0001564590-23-004830 | 10-K | XBRL Viewer

Print Document View Excel Document

Document and Entity Information - USD ($)	12 Months Ended
Document and Entity Information - USD ($)	Dec. 31, 2022	Mar. 24, 2023	Jun. 30, 2022
Cover [Abstract]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2022
Document Fiscal Year Focus	2022
Document Fiscal Period Focus	FY
Trading Symbol	CBIO
Entity Registrant Name	Catalyst Biosciences, Inc.
Entity Central Index Key	0001124105
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	No
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Filer Category	Non-accelerated Filer
Entity Shell Company	false
Entity Small Business	true
Entity Emerging Growth Company	false
Entity Common Stock, Shares Outstanding		37,759,825
Entity Public Float			$ 55,642,222
ICFR Auditor Attestation Flag	false
Entity Interactive Data Current	Yes
Title of 12(b) Security	Common stock
Security Exchange Name	NASDAQ
Entity File Number	000-51173
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	56-2020050
Entity Address, Address Line One	611 Gateway Blvd
Entity Address, Address Line Two	Suite 710
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	871-0761
Document Annual Report	true
Document Transition Report	false
Auditor Firm ID	274
Auditor Name	EISNERAMPER LLP
Auditor Location	Philadelphia, Pennsylvania
Documents Incorporated by Reference	DOCUMENTS INCORPORATED BY REFERENCE Portions of the Registrant’s proxy statement for its 2023 Annual Meeting of Stockholders (the “Proxy Statement”), to be filed with the U.S. Securities and Exchange Commission, no later than 120 days after the Registrant’s fiscal year ended December 31, 2022, are incorporated by reference to Part III of this Annual Report on Form 10-K.

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Current assets:
Cash and cash equivalents	$ 21,666	$ 44,347
Short-term investments		2,504
Accounts and other receivables	5,000	1,818
Prepaid and other current assets	1,540	2,807
Total current assets	28,206	51,476
Other assets, noncurrent	168	472
Right-of-use assets	66	2,744
Property and equipment, net	4	970
Total assets	28,444	55,662
Current liabilities:
Accounts payable	194	6,419
Accrued compensation	2,582	1,467
Deferred revenue		230
Other accrued liabilities	1,452	4,072
Dividends payable	7,558
CVR derivative liability	5,000
Operating lease liability	38	1,977
Total current liabilities	16,824	14,165
Operating lease liability, noncurrent		408
Total liabilities	16,824	14,573
Commitments and Contingencies (Note 8)
Stockholders’ equity (deficit):
Common stock, $0.001 par value, 100,000,000 shares authorized; 37,756,574 and 31,409,707 shares issued and outstanding at December 31, 2022 and 2021, respectively	37	31
Additional paid-in capital	389,210	443,752
Accumulated deficit	(410,936)	(402,694)
Total stockholders’ equity (deficit)	(21,689)	41,089
Total liabilities, redeemable convertible preferred stock and stockholders’ equity (deficit)	28,444	$ 55,662
Redeemable Convertible Preferred Stock
Current liabilities:
Redeemable convertible preferred stock, $0.001 par value, 123,418 shares authorized; 12,340 shares issued and outstanding as of December 31, 2022 and no shares issued and outstanding as of December 31, 2021	$ 33,309

Consolidated Balance Sheets (Parenthetical) - $ / shares	Dec. 31, 2022	Dec. 31, 2021
Common stock, par value	$ 0.001	$ 0.001
Common stock, shares authorized	100,000,000	100,000,000
Common stock, shares issued	37,756,574	31,409,707
Common stock, shares outstanding	37,756,574	31,409,707
Redeemable Convertible Preferred Stock
Temporary equity,par value	$ 0.001	$ 0.001
Temporary equity, shares authorized	123,418	123,418
Temporary equity, shares issued	12,340	0
Temporary equity, shares outstanding	12,340	0

Consolidated Statements of Operations - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Operating expenses (income):
Research and development	$ 13,037	$ 68,889
General and administrative	17,366	18,963
Acquired in-process research and development	35,390
Gain on disposal of assets, net	(57,186)
Total operating expenses	9,405	95,232
Loss from operations	(8,611)	(87,894)
Interest and other income (expense), net	717	(39)
Loss before income taxes	(7,894)	(87,933)
Income tax expenses	348
Net loss	$ (8,242)	$ (87,933)
Net loss per share attributable to common stockholders, basic	$ (0.26)	$ (2.87)
Net loss per share attributable to common stockholders, diluted	$ (0.26)	$ (2.87)
Shares used to compute net loss per share attributable to common stockholders, basic	31,545,723	30,640,977
Shares used to compute net loss per share attributable to common stockholders, diluted	31,545,723	30,640,977
Cash dividends paid per common share	$ 1.43
Cash dividends declared, unpaid, per common share	$ 0.24
Collaboration
Revenue:
License and collaboration revenue	$ 794	$ 7,338
Cost of collaboration
Operating expenses (income):
Cost of license and collaboration	$ 798	$ 7,380

Consolidated Statements of Comprehensive Loss - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Statement Of Income And Comprehensive Income [Abstract]
Net loss	$ (8,242)	$ (87,933)
Other comprehensive loss:
Unrealized loss on available-for-sale debt securities		(5)
Total comprehensive loss	$ (8,242)	$ (87,938)

- Definition

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 220
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-04(22))
-URI https://asc.fasb.org/extlink&oid=120399700&loc=SL114874048-224260

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 32
-Subparagraph (f)
-URI https://asc.fasb.org/extlink&oid=126901519&loc=d3e8933-108599

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 250
-SubTopic 10
-Section 50
-Paragraph 4
-URI https://asc.fasb.org/extlink&oid=124431687&loc=d3e22595-107794

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 220
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-04(18))
-URI https://asc.fasb.org/extlink&oid=120400993&loc=SL114874131-224263

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 40
-Section 65
-Paragraph 1
-Subparagraph (f)
-URI https://asc.fasb.org/extlink&oid=126732423&loc=SL123482106-238011

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 50
-Paragraph 6
-URI https://asc.fasb.org/extlink&oid=124431353&loc=SL124452729-227067

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 10
-Section S99
-Paragraph 1B
-Subparagraph (SX 210.13-02(a)(5))
-URI https://asc.fasb.org/extlink&oid=126975872&loc=SL124442552-122756

Reference 8: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03(20))
-URI https://asc.fasb.org/extlink&oid=126953954&loc=SL114868664-224227

Reference 9: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-URI https://asc.fasb.org/extlink&oid=126954810&loc=d3e3602-108585

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 250
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (b)(2)
-URI https://asc.fasb.org/extlink&oid=124431687&loc=d3e22499-107794

Reference 11: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 10
-Section S99
-Paragraph 1A
-Subparagraph (SX 210.13-01(a)(4)(iv))
-URI https://asc.fasb.org/extlink&oid=126975872&loc=SL124442526-122756

Reference 12: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 10
-Section S99
-Paragraph 1A
-Subparagraph (SX 210.13-01(a)(4)(iii)(A))
-URI https://asc.fasb.org/extlink&oid=126975872&loc=SL124442526-122756

Reference 13: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 10
-Section S99
-Paragraph 1B
-Subparagraph (SX 210.13-02(a)(4)(i))
-URI https://asc.fasb.org/extlink&oid=126975872&loc=SL124442552-122756

Reference 14: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 10
-Section S99
-Paragraph 1A
-Subparagraph (SX 210.13-01(a)(4)(i))
-URI https://asc.fasb.org/extlink&oid=126975872&loc=SL124442526-122756

Reference 15: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 250
-SubTopic 10
-Section 50
-Paragraph 9
-URI https://asc.fasb.org/extlink&oid=124431687&loc=d3e22663-107794

Reference 16: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 10
-Section S99
-Paragraph 1B
-Subparagraph (SX 210.13-02(a)(4)(iv))
-URI https://asc.fasb.org/extlink&oid=126975872&loc=SL124442552-122756

Reference 17: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 10
-Section S99
-Paragraph 1A
-Subparagraph (SX 210.13-01(a)(4)(ii))
-URI https://asc.fasb.org/extlink&oid=126975872&loc=SL124442526-122756

Reference 18: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 28
-Subparagraph (f)
-URI https://asc.fasb.org/extlink&oid=123596393&loc=d3e14064-108612

Reference 19: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 250
-SubTopic 10
-Section 50
-Paragraph 3
-URI https://asc.fasb.org/extlink&oid=124431687&loc=d3e22583-107794

Reference 20: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(g)(1)(ii))
-URI https://asc.fasb.org/extlink&oid=120395691&loc=d3e23780-122690

Reference 21: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 260
-SubTopic 10
-Section 45
-Paragraph 60B
-Subparagraph (a)
-URI https://asc.fasb.org/extlink&oid=126958026&loc=SL5780133-109256

Reference 22: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 323
-SubTopic 10
-Section 50
-Paragraph 3
-Subparagraph (c)
-URI https://asc.fasb.org/extlink&oid=114001798&loc=d3e33918-111571

Reference 23: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 250
-SubTopic 10
-Section 50
-Paragraph 8
-URI https://asc.fasb.org/extlink&oid=124431687&loc=d3e22658-107794

Reference 24: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 1A
-Subparagraph (a)
-URI https://asc.fasb.org/extlink&oid=126968391&loc=SL7669619-108580

Reference 25: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 31
-URI https://asc.fasb.org/extlink&oid=126901519&loc=d3e8924-108599

Reference 26: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 250
-SubTopic 10
-Section 50
-Paragraph 11
-Subparagraph (b)
-URI https://asc.fasb.org/extlink&oid=124431687&loc=d3e22694-107794

Reference 27: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 250
-SubTopic 10
-Section 50
-Paragraph 11
-Subparagraph (a)
-URI https://asc.fasb.org/extlink&oid=124431687&loc=d3e22694-107794

Reference 28: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 205
-SubTopic 20
-Section 50
-Paragraph 7
-URI https://asc.fasb.org/extlink&oid=109222650&loc=SL51721683-107760

Reference 29: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 1B
-Subparagraph (a)
-URI https://asc.fasb.org/extlink&oid=126968391&loc=SL7669625-108580

Reference 30: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 22
-URI https://asc.fasb.org/extlink&oid=126901519&loc=d3e8736-108599

Reference 31: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 10
-Section S99
-Paragraph 1A
-Subparagraph (SX 210.13-01(a)(5))
-URI https://asc.fasb.org/extlink&oid=126975872&loc=SL124442526-122756

Reference 32: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 10
-Section S99
-Paragraph 1B
-Subparagraph (SX 210.13-02(a)(4)(iii)(B))
-URI https://asc.fasb.org/extlink&oid=126975872&loc=SL124442552-122756

Reference 33: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 10
-Section S99
-Paragraph 1B
-Subparagraph (SX 210.13-02(a)(4)(iii)(A))
-URI https://asc.fasb.org/extlink&oid=126975872&loc=SL124442552-122756

Reference 34: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 30
-Subparagraph (b)
-URI https://asc.fasb.org/extlink&oid=126901519&loc=d3e8906-108599

Reference 35: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 32
-Subparagraph (c)
-URI https://asc.fasb.org/extlink&oid=126901519&loc=d3e8933-108599

+ Details

Consolidated Statements of Redeemable Convertible Preferred Stock and Stockholders' Equity (Deficit) - USD ($) $ in Thousands	Total	Redeemable Convertible Preferred Stock	Common Stock	Additional Paid-In Capital	Accumulated Other Comprehensive Income (Loss)	Accumulated Deficit
Balance at Dec. 31, 2020	$ 76,069		$ 22	$ 390,803	$ 5	$ (314,761)
Balance (in shares) at Dec. 31, 2020			22,097,820
Stock-based compensation expense	3,405			3,405
Stock-based compensation expense			56,912
Issuance of common stock from stock grants and option exercises	303			303
Issuance of common stock from stock grants and option exercises, shares			69,975
Issuance of common stock for public offering, net of issuance costs	49,250		$ 9	49,241
Issuance of common stock for public offering, net of issuance costs, shares			9,185,000
Unrealized loss on available-for-sale debt securities	(5)				$ (5)
Net loss	(87,933)					(87,933)
Balance at Dec. 31, 2021	41,089		$ 31	443,752		(402,694)
Temporary Equity, Balance (in shares) at Dec. 31, 2021		0
Balance (in shares) at Dec. 31, 2021			31,409,707
Stock-based compensation expense	1,342			1,342
Stock-based compensation expense			32,684
Issuance of common stock from stock grants and option exercises	20			20
Issuance of common stock from stock grants and option exercises, shares			47,662
Issuance of preferred stock upon acquisition of F351 Assets		$ 33,309
Issuance of preferred stock upon acquisition of F351 Assets, shares		12,340
Issuance of common stock upon acquisition of F351 Assets	1,691		$ 6	1,685
Issuance of common upon acquisition of F351 Assets, shares			6,266,521
Cash dividends paid ($1.43 per share)	(45,031)			(45,031)
Cash dividends declared, unpaid ($0.24 per share)	(7,558)			(7,558)
CVR derivative liability	(5,000)			(5,000)
Net loss	(8,242)					(8,242)
Balance at Dec. 31, 2022	$ (21,689)		$ 37	$ 389,210		$ (410,936)
Temporary Equity, Balance (in shares) at Dec. 31, 2022		12,340
Temporary Equity, Balance at Dec. 31, 2022		$ 33,309
Balance (in shares) at Dec. 31, 2022			37,756,574

Consolidated Statements of Redeemable Convertible Preferred Stock and Stockholders' Equity (Deficit) (Parenthetical) $ in Thousands	12 Months Ended
	Dec. 31, 2021 USD ($)
Statement Of Stockholders Equity [Abstract]
Issuance costs of issuance of common stock for public offering	$ 3,563

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Operating Activities
Net loss	$ (8,242)	$ (87,933)
Adjustments to reconcile net loss to net cash used in operating activities:
Acquired in-process research and development	35,390
Stock-based compensation expense	1,342	3,405
Depreciation and amortization	230	290
Bad debt expense	200
Loss on lease termination	115
Net gain on disposal of assets	(57,186)
Changes in operating assets and liabilities:
Accounts and other receivables	1,618	1,495
Prepaid and other current assets	1,609	3,880
Accounts payable	(6,225)	500
Accrued compensation and other accrued liabilities	(1,895)	(3,680)
Operating lease liability and right-of-use asset	178	41
Deferred revenue	(230)	(1,753)
Net cash flows used in operating activities	(33,096)	(83,755)
Investing Activities
Proceeds from maturities of short-term investments	2,504	49,028
Purchases of property and equipment		(839)
Proceeds from the sale of property and equipment	498
Proceeds from the sale of complement portfolio to Vertex	55,000
Payment of transaction costs in connection with sale of complement portfolio to Vertex	(2,576)
Net cash flows provided by investing activities	55,426	48,189
Financing Activities
Issuance of common stock for public offering, net of issuance costs		49,250
Payment of dividends	(45,031)
Issuance of common stock from stock grants and option exercises	20	303
Net cash flows (used in) provided by financing activities	(45,011)	49,553
Net (decrease) increase in cash and cash equivalents	(22,681)	13,987
Cash and cash equivalents at beginning of the period	44,347	30,360
Cash and cash equivalents at end of the period	21,666	44,347
Supplemental Disclosure of Non-Cash Investing and Financing Activities:
Dividend declared, unpaid	7,558
CVR derivative liability	$ 5,000
Right-of-use assets obtained in exchange for operating lease liabilities		1,850
Remeasurement of right-of-use asset due to operating lease modification		$ 624

Nature of Operations

12 Months Ended

Dec. 31, 2022

Organization Consolidation And Presentation Of Financial Statements [Abstract]

Nature of Operations

1.	Nature of Operations

Catalyst Biosciences, Inc. and its subsidiary (the “Company” or “Catalyst”) was a biopharmaceutical company with expertise in protease engineering. Prior to ceasing research and development activities in March 2022, the Company had several protease assets that were designed to address unmet medical needs in disorders of the complement or coagulation systems. As discussed further below, the Company recently completed a purchase agreement to acquire a clinical-stage drug candidate for the treatment of NASH (nonalcoholic steatohepatitis, a severe form of nonalcoholic fatty liver disease). Concurrent with this purchase agreement, the Company entered into a separate business combination agreement to acquire an indirect controlling interest in a China-based pharmaceutical company. The Company will continue to evaluate the impact of the novel coronavirus disease (“COVID-19”) pandemic on its business, operations, and cash requirements. The Company is located in South San Francisco, California and operates in one segment.

