaction price was determined to be the non-refundable upfront payment. Variable consideration related to future milestones was fully constrained because the Company

cannot conclude that it is probable that a significant reversal in the amount of cumulative revenue recognized will not occur, given the inherent uncertainty of success with these future milestones. At the end of each subsequent reporting period, the Company re-evaluates the probability of achievement of such milestones and any related constraint, and if necessary, adjusts its estimate of the overall transaction price. The Company will recognize sales-based royalties as revenue at the later of (i) when the related sales occur, or (ii) when the performance obligation to which some or all of the royalties that have been allocated have been satisfied (or partially satisfied).

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 shares of 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 (in thousands):


	June 30,
	2023		2022
Options outstanding		4,998		3,503
Unvested restricted stock		81		130
Unvested common stock subject to repurchase		6		38
Warrants to purchase common stock		5,907		7,219
Total		10,992		10,890

Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022
Operating activities:
Net loss	$ (23,684)	$ (21,872)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation	977	1,007
Stock-based compensation	2,287	1,895
Non-cash operating lease expense	613	745
Amortization of (discount) premium on marketable securities, net	(480)	235
Change in fair value of warrant liabilities	0	(6,919)
Other expense related to the commitment shares issued to Lincoln Park	0	273
Changes in operating assets and liabilities:
Prepaid expenses and other current assets	1,696	1,309
Other assets	20	(418)
Accounts payable	(472)	(2,278)
Accrued and other liabilities	(2,802)	(2,590)
Operating Lease liabilities	(1,074)	(1,174)
Net cash used in operating activities	(22,919)	(29,787)
Investing activities:
Purchases of property and equipment	(398)	(435)
Purchases of marketable securities	(18,690)	0
Proceeds from maturities of marketable securities	53,665	14,000
Net cash provided by (used in) investing activities	34,577	13,565
Financing activities:
Repurchase of early exercised stock options	(39)	(3)
ProceedsFromIssuanceOfCommonStockUponEmployeeStockPlanPurchases	187	0
Net cash (used in) provided by financing activities	148	(3)
Net (decrease) increase in cash, cash equivalents and restricted cash	11,806	(16,225)
Cash, cash equivalents and restricted cash at beginning of period	25,095	33,496
Cash, cash equivalents and restricted cash at end of period	36,901	17,271
Supplemental disclosure of noncash investing and financing activities:
Vesting of early exercises of stock options	21	57
Reconciliation Of Cash Cash Equivalents And Restricted Cash To Consolidated Balance Sheets Abstract
Cash and cash equivalents	36,496	16,866
Restricted cash	405	405
Cash, cash equivalents and restricted cash	$ 36,901	$ 17,271

Subsequent Events - Additional Information (Details) - USD ($)	1 Months Ended	6 Months Ended
	Jul. 31, 2023	Jun. 30, 2023
Subsequent Event [Line Items]
Restructuring Charges		$ 1,200,000
Subsequent Event [Member]
Subsequent Event [Line Items]
Workforce reduction, percent	38.00%
Restructuring Charges	$ 1,600

Subsequent Events

6 Months Ended

Jun. 30, 2023

Subsequent Events [Abstract]

Subsequent Events

Note 12. Subsequent Events

In July 2023, the Company adopted and executed a restructuring plan approved by the board of directors to reduce its overall workforce by approximately 38%. The Company believes that the restructuring plan will enable the Company to better align its workforce with the business needs and focus more of its capital resources on its clinical stage programs. The Company expects to substantially complete the workforce reduction by the end of the third quarter of 2023 and estimates to incur one-time restructuring charges of approximately $1.6 million, including employee severance and other termination benefits.