On May 19, 2022, Catalyst entered into and closed on an asset purchase agreement with Vertex Pharmaceuticals Inc. (“Vertex”), pursuant to which Vertex acquired Catalyst’s complement portfolio, including CB 2782-PEG and CB 4332, as well as its complement-related intellectual property including the ProTUNE^TM and ImmunoTUNE^TM platforms. See Note 16, Restructuring. After the transaction of its complement portfolio, Catalyst’s product candidates consisted of the coagulation related assets marzeptacog alfa (activated) (“MarzAA”), dalcinonacog alfa (“DalcA”), and CB 2679d-GT. MarzAA is a SQ administered next generation engineered coagulation Factor VIIa (“FVIIa”) for the treatment of episodic bleeding and prophylaxis in subjects with rare bleeding disorders. DalcA is a next-generation SQ administered FIX. CB 2679d-GT is an AAV-based gene therapy construct harboring the DalcA sequence. Both MarzAA and DalcA have shown sustained efficacy and safety in mid-stage clinical trials. CB 2679d-GT has obtained preclinical proof-of-concept. Catalyst sold MarzAA, DalcA and CB-2679d-GT in February 2023 to GC Biopharma Corp. (“GCBP”). See Note 17, Subsequent Events.

F351 Asset Acquisition

On December 26, 2022, the Company executed and closed an Asset Purchase Agreement (the “F351 Agreement”), with GNI Group Ltd. and GNI Hong Kong Limited (together “GNI”) to purchase all of the assets and intellectual property rights primarily related to the proprietary Hydronidone compound (collectively, the “F351 Assets”), other than such assets and intellectual property rights located in the People’s Republic of China. At the closing of the agreement on December 26, 2022, the Company paid $35.0 million in the form of 6,266,521 shares of Catalyst common stock and 12,340 shares of newly designated Series X redeemable convertible preferred stock (“Catalyst Convertible Preferred Stock”). Each share of Catalyst Convertible Preferred Stock is convertible into 10,000 shares of common stock, subject to stockholder approval under Nasdaq rules and subject to a beneficial ownership conversion blocker. For additional information, see Note 4, F351 Asset Acquisition and Note 14, Stockholders’ Equity.

Business Combination Agreement

Concurrent with the F351 Asset acquisition, the Company signed a definitive agreement with GNI Group Ltd., GNI Hong Kong Limited, GNI USA, Inc., Continent Pharmaceuticals Inc. and Shanghai Genomics, Inc. (collectively, “GNI”) and other minority stockholders to acquire an indirect controlling interest in Beijing Continent Pharmaceutical Co Ltd. (“BC”), a commercial-stage pharmaceutical company based in China and majority-owned subsidiary of GNI, in exchange for newly issued shares of common stock (the “Business Combination Agreement”). The closing of the Business Combination Agreement will be subject to stockholder approval at a stockholder meeting expected to be held in the third quarter of 2023 and certain customary closing conditions. For additional information, see Note 8, Commitments and Contingencies.

Contingent Value Rights Agreement

Pursuant to the Business Combination Agreement, on December 26, 2022, Catalyst and the Rights Agent (as defined therein) executed a contingent value rights agreement (the “CVR Agreement”), pursuant to which each holder of Catalyst common stock as of January 5, 2023 (the “CVR Holders”), excluding GNI, received one

contractual contingent value right (a “CVR”) issued by the Company for each share of Catalyst common stock held by such holder. Each CVR entitles the holder thereof to receive certain cash payments in the future. For additional information, see Note 8, Commitments and Contingencies.

Liquidity

12 Months Ended

Dec. 31, 2022

Organization Consolidation And Presentation Of Financial Statements [Abstract]

Liquidity

In October 2021, the Company entered into a sales agreement with Piper Sandler & Co. (“Piper Sandler”), pursuant to which the Company could issue and sell shares of common stock, par value of $0.001 per share, through an at-the-market offering program (the “ATM Program”). The Company pays Piper Sandler 3% of the gross proceeds from any common stock sold through the sales agreement. There was no activity from the ATM Program during the years ended December 31, 2022 and 2021.

On September 20, 2022, the Company paid a special, one-time cash dividend of $1.43 per share to the Company’s common stockholders of record as of close of business on September 6, 2022. The aggregate amount of the special dividend payment was approximately $45.0 million.

On December 27, 2022, the Company declared a special, one-time cash dividend of $0.24 per share, or approximately $7.6 million, to the Company’s common stockholders of record as of close of business on January 5, 2022, excluding GNI. This dividend was paid on January 12, 2023.

For the year ended December 31, 2022, the Company had a net loss of $8.2 million. As of December 31, 2022, the Company had an accumulated deficit of $410.9 million and cash and cash equivalents of $21.7 million. Its primary uses of cash are to fund operating expenses and general and administrative expenditures. As part of the F351 Agreement, the Company issued 12,340 shares of Catalyst Convertible Preferred Stock, which upon stockholder approval, will be converted to 123,400,000 shares of common stock, subject to applicable beneficial ownership limitations. The terms of the Catalyst Convertible Preferred Stock include a cash settlement feature which, as described in Note 14, Stockholders’ Equity, provide that, if the Company’s stockholders fail to approve the conversion of the Catalyst Convertible Preferred Stock by June 26, 2023 (which has been extended to September 30, 2023, see Note 17, Subsequent Events), the Company could be required to make cash payments to the holders of Catalyst Convertible Preferred Stock significantly in excess of its current liquidity. The Company believes that stockholders who are entitled to vote on the conversion proposal at the Company’s 2023 Annual Meeting of Stockholders, which is expected to be held in the third quarter of 2023, will vote to approve the proposal. However, as the vote of the Company’s common stockholders is outside of the control of the Company, there is substantial doubt about its ability to continue as a going concern for at least 12 months following the issuance of these consolidated financial statements. The accompanying consolidated financial statements have been prepared on a going concern basis, which contemplates the realization of assets and satisfaction of liabilities in the ordinary course of business. The consolidated financial statements do not include any adjustments relating to the recoverability and classification of recorded asset amounts or the amounts and classification of liabilities that might result from the outcome of this uncertainty.

Summary of Significant Accounting Policies

12 Months Ended

Dec. 31, 2022

Accounting Policies [Abstract]

Summary of Significant Accounting Policies

3.	Summary of Significant Accounting Policies

Basis of Presentation

The accompanying consolidated financial statements include the accounts of the Company and its subsidiary. Intercompany accounts and transactions, if applicable, have been eliminated in consolidation. The Company’s consolidated financial statements have been prepared in accordance with United States generally accepted accounting principles (“GAAP”).

Use of Estimates

The preparation of consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the amounts reported in the consolidated financial statements and accompanying notes. On an ongoing basis, management evaluates its estimates, including those related to revenue recognition, allowance of doubtful accounts, contingent value rights, operating lease right-of-use assets and liabilities, accrued expenses, income taxes and stock-based compensation. The Company bases its estimates on various assumptions that the Company believes to be reasonable under the circumstances. Actual results could differ from those estimates.

Accounting Pronouncements Recently Adopted

In May 2021, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2021-04, Earnings Per Share (Topic 260), Debt—Modifications and Extinguishments (Subtopic 470-50), Compensation—Stock Compensation (Topic 718), and Derivatives and Hedging—Contracts in Entity’s Own Equity (Subtopic 815-40): Issuer’s Accounting for Certain Modifications or Exchanges of Freestanding Equity-Classified Written Call Options. The amendments in ASU 2021-04 provide guidance to clarify and reduce diversity in an issuer’s accounting for modifications or exchanges of freestanding equity-classified written call options (for example, warrants) that remain equity classified after modification or exchange. The amendments in this ASU 2021-04 are effective for all entities for fiscal years beginning after December 15, 2021, and interim periods within those fiscal years. The Company adopted ASU 2021-04 and related updates on January 1, 2022, and the adoption did not have a material impact on its consolidated financial statements.

In August 2020, FASB issued ASU 2020-06, Debt - Debt with Conversion and Other Options (Subtopic 470-20) and Derivatives and Hedging - Contracts in Entity’s Own Equity (Subtopic 815-40) to simplify accounting for certain financial instruments. ASU 2020-06 eliminates the previous models that require separation of beneficial conversion and cash conversion features from convertible instruments and simplifies the derivative scope exception guidance pertaining to equity classification of contracts in an entity’s own equity. The amendments in this ASU are effective for public business entities for fiscal years beginning after December 15, 2021. The Company adopted ASU 2020-06 on January 1, 2022, and the adoption did not have a material impact on its consolidated financial statements.

New Accounting Pronouncements – Issued But Not Yet Adopted

In June 2016, the FASB issued ASU 2016-13, Measurement of Credit Losses on Financial Instruments. The main objective of ASU 2016-13 is to provide financial statement users with more decision-useful information about an entity’s expected credit losses on financial instruments and other commitments to extend credit at each reporting date. To achieve this objective, the amendments in this update replace the incurred loss impairment methodology currently used today with a methodology that reflects expected credit losses and requires consideration of a broader range of reasonable and supportable information to develop credit loss estimates. ASU 2016-13 will be effective for the Company for fiscal years beginning after December 15, 2022, including interim periods within those fiscal years, using a modified retrospective approach. The Company adopted ASU 2016-13 and related updates on January 1, 2023 and the adoption did not have a material impact on its consolidated financial statements.

Cash and Cash Equivalents

The Company invests its excess cash in bank deposits, consisting primarily of money market mutual funds. The Company considers all highly liquid investments with original maturities of three months or less from the date of purchase to be cash equivalents.

Fair Value of Financial Instruments

The Company applies fair value accounting for all financial assets and liabilities and non-financial assets and liabilities that are recognized or disclosed at fair value in the consolidated financial statements on a recurring basis. Fair value is defined as the exchange price that would be received for an asset or an exit price that would be paid to transfer a liability in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date.

The fair value hierarchy requires that an entity maximize the use of observable inputs when estimating fair value. The fair value hierarchy includes the following three-level classification which is based on the market observability of the inputs used for estimating the fair value of the assets or liabilities being measured:

Level 1 – Quoted prices in active markets for identical assets or liabilities.

Level 2 – Observable inputs other than quoted prices in active markets for identical assets and liabilities, quoted prices for identical or similar assets or liabilities in inactive markets, or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities.

Level 3 – Inputs that are generally unobservable and typically reflect management’s estimate of assumptions that market participants would use in pricing the asset or liability.

Derivative Financial Instruments

The Company evaluates its contracts to determine if those contracts qualify as derivatives under ASC 815, Derivatives and Hedging. For derivative financial instruments that are accounted for as liabilities, the derivative instrument is initially recorded at its fair value and is then re-valued at each reporting date. Any changes in fair value are recorded as non-operating, non-cash other income or expense for each reporting period. Derivative instrument liabilities are classified in the balance sheet as current or non-current based on whether or not net-cash settlement of the derivative instrument is probable within the next 12 months from the balance sheet date.

The Company determined that certain contingent payments under the CVR Agreement qualified as derivatives under ASC 815, and as such, were recorded as a liability on the balance sheet as of December 31, 2022. Refer to Note 5, Fair Value Measurement and Note 8, Commitments and Contingencies, for additional information regarding the CVR derivative liability.

Property and Equipment

Property and equipment are stated at cost, less accumulated depreciation. Depreciation is computed using the straight-line method over the estimated useful lives of the respective assets, which are three years for computer equipment and software, and three to seven years for furniture and leasehold improvements.

Investments

The Company invests its excess cash in investment grade, short to intermediate-term, fixed income securities and recognizes purchased securities on the settlement date. All investments have been classified as “available-for-sale” and are carried at estimated fair value based upon quoted market prices or pricing models for similar securities. Management determines the appropriate classification of its investments at the time of purchase and reevaluates such designation as of each consolidated balance sheet date. Unrealized gains and losses on available-for-sale debt securities are excluded from earnings and are reported as a component of comprehensive loss. Realized gains and losses and declines in fair value determined to be other-than-temporary, if any, on available-for-sale debt securities are included in interest and other income (expense), net. The cost of securities sold is based on the specific-identification method. Interest on short-term investments is included in interest and other income (expense), net.

Revenue Recognition

License and Collaboration Arrangements

The Company may enter into collaboration arrangements that fall under the scope Collaborative Arrangements (Topic 808). The Company analyzes its collaboration arrangements to assess whether they are within the scope of ASC 808 to determine whether such arrangements involve joint operating activities performed by parties that are both active participants in the activities and exposed to significant risks and rewards dependent on the commercial success of such activities. This assessment is performed throughout the life of the arrangement based on changes in the responsibilities of all parties in the arrangement. The accounting for some of the activities under collaboration arrangements may be analogized to ASC 606 for distinct units of account that are reflective of a vendor-customer relationship.

Under ASC 606, in determining the appropriate amount of revenue to be recognized as it fulfills its obligations under its agreements, the Company performs the following steps: (i) identification of the promised goods or services in the contract; (ii) determination of whether the promised goods or services are performance obligations including whether they are distinct in the context of the contract; (iii) measurement of the transaction price, including the constraint on variable consideration; (iv) allocation of the transaction price to the

performance obligations based on estimated selling prices; and (v) recognition of revenue when the Company satisfies each performance obligation.

If a license to the Company’s intellectual property is determined to be distinct from the other performance obligations identified in the arrangement, the Company recognizes revenues attributed to the license when the license is transferred to the customer and the customer is able to use and benefit from the license. For licenses that are bundled with other promises, the Company utilizes judgement to assess the nature of the combined performance obligation to determine whether the combined performance obligation is satisfied over time or at a point in time.

At the inception of each arrangement that contain development milestones, the Company evaluates whether the development milestones included are considered probable of being reached and estimates the amount to be included in the transaction price using the most likely amount method. If it is probable that a significant revenue reversal would not occur, the associated milestone value is included in the transaction price. Milestone payments that are not within the control of the Company or the licensee, such as regulatory approvals, are not generally considered probable of being achieved until those approvals are received.

At the end of each reporting period, the Company re-evaluates the probability of achievement of any development milestones, and if necessary, adjusts its estimate of the transaction price. Any such adjustments would be recorded on a cumulative catch-up basis, which would affect revenues and earnings in the period of adjustment.

For research and development services, the Company elected the practical expedient to recognize revenue as the research and development services are invoiced. As the Company has a right to consideration from the collaboration agreement with Biogen International GmbH (“Biogen”), in an amount that corresponds directly with the value of the Company’s performance completed to date for the research services, the Company recognized revenue related to the research services as invoiced, in line with the practical expedient in ASC 606-10-55-18.

The transaction price is allocated to each performance obligation on a relative stand-alone selling price (“SSP”) basis. The Company recognizes revenue as or when the performance obligations under the contract are satisfied. As part of the accounting for these arrangements, the Company must develop assumptions that require judgment to determine the timing of recognition and the SSP for each performance obligation identified in the contract.

The SSP for licenses are calculated using the residual approach if the Company has not yet established a price for such license and the license has not previously been sold on a standalone basis. Otherwise, selling prices for licenses are determined using an income approach model and include key assumptions such as: development timeline, revenue forecast, commercialization expenses, discount rate and probabilities of technical and regulatory success. To estimate the SSP for research and development services, the Company uses a cost-plus margin approach.

Cost of License and Collaboration

Cost of license revenue includes sublicense fees paid or payable to Mosaic Biosciences, Inc. (“Mosaic”), incurred in the period, under the terms of the Mosaic collaboration agreement, and fees for patent development and protection paid or payable to other third-party vendors corresponding to the recognition of license revenue from the Company’s collaboration agreement with Biogen. See Note 12, Collaborations. Cost of license revenue does not include any allocated overhead costs.

Cost of collaboration revenue includes fees for research and development services paid or payable to Mosaic and other third-party vendors and personnel cost, incurred in the period pertaining to the Company’s agreement with Biogen. See Note 12, Collaborations. Cost of collaboration revenue does not include any allocated overhead costs.

Research and Development Expenses

Research and development costs are expensed as incurred. Nonrefundable advance payments for goods or services used in research and development are initially deferred and capitalized in prepaid and other current assets. The capitalized amounts are then expensed as the related goods are delivered or services are performed, or until it is no longer expected that the goods or services will be delivered. Research and development costs consist of payroll and other personnel-related expenses, laboratory supplies and reagents, contract research and development services, materials, and consulting costs, as well as allocations of facilities and other overhead costs. Under the Company’s collaboration agreement with Biogen, certain specific expenditures are reimbursed by third parties. During the years ended December 31, 2022 and 2021, $0.7 million and $6.5 million, respectively, of research and development expense was recorded as cost of collaboration revenue related to the collaboration agreement with Biogen signed in December 2019 and terminated as of May 2022.

Accrued Research and Development Expenses

Accrued expenses include estimated costs of research and development activities conducted by external service providers, which include the conduct of preclinical studies and clinical trials and contract manufacturing activities. The Company records the estimated costs of research and development activities based upon the estimated amount of services provided but not yet invoiced and includes these costs in other accrued liabilities in the consolidated balance sheet and within research and development expense in the consolidated statement of operations. These costs are a significant component of the research and development expenses. The Company records accrued expenses for these costs based on the estimated amount of work completed and in accordance with agreements established with these external service providers.

Acquired In-Process Research and Development

The Company measures and recognizes asset acquisitions that are not deemed to be business combinations based on the cost to acquire the assets, which includes transaction costs. Goodwill is not recognized in asset acquisitions. In an asset acquisition, the cost allocated to acquired in-process research and development (“IPR&D”) with no alternative future use is charged to expense at the acquisition date. Refer to Note 4, F351 Asset Acquisition, for a more detailed description of the accounting policy utilized for the recent asset acquisition.

Concentration of Credit Risk

Financial instruments that potentially subject the Company to concentrations of credit risk consist principally of cash, cash equivalents, investments and accounts receivable. The Company’s investment policy restricts cash investments to high credit quality, investment grade investments. The Company believes that it has established guidelines for investment of its excess cash that maintain safety and liquidity through its policies on high quality of investment and investment duration. The Company is exposed to credit risk of $21.4 million in the event of default by the institutions holding the cash and cash equivalents to the extent beyond the amount insured by the federal depository insurance corporation.

Accounts Receivable and Allowance for Doubtful Accounts

Amounts payable to the Company are recorded as accounts receivable when the Company’s right to consideration is unconditional. Customer payments are recorded as deferred revenue upon receipt or when due and may require deferral of revenue recognition to a future period until the Company performs its obligations under the arrangements. The Company continuously monitors collections and payments from its customers and maintains a provision for estimated credit losses. The Company determines its allowance for doubtful accounts by considering a number of factors, including the length of time balances are past due, the Company’s previous loss history, the customer’s current ability to pay its obligations to the Company and the condition of the general economy and the industry as a whole. The Company writes off accounts receivable when they are determined to be uncollectible. For the year ended December 31, 2022, the Company recognized $0.2 million of bad debt expense and no bad debt expense was recognized during the year ended December 31, 2021.

Income Taxes

Income taxes are computed using the liability method. Deferred tax assets and liabilities are determined based on the differences between the financial reporting and tax basis of assets and liabilities and are measured using the enacted tax rates and laws that will be in effect when the differences are expected to reverse.

The Company follows the authoritative guidance on accounting for uncertainty in income taxes. This guidance prescribes a more-likely-than-not threshold for financial statement recognition and measurement of a tax position taken in the Company’s income tax returns. This interpretation also provides guidance on accounting for interest and penalties and associated with tax positions, accounting for income taxes in interim periods and income tax disclosures.

The Company’s policy is to include penalties and interest expense related to income taxes as a component of other expense and interest expense, respectively, as necessary.

Stock-Based Compensation

The Company measures the cost of employee, non-employee and director services received in exchange for an award of equity instruments based on the fair value of the award on the date of grant and recognizes the related expense over the period during which the employee, non-employee or director is required to provide service in exchange for the award on a straight-line basis. The estimated fair value of equity awards that contain performance conditions is expensed over the term of the award once the Company has determined that it is probable that performance conditions will be satisfied.

The Company uses the Black-Scholes option-pricing valuation model to estimate the grant-date fair value of stock-based awards. The determination of fair value for stock-based awards on the date of grant using an option-pricing model requires management to make certain assumptions regarding a number of variables. The Company elected to account for forfeitures when they occur. As such, the Company recognizes stock-based compensation expense, over their requisite service period, based on the vesting provisions of the individual grants.

Restructuring Charges

Costs and liabilities associated with restructuring are recorded in the period management commits to a restructuring or cost reduction plan, or executes specific actions contemplated by the plan and all criteria for liability recognition have been met. One-time employee termination costs are recognized at the time of communication to employees, unless future service is required, in which case the costs are recognized ratably over the future service period. Restructuring charges are recognized as an operating expense within the consolidated statements of operations and related liabilities are recorded within accrued compensation on the consolidated balance sheets. The Company periodically evaluates and, if necessary, adjusts its estimates based on currently available information.

Leases

At the inception of an arrangement, the Company determines whether the arrangement is or contains a lease based on the unique facts and circumstances present. Operating lease liabilities and their corresponding right-of-use assets are recorded based on the present value of lease payments over the expected lease term. The interest rate implicit in lease contracts is typically not readily determinable. As such, the Company utilizes its incremental borrowing rate, which is the rate incurred to borrow on a collateralized basis over a similar term an amount equal to the lease payments in a similar economic environment. Certain adjustments to the right-of-use asset may be required for items such as initial direct costs paid or incentives received.

The Company has elected to combine lease and non-lease components as a single component. The lease expense is recognized over the expected term on a straight-line basis. Operating leases are recognized on the consolidated balance sheet as right-of-use assets, operating lease liabilities, current and operating lease liabilities, non-current.

Redeemable Convertible Preferred Stock

The Company records shares of non-voting redeemable Catalyst Convertible Preferred Stock at its relative fair value on the date of issuance. The Company applied the guidance in ASC 480-10-S99-3A, SEC Staff Announcement: Classification and Measurement of Redeemable Securities, and at issuance classified the Catalyst Convertible Preferred Stock as temporary equity on the consolidated balance sheet because if conversion to common stock is not approved by the shareholders, the Catalyst Convertible Preferred Stock would be redeemable at the option of the holders for cash equal to the closing price of the common stock on last trading day prior to the holder’s redemption request. Refer to Note 14, Stockholders’ Equity for additional information.

Net Loss per Share Attributable to Common Stockholders

The Company calculates basic and diluted net loss per share attributable to common stockholders in conformity with the two-class method required for participating securities. The Company’s redeemable convertible preferred stock contractually entitled the holders of such shares to participate in dividends but does not contractually require the holders of such shares to participate in the Company’s losses. As such, net losses for the periods presented were not allocated to these securities.

Basic net loss per share is calculated by dividing the net loss attributable to common stockholders by the weighted-average number of shares of common stock outstanding during the period, without consideration for potentially dilutive securities. Diluted net loss per share is the same as basic net loss per share for each period presented since the effects of potentially dilutive securities are antidilutive given the Company’s net loss.

F351 Asset Acquisition

12 Months Ended

Dec. 31, 2022

Business Combinations [Abstract]

F351 Asset Acquisition

4.	F351 Asset Acquisition

On December 26, 2022, the Company acquired the F351 Assets from GNI in accordance with the terms of the F351 Agreement as discussed in Note 1, Nature of Operations. Under the terms of F351 Agreement, the Company issued 6,266,521 shares of common stock and 12,340 shares of Catalyst Convertible Preferred Stock. Each share of Catalyst Convertible Preferred Stock is convertible into 10,000 shares of common stock, subject to certain conditions.

The Company concluded that the F351 acquisition was not the acquisition of a business, as substantially all of the fair value of the gross assets acquired was concentrated in a single identifiable asset, the intellectual property rights (outside of China) to a clinical stage drug candidate for the treatment of liver fibrosis, or the F351 Assets.

The Company determined that the cost to acquire the F351 Assets was $35.4 million, based on the estimated fair value of the F351 Assets acquired and including direct costs of the acquisition of $0.4 million. The cost of the acquisition was allocated entirely to acquired IPR&D as no other assets or liabilities were acquired or assumed.

As the F351 Assets had not, at the time of the F351 Asset acquisition, received regulatory approval in any territory, the cost attributable to the IPR&D was expensed in the Company’s consolidated statements of operations for the year ended December 31, 2022 since the acquired IPR&D had no alternative future use, as determined by the Company in accordance with GAAP.

Fair Value Measurements

12 Months Ended

Dec. 31, 2022

Fair Value Disclosures [Abstract]

Fair Value Measurements

5.	Fair Value Measurements

For a description of the fair value hierarchy and fair value methodology, see Note 3, Summary of Significant Accounting Policies. As of December 31, 2022 and 2021, the Company’s highly liquid money market funds included within cash equivalents and U.S. government agency securities are valued using Level 1 inputs. There were no transfers in or out of Level 1 and Level 2 during the periods presented. U.S. government agency securities are bonds issued by the U.S. government and are fully backed by the U.S. government. Given the frequency at which U.S. government agency securities trade and the accessibility of observable, quoted prices for such assets in active markets, they are recognized as Level 1 assets.

The following tables present the fair value hierarchy for financial assets and liabilities measured at fair value on a recurring basis as of December 31, 2022 and 2021 (in thousands):

	December 31, 2022
	Level 1		Level 2		Level 3		Total
Financial assets:
Money market funds⁽¹⁾	$	21,666	$	—	$	—	$	21,666
Total financial assets	$	21,666	$	—	$	—	$	21,666

Financial liabilities:
CVR derivative liability	$	—	$	—	$	5,000	$	5,000
Total financial liabilities	$	—	$	—	$	5,000	$	5,000

	December 31, 2021
	Level 1		Level 2		Level 3		Total
Financial assets:
Money market funds⁽¹⁾	$	44,347	$	—	$	—	$	44,347
U.S. government agency securities⁽²⁾		2,504		—		—		2,504
Total financial assets	$	46,851	$	—	$	—	$	46,851

(1)	Included in cash and cash equivalents on accompanying consolidated balance sheet.

(2)	Included in short-term investments on accompanying consolidated balance sheet and are classified as available-for-sale debt securities.

The carrying amounts of accounts and other receivables, accounts payable, and accrued liabilities approximate their fair values due to the short-term maturity of these instruments.

Derivative Liabilities

The CVR derivative liability relates to the CVR Agreement executed in connection with the Business Combination Agreement. The fair value of this derivative liability is based on significant unobservable inputs, which represent Level 3 measurements within the fair value hierarchy. The estimated fair value of the CVR liability was determined based on the anticipated amount and timing of projected cash flows to be received from Vertex pursuant to the Vertex asset purchase agreement. As of December 31, 2022, the Company expects to receive a $5.0 million hold-back payment from Vertex in the second quarter of 2023, which will be immediately distributed to the holders of Catalyst common stock as of January 5, 2023 under the CVR Agreement. The CVR liability was initially recorded at $5.0 million at issuance on December 26, 2022 and there was no change in the estimated fair value as of December 31, 2022.

- Definition

The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.

+ References + Details

Financial Instruments

12 Months Ended

Dec. 31, 2022

Investments All Other Investments [Abstract]

Financial Instruments

6.	Financial Instruments

Cash equivalents and investments (debt securities) which are classified as available-for-sale securities, consisted of the following (in thousands):

December 31, 2022	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Estimated Fair Value
Money market funds (cash equivalents)	$	21,666	$	—	$	—	$	21,666
Total financial assets	$	21,666	$	—	$	—	$	21,666
Classified as:
Cash and cash equivalents							$	21,666
Total financial assets							$	21,666

December 31, 2021	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Estimated Fair Value
Money market funds (cash equivalents)	$	44,347	$	—	$	—	$	44,347
U.S. government agency securities		2,504		—		—		2,504
Total financial assets	$	46,851	$	—	$	—	$	46,851
Classified as:
Cash and cash equivalents							$	44,347
Short-term investments								2,504
Total financial assets							$	46,851

There have been no material realized gains or losses on available-for-sale debt securities for the periods presented. As of December 31, 2022, the Company had no available-for-sale debt securities.

Other Accrued Liabilities

12 Months Ended

Dec. 31, 2022

Payables And Accruals [Abstract]

Other Accrued Liabilities

7.	Other Accrued Liabilities

Other accrued liabilities consisted of the following (in thousands):

	Year Ended December 31,
	2022		2021
Professional and consulting services	$	1,417	$	509
Manufacturing		22		1,381
Biogen		—		868
Pre-clinical		—		773
Clinical		—		361
Other		13		180
Total other accrued liabilities	$	1,452	$	4,072

Commitments and Contingencies

12 Months Ended

Dec. 31, 2022

Commitments And Contingencies Disclosure [Abstract]

Commitments and Contingencies

8.	Commitments and Contingencies

Business Combination Agreement

Concurrent with the F351 Asset acquisition, the Company signed a definitive agreement with GNI and other minority stockholders (“Sellers” and each a “Seller”) to acquire an indirect controlling interest in BC, a commercial-stage pharmaceutical company based in China and majority-owned subsidiary of GNI, in exchange for newly issued shares of Catalyst common stock. The closing of the Business Combination Agreement will be subject to stockholder approval at a stockholder meeting expected to be held in the third quarter of 2023 and certain customary closing conditions. If the transaction is approved by stockholders, the Company would issue at closing a total of up to 1,110,776,224 shares of Catalyst common stock for an indirect controlling interest in BC. Each Seller may elect to be issued Catalyst Convertible Preferred Stock in lieu of the Company’s common stock.

The Business Combination Agreement contains certain termination rights, including the right for Catalyst to terminate the Business Combination Agreement to enter into a definitive agreement for a superior proposal. Upon termination of the Business Combination Agreement under specified circumstances, the Company may be required to pay a termination fee of $2.0 million and either party, as the case may be, may be required to reimburse the other party for reasonable out-of-pocket fees and expenses incurred by such party in connection with the Business Combination Agreement, up to a maximum amount of $2.0 million.

Contingent Value Rights Agreement

Pursuant to the Business Combination Agreement, on December 26, 2022, Catalyst and the Rights Agent (as defined therein) executed a CVR Agreement, pursuant to which the CVR Holders received one contractual CVR issued by the Company, subject to and in accordance with the terms and conditions of the CVR Agreement, for

each share of Catalyst common stock held by such holder. Each CVR entitles the holder thereof to receive (i) certain cash payments from the net proceeds related to the disposition of the Company’s legacy assets (MarzAA, DalcA, and CB 2679d-GT), (ii) 100% of the excess cash (net of all current or contingent liabilities, including transaction-related expenses) retained by the Company in excess of $1.0 million as of the closing date of the Business Combination Agreement, (iii) 100% of the amount actually received by the Company pursuant to the Vertex asset purchase agreement and (iv) 100% of the excess, by which the preapproved costs to manage, negotiate, settle and finalize certain third party claims exceed the costs actually incurred with respect to such claims. The CVRs are not transferable, except in certain limited circumstances as provided for in the CVR Agreement, will not be certificated or evidenced by any instrument, and will not be registered with the SEC or listed for trading on any exchange.

Manufacturing Agreements

The Company previously signed an agreement with AGC Biologics, Inc. (“AGC”) to perform certain manufacturing services related to the Company’s collaboration agreement with Biogen, which included firm work orders totaling $0.7 million. The payment obligations were fully paid off as of March 31, 2022, and Vertex assumed responsibility for further complement-related manufacturing in connection with the sale of the Company’s complement portfolio to Vertex. See Note 16, Restructuring. During the year ended December 31, 2022, the Company terminated its manufacturing agreement with AGC for Catalyst’s remaining programs and has no remaining obligations under the agreement as of December 31, 2022.

In July 2021, the Company entered into an agreement for the Company’s screening and natural history of disease clinical studies related to CFI deficiency, with total payments of up to $6.5 million. During the year ended December 31, 2022, the Company terminated this agreement and incurred $0.8 million for clinical trial services incurred prior to termination and reasonable wind-down expenses. As of December 31, 2022, the Company has no remaining obligations under this agreement.

On September 16, 2021, the Company signed a Manufacturing and Research and Development Studies Agreement to support the lyophilized drug product, CB 4332. The agreement covers analytical method qualification to support good manufacturing practices (“GMP”) manufacturing. The Company had firm work orders related to this agreement totaling $0.3 million. During the year ended December 31, 2022, the Company terminated this agreement and has no remaining obligations under the agreement as of December 31, 2022.

Legal Proceedings

On June 15, 2022, certain Company stockholders who beneficially held in the aggregate more than five percent (5%) of the Company’s common stock filed a lawsuit in Delaware Chancery Court, captioned JDS1, LLC v. Catalyst Biosciences, Inc., alleging that the Company violated Section 271 of the Delaware General Corporation Law and breach of fiduciary duty in connection with the Company’s asset sale to Vertex, as well as certain claims related to the alleged failure to disclose information related to the Vertex transaction. In August 2022, the lawsuit was dismissed with prejudice and the Company reimbursed JDS1, LLC for its legal and other expenses related to the litigation in the amount of $0.4 million.

COVID-19

The current COVID-19 pandemic has presented a substantial public health and economic challenge around the world and is affecting the Company’s employees and business operations. The full extent to which the COVID-19 pandemic will directly or indirectly impact the Company’s business, results of operations and financial condition will depend on future developments that are highly uncertain and cannot be accurately predicted, including new information that may emerge concerning COVID-19, the actions taken to contain it or treat its impact and the economic impact on local, regional, national, and international markets. The COVID-19 pandemic may disrupt the Company’s ability to out-license any of its remaining assets.