Commitments and Contingencies - Additional Information (Details) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023 USD ($)	Jun. 30, 2022 USD ($)	Jun. 30, 2023 USD ($)	Jun. 30, 2022 USD ($)	Aug. 31, 2016 ft²
Lessee, Lease, Description [Line Items]
Operating Lease, Expense	$ 0.4	$ 0.5	$ 0.8	$ 1.0
CALIFORNIA \| Eight Years [Member]
Lessee, Lease, Description [Line Items]
Area of Real Estate Property \| ft²					32,813
Restricted Cash	$ 0.4		$ 0.4

Restructuring (Tables)

6 Months Ended

Jun. 30, 2023

Restructuring Reserve [Abstract]

ScheduleOfRestructuringAndRelatedCosts

The outstanding restructuring liabilities are included in accrued and other liabilities on the condensed consolidated balance sheet. The following table summarizes activity during the six months ended June 30, 2023 (in thousands):


	Employee Severance and Other Benefits
Balance, December 31, 2022	$	—
Restructuring charges		1,207
Cash payments		(726	)
Balance, March 31, 2023		481
Cash payments		(457	)
Balance, June 30, 2023	$	24

License Agreements

6 Months Ended

Jun. 30, 2023

License Agreements [Abstract]

License Agreements

Note 6. License Agreements

Stanford License Agreements

In March 2016, the Company entered into a license agreement with Stanford University, or the 2016 Stanford Agreement, which was amended in July 2016, October 2016 and January 2021, pursuant to which the Company obtained from Stanford a worldwide, exclusive, sublicensable license under certain patents, rights, or licensed patents and technology related to its engineered Wnt surrogate molecules to make, use, import, offer to sell and sell products that are claimed by the licensed patents or that use or incorporate such technology, or licensed products, for the treatment, diagnosis and prevention of human and veterinary diseases. The Company agreed to pay Stanford (i) nominal annual license maintenance fees which are creditable against earned royalties owed to Stanford for the same year, (ii) an aggregate of up to $0.9 million for the achievement of specified development and regulatory milestones, and (iii) 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. However, the Company and Stanford may be able to negotiate a lower non-royalty sublicense percentage based on then-current value of the licensed patents for each sublicense product. If the Company is acquired, it agreed to pay 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. The Company agreed to pay Stanford an aggregate of up to $0.4 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, Stanford is entitled to receive 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.

For the three and six months ended June 30, 2023 and 2022, the Company incurred de minimis research and development expenses under the Stanford agreements. No milestones have been achieved as of June 30, 2023.

UCSF License and Option Agreements

In September and October 2016, the Company entered into two separate license and option agreements with The Regents of the University of California, or the UCSF Agreements, pursuant to which the Company obtained exclusive licenses from UCSF for internal research and antibody discovery purposes and an option to negotiate with UCSF to obtain an exclusive license under UCSF’s rights in the applicable library to make, use, sell, offer for sale and import products incorporating antibodies identified or resulting from the Company’s use of such library, or licensed products.

In 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 commercial 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 March 2022, the Company exercised the option under the UCSF Agreements and entered into a non-exclusive commercial license agreement to make and use licensed products derived from the phage display llama VHH single domain antibody library. Under the commercial license agreement, the Company paid UCSF a nominal license issue fee and agreed to pay a nominal annual license maintenance fee, five- to six-digit payments per licensed product upon achievement of a regulatory milestone, nominal minimum annual royalties, and earned royalties equal to a sub-single digit percentage of the Company’s and the Company’s sublicensees’ net sales of licensed products.

For the three and six months ended June 30, 2023 and 2022, the Company incurred de minimis research and development expenses under the UCSF Agreements and the commercial license agreement. No milestones have been achieved as of June 30, 2023.

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, Inc., 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. The Company agreed to pay Distributed Bio an annual fee in the low six figures after the first three years. Additionally, the Company agreed to pay Distributed Bio an aggregate of $5.9 million for each licensed product that achieves specified development, regulatory and commercial milestones and royalties equal to a very low single digit percentage of the Company’s and its sublicensees’ net sales of licensed products. The Company’s obligation to pay royalties will end for each licensed product ten years after its first commercial sale.