Leases

12 Months Ended

Dec. 31, 2022

Lessee Disclosure [Abstract]

Leases

Operating lease liabilities are recognized based on the present value of the future minimum lease payments over the lease term. In calculating the present value of the lease payments, the Company has elected to utilize its

incremental borrowing rate based on the original lease term and not the remaining lease term. The lease includes non-lease components (e.g., common area maintenance) that are paid separately from rent based on actual costs incurred and, therefore, were not included in the right-of-use asset and lease liability but are reflected as an expense in the period incurred.

The Company leases office space for its corporate headquarters, located in South San Francisco, CA. The lease term is through April 30, 2023 and there are no stated renewal options.

In April 2021, the Company entered into a license agreement (the “License Agreement”) for the use of laboratory facilities in South San Francisco, CA, for an aggregated undiscounted future payment of $1.9 million. This License Agreement commenced during the second quarter of 2021. In October 2021, the Company amended the License Agreement to extend the lease term for a period of one year. The amendment was not accounted for as a separate lease, and resulted in an adjustment to the right-of-use asset and lease liability of $0.6 million. In August 2022, the Company terminated the License Agreement.

In March 2022, the Company entered into a sublease agreement for one of its leased facilities that commenced in April 2022. Under the terms of the sublease agreement, the Company will receive $0.2 million in base lease payments over the term of the sublease, which ends in April 2023. For the year ended December 31, 2022, the Company recognized sublease income of $0.1 million.

During the year ended December 31, 2022, the Company terminated several of its lease agreements. Pursuant to the termination agreements, the Company paid $0.2 million in termination fees. The termination resulted in the derecognition of the related right-of-use assets of $1.1 million and lease liabilities of $1.0 million, and the recognition of a $0.2 million loss on lease termination for the year ended December 31, 2022, which is included in general and administrative operating expenses in the consolidated statements of operations.

For the years ended December 31, 2022 and 2021, the Company’s operating lease expense was $1.7 million and $1.7 million, respectively.

The present value assumptions used in calculating the present value of the lease payments were as follows:

	December 31,
	2022			2021
Weighted-average remaining lease term	0.3 years			1.3 years
Weighted-average discount rate		4.3	%		4.8	%

The maturity of the Company’s operating lease liabilities as of December 31, 2022 were as follows (in thousands):

Year Ending December 31,	Amount
2023	$	38
Total undiscounted lease payments		38
Less: imputed interest		—
Total operating lease liability	$	38

Under the terms of the lease agreements, the Company is also responsible for certain variable lease payments that are not included in the measurement of the lease liability. The Company did not incur significant variable lease costs for the years ended December 31, 2022 and 2021.

Supplemental cash flow information related to operating leases was as follows (in thousands):


	Year Ended December 31,
	2022		2021
Cash paid for amounts included in the measurement of lease liabilities	$	1,512	$	1,641
Prepaid cash payment for lease		—		208
Cash paid for operating leases that were included in operating cash outflows	$	1,512	$	1,849

Stock Based Compensation

12 Months Ended

Dec. 31, 2022

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Stock Based Compensation

10.	Stock Based Compensation

2018 Omnibus Incentive Plan

In June 2018, stockholders of the Company approved the Company’s 2018 Omnibus Incentive Plan (the “2018 Plan”). The 2018 Plan had previously been approved by the Company’s Board of Directors (the “Board”) and the Compensation Committee (the “Committee”) of the Board, subject to stockholder approval. The 2018 Plan became effective on June 13, 2018. On June 9, 2021, the stockholders of the Company approved an amendment previously approved by the Board to increase the number of shares of common stock reserved for issuance under the 2018 Plan by 2,500,000 to a total of 5,300,000 shares. The amendment became effective immediately upon stockholder approval. After the option modification (as discussed below), the number of shares of common stock reserved for issuance under the 2018 Plan increased by 14,860,784 to a total of 20,160,784. As of December 31, 2022, there were 12,990,839 shares of common stock available for future grant.

Performance-Based Stock Option Grants

In June 2022, the Committee approved the issuance of an option grant to purchase 400,000 shares (1,521,568 shares after the option modification discussed below) of common stock to the Chief Executive Officer pursuant to the 2018 Plan, which will vest upon (a) the achievement of a specified performance goal and (b) the grantee’s continued employment during the service period. For the year ended December 31, 2022, no expense has been recognized related to this award and no options have vested as of December 31, 2022.

Special Cash Dividend

On September 20, 2022, the Company paid a special, one-time cash dividend of $45.0 million (or $1.43 per share) to the Company’s common stockholders of record as of the close of business on September 6, 2022. The Company determined, in accordance with the adjustment provision of the 2018 Plan, that the special cash dividend was unusual and non-recurring and that appropriate adjustment to the stock options to purchase shares of the Company’s common stock outstanding under the 2018 Plan was required. The Company treated this adjustment as a modification to the original stock option grants because the terms of the agreements were modified in order to preserve the value of the option awards after a large non-recurring cash dividend. These options were amended to decrease the exercise price and increase the number of shares subject to the stock option on a proportionate basis. No incremental value was provided to the option holders as a result of the modification and no additional compensation cost was recorded by the Company.

The following table summarizes stock option activity under the Company’s 2018 Plan and related information:

	Number of Shares Underlying Outstanding Options			Weighted- Average Exercise Price		Weighted- Average Remaining Contractual Term (Years)		Aggregate Intrinsic Value (thousands)
Outstanding — December 31, 2021		2,603,630		$	7.70		7.46	$	—
Options granted ⁽¹⁾		10,270,911			1.34
Options forfeited and cancelled ⁽¹⁾		(4,148,455	)		4.96
Options expired		(47,319	)		13.27
Outstanding — December 31, 2022		8,678,767		$	1.42		7.47	$	1,051
Exercisable — December 31, 2022		4,317,076		$	2.38		5.94	$	—

(1)

Includes options that were cancelled and re-granted as part of the option modification from the special cash dividend, as further discussed above.

The weighted-average grant date fair value of options granted during the years ended December 31, 2022 and 2021 was $0.96 and $4.00, respectively.

No options were exercised during the year ended December 31, 2022. The aggregate intrinsic value of options exercised during the year ended December 31, 2021 was $3,000.

The fair value of options vested during the years ended December 31, 2022 and 2021 was $1.9 million and $2.6 million, respectively.

Valuation Assumptions

The Company estimated the fair value of stock options granted using the Black-Scholes option-pricing formula and a single option award approach. Due to its limited relevant historical data, the Company estimated its volatility considering a number of factors including the use of the volatility of comparable public companies. The expected term of options granted under the Plan, all of which qualify as “plain vanilla” per SEC Staff Accounting Bulletin 107, is determined based on the simplified method due to the Company’s limited relevant history. The risk-free rate is based on the yield of a U.S. Treasury security with a term consistent with the option. This fair value is being amortized ratably over the requisite service periods of the awards, which is generally the vesting period.

The fair value of employee stock options was estimated using the following weighted-average assumptions:

	Year Ended December 31,
	2022			2021
Employee Stock Options:
Expected term (in years)		6.02			6.00
Risk-free interest rate		3.00	%		0.84	%
Dividend yield		—			—
Volatility		92.58	%		93.25	%

Total stock-based compensation recognized was as follows (in thousands):

	Year Ended December 31,
	2022		2021
Research and development	$	330	$	1,202
General and administrative⁽¹⁾		1,012		2,203
Total stock-based compensation	$	1,342	$	3,405

(1)

Included in general and administrative stock-based compensation for the years ended December 31, 2022 and 2021 is $30,000 and $0.3 million in expense related to 32,684 shares and 56,912 shares of common stock, respectively, issued to certain board members in lieu of their cash compensation.

As of December 31, 2022, the Company had unrecognized employee stock-based compensation expense of $1.1 million, related to unvested stock option awards, which is expected to be recognized over an estimated weighted-average period of 1.93 years.

Employee Stock Purchase Plan

In June 2018, the Company’s stockholders approved the 2018 Employee Stock Purchase Plan (the “ESPP”). The ESPP had previously been approved by the Board and the Compensation Committee of the Board, subject to stockholder approval which became effective as of June 13, 2018. Under the ESPP, employees meeting certain specific employment qualifications are eligible to participate and can purchase shares of common stock semi-annually on February 9^th and August 9^th of each year, through payroll deductions. The purchase price is 85% of the lower of the fair market value of the stock at the commencement or end of the offering period. The ESPP permits eligible employees to purchase shares of common stock through payroll deductions for up to 15% of qualified compensation.

The Company’s ESPP is subject to an Evergreen provision which shares may be added to the pool as needed. As of December 31, 2022, a total of 359,545 shares of common stock may be granted in accordance with the terms of the ESPP.

For the year ended December 31, 2022, a total of 47,662 shares of common stock for $20,000 have been issued to employees participating in the two ESPP purchases during 2022 and 187,807 shares are available for issuance under the ESPP as of December 31, 2022.

Stock-based compensation expense for the ESPP was not significant and $0.1 million for the years ended December 31, 2022 and 2021, respectively, and is included in total stock-based compensation recognized.

Income Taxes

12 Months Ended

Dec. 31, 2022

Income Tax Disclosure [Abstract]

Income Taxes

11.	Income Taxes

The components of the provision for income taxes for the years ended December 31, 2022 and 2021 consist of the following:

	Year Ended December 31,
	2022		2021
Current tax provision:
Federal	$	341	$	—
State		7		—
Total tax provision	$	348	$	—

The reconciliation of the federal statutory income tax rate to the Company’s effective tax rate for the years ended December 31, 2022 and 2021 are as follows:

	Year Ended December 31,
	2022			2021
Tax at statutory federal rate		-21.00	%		-21.00	%
State Tax (benefit)—net of federal benefit		-0.01	%		0.00	%
Permanent differences		1.00	%		0.35	%
Tax credits		-42.08	%		-5.86	%
Derecognition due to Sec. 382 and 383 limitations		139.00	%		0.00	%
Change in valuation allowance		-69.24	%		26.26	%
Fixed assets other adjustment		-1.19	%		0.00	%
Other		-2.07	%		0.25	%
Effective tax rate		4.41	%		0.00	%

Significant components of the Company’s deferred tax assets as of December 31, 2022 and 2021 consist of the following (in thousands):

	Year Ended December 31,
	2022			2021
Deferred tax assets:
Accruals and reserves	$	1,273		$	1,000
Net operating loss carry forwards		40,770			47,541
Tax credit carry forwards		4,463			12,939
Fixed and intangible assets		9,510			3
Valuation allowance		(56,016	)		(61,483	)
Net deferred tax assets:	$	—		$	—

Based on the available objective evidence at December 31, 2022, the Company does not believe it is more likely than not that the net deferred tax assets will be realizable. Accordingly, the Company has provided a full valuation allowance against its net deferred tax assets at December 31, 2022 and 2021. The net valuation allowance decreased by approximately $5.5 million and increased by approximately $23.1 million during the years ended December 31, 2022 and 2021, respectively.

As of December 31, 2022, after consideration of certain limitations (see below), the Company had approximately $194.1 million federal and $3.6 million state net operating loss carryforwards (“NOL”) available to reduce future taxable income which, if unused, will begin to expire in 2037 for federal and 2032 for state tax purposes. The federal net operating loss carryforward includes $192.4 million that have an indefinite life.

As of December 31, 2022, the Company also had tax credit carry forwards available to offset future tax liabilities of approximately $8,500 for federal and $7.5 million for state. If unused, the federal credit will begin to expire in 2042 and the state tax credit does not expire.

If the Company experiences a greater than 50 percent aggregate change in ownership over a three-year period (a Section 382 ownership change), utilization of its pre-change NOL carryforwards are subject to annual limitation under Section 382 of the Internal Revenue Code (California has similar provisions). The annual limitation is determined by multiplying the value of the Company’s stock at the time of such ownership change by the applicable long-term tax-exempt rate. Such limitations may result in expiration of a portion of the NOL carryforwards before utilization. The Company determined that ownership changes occurred on December 31, 2007, August 20, 2015, April 13, 2017, February 15, 2018, February 18, 2020, and December 26, 2022. Approximately $156.5 million and $75.2 million of the NOLs will expire unutilized for federal and California purposes, respectively. The Company has derecognized NOL related deferred tax assets in the tax affected amounts of $32.9 million and $0 for federal and California purposes, respectively through the year ended December 31, 2022.

All of the federal R&D credits could expire unutilized, whereas none of the California R&D credits are subject to expiration. Approximately $26.1 million of gross federal R&D credit-related deferred tax assets were derecognized due to the Section 383 limitation. The ability of the Company to use its remaining NOL and carryforwards may be further limited if the Company experiences a Section 382 ownership change as a result of future changes in its stock ownership.

On June 29, 2020, the California Governor signed Assembly Bill 85 (“A.B. 85”), which now becomes California law. A.B. 85, which includes several tax measures, provides for a three-year suspension of the use of net operating losses for medium and large businesses and a three-year cap on the use of business incentive tax credits to offset no more than $5 million of tax per year. Generally, A.B. 85 suspends the use of net operating losses for taxable years 2020, 2021, and 2022 for taxpayers with taxable income of $1 million or more. Since the Company is not expected to generate California source taxable income of more than $1 million, no material impact is anticipated at this time.

Accounting for Uncertainty in Income Taxes

The Company only recognizes tax benefits if it is more likely than not that they will be sustained upon audit by the relevant tax authority based upon their technical merits. An uncertain tax position will not be recognized if it has less than a 50% likelihood of being sustained.

The Company had approximately $1.9 million and $4.7 million of unrecognized tax benefits as of December 31, 2022 and 2021, respectively. As the Company has a full valuation allowance on its deferred tax assets, the unrecognized tax benefits have reduced the deferred tax assets and the valuation allowance in the same amount. The Company does not expect the amount of unrecognized tax benefits to materially change in the next twelve months.

A reconciliation of the beginning and ending balance of the unrecognized tax benefits is as follows (in thousands):

Beginning Balance at January 1, 2021	$	2,955
Increase/(Decrease) of unrecognized tax benefits taken in prior years		—
Increase/(Decrease) of unrecognized tax benefits related to current year		1,749
Ending Balance at December 31, 2021	$	4,704
Increase/(Decrease) of unrecognized tax benefits taken in prior years		(2,841	)
Increase/(Decrease) of unrecognized tax benefits related to current year		20
Ending Balance at December 31, 2022	$	1,883

Interest and penalties related to unrecognized tax benefits would be included as income tax expense in the Company’s consolidated statements of operations. As of December 31, 2022 and 2021, the Company had not recognized any tax-related penalties or interest in its consolidated financial statements.

The Company files income tax returns in the United States federal and California, with a new filing in Florida for tax year 2022. The Company filed final returns in 2021 in Kansas, Missouri and New Jersey state jurisdictions. The Company is not currently under examination by income tax authorities in federal, state or other jurisdictions. As of December 31, 2022 and 2021, the Company had no uncertain tax positions which affected its financial position as its results of operations or its cash flow, and will continue to evaluate for uncertain tax positions in the future. The Company is subject to United States federal and state income tax examinations by authorities for all tax years due to accumulated net operating losses that are being carried forward for tax purposes.

- Definition

The entire disclosure for income taxes. Disclosures may include net deferred tax liability or asset recognized in an enterprise's statement of financial position, net change during the year in the total valuation allowance, approximate tax effect of each type of temporary difference and carryforward that gives rise to a significant portion of deferred tax liabilities and deferred tax assets, utilization of a tax carryback, and tax uncertainties information.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 21
-URI https://asc.fasb.org/extlink&oid=121826272&loc=d3e32857-109319

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SAB Topic 11.C)
-URI https://asc.fasb.org/extlink&oid=122134291&loc=d3e330215-122817

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 17
-Subparagraph (b)
-URI https://asc.fasb.org/extlink&oid=121826272&loc=d3e32809-109319

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SAB TOPIC 6.I.5.Q1)
-URI https://asc.fasb.org/extlink&oid=122134291&loc=d3e330036-122817

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 14
-URI https://asc.fasb.org/extlink&oid=121826272&loc=d3e32705-109319

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 270
-Section 50
-Paragraph 1
-URI https://asc.fasb.org/extlink&oid=6424409&loc=d3e44925-109338

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-URI https://asc.fasb.org/topic&trid=2144680

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 30
-Section 50
-Paragraph 2
-Subparagraph (a)
-URI https://asc.fasb.org/extlink&oid=6424122&loc=d3e41874-109331

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(h)(2))
-URI https://asc.fasb.org/extlink&oid=120395691&loc=d3e23780-122690

+ Details

Collaborations

12 Months Ended

Dec. 31, 2022

Organization Consolidation And Presentation Of Financial Statements [Abstract]

Collaborations

12.	Collaborations

Mosaic

In October 2017, the Company entered into a strategic research collaboration with Mosaic to develop intravitreal anti-complement factor 3 (C3) products for the treatment of dry Age-related Macular Degeneration (AMD) and other retinal diseases. The Company subsequently amended this agreement in December 2018, December 2019 and May 2020.

Under the as amended Mosaic collaboration agreement, Mosaic is eligible to receive up to $4.0 million in potential future milestone payments related to regulatory and clinical development events for CB 2782-PEG and an additional anti-complement product candidate in lieu of the Company’s prior obligations to pay Mosaic a double-digit percentage of funds the Company receives from Biogen or any other amounts the Company receives related to sublicense fees, research and development payments, or any other research, regulatory, clinical or commercial milestones and royalties on any other development candidates.

As a result of the sale of the Company’s complement portfolio, including CB 2782-PEG and other assets, to Vertex in May 2022, the Mosaic collaboration agreement was transferred to Vertex. See Note 16, Restructuring.

ISU Abxis

In December 2018, the Company entered into an amended and restated license agreement with ISU Abxis (the “A&R ISU Abxis Agreement”). Under the A&R ISU Abxis Agreement, ISU Abxis will receive commercialization rights in South Korea to the Company’s engineered Factor IX dalcinonacog alfa - DalcA and the Company will receive clinical development and commercialization rights in the rest of world (excluding South Korea) and manufacturing development and manufacturing rights worldwide (including South Korea). The A&R ISU Abxis Agreement provides for a low single-digit royalty payment to ISU Abxis, on a country-by-country basis, for net product sales of DalcA by the Company or its affiliates in each country other than South Korea. Pursuant to the A&R ISU Abxis Agreement, the Company will also pay up to an aggregate of $19.5 million in milestone payments to ISU Abxis, including $2.5 million in regulatory and development milestone payments and up to $17.0 million in commercial milestone payments, if the applicable milestones are met. As of December 31, 2022, no milestones have been met.

As a result of the sale of the Company’s rare bleeding disorders programs, including DalcA and other assets, to GCBP in February 2023, the A&R ISU Abxis Agreement was transferred to GCBP. See Note 17, Subsequent Events.

Biogen

On December 18, 2019, the Company and Biogen entered into a License and Collaboration Agreement (the “Biogen Agreement”), under which the Company granted Biogen a worldwide, royalty-bearing, exclusive, with the right to sublicense, license (“Exclusive License”) to develop and commercialize CB 2782-PEG and other anti-C3 proteases for potential treatment of dry AMD and other disorders. Pursuant to the Biogen Agreement, the Company performed certain pre-clinical and manufacturing activities (“Research Services”), and Biogen was solely responsible for funding the pre-clinical and manufacturing activities and performing IND-enabling activities, worldwide clinical development, and commercialization.

Under the terms of the Biogen Agreement, the Company received an up-front payment for the transfer of the Exclusive License (inclusive of certain know-how) of $15.0 million in January 2020. The Company was eligible to receive development milestones and sales milestones of up to $340.0 million. In addition, the Company was eligible to receive royalties in the range of single-digit to low double-digit percentage rates of annual net sales on a product-by-product and country-by-country basis. The Company also received reimbursements for costs associated with the performance of the Research Services.

The Company determined that the performance obligations under the Biogen Agreement were the Exclusive License and the Research Services. For the Exclusive License, the Company used the residual approach in determining the standalone selling price, or SSP, which includes the upfront payments, milestones and royalties. For the Research Services, the Company used the historical pricing approach for determining the SSP, which includes the reimbursement of personnel and out-of-pocket costs.

In March 2022, the Company received written notice from Biogen declaring intent to terminate the Biogen Agreement which was effective as of May 2022. As a result of the termination, Biogen no longer has the Exclusive License to develop, manufacture and commercialize CB 2782-PEG and other anti-C3 proteases for potential treatment of dry AMD and other disorders. In March 2022, Biogen returned full rights to CB 2782-PEG.

In June 2022, Biogen and the Company reached an agreement to resolve the outstanding obligations and monetary disputes between the parties. The Company agreed to forgive approximately $0.6 million of accounts receivable due from Biogen and to pay Biogen $10,000 in cash. This resulted in the Company recognizing a $0.6 million settlement expense for the year ended December 31, 2022, which is included in general and administrative operating expenses in the consolidated statements of operations.

For the years ended December 31, 2022 and 2021, the Company recognized no license revenue from the Biogen Agreement.

For the years ended December 31, 2022 and 2021, the Company recognized $0.8 million and $7.3 million in collaboration revenue for reimbursable out-of-pocket and personnel costs incurred related to Research Services.

For the year ended December 31, 2022, the Company recognized $0.2 million in collaboration revenue from the beginning of period deferred revenue balance.

Interest and Other Income (Expense), Net

12 Months Ended

Dec. 31, 2022

Other Income And Expenses [Abstract]

Interest and Other Income (Expense), Net

13.	Interest and Other Income (Expense), Net

The following table shows the detail of interest and other income (expense), net as follows (in thousands):

	Year Ended December 31,
	2022		2021
Interest income	$	537	$	39
Gain from extinguishment of liability		180		—
Other		—		(78	)
Total interest and other income (expense), net	$	717	$	(39	)

Stockholders' Equity

12 Months Ended

Dec. 31, 2022

Equity [Abstract]

Stockholders' Equity

14.	Stockholders’ Equity

Common Stock

Under the Company’s amended and restated certificate of incorporation, the Company has 100,000,000 shares of common stock authorized for issuance with a $0.001 par value per share. The number of authorized shares of common stock may be increased or decreased by the affirmative vote of the holders of a majority of the Company’s stock who are entitled to vote. Each share of common stock is entitled to one vote. The holders of common stock are entitled to receive dividends when and as declared or paid by the Board.

The Company had 0 and 85 issued and outstanding common stock warrants as of December 31, 2022 and 2021, respectively, with a weighted-average exercise price of $392.70. The warrants expired in August 2022.

2021 ATM Program

On October 15, 2021, the Company entered into an Equity Distribution Agreement (the “ATM Agreement”) with Piper Sandler, as sales agent, pursuant to which the Company may offer and sell, from time to time, through Piper Sandler, shares of the Company’s common stock, par value of $0.001 per share, with aggregate gross sales proceeds of up to $50.0 million through the ATM Program. The Company will pay Piper Sandler a commission of 3.0% of the gross proceeds of any shares sold. The Company also agreed to reimburse Piper Sandler for certain expenses incurred in connection with its services under the ATM Agreement, including up to $50,000 for legal expenses in connection with the establishment of the ATM Program.

Sales of shares of common stock under the ATM Program will be made pursuant to the registration statement on Form S-3 (File No. 333-253874), which was declared effective by the SEC on May 3, 2021, and a related prospectus supplement file with the SEC on October 15, 2021. For the years ended December 31, 2022 and 2021, no shares of common stock were sold under the ATM Program.

Redeemable Convertible Preferred Stock

The Company is authorized to issue 5,000,000 shares of preferred stock with a par value of $0.001 per share under its restated certificate of incorporation. Under the Catalyst Convertible Preferred Stock Certificate of Designation, the Company has designated 123,418 shares to be Catalyst Convertible Preferred Stock and is authorized to issue up to 12,340 shares of Catalyst Convertible Preferred Stock pursuant to the terms of the F351 Agreement and up to 111,078 shares of Catalyst Convertible Preferred stock pursuant to the terms of the Business Combination Agreement. As of December 31, 2022, the Company has 12,340 shares of Catalyst Convertible Preferred Stock issued and outstanding. Refer to Note 1, Nature of Operations, regarding the Company’s issuance of Catalyst Convertible Preferred Stock in December 2022.

Subject to stockholder approval, each share of Catalyst Convertible Preferred Stock issued under the F351 Agreement is convertible into 10,000 shares of common stock. The Company is required to hold a stockholders’ meeting to request the approval of the conversion of the Catalyst Convertible Preferred Stock into shares of common stock in accordance with Nasdaq Listing Rule 5635(a) (the “Conversion Proposal”). The Company expects to hold its 2023 Annual Meeting of Stockholders in the third quarter of 2023 and will include the following matters as proposals to be voted on at the meeting: (i) the Conversion Proposal and (ii) if necessary or appropriate, the approval of an amendment to the Company’s certificate of incorporation to authorize sufficient shares of common stock for the conversion of the Catalyst Convertible Preferred Stock issued pursuant to the F351 Agreement.

If the Company’s stockholders do not approve the conversion of the Catalyst Convertible Preferred Stock by June 26, 2023 (which has been extended to September 30, 2023, see Note 17, Subsequent Events), then the holders of the Catalyst Convertible Preferred Stock are entitled to require the Company to make cash payments at a price per share equal to the fair value of undelivered shares of common stock, defined as the last reported closing price of the Company’s common stock on the trading day on which notice of conversion is delivered to the Company. Using the closing price on March 24, 2023 of $0.21, if all the currently outstanding Catalyst Convertible Preferred Stock was redeemed for cash, the Company would be required to make a payment of approximately $25.7 million. The Company has insufficient liquidity to make such a payment, if required.

Holders of Catalyst Convertible Preferred Stock are entitled to receive dividends on shares of Catalyst Convertible Preferred Stock equal, on an as-if-converted-to-common-stock basis, and in the same form as dividends actually paid on shares of the Company’s common stock. Except as otherwise required by law, the Catalyst Convertible Preferred Stock does not have voting rights. However, as long as any shares of Catalyst Convertible Preferred Stock are outstanding, the Company may not, without the affirmative vote of the holders of a majority of the then outstanding shares of the Catalyst Convertible Preferred Stock, (i) alter or change adversely the powers, preferences or rights given to the Catalyst Convertible Preferred Stock or alter or amend this Certificate of Designation that authorized the Catalyst Convertible Preferred Stock, amend or repeal any provision of or add any provision to, the Certificate of Incorporation or bylaws of the Company, or file any articles of amendment, certificate of designations, preferences, limitations and relative rights of any series of preferred stock, if such action would adversely alter or change the preferences, rights, privileges or powers of, or restrictions provided for the benefit of the Catalyst Convertible Preferred Stock, (ii) issue further shares of Catalyst Convertible Preferred Stock or increase or decrease (other than by conversion) the number of authorized shares of Catalyst Convertible Preferred Stock, or (iii) enter into any agreement with respect to any of the foregoing. Additionally, the approval of the holders of a majority of the Catalyst Convertible Preferred Stock is required for certain change of control transactions, provided that this approval right will terminate upon stockholder approval of the Conversion Proposal. The Catalyst Convertible Preferred Stock does not have a preference upon any liquidation, dissolution or winding-up of the Company.

Following stockholder approval of the Conversion Proposal, each share of Catalyst Convertible Preferred Stock is convertible into shares of common stock at any time at the option of the holder thereof, into 10,000 shares of the Company’s common stock, subject to certain beneficial ownership limitations, including that a holder of Catalyst Convertible Preferred Stock is prohibited from converting shares of Catalyst Convertible Preferred Stock into shares of the Company’s common stock if, as a result of such conversion, such holder, together with its affiliates, would beneficially own more than a specified percentage (to be initially set at 9.99% and thereafter adjustable by the holder to a number between 4.99% and 19.99%) of the total number of shares of the Company’s common stock issued and outstanding immediately after giving effect to such conversion.

The Catalyst Convertible Preferred Stock is classified as temporary equity on the consolidated balance sheet because if conversion to common stock is not approved by the shareholders, the Catalyst Convertible Preferred Stock would be redeemable at the option of the holders for cash equal to the closing price of the common stock on last trading day prior to the holder’s redemption request. The Catalyst Convertible Preferred Stock is recorded at its relative fair value on the date of issuance (i.e., the closing date of the F351 Asset acquisition) and the Company has not adjusted the carrying value to its redemption value since the Catalyst Convertible Preferred Stock is not currently redeemable, and it is not probable that it will become redeemable in the future at the balance sheet date. Subsequent adjustments to the carrying value will be made only when it becomes probable that such redemption will occur.

- Definition

The entire disclosure for shareholders' equity comprised of portions attributable to the parent entity and noncontrolling interest, including other comprehensive income. Includes, but is not limited to, balances of common stock, preferred stock, additional paid-in capital, other capital and retained earnings, accumulated balance for each classification of other comprehensive income and amount of comprehensive income.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-URI https://asc.fasb.org/topic&trid=2208762

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 13
-Subparagraph (b)
-URI https://asc.fasb.org/extlink&oid=126973232&loc=SL123496158-112644

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 13
-URI https://asc.fasb.org/extlink&oid=126973232&loc=SL123496158-112644

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 14
-Subparagraph (c)
-URI https://asc.fasb.org/extlink&oid=126973232&loc=SL123496171-112644

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 14
-Subparagraph (b)
-URI https://asc.fasb.org/extlink&oid=126973232&loc=SL123496171-112644

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.3-04)
-URI https://asc.fasb.org/extlink&oid=120397183&loc=d3e187085-122770

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 18
-Subparagraph (d)
-URI https://asc.fasb.org/extlink&oid=126973232&loc=SL123496189-112644

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 13
-Subparagraph (g)
-URI https://asc.fasb.org/extlink&oid=126973232&loc=SL123496158-112644

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 18
-Subparagraph (a)
-URI https://asc.fasb.org/extlink&oid=126973232&loc=SL123496189-112644

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 13
-Subparagraph (h)
-URI https://asc.fasb.org/extlink&oid=126973232&loc=SL123496158-112644

Reference 11: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 14
-Subparagraph (a)
-URI https://asc.fasb.org/extlink&oid=126973232&loc=SL123496171-112644

Reference 12: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 18
-Subparagraph (b)
-URI https://asc.fasb.org/extlink&oid=126973232&loc=SL123496189-112644

Reference 13: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 16
-Subparagraph (b)
-URI https://asc.fasb.org/extlink&oid=126973232&loc=SL123496180-112644

Reference 14: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 13
-Subparagraph (i)
-URI https://asc.fasb.org/extlink&oid=126973232&loc=SL123496158-112644

Reference 15: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(e)(1))
-URI https://asc.fasb.org/extlink&oid=120395691&loc=d3e23780-122690

Reference 16: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 40
-Section 50
-Paragraph 6
-Subparagraph (a)
-URI https://asc.fasb.org/extlink&oid=126731327&loc=SL126733271-114008

+ Details

Net Loss per Share Attributable to Common Stockholders

12 Months Ended

Dec. 31, 2022

Earnings Per Share [Abstract]

Net Loss per Share Attributable to Common Stockholders

15.	Net Loss per Share Attributable to Common Stockholders

Since the Company was in a loss position for all periods presented, diluted net loss per share is the same as basic net loss per share for all periods as the inclusion of all potential common shares outstanding would have been anti-dilutive. Potentially dilutive securities that were not included in the diluted per share calculations because they would be anti-dilutive were as follows:

	Year Ended December 31,
	2022		2021
Options to purchase common stock		8,678,767		2,603,630
Redeemable convertible preferred stock ⁽¹⁾		123,400,000		—
Common stock warrants		—		85
Total		132,078,767		2,603,715

(1) Shown as common stock equivalents

Restructuring

12 Months Ended

Dec. 31, 2022

Restructuring And Related Activities [Abstract]

Restructuring

16.	Restructuring

In November 2021, the Board approved a restructuring of its business based on its decision to stop the clinical development of MarzAA and focus solely on its complement programs and protease medicines platform. The restructuring included a reduction-in-force whereby approximately 35% of employees were terminated. During the year ended December 31, 2021, the Company recorded charges of $0.4 million related to one-time severance costs and related expenses in connection with the workforce reduction, and charges of $3.8 million related to the write-off of prepaid manufacturing costs that will no longer be used for the clinical development of MarzAA. As of December 31, 2021, the remaining restructuring liability was $0.2 million, which the Company paid during the second quarter of 2022.

In March 2022, the Board approved a further reduction of its workforce as part of its restructuring plan whereby 22 full-time employees were terminated. Following this reduction, the Company had five full-time employees remaining. During the quarter ended March 31, 2022, the Company recorded additional charges of $1.0 million for severance and other costs related to the reduction-in-force, recognized as an operating expense within the consolidated statements of operations, which the Company paid during the second quarter of 2022.