For the three and six months ended June 30, 2023, the Company incurred $0.1 million research and development expenses under the Distributed Bio Agreement, respectively. For the three and six months ended June 30, 2022, the Company incurred $0.1 million research and development expenses under the Distributed Bio Agreement as the Company achieved a milestone with regard to the initiation of the Phase 1 clinical trial for SZN-1326 in May 2022.

Condensed Consolidated Statements of Operations and Comprehensive Loss (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Operating expenses:
Research and development	$ 6,937	$ 9,581	$ 15,023	$ 18,952
General and administrative	3,338	4,491	8,637	9,613
Restructuring	0	0	1,207	0
Total operating expenses	10,275	14,072	24,867	28,565
Loss from operations	(10,275)	(14,072)	(24,867)	(28,565)
Interest income	623	60	1,170	109
Other income (expense), net	265	87	13	6,584
Net loss	(9,387)	(13,925)	(23,684)	(21,872)
Unrealized gain (loss) on marketable securities, net of tax	55	(47)	246	(357)
Comprehensive loss	$ (9,332)	$ (13,972)	$ (23,438)	$ (22,229)
Net loss per share attributable to common stockholders, basic	$ (0.31)	$ (0.4)	$ (0.79)	$ (0.63)
Net loss per share attributable to common stockholders, diluted	$ (0.31)	$ (0.4)	$ (0.79)	$ (0.63)
Weighted-average shares used in computing net loss per share attributable to common stockholders, basic	30,073	34,945	30,022	34,904
Weighted-average shares used in computing net loss per share attributable to common stockholders, diluted	30,073	34,945	30,022	34,904

Commitments and Contingencies - Summary Of Lessee, Operating Lease, Liability, Maturity (Detail) $ in Thousands	Jun. 30, 2023 USD ($)
Commitments and Contingencies Disclosure [Abstract]
Remaining six months ending December 31, 2023	$ 1,311
Year ending December 31, 2024	2,670
Year ending December 31, 2025	891
Total lease payments	4,872
Less: Imputed interest	(344)
Operating lease liabilities	$ 4,528

Commitments and Contingencies (Tables)

6 Months Ended

Jun. 30, 2023

Commitments and Contingencies Disclosure [Abstract]

Summary of Lessee, Operating Lease, Liability, Maturity

Aggregate future minimum rental payments under the operating leases as of June 30, 2023, were as follows (in thousands):


Remaining six months ending December 31, 2023	$	1,311
Year ending December 31, 2024		2,670
Year ending December 31, 2025		891
Total lease payments		4,872
Less: Imputed interest		(344	)
Operating lease liabilities	$	4,528

Stock Based Compensation Plan - Summary of Stock Option Activity for Company's Stock Option Plans (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2023	Dec. 31, 2022
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Number of Options Outstanding Beginning Balance	3,896
Number of Options Granted	1,804
Number of options Forfeited	(455)
Number of Options Expired	(247)
Number of Options Outstanding Ending Balance	4,998	3,896
Number of Options outstanding and exercisable	1,966
Weighted Average Exercise Price Outstanding, Beginning Balance	$ 2.43
Weighted Average Exercise Price Granted	0.86
Weighted Average Exercise Price Forfeited	2.64
Weighted Average Exercise Price Expired	2.06
Weighted Average Exercise Price Outstanding, Ending Balance	1.86	$ 2.43
Weighted Average Exercise Price Options outstanding and exercisable	$ 1.98
Weighted Average Remaining Contractual Life (In Years)	8 years 5 months 15 days	8 years 5 months 8 days
Weighted Average Remaining Contractual Life, exercisable (In Years)	7 years 5 months 26 days
Aggregate Intrinsic Value	$ 0
Aggregate Intrinsic Value Options outstanding and exercisable	$ 0

Restructuring - Schedule of outstanding restructuring liabilities on the condensed consolidated balance sheets (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Mar. 31, 2023	Jun. 30, 2023
Restructuring Cost and Reserve [Line Items]
Restructuring Charges			$ 1,200
Employee Severance and Other Benefits [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring begining balance		$ 0	0
Restructuring Charges		1,207
Cash payments	$ (457)	(726)
Restructuring ending balance	$ 24	$ 481	$ 24

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References + Details

Collaboration and License Agreements (Additional Information) (Details) - Collaboration and License Agreement with BI [Member] - USD ($) $ in Millions	1 Months Ended		6 Months Ended	12 Months Ended
	Nov. 30, 2022	Oct. 31, 2022	Jun. 30, 2023	Dec. 31, 2022
Research and Development Arrangement, Contract to Perform for Others [Line Items
Non-refundable upfront payment received		$ 12.5
Success-based milestone payments		587.0
Upfront payment	$ 10.5
Associated withholding tax		2.0
Transaction price		$ 12.5
Accounts Receivable [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items
Associated withholding tax			$ 2.0	$ 2.0

Fair Value Measurement - Schedule of Financial Assets and Liabilities Measured at Fair Value on Recurring Basis (Details) - Fair Value, Recurring [Member] - USD ($)
$ in Thousands

Jun. 30, 2023

Dec. 31, 2022

Fair Value Measurement - Schedule of Individual Securities Unrealized Loss Position (Details) $ in Thousands	Jun. 30, 2023 USD ($) Investments	Dec. 31, 2022 USD ($) Investments
Debt Securities, Available-for-Sale [Line Items]
Number Of Positions \| Investments \| Investments	0	7
Less then 12 Months, Fair Value	$ 0	$ 27,521
Less then 12 Months, Unrealized Losses	$ 0	$ 242
Corporate Bond [Member]
Debt Securities, Available-for-Sale [Line Items]
Number Of Positions \| Investments \| Investments	0	4
Less then 12 Months, Fair Value	$ 0	$ 9,719
Less then 12 Months, Unrealized Losses	$ 0	$ 21
Government bonds [Member]
Debt Securities, Available-for-Sale [Line Items]
Number Of Positions \| Investments \| Investments	0	3
Less then 12 Months, Fair Value	$ 0	$ 17,802
Less then 12 Months, Unrealized Losses	$ 0	$ 221

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Jun. 30, 2023	Dec. 31, 2022
Current assets:
Cash and cash equivalents	$ 36,496	$ 24,690
Accounts receivable	1,978	1,978
Short-term marketable securities	16,899	51,148
Prepaid expenses and other current assets	2,206	3,489
Total current assets	57,579	81,305
Property and equipment, net	2,966	3,630
Operating lease right-of-use assets	2,655	3,268
Restricted cash	405	405
Other assets	394	827
Total assets	63,999	89,435
Current liabilities:
Accounts payable	186	658
Accrued and other liabilities	3,901	6,848
Lease liabilities, current portion	2,364	2,226
Total current liabilities	6,451	9,732
Lease liabilities, noncurrent portion	2,164	3,376
Warrant liabilities	326	326
Total liabilities	8,941	13,434
Commitments and contingencies (Note 8)
Stockholders’ equity:
Preferred stock, $0.0001 par value, 10,000 shares authorized; no shares issued and outstanding as of June 30, 2023 and December 31, 2022	0	0
Common stock, $0.0001 par value, 500,000 shares authorized as of June 30, 2023 and December 31, 2022; 30,571 and 30,088 shares issued and outstanding as of June 30, 2023 and December 31, 2022, respectively	3	3
Additional paid-in-capital	257,387	254,892
Accumulated other comprehensive income (loss)	5	(241)
Accumulated deficit	(202,337)	(178,653)
Total stockholders' equity	55,058	76,001
Total liabilities and stockholders’ equity	$ 63,999	$ 89,435

Common Stock Warrants - (Details) - $ / shares shares in Thousands	6 Months Ended
	Jun. 30, 2023	Dec. 31, 2022
Class Of Warrant Or Right [Line Items]
Common Stock Warrants Expiration Date	Aug. 12, 2026
Common stock warrants exercise price per share	$ 11.5
Common Stock Warrants Outstanding	5,907	5,907
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	$ 11.50
Common Stock Warrants Outstanding	2,733	2,733
PIPE Warrants
Class Of Warrant Or Right [Line Items]
Common Stock Warrant Classification	Liability
Common Stock Warrants Expiration Date	Aug. 12, 2026
Common stock warrants exercise price per share	$ 11.50
Common Stock Warrants Outstanding	3,174	3,174