The following table summarizes restructuring charges recorded in each component of operating expenses in the Company’s consolidated statements of operations (in thousands):

	Year Ended December 31,
	2022		2021
Research and development	$	609	$	4,025
General and administrative		402		143
Total restructuring charges	$	1,011	$	4,168

Sale of Assets

During the year ended December 31, 2022, the Company entered into sales agreements, pursuant to which the Company sold various lab equipment, consumables, and furniture and fixtures for total consideration of $0.5 million. The Company recorded a loss on disposal of $0.2 million, which is included in gain on disposal of assets, net in the consolidated statements of operations.

In May 2022, the Company entered into an asset purchase agreement with Vertex, pursuant to which Vertex purchased the Company’s complement portfolio, including CB 2782-PEG and CB 4332, as well as its complement-related intellectual property including the ProTUNE^TM and ImmunoTUNE^TM platforms for $60.0 million in cash consideration. Cash of $55.0 million was received upfront in May 2022 and the remaining $5.0 million will be paid one year after the closing upon satisfaction of certain post-closing indemnification obligations. The hold-back amount is recorded within accounts and other receivables on the consolidated balance sheet. There were no carrying amounts associated with the intellectual property sold to Vertex, and,

therefore, the Company recorded a gain of $57.4 million related to the disposal, net of $2.6 million of transaction costs, which is included in gain on disposal of assets, net in the consolidated statements of operations.

Subsequent Events

12 Months Ended

Dec. 31, 2022

Subsequent Events [Abstract]

Subsequent Events

17.	Subsequent Events

Payment of Dividend

On January 12, 2023, the Company paid a one-time cash dividend of $0.24 per share, or approximately $7.6 million, to the Company’s common stockholders of record as of close of business on January 5, 2023. GNI common stockholders were not entitled to such dividend payment.

Sale of Assets

On February 27, 2023, Catalyst entered into an asset purchase agreement with GC Biopharma Corp. (“GCBP”), pursuant to which GCBP acquired the Company’s legacy rare bleeding disorders programs including MarzAA, DalcA and CB-2679d-GT for $6.0 million in cash consideration. Cash of $1.0 million was received upfront in February 2023 and the remaining $5.0 million will be paid two years after the closing upon satisfaction of certain post-closing indemnification obligations. In March 2023, the Company distributed the net cash proceeds received upfront of $0.2 million to the CVR Holders. Once received, the remaining net proceeds from the transaction will be distributed to the CVR Holders.

Silicon Valley Bank Closure

As of March 10, 2023, the Company maintained two accounts at Silicon Valley Bank (“SVB”) holding cash deposits of approximately $9.0 million. On March 10, 2023, SVB was closed by the California Department of Financial Protection and Innovation, and the Federal Deposit Insurance Corporation (“FDIC”) was appointed receiver. The FDIC initially announced that all insured depositors will have full access to their insured deposits no later than, March 13, 2023, with uninsured depositors receiving an advance dividend receivership certificate for their uninsured funds. On March 12, 2023, the U.S. Treasury Department, the Federal Reserve and the FDIC jointly announced enabling actions that fully protect all SVB depositors’ insured and uninsured deposits, and that such depositors would have access to all of their funds starting March 13, 2023. On March 13, 2023, the Company was able to access its full deposits with SVB.

F351 Agreement Amendment

In March 2023, the Company amended the F351 Agreement and the Catalyst Convertible Preferred Stock Certificate of Designation to extend the deadline for the cash settlement of the Catalyst Convertible Preferred Stock to September 30, 2023. Under the amended terms, if the Company’s stockholders do not approve the conversion of the Catalyst Convertible Preferred Stock by September 30, 2023, then the Catalyst Convertible Preferred Stock would be redeemable at the option of the holders for cash equal to the closing price of the common stock on last trading day prior to the holder’s redemption request.

Summary of Significant Accounting Policies (Policies)	12 Months Ended
Summary of Significant Accounting Policies (Policies)	Dec. 31, 2022
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The accompanying consolidated financial statements include the accounts of the Company and its subsidiary. Intercompany accounts and transactions, if applicable, have been eliminated in consolidation. The Company’s consolidated financial statements have been prepared in accordance with United States generally accepted accounting principles (“GAAP”).
Use of Estimates	Use of Estimates The preparation of consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the amounts reported in the consolidated financial statements and accompanying notes. On an ongoing basis, management evaluates its estimates, including those related to revenue recognition, allowance of doubtful accounts, contingent value rights, operating lease right-of-use assets and liabilities, accrued expenses, income taxes and stock-based compensation. The Company bases its estimates on various assumptions that the Company believes to be reasonable under the circumstances. Actual results could differ from those estimates.
Accounting Pronouncements Recently Adopted	Accounting Pronouncements Recently Adopted In May 2021, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2021-04, Earnings Per Share (Topic 260), Debt—Modifications and Extinguishments (Subtopic 470-50), Compensation—Stock Compensation (Topic 718), and Derivatives and Hedging—Contracts in Entity’s Own Equity (Subtopic 815-40): Issuer’s Accounting for Certain Modifications or Exchanges of Freestanding Equity-Classified Written Call Options. The amendments in ASU 2021-04 provide guidance to clarify and reduce diversity in an issuer’s accounting for modifications or exchanges of freestanding equity-classified written call options (for example, warrants) that remain equity classified after modification or exchange. The amendments in this ASU 2021-04 are effective for all entities for fiscal years beginning after December 15, 2021, and interim periods within those fiscal years. The Company adopted ASU 2021-04 and related updates on January 1, 2022, and the adoption did not have a material impact on its consolidated financial statements. In August 2020, FASB issued ASU 2020-06, Debt - Debt with Conversion and Other Options (Subtopic 470-20) and Derivatives and Hedging - Contracts in Entity’s Own Equity (Subtopic 815-40) to simplify accounting for certain financial instruments. ASU 2020-06 eliminates the previous models that require separation of beneficial conversion and cash conversion features from convertible instruments and simplifies the derivative scope exception guidance pertaining to equity classification of contracts in an entity’s own equity. The amendments in this ASU are effective for public business entities for fiscal years beginning after December 15, 2021. The Company adopted ASU 2020-06 on January 1, 2022, and the adoption did not have a material impact on its consolidated financial statements. New Accounting Pronouncements – Issued But Not Yet Adopted In June 2016, the FASB issued ASU 2016-13, Measurement of Credit Losses on Financial Instruments. The main objective of ASU 2016-13 is to provide financial statement users with more decision-useful information about an entity’s expected credit losses on financial instruments and other commitments to extend credit at each reporting date. To achieve this objective, the amendments in this update replace the incurred loss impairment methodology currently used today with a methodology that reflects expected credit losses and requires consideration of a broader range of reasonable and supportable information to develop credit loss estimates. ASU 2016-13 will be effective for the Company for fiscal years beginning after December 15, 2022, including interim periods within those fiscal years, using a modified retrospective approach. The Company adopted ASU 2016-13 and related updates on January 1, 2023 and the adoption did not have a material impact on its consolidated financial statements.
Cash and Cash Equivalents	Cash and Cash Equivalents The Company invests its excess cash in bank deposits, consisting primarily of money market mutual funds. The Company considers all highly liquid investments with original maturities of three months or less from the date of purchase to be cash equivalents.
Fair Value of Financial Instruments	Fair Value of Financial Instruments The Company applies fair value accounting for all financial assets and liabilities and non-financial assets and liabilities that are recognized or disclosed at fair value in the consolidated financial statements on a recurring basis. Fair value is defined as the exchange price that would be received for an asset or an exit price that would be paid to transfer a liability in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. The fair value hierarchy requires that an entity maximize the use of observable inputs when estimating fair value. The fair value hierarchy includes the following three-level classification which is based on the market observability of the inputs used for estimating the fair value of the assets or liabilities being measured: Level 1 – Quoted prices in active markets for identical assets or liabilities. Level 2 – Observable inputs other than quoted prices in active markets for identical assets and liabilities, quoted prices for identical or similar assets or liabilities in inactive markets, or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities. Level 3 – Inputs that are generally unobservable and typically reflect management’s estimate of assumptions that market participants would use in pricing the asset or liability.
Derivative Financial Instruments	Derivative Financial Instruments The Company evaluates its contracts to determine if those contracts qualify as derivatives under ASC 815, Derivatives and Hedging. For derivative financial instruments that are accounted for as liabilities, the derivative instrument is initially recorded at its fair value and is then re-valued at each reporting date. Any changes in fair value are recorded as non-operating, non-cash other income or expense for each reporting period. Derivative instrument liabilities are classified in the balance sheet as current or non-current based on whether or not net-cash settlement of the derivative instrument is probable within the next 12 months from the balance sheet date. The Company determined that certain contingent payments under the CVR Agreement qualified as derivatives under ASC 815, and as such, were recorded as a liability on the balance sheet as of December 31, 2022. Refer to Note 5, Fair Value Measurement and Note 8, Commitments and Contingencies, for additional information regarding the CVR derivative liability.
Property and Equipment	Property and Equipment Property and equipment are stated at cost, less accumulated depreciation. Depreciation is computed using the straight-line method over the estimated useful lives of the respective assets, which are three years for computer equipment and software, and three to seven years for furniture and leasehold improvements.
Investments	Investments The Company invests its excess cash in investment grade, short to intermediate-term, fixed income securities and recognizes purchased securities on the settlement date. All investments have been classified as “available-for-sale” and are carried at estimated fair value based upon quoted market prices or pricing models for similar securities. Management determines the appropriate classification of its investments at the time of purchase and reevaluates such designation as of each consolidated balance sheet date. Unrealized gains and losses on available-for-sale debt securities are excluded from earnings and are reported as a component of comprehensive loss. Realized gains and losses and declines in fair value determined to be other-than-temporary, if any, on available-for-sale debt securities are included in interest and other income (expense), net. The cost of securities sold is based on the specific-identification method. Interest on short-term investments is included in interest and other income (expense), net.
Revenue Recognition	Revenue Recognition License and Collaboration Arrangements The Company may enter into collaboration arrangements that fall under the scope Collaborative Arrangements (Topic 808). The Company analyzes its collaboration arrangements to assess whether they are within the scope of ASC 808 to determine whether such arrangements involve joint operating activities performed by parties that are both active participants in the activities and exposed to significant risks and rewards dependent on the commercial success of such activities. This assessment is performed throughout the life of the arrangement based on changes in the responsibilities of all parties in the arrangement. The accounting for some of the activities under collaboration arrangements may be analogized to ASC 606 for distinct units of account that are reflective of a vendor-customer relationship. Under ASC 606, in determining the appropriate amount of revenue to be recognized as it fulfills its obligations under its agreements, the Company performs the following steps: (i) identification of the promised goods or services in the contract; (ii) determination of whether the promised goods or services are performance obligations including whether they are distinct in the context of the contract; (iii) measurement of the transaction price, including the constraint on variable consideration; (iv) allocation of the transaction price to the performance obligations based on estimated selling prices; and (v) recognition of revenue when the Company satisfies each performance obligation. If a license to the Company’s intellectual property is determined to be distinct from the other performance obligations identified in the arrangement, the Company recognizes revenues attributed to the license when the license is transferred to the customer and the customer is able to use and benefit from the license. For licenses that are bundled with other promises, the Company utilizes judgement to assess the nature of the combined performance obligation to determine whether the combined performance obligation is satisfied over time or at a point in time. At the inception of each arrangement that contain development milestones, the Company evaluates whether the development milestones included are considered probable of being reached and estimates the amount to be included in the transaction price using the most likely amount method. If it is probable that a significant revenue reversal would not occur, the associated milestone value is included in the transaction price. Milestone payments that are not within the control of the Company or the licensee, such as regulatory approvals, are not generally considered probable of being achieved until those approvals are received. At the end of each reporting period, the Company re-evaluates the probability of achievement of any development milestones, and if necessary, adjusts its estimate of the transaction price. Any such adjustments would be recorded on a cumulative catch-up basis, which would affect revenues and earnings in the period of adjustment. For research and development services, the Company elected the practical expedient to recognize revenue as the research and development services are invoiced. As the Company has a right to consideration from the collaboration agreement with Biogen International GmbH (“Biogen”), in an amount that corresponds directly with the value of the Company’s performance completed to date for the research services, the Company recognized revenue related to the research services as invoiced, in line with the practical expedient in ASC 606-10-55-18. The transaction price is allocated to each performance obligation on a relative stand-alone selling price (“SSP”) basis. The Company recognizes revenue as or when the performance obligations under the contract are satisfied. As part of the accounting for these arrangements, the Company must develop assumptions that require judgment to determine the timing of recognition and the SSP for each performance obligation identified in the contract. The SSP for licenses are calculated using the residual approach if the Company has not yet established a price for such license and the license has not previously been sold on a standalone basis. Otherwise, selling prices for licenses are determined using an income approach model and include key assumptions such as: development timeline, revenue forecast, commercialization expenses, discount rate and probabilities of technical and regulatory success. To estimate the SSP for research and development services, the Company uses a cost-plus margin approach.
Cost of License and Collaboration Revenue	Cost of License and Collaboration Cost of license revenue includes sublicense fees paid or payable to Mosaic Biosciences, Inc. (“Mosaic”), incurred in the period, under the terms of the Mosaic collaboration agreement, and fees for patent development and protection paid or payable to other third-party vendors corresponding to the recognition of license revenue from the Company’s collaboration agreement with Biogen. See Note 12, Collaborations. Cost of license revenue does not include any allocated overhead costs. Cost of collaboration revenue includes fees for research and development services paid or payable to Mosaic and other third-party vendors and personnel cost, incurred in the period pertaining to the Company’s agreement with Biogen. See Note 12, Collaborations. Cost of collaboration revenue does not include any allocated overhead costs.
Research and Development Expenses	Research and Development Expenses Research and development costs are expensed as incurred. Nonrefundable advance payments for goods or services used in research and development are initially deferred and capitalized in prepaid and other current assets. The capitalized amounts are then expensed as the related goods are delivered or services are performed, or until it is no longer expected that the goods or services will be delivered. Research and development costs consist of payroll and other personnel-related expenses, laboratory supplies and reagents, contract research and development services, materials, and consulting costs, as well as allocations of facilities and other overhead costs. Under the Company’s collaboration agreement with Biogen, certain specific expenditures are reimbursed by third parties. During the years ended December 31, 2022 and 2021, $0.7 million and $6.5 million, respectively, of research and development expense was recorded as cost of collaboration revenue related to the collaboration agreement with Biogen signed in December 2019 and terminated as of May 2022.
Accrued Research and Development Expenses	Accrued Research and Development Expenses Accrued expenses include estimated costs of research and development activities conducted by external service providers, which include the conduct of preclinical studies and clinical trials and contract manufacturing activities. The Company records the estimated costs of research and development activities based upon the estimated amount of services provided but not yet invoiced and includes these costs in other accrued liabilities in the consolidated balance sheet and within research and development expense in the consolidated statement of operations. These costs are a significant component of the research and development expenses. The Company records accrued expenses for these costs based on the estimated amount of work completed and in accordance with agreements established with these external service providers.
Acquired In-Research and Development	Acquired In-Process Research and Development The Company measures and recognizes asset acquisitions that are not deemed to be business combinations based on the cost to acquire the assets, which includes transaction costs. Goodwill is not recognized in asset acquisitions. In an asset acquisition, the cost allocated to acquired in-process research and development (“IPR&D”) with no alternative future use is charged to expense at the acquisition date. Refer to Note 4, F351 Asset Acquisition, for a more detailed description of the accounting policy utilized for the recent asset acquisition.
Concentration Risk Credit Risk	Concentration of Credit Risk Financial instruments that potentially subject the Company to concentrations of credit risk consist principally of cash, cash equivalents, investments and accounts receivable. The Company’s investment policy restricts cash investments to high credit quality, investment grade investments. The Company believes that it has established guidelines for investment of its excess cash that maintain safety and liquidity through its policies on high quality of investment and investment duration. The Company is exposed to credit risk of $21.4 million in the event of default by the institutions holding the cash and cash equivalents to the extent beyond the amount insured by the federal depository insurance corporation.
Accounts Receivable, net and Allowance for Doubtful Accounts	Accounts Receivable and Allowance for Doubtful Accounts Amounts payable to the Company are recorded as accounts receivable when the Company’s right to consideration is unconditional. Customer payments are recorded as deferred revenue upon receipt or when due and may require deferral of revenue recognition to a future period until the Company performs its obligations under the arrangements. The Company continuously monitors collections and payments from its customers and maintains a provision for estimated credit losses. The Company determines its allowance for doubtful accounts by considering a number of factors, including the length of time balances are past due, the Company’s previous loss history, the customer’s current ability to pay its obligations to the Company and the condition of the general economy and the industry as a whole. The Company writes off accounts receivable when they are determined to be uncollectible. For the year ended December 31, 2022, the Company recognized $0.2 million of bad debt expense and no bad debt expense was recognized during the year ended December 31, 2021.
Income Taxes	Income Taxes Income taxes are computed using the liability method. Deferred tax assets and liabilities are determined based on the differences between the financial reporting and tax basis of assets and liabilities and are measured using the enacted tax rates and laws that will be in effect when the differences are expected to reverse. The Company follows the authoritative guidance on accounting for uncertainty in income taxes. This guidance prescribes a more-likely-than-not threshold for financial statement recognition and measurement of a tax position taken in the Company’s income tax returns. This interpretation also provides guidance on accounting for interest and penalties and associated with tax positions, accounting for income taxes in interim periods and income tax disclosures. The Company’s policy is to include penalties and interest expense related to income taxes as a component of other expense and interest expense, respectively, as necessary.
Stock-Based Compensation	Stock-Based Compensation The Company measures the cost of employee, non-employee and director services received in exchange for an award of equity instruments based on the fair value of the award on the date of grant and recognizes the related expense over the period during which the employee, non-employee or director is required to provide service in exchange for the award on a straight-line basis. The estimated fair value of equity awards that contain performance conditions is expensed over the term of the award once the Company has determined that it is probable that performance conditions will be satisfied. The Company uses the Black-Scholes option-pricing valuation model to estimate the grant-date fair value of stock-based awards. The determination of fair value for stock-based awards on the date of grant using an option-pricing model requires management to make certain assumptions regarding a number of variables. The Company elected to account for forfeitures when they occur. As such, the Company recognizes stock-based compensation expense, over their requisite service period, based on the vesting provisions of the individual grants.
Restructuring Charges	Restructuring Charges Costs and liabilities associated with restructuring are recorded in the period management commits to a restructuring or cost reduction plan, or executes specific actions contemplated by the plan and all criteria for liability recognition have been met. One-time employee termination costs are recognized at the time of communication to employees, unless future service is required, in which case the costs are recognized ratably over the future service period. Restructuring charges are recognized as an operating expense within the consolidated statements of operations and related liabilities are recorded within accrued compensation on the consolidated balance sheets. The Company periodically evaluates and, if necessary, adjusts its estimates based on currently available information.
Leases	Leases At the inception of an arrangement, the Company determines whether the arrangement is or contains a lease based on the unique facts and circumstances present. Operating lease liabilities and their corresponding right-of-use assets are recorded based on the present value of lease payments over the expected lease term. The interest rate implicit in lease contracts is typically not readily determinable. As such, the Company utilizes its incremental borrowing rate, which is the rate incurred to borrow on a collateralized basis over a similar term an amount equal to the lease payments in a similar economic environment. Certain adjustments to the right-of-use asset may be required for items such as initial direct costs paid or incentives received. The Company has elected to combine lease and non-lease components as a single component. The lease expense is recognized over the expected term on a straight-line basis. Operating leases are recognized on the consolidated balance sheet as right-of-use assets, operating lease liabilities, current and operating lease liabilities, non-current.
Redeemable Convertible Preferred Stock	Redeemable Convertible Preferred Stock The Company records shares of non-voting redeemable Catalyst Convertible Preferred Stock at its relative fair value on the date of issuance. The Company applied the guidance in ASC 480-10-S99-3A, SEC Staff Announcement: Classification and Measurement of Redeemable Securities, and at issuance classified the Catalyst Convertible Preferred Stock as temporary equity on the consolidated balance sheet because if conversion to common stock is not approved by the shareholders, the Catalyst Convertible Preferred Stock would be redeemable at the option of the holders for cash equal to the closing price of the common stock on last trading day prior to the holder’s redemption request. Refer to Note 14, Stockholders’ Equity for additional information.
Net Loss per Share	Net Loss per Share Attributable to Common Stockholders The Company calculates basic and diluted net loss per share attributable to common stockholders in conformity with the two-class method required for participating securities. The Company’s redeemable convertible preferred stock contractually entitled the holders of such shares to participate in dividends but does not contractually require the holders of such shares to participate in the Company’s losses. As such, net losses for the periods presented were not allocated to these securities. Basic net loss per share is calculated by dividing the net loss attributable to common stockholders by the weighted-average number of shares of common stock outstanding during the period, without consideration for potentially dilutive securities. Diluted net loss per share is the same as basic net loss per share for each period presented since the effects of potentially dilutive securities are antidilutive given the Company’s net loss.