Summary of Significant Accounting Policies - Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share (Details) - shares	6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022
Accounting Policies [Line Items]
Antidilutive securities excluded from computation of diluted net loss per share	10,992	10,890
Options Outstanding [Member]
Accounting Policies [Line Items]
Antidilutive securities excluded from computation of diluted net loss per share	4,998	3,503
Restricted Stock Award [Member]
Accounting Policies [Line Items]
Antidilutive securities excluded from computation of diluted net loss per share	81	130
Unvested common stock subject to repurchase [Member]
Accounting Policies [Line Items]
Antidilutive securities excluded from computation of diluted net loss per share	6	38
Warrants To Purchase Common Stock [Member]
Accounting Policies [Line Items]
Antidilutive securities excluded from computation of diluted net loss per share	5,907	7,219

Stockholders' Equity - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended	6 Months Ended
	Feb. 28, 2022	Jun. 30, 2023	Dec. 31, 2022
Common shares, shares issued		30,571,000	30,088,000
Common stock issued		$ 3	$ 3
Maximum
Sale of Stock, Consideration Received on Transaction	$ 3,500
Closing Sale Price Below 10.00 per share [Member] \| Maximum
Common shares, shares issued	35,000
Closing Sale Price Below 12.00 per share [Member]
Common stock per share	$ 12
Closing Sale Price Below 12.00 per share [Member] \| Maximum
Common shares, shares issued	40,000
Lincoln Park [Member]
Common shares, shares issued	100,000	0
Common stock with the fair value	$ 300
Common stock per share	$ 1
Description of common stock closing sale transaction		The Regular Purchase Share Limit may be increased to up to 35,000 shares and 40,000 shares if the closing price of the Company’s common stock is not below $10.00 per share and $12.00 per share, respectively. Any single purchase of the Company’s common stock shall not exceed $3.5 million.
Sole discretion purchase common stock	30,000
Payments of Stock Issuance Costs	$ 100
Purchase price of additional shares	purchase price per share equal to 96% of the lower of (i) the closing price of the Company’s common stock on the purchase date and (ii) the volume weighted average price of the Company’s common stock on the purchase date.
Stock issued during period shares new shares		0
Lincoln Park [Member] \| Maximum
Sale of Stock, Consideration Received on Transaction	$ 50,000
Purchase of additional shares	500,000
Lincoln Park [Member] \| Minimum
Sale of Stock, Consideration Received on Transaction	$ 30,000
Lincoln Park [Member] \| Closing Sale Price Below 10.00 per share [Member]
Common stock per share	$ 10
Guggenheim Securities, LLC [Member]
Common stock issued			$ 23,000
Compensation payable			3.00%

Common Stock Warrants - Additional Information (Details) shares in Thousands	6 Months Ended
	Jun. 30, 2023 $ / shares shares
Class Of Warrant Or Right Exercise Price Of Warrants Or Rights1	$ 11.5
Common Stock Warrants Expiration Date	Aug. 12, 2026
Warrant Redemption Condition Minimum Share Price Scenario Two	$ 18
Public Warrants
Class Of Warrant Or Right Exercise Price Of Warrants Or Rights1	$ 11.50
Common Stock Warrants Expiration Date	Aug. 12, 2026
Warrant Redemption Period	30 days
Warrant redemption condition minimum share price scenario one	$ 10
Public Warrants \| Common Stock, Closing Price equals or Exceeds $18 Per Share [Member]
Redemption Price Per Public Warrant	0.01
Issuance of common stock Per Share	18
Public Warrants \| Common Stock, Closing Price equals or Exceeds $10 Per Share [Member]
Redemption Price Per Public Warrant	0.1
Issuance of common stock Per Share	10
PIPE Warrants
Class Of Warrant Or Right Exercise Price Of Warrants Or Rights1	$ 11.50
Common Stock Warrants Expiration Date	Aug. 12, 2026
Number of shares converted \| shares	0