Fair Value Measurements (Tables)

12 Months Ended

Dec. 31, 2022

Fair Value Disclosures [Abstract]

Financial Assets and Liabilities Measured at Fair Value on a Recurring Basis

The following tables present the fair value hierarchy for financial assets and liabilities measured at fair value on a recurring basis as of December 31, 2022 and 2021 (in thousands):

	December 31, 2022
	Level 1		Level 2		Level 3		Total
Financial assets:
Money market funds⁽¹⁾	$	21,666	$	—	$	—	$	21,666
Total financial assets	$	21,666	$	—	$	—	$	21,666

Financial liabilities:
CVR derivative liability	$	—	$	—	$	5,000	$	5,000
Total financial liabilities	$	—	$	—	$	5,000	$	5,000

	December 31, 2021
	Level 1		Level 2		Level 3		Total
Financial assets:
Money market funds⁽¹⁾	$	44,347	$	—	$	—	$	44,347
U.S. government agency securities⁽²⁾		2,504		—		—		2,504
Total financial assets	$	46,851	$	—	$	—	$	46,851

(1)	Included in cash and cash equivalents on accompanying consolidated balance sheet.

(2)	Included in short-term investments on accompanying consolidated balance sheet and are classified as available-for-sale debt securities.

Financial Instruments (Tables)

12 Months Ended

Dec. 31, 2022

Investments All Other Investments [Abstract]

Cash Equivalents and Investments (Debt Securities) Classified as Available-for-sale Securities

Cash equivalents and investments (debt securities) which are classified as available-for-sale securities, consisted of the following (in thousands):

December 31, 2022	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Estimated Fair Value
Money market funds (cash equivalents)	$	21,666	$	—	$	—	$	21,666
Total financial assets	$	21,666	$	—	$	—	$	21,666
Classified as:
Cash and cash equivalents							$	21,666
Total financial assets							$	21,666

December 31, 2021	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Estimated Fair Value
Money market funds (cash equivalents)	$	44,347	$	—	$	—	$	44,347
U.S. government agency securities		2,504		—		—		2,504
Total financial assets	$	46,851	$	—	$	—	$	46,851
Classified as:
Cash and cash equivalents							$	44,347
Short-term investments								2,504
Total financial assets							$	46,851

Other Accrued Liabilities (Tables)

12 Months Ended

Dec. 31, 2022

Payables And Accruals [Abstract]

Schedule of Other Accrued Liabilities

Other accrued liabilities consisted of the following (in thousands):

	Year Ended December 31,
	2022		2021
Professional and consulting services	$	1,417	$	509
Manufacturing		22		1,381
Biogen		—		868
Pre-clinical		—		773
Clinical		—		361
Other		13		180
Total other accrued liabilities	$	1,452	$	4,072

Leases (Tables)

12 Months Ended

Dec. 31, 2022

Lessee Disclosure [Abstract]

Summary of Present Value Assumptions used in Calculating Present Value of Lease Payments

The present value assumptions used in calculating the present value of the lease payments were as follows:

	December 31,
	2022			2021
Weighted-average remaining lease term	0.3 years			1.3 years
Weighted-average discount rate		4.3	%		4.8	%

Schedule of Maturity of Operating Lease Liabilities

The maturity of the Company’s operating lease liabilities as of December 31, 2022 were as follows (in thousands):

Year Ending December 31,	Amount
2023	$	38
Total undiscounted lease payments		38
Less: imputed interest		—
Total operating lease liability	$	38

Schedule of Supplemental Cash Flow Information

Supplemental cash flow information related to operating leases was as follows (in thousands):


	Year Ended December 31,
	2022		2021
Cash paid for amounts included in the measurement of lease liabilities	$	1,512	$	1,641
Prepaid cash payment for lease		—		208
Cash paid for operating leases that were included in operating cash outflows	$	1,512	$	1,849

Stock Based Compensation (Tables)

12 Months Ended

Dec. 31, 2022

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Summary of Option Activity Under Company's Equity Incentive Plans

The following table summarizes stock option activity under the Company’s 2018 Plan and related information:

	Number of Shares Underlying Outstanding Options			Weighted- Average Exercise Price		Weighted- Average Remaining Contractual Term (Years)		Aggregate Intrinsic Value (thousands)
Outstanding — December 31, 2021		2,603,630		$	7.70		7.46	$	—
Options granted ⁽¹⁾		10,270,911			1.34
Options forfeited and cancelled ⁽¹⁾		(4,148,455	)		4.96
Options expired		(47,319	)		13.27
Outstanding — December 31, 2022		8,678,767		$	1.42		7.47	$	1,051
Exercisable — December 31, 2022		4,317,076		$	2.38		5.94	$	—

(1)

Includes options that were cancelled and re-granted as part of the option modification from the special cash dividend, as further discussed above.

Summary of Weighted Average Valuation Assumptions Used to Estimate Fair Value of Employee Stock Options

The fair value of employee stock options was estimated using the following weighted-average assumptions:

	Year Ended December 31,
	2022			2021
Employee Stock Options:
Expected term (in years)		6.02			6.00
Risk-free interest rate		3.00	%		0.84	%
Dividend yield		—			—
Volatility		92.58	%		93.25	%

Summary of Stock-Based Compensation Recognized

Total stock-based compensation recognized was as follows (in thousands):

	Year Ended December 31,
	2022		2021
Research and development	$	330	$	1,202
General and administrative⁽¹⁾		1,012		2,203
Total stock-based compensation	$	1,342	$	3,405

(1)

Income Taxes (Tables)

12 Months Ended

Dec. 31, 2022

Income Tax Disclosure [Abstract]

Components of Provision for Income Taxes

The components of the provision for income taxes for the years ended December 31, 2022 and 2021 consist of the following:

	Year Ended December 31,
	2022		2021
Current tax provision:
Federal	$	341	$	—
State		7		—
Total tax provision	$	348	$	—

Reconciliation of Federal Statutory Income Tax Rate to Company's Effective Tax Rate

The reconciliation of the federal statutory income tax rate to the Company’s effective tax rate for the years ended December 31, 2022 and 2021 are as follows:

	Year Ended December 31,
	2022			2021
Tax at statutory federal rate		-21.00	%		-21.00	%
State Tax (benefit)—net of federal benefit		-0.01	%		0.00	%
Permanent differences		1.00	%		0.35	%
Tax credits		-42.08	%		-5.86	%
Derecognition due to Sec. 382 and 383 limitations		139.00	%		0.00	%
Change in valuation allowance		-69.24	%		26.26	%
Fixed assets other adjustment		-1.19	%		0.00	%
Other		-2.07	%		0.25	%
Effective tax rate		4.41	%		0.00	%

Significant Components of the Company's Deferred Tax Assets

Significant components of the Company’s deferred tax assets as of December 31, 2022 and 2021 consist of the following (in thousands):

	Year Ended December 31,
	2022			2021
Deferred tax assets:
Accruals and reserves	$	1,273		$	1,000
Net operating loss carry forwards		40,770			47,541
Tax credit carry forwards		4,463			12,939
Fixed and intangible assets		9,510			3
Valuation allowance		(56,016	)		(61,483	)
Net deferred tax assets:	$	—		$	—

Reconciliation of Beginning and Ending Balance of Unrecognized Tax Benefits

A reconciliation of the beginning and ending balance of the unrecognized tax benefits is as follows (in thousands):

Beginning Balance at January 1, 2021	$	2,955
Increase/(Decrease) of unrecognized tax benefits taken in prior years		—
Increase/(Decrease) of unrecognized tax benefits related to current year		1,749
Ending Balance at December 31, 2021	$	4,704
Increase/(Decrease) of unrecognized tax benefits taken in prior years		(2,841	)
Increase/(Decrease) of unrecognized tax benefits related to current year		20
Ending Balance at December 31, 2022	$	1,883

Interest and Other Income (Expense), Net (Tables)

12 Months Ended

Dec. 31, 2022

Other Income And Expenses [Abstract]

Detail of Interest and Other Income (Expense), Net

The following table shows the detail of interest and other income (expense), net as follows (in thousands):

	Year Ended December 31,
	2022		2021
Interest income	$	537	$	39
Gain from extinguishment of liability		180		—
Other		—		(78	)
Total interest and other income (expense), net	$	717	$	(39	)

Net Loss per Share Attributable to Common Stockholders (Tables)

12 Months Ended

Dec. 31, 2022

Earnings Per Share [Abstract]

Anti-dilutive Security not Included in Diluted per Share Calculations

	Year Ended December 31,
	2022		2021
Options to purchase common stock		8,678,767		2,603,630
Redeemable convertible preferred stock ⁽¹⁾		123,400,000		—
Common stock warrants		—		85
Total		132,078,767		2,603,715

(1) Shown as common stock equivalents

Restructuring (Tables)

12 Months Ended

Dec. 31, 2022

Restructuring And Related Activities [Abstract]

Summary of Restructuring Charges Recorded in Component of Operating Expenses

The following table summarizes restructuring charges recorded in each component of operating expenses in the Company’s consolidated statements of operations (in thousands):

	Year Ended December 31,
	2022		2021
Research and development	$	609	$	4,025
General and administrative		402		143
Total restructuring charges	$	1,011	$	4,168

Nature of Operations - Additional Information (Detail) $ in Millions		12 Months Ended
	Dec. 26, 2022 USD ($) shares	Dec. 31, 2022 Segment shares
Organization and Nature of Operations [Line Items]
Number of operating segment \| Segment		1
F351 Agreement
Organization and Nature of Operations [Line Items]
Assets acquisition, paid \| $	$ 35.0
Convertible Preferred Stock \| F351 Agreement
Organization and Nature of Operations [Line Items]
Preferred stock shares issued	12,340
Preferred stock, shares issued upon conversion of common stock	10,000
Common Stock
Organization and Nature of Operations [Line Items]
Assets acquisition, shares issued		6,266,521
Common Stock \| F351 Agreement
Organization and Nature of Operations [Line Items]
Assets acquisition, shares issued	6,266,521

Liquidity - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands				12 Months Ended
	Dec. 27, 2022	Dec. 26, 2022	Sep. 20, 2022	Dec. 31, 2022	Dec. 31, 2021	Oct. 15, 2021
Liquidity [Line Items]
Common stock, par value				$ 0.001	$ 0.001
Accumulated deficit				$ 410,936	$ 402,694
Cash, cash equivalents and short-term investments				21,700
Net loss				$ 8,242	$ 87,933
Cash dividends paid per common share			$ 1.43	$ 1.43
Aggregate amount of special dividend payment	$ 7,600		$ 45,000
Common stock, dividend payable, date of record	Jan. 05, 2022		Sep. 06, 2022
Convertible Preferred Stock \| F351 Agreement
Liquidity [Line Items]
Preferred stock shares issued		12,340
Common Stock
Liquidity [Line Items]
Cash dividends payable per common share				$ 0.24
Common Stock \| F351 Agreement
Liquidity [Line Items]
Conversion of stock shares, issued		123,400,000
2021 ATM Program
Liquidity [Line Items]
Common stock, par value						$ 0.001
Percentage of commission for shares sold						3.00%

Summary of Significant Accounting Policies - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Summary Of Significant Accounting Policies [Line Items]
Accounts receivable, allowance for doubtful accounts	$ 200,000	$ 0
Concentration of credit risk	21,400,000
Research and Development Expense
Summary Of Significant Accounting Policies [Line Items]
Cost of collaboration revenue	$ 700,000	$ 6,500,000
Software
Summary Of Significant Accounting Policies [Line Items]
Estimated useful lives	3 years
Computer equipment
Summary Of Significant Accounting Policies [Line Items]
Estimated useful lives	3 years
Furniture \| Minimum
Summary Of Significant Accounting Policies [Line Items]
Estimated useful lives	3 years
Furniture \| Maximum
Summary Of Significant Accounting Policies [Line Items]
Estimated useful lives	7 years
Leasehold improvements \| Minimum
Summary Of Significant Accounting Policies [Line Items]
Estimated useful lives	3 years
Leasehold improvements \| Maximum
Summary Of Significant Accounting Policies [Line Items]
Estimated useful lives	7 years
ASU 2021-04
Summary Of Significant Accounting Policies [Line Items]
Change in accounting principle, accounting standards update, adoption date	Jan. 01, 2022
Change in accounting principle, accounting standards update, adopted	true
Change in accounting principle, accounting standards update, immaterial effect	true
ASU 2020-06
Summary Of Significant Accounting Policies [Line Items]
Change in accounting principle, accounting standards update, adoption date	Jan. 01, 2022
Change in accounting principle, accounting standards update, adopted	true
Change in accounting principle, accounting standards update, immaterial effect	true

F351 Asset Acquisition - Additional Information (Detail) - USD ($)		12 Months Ended
	Dec. 26, 2022	Dec. 31, 2022
F351 Agreement
Asset Acquisition [Line Items]
Assets acquisition, cost	$ 35,400,000
Asset acquisition, direct cost	400,000
Asset acquisition, assumed other assets	0
Asset acquisition, assumed liabilities	$ 0
Common Stock
Asset Acquisition [Line Items]
Assets acquisition, shares issued		6,266,521
Common Stock \| F351 Agreement
Asset Acquisition [Line Items]
Assets acquisition, shares issued	6,266,521
Convertible Preferred Stock \| F351 Agreement
Asset Acquisition [Line Items]
Preferred stock shares issued	12,340
Preferred stock, shares issued upon conversion of common stock	10,000

Fair Value Measurements - Financial Assets and Liabilities Measured at Fair Value (Detail) - USD ($)
$ in Thousands

Dec. 31, 2022

Dec. 31, 2021

Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]

Assets, fair value

$ 21,666

$ 46,851

Liabilities, fair value

5,000

U.S. Government Agency Securities

Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]

Assets, fair value

^[1]

2,504

Fair Value, Inputs, Level 1

Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]

Assets, fair value

21,666

46,851

Fair Value, Inputs, Level 1 | U.S. Government Agency Securities

Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]

Assets, fair value

^[1]

2,504

Fair Value, Inputs, Level 3

Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]

Liabilities, fair value

5,000

Money Market Funds

Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]

Assets, fair value

^[2]

21,666

44,347

Money Market Funds | Fair Value, Inputs, Level 1

Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]

Assets, fair value

^[2]

21,666

$ 44,347

CVR Derivative Liability

Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]

Liabilities, fair value

5,000

CVR Derivative Liability | Fair Value, Inputs, Level 3

Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]

Liabilities, fair value

$ 5,000

[1]	Included in short-term investments on accompanying consolidated balance sheet and are classified as available-for-sale debt securities.
[2]	Included in cash and cash equivalents on accompanying consolidated balance sheet.