Balance Sheet Components - Schedule of Accrued Liabilities (Detail) - USD ($) $ in Thousands	Jun. 30, 2023	Dec. 31, 2022
Balance Sheet Related Disclosures [Abstract]
Accrued payroll and related expenses	$ 2,456	$ 3,964
Accrued research and development expenses	944	1,665
Accrued professional service fees	289	638
Liability for early exercised stock options	29	89
Other	183	492
Accrued and other liabilities	$ 3,901	$ 6,848

Balance Sheet Component - Schedule of Prepaid Expenses and Other Current Assets (Details) - USD ($) $ in Thousands	Jun. 30, 2023	Dec. 31, 2022
Balance Sheet Related Disclosures [Abstract]
Prepaid expenses and other current assets	$ 2,206	$ 3,489

Condensed Consolidated Statements of Stockholders' Equity (Unaudited) - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Income (loss)	Accumulated Deficit
Balance at the beginning at Dec. 31, 2021	$ 109,700	$ 4	$ 252,464	$ (119)	$ (142,649)
Balance at the beginning (in shares) at Dec. 31, 2021		35,034,000
Issuance of common stock under Equity Purchase Agreement, shares		100,000
Issuance of common stock under Equity Purchase Agreement	273		273
Repurchase of early exercised stock options	$ 0
Repurchase of early exercised stock options, shares		(8,000)
Vesting of early exercised stock options	30		$ 30
Stock-based compensation expense	916		916
Other comprehensive income	(310)			(310)
Net loss	(7,947)				(7,947)
Balance at the end at Mar. 31, 2022	102,662	$ 4	253,683	(429)	(150,596)
Balance at the end (in shares) at Mar. 31, 2022		35,126,000
Balance at the beginning at Dec. 31, 2021	109,700	$ 4	252,464	(119)	(142,649)
Balance at the beginning (in shares) at Dec. 31, 2021		35,034,000
Issuance of common stock under Equity Purchase Agreement	273
Repurchase of early exercised stock options	3
Net loss	(21,872)
Balance at the end at Jun. 30, 2022	89,696	$ 4	254,689	(476)	(164,521)
Balance at the end (in shares) at Jun. 30, 2022		35,124,000
Balance at the beginning at Mar. 31, 2022	102,662	$ 4	253,683	(429)	(150,596)
Balance at the beginning (in shares) at Mar. 31, 2022		35,126,000
Repurchase of early exercised stock options, shares		(2,000)
Vesting of early exercised stock options	27		27
Stock-based compensation expense	979		979
Other comprehensive income	47			47
Net loss	(13,925)				(13,925)
Balance at the end at Jun. 30, 2022	89,696	$ 4	254,689	(476)	(164,521)
Balance at the end (in shares) at Jun. 30, 2022		35,124,000
Balance at the beginning at Dec. 31, 2022	76,001	$ 3	254,892	(241)	(178,653)
Balance at the beginning (in shares) at Dec. 31, 2022		30,088,000
Repurchase of early exercised stock options, shares		(9,000)
Vesting of early exercised stock options	13		13
Stock-based compensation expense	1,129		1,129
Other comprehensive income	191			191
Net loss	(14,297)				(14,297)
Balance at the end at Mar. 31, 2023	63,037	$ 3	256,034	(50)	(192,950)
Balance at the end (in shares) at Mar. 31, 2023		30,079,000
Balance at the beginning at Dec. 31, 2022	76,001	$ 3	254,892	(241)	(178,653)
Balance at the beginning (in shares) at Dec. 31, 2022		30,088,000
Issuance of common stock under Equity Purchase Agreement	0
Repurchase of early exercised stock options	39
Net loss	(23,684)
Balance at the end at Jun. 30, 2023	55,058	$ 3	257,387	5	(202,337)
Balance at the end (in shares) at Jun. 30, 2023		30,571,000
Balance at the beginning at Mar. 31, 2023	63,037	$ 3	256,034	(50)	(192,950)
Balance at the beginning (in shares) at Mar. 31, 2023		30,079,000
Issuance of common stock under employee stock purchase plan	187		187
Repurchase of early exercised stock options, shares		492,000
Vesting of early exercised stock options	8		8
Stock-based compensation expense	1,158		1,158
Other comprehensive income	55			55
Net loss	(9,387)				(9,387)
Balance at the end at Jun. 30, 2023	$ 55,058	$ 3	$ 257,387	$ 5	$ (202,337)
Balance at the end (in shares) at Jun. 30, 2023		30,571,000