Fair Value Measurements - Additional Information (Detail) - Contingent Value Rights Agreement - USD ($)	12 Months Ended
	Dec. 31, 2022	Jun. 30, 2023	Dec. 26, 2022
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Initial derivative liability			$ 5,000,000.0
Change in the estimated fair value	$ 0
Forecast \| Vertex Asset Purchase Agreement
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Amount to be received under agreement		$ 5,000,000.0

Financial Instruments - Cash Equivalents and Investments (Debt Securities) Classified as Available-for-sale Securities (Detail) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	$ 21,666	$ 46,851
Estimated Fair Value	21,666	46,851
Money Market Funds
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	21,666	44,347
Estimated Fair Value	21,666	44,347
Cash and Cash Equivalents
Schedule Of Available For Sale Securities [Line Items]
Estimated Fair Value	$ 21,666	44,347
U.S. Government Agency Securities
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost		2,504
Estimated Fair Value		2,504
Short-Term Investments
Schedule Of Available For Sale Securities [Line Items]
Estimated Fair Value		$ 2,504

Financial Instruments - Additional Information (Detail)	12 Months Ended
Financial Instruments - Additional Information (Detail)	Dec. 31, 2022 USD ($)
Fair Value Disclosures [Abstract]
Material realized gains or losses on available-for-sale securities	$ 0
Available-for-sale debt securities current	$ 0

Other Accrued Liabilities - Schedule of Other Accrued Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Payables And Accruals [Abstract]
Professional and consulting services	$ 1,417	$ 509
Manufacturing	22	1,381
Biogen		868
Pre-clinical		773
Clinical		361
Other	13	180
Total other accrued liabilities	$ 1,452	$ 4,072

Commitments and Contingencies - Additional Information (Detail) - USD ($)		1 Months Ended	12 Months Ended
	Jun. 15, 2022	Aug. 31, 2022	Dec. 31, 2022	Sep. 16, 2021	Jul. 31, 2021
Commitments And Contingencies Disclosure [Line Items]
Percentage of common stock filed a lawsuit	5.00%
Legal and Other Expenses
Commitments And Contingencies Disclosure [Line Items]
Litigation amount		$ 400,000
Contingent Value Rights Agreement
Commitments And Contingencies Disclosure [Line Items]
Percentage of excess cash on dispositions net			100.00%
Excess amount retained from net proceeds related to disposition of assets			$ 1,000,000.0
Percentage of excess preapproved costs			100.00%
Vertex Asset Purchase Agreement \| Contingent Value Rights Agreement
Commitments And Contingencies Disclosure [Line Items]
Percentage of amount received on agreement			100.00%
F351 \| G N I \| Business Combination Agreement
Commitments And Contingencies Disclosure [Line Items]
Termination fee required to pay upon termination of agreement			$ 2,000,000.0
F351 \| G N I \| Maximum \| Business Combination Agreement
Commitments And Contingencies Disclosure [Line Items]
Common stock, shares issued			1,110,776,224
Reimbursement for out-of-pocket fees and expenses			$ 2,000,000.0
Dalcinonacog Alfa \| Service Agreements
Commitments And Contingencies Disclosure [Line Items]
Remaining obligations			0
Clinical trial services cost incurred on agreement termination			800,000
Dalcinonacog Alfa \| Maximum \| Service Agreements
Commitments And Contingencies Disclosure [Line Items]
Cost of services as per agreement					$ 6,500,000
Catalent Indiana, LLC. \| Dalcinonacog alfa.
Commitments And Contingencies Disclosure [Line Items]
Remaining obligations			$ 0
Firm work order supporting clinical trials				$ 300,000

Leases - Additional Information (Detail) - USD ($) $ in Thousands	1 Months Ended			12 Months Ended
	Mar. 31, 2022	Oct. 31, 2021	Apr. 30, 2021	Dec. 31, 2022	Dec. 31, 2021
Lessee Lease Description [Line Items]
Lease expiration date				Apr. 30, 2023
Lessee operating lease renewal term description				no stated renewal options
Right-of-use asset and lease liability		$ 600
Undiscounted future payment				$ 38
Right-of-use assets				66	$ 2,744
Operating lease, liability				38
Operating lease expense				1,700	$ 1,700
Sublease Arrangement
Lessee Lease Description [Line Items]
Lease commencement month and year	2022-04
Lease payments receivable	$ 200
Lease expiration month and year	2023-04
Sublease Income				$ 100
Lease Lab And Office Space \| Sublease Arrangement
Lessee Lease Description [Line Items]
Undiscounted future payment			$ 1,900
Operating lease commenced description			commenced during the second quarter of 2021
License agreement termination month and year				2022-08
Termination fees paid				$ 200
Right-of-use assets				1,100
Operating lease, liability				1,000
Lease Lab And Office Space \| Sublease Arrangement \| General and Administrative
Lessee Lease Description [Line Items]
Loss on lease termination				$ 200

Leases - Summary of Present Value Assumptions used in Calculating Present Value of Lease Payments (Detail)	Dec. 31, 2022	Dec. 31, 2021
Lessee Disclosure [Abstract]
Weighted-average remaining lease term	3 months 18 days	1 year 3 months 18 days
Weighted-average discount rate	4.30%	4.80%

Leases - Schedule of Maturity of Operating Lease Liabilities - (Detail) $ in Thousands	Dec. 31, 2022 USD ($)
Operating Lease Liabilities Payments Due [Abstract]
2023	$ 38
Total undiscounted lease payments	38
Operating lease, liability	$ 38

Leases - Schedule of Supplemental Cash Flow Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Operating Lease Liabilities Payments Due [Abstract]
Cash paid for amounts included in the measurement of lease liabilities	$ 1,512	$ 1,641
Prepaid cash payment for lease		208
Cash paid for operating leases that were included in operating cash outflows	$ 1,512	$ 1,849

Stock Based Compensation - Additional Information (Detail) - USD ($)					12 Months Ended
	Dec. 27, 2022	Sep. 20, 2022	Jun. 09, 2021	Jun. 13, 2018	Dec. 31, 2022	Dec. 31, 2021
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of common stock available for future grant					12,990,839
Options vested					0
Aggregate amount of special dividend payment	$ 7,600,000	$ 45,000,000.0
Common stock, cash dividend paid		$ 1.43			$ 1.43
Weighted average grant date fair value of stock options					$ 0.96	$ 4.00
Option exercised					0
Aggregate intrinsic value of options exercised						$ 3,000
Fair value of options vested					$ 1,900,000	2,600,000
Total stock-based compensation					1,342,000	3,405,000
Employee Stock Option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized employee stock based compensation expense					$ 1,100,000
Unrecognized employee stock based compensation expense, period for recognition					1 year 11 months 4 days
2018 Omnibus Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Increase in number of shares of common stock reserved for issuance			2,500,000		14,860,784
Common stock, capital shares reserved for future issuance			5,300,000		20,160,784
2018 Omnibus Incentive Plan \| Performance-Based Stock Option Grants
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Issuance of option grants to purchase common stock shares					400,000
2018 Omnibus Incentive Plan \| ASU 2021-04 \| Performance-Based Stock Option Grants
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Issuance of option grants to purchase common stock shares					1,521,568
2018 Employee Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of common stock available for future grant					187,807
Maximum employee subscription rate				15.00%
Number of common stock authorized for issuance					359,545
Number of common stock stock issued					47,662
Proceeds from Issuance					$ 20,000
Total stock-based compensation						$ 100,000
2018 Employee Stock Purchase Plan \| Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of fair market value of common stock				85.00%

Stock Based Compensation - Summary of Option Activity Under Company's 2018 Plan (Detail) - USD ($)
$ / shares in Units, $ in Thousands

12 Months Ended

Dec. 31, 2022

Dec. 31, 2021

Number of Shares Underlying Outstanding Options

Number of Shares Underlying Outstanding Options, Beginning Balance

2,603,630

Number of Shares Underlying Outstanding Options, Options granted

^[1]

10,270,911

Number of Shares Underlying Outstanding Options, Options forfeited and cancelled

^[1]

(4,148,455)

Number of Shares Underlying Outstanding Options, Options expired

(47,319)

Number of Shares Underlying Outstanding Options, Ending Balance

8,678,767

2,603,630

Number of Shares Underlying Outstanding Options, Exercisable- December 31, 2022

4,317,076

Weighted- Average Exercise Price

Weighted- Average Exercise Price, Beginning Balance

$ 7.70

Weighted- Average Exercise Price, Options granted

^[1]

1.34

Weighted- Average Exercise Price, Options forfeited and cancelled

^[1]

4.96

Weighted- Average Exercise Price, Options expired

13.27

Weighted- Average Exercise Price, Ending Balance

1.42

$ 7.70

Weighted- Average Exercise Price, Exercisable - December 31, 2022

$ 2.38

Weighted-Average Remaining Contractual Term (Years)

Weighted-Average Remaining Contractual Term (Years), Outstanding Balance

7 years 5 months 19 days

7 years 5 months 15 days

Weighted Average Remaining Contractual Term, Exercisable - December 31, 2022

5 years 11 months 8 days

Aggregate Intrinsic Value

Aggregate Intrinsic Value, Outstanding

$ 1,051

[1]	Includes options that were cancelled and re-granted as part of the option modification from the special cash dividend, as further discussed above.

Stock Based Compensation - Fair Values of Stock Options Estimated Using Black-Scholes Valuation Model (Detail) - Employee Stock Option	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions Black Scholes Method Used [Line Items]
Expected term (in years)	6 years 7 days	6 years
Risk-free interest rate	3.00%	0.84%
Dividend yield	0.00%	0.00%
Volatility	92.58%	93.25%

Stock Based Compensation - Summary of Stock-Based Compensation Recognized (Detail) - USD ($)
$ in Thousands

12 Months Ended

Dec. 31, 2022

Dec. 31, 2021

Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]

Total stock-based compensation

$ 1,342

$ 3,405

Research and development

Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]

Total stock-based compensation

330

1,202

General and Administrative

Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]

Total stock-based compensation

^[1]

$ 1,012

$ 2,203

[1]	Included in general and administrative stock-based compensation for the years ended December 31, 2022 and 2021 is $30,000 and $0.3 million in expense related to 32,684 shares and 56,912 shares of common stock, respectively, issued to certain board members in lieu of their cash compensation.

Stock Based Compensation - Summary of Stock-Based Compensation Recognized (Parenthetical) (Detail) - USD ($)

12 Months Ended

Dec. 31, 2022

Dec. 31, 2021

Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]

Number of shares of common stock issued to certain board members in lieu of cash compensation

32,684

56,912

Total stock-based compensation

$ 1,342,000

$ 3,405,000

General and Administrative

Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]

Total stock-based compensation

^[1]

1,012,000

2,203,000

General and Administrative | Common Stock

Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]

Total stock-based compensation

$ 30,000

$ 300,000

[1]	Included in general and administrative stock-based compensation for the years ended December 31, 2022 and 2021 is $30,000 and $0.3 million in expense related to 32,684 shares and 56,912 shares of common stock, respectively, issued to certain board members in lieu of their cash compensation.

Income Taxes - Components of Provision for Income Taxes (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2022 USD ($)
Current tax provision:
Federal	$ 341
State	7
Total tax provision	$ 348

Income Taxes - Reconciliation of Federal Statutory Income Tax Rate to Company's Effective Tax Rate (Detail)	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Income Tax Disclosure [Abstract]
Tax at statutory federal rate	(21.00%)	(21.00%)
State Tax (benefit)—net of federal benefit	(0.01%)	(0.00%)
Permanent differences	1.00%	0.35%
Tax credits	(42.08%)	(5.86%)
Derecognition due to Sec. 382 and 383 limitations	139.00%	(0.00%)
Change in valuation allowance	(69.24%)	26.26%
Fixed assets other adjustment	(1.19%)	(0.00%)
Other	(2.07%)	0.25%
Effective tax rate	4.41%	0.00%

Income Taxes - Significant Components of the Company's Deferred Tax Assets (Detail) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Deferred tax assets:
Accruals and reserves	$ 1,273	$ 1,000
Net operating loss carry forwards	40,770	47,541
Tax credit carry forwards	4,463	12,939
Fixed and intangible assets	9,510	3
Valuation allowance	$ (56,016)	$ (61,483)

Income Taxes - Additional Information (Detail) - USD ($)		12 Months Ended
	Jun. 29, 2020	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2007
Income Tax [Line Items]
Increase (decrease) in valuation allowance		$ (5,500,000)	$ 23,100,000
Gross federal R&D credit-related deferred tax assets derecognized		26,100,000
Unrecognized tax benefit		1,883,000	4,704,000	$ 2,955,000
Tax-related penalties or interest recognized		0	0
Uncertain tax positions		0	$ 0
Federal Income Tax
Income Tax [Line Items]
Net operating loss carryforwards		$ 194,100,000			$ 156,500,000
Net operating loss carryforwards expiration year		2037
Net operating loss carryforwards having indefinite life		$ 192,400,000
Tax credit carryforwards available to offset future federal tax liabilities		$ 8,500
Credit carryforward, expire year		2042
Net operating loss carryforward, derecognized		$ 32,900,000
State Income Tax
Income Tax [Line Items]
Net operating loss carryforwards		$ 3,600,000
Net operating loss carryforwards expiration year		2032
Tax credit carryforwards available to offset future federal tax liabilities		$ 7,500,000
CALIFORNIA
Income Tax [Line Items]
Net operating loss carryforwards		75,200,000
Net operating loss carryforward, derecognized		$ 0
Maximum amount of tax offset per year	$ 5,000,000
Required Minimum Taxable Income	$ 1,000,000

Income Taxes - Reconciliation of Beginning and Ending Balance of Unrecognized Tax Benefits (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Income Tax Disclosure [Abstract]
Beginning Balance	$ 4,704	$ 2,955
Increase/(Decrease) of unrecognized tax benefits taken in prior years	(2,841)
Increase/(Decrease) of unrecognized tax benefits related to current year	20	1,749
Ending Balance	$ 1,883	$ 4,704

Collaborations - Additional Information (Detail) - USD ($)		1 Months Ended			12 Months Ended
	May 08, 2020	Jun. 30, 2022	Jan. 31, 2020	Dec. 31, 2018	Dec. 31, 2022	Dec. 31, 2021
Revenue Recognition Multiple Deliverable Arrangements [Line Items]
Deferred revenue, recognized					$ 200,000
Collaboration
Revenue Recognition Multiple Deliverable Arrangements [Line Items]
License and collaboration revenue					794,000	$ 7,338,000
Mosaic Biosciences Inc \| Maximum
Revenue Recognition Multiple Deliverable Arrangements