Document and Entity Information - shares	6 Months Ended
Document and Entity Information - shares	Jun. 30, 2023	Aug. 07, 2023
Document Information [Line Items]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Jun. 30, 2023
Document Fiscal Year Focus	2023
Document Fiscal Period Focus	Q2
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 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 Quarterly Report	true
Document Transition Report	false
Entity Common Stock, Shares Outstanding		30,575,450
Common Stock [Member]
Document Information [Line Items]
Trading Symbol	SRZN
Title of 12(b) Security	Common Stock, $0.0001 par value per share
Security Exchange Name	NASDAQ
Redeemable Warrant [Member]
Document Information [Line Items]
Trading Symbol	SRZNW
Title of 12(b) Security	Redeemable warrants, each whole warrant exercisable for one share of Common Stock
Security Exchange Name	NASDAQ

Condensed Consolidated Balance Sheets (Parenthetical) - $ / shares	Jun. 30, 2023	Dec. 31, 2022
Statement of Financial Position [Abstract]
Preferred stock, par value	$ 0.0001	$ 0.0001
Preferred stock, shares authorized	10,000,000	10,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value	$ 0.0001	$ 0.0001
Common shares, shares authorized	500,000,000	500,000,000
Common shares, shares issued	30,571,000	30,088,000
Common shares, shares outstanding	30,571,000	30,088,000

Fair Value Measurement - Schedule of Marketable Securities by Security Type (Details) $ in Thousands	Jun. 30, 2023 USD ($) Investments	Dec. 31, 2022 USD ($) Investments
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Amortized Cost Current	$ 16,894	$ 51,389
Gross Unrealized Gains, Current	5	1
Gross Unrealized Losses, Current	0	(242)
Fair Value, Current	$ 16,899	$ 51,148
Number Of Positions \| Investments \| Investments	0	7
Less then 12 Months, Fair Value	$ 0	$ 27,521
Less then 12 Months, Unrealized Losses	0	242
Commercial Paper
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Amortized Cost Current	2,975	22,549
Gross Unrealized Gains, Current	0	0
Gross Unrealized Losses, Current	0	0
Fair Value, Current	$ 2,975	22,549
Corporate Bonds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Amortized Cost Current		10,817
Gross Unrealized Gains, Current		1
Gross Unrealized Losses, Current		(21)
Fair Value, Current		$ 10,797
Number Of Positions \| Investments \| Investments	0	4
Less then 12 Months, Fair Value	$ 0	$ 9,719
Less then 12 Months, Unrealized Losses	0	21
Government bonds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Amortized Cost Current	11,934
Amortized Cost, Non-current		18,023
Gross Unrealized Gains, Current	4
Gross Unrealized Gains, Non-current		0
Gross Unrealized Losses, Current	0
Gross Unrealized Losses, Non-current		(221)
Fair Value, Current	$ 11,938
Fair Value, Non-current		$ 17,802
Number Of Positions \| Investments \| Investments	0	3
Less then 12 Months, Fair Value	$ 0	$ 17,802
Less then 12 Months, Unrealized Losses	0	$ 221
Government agency debt securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Amortized Cost Current	1,985
Gross Unrealized Gains, Current	1
Gross Unrealized Losses, Current	0
Fair Value, Current	$ 1,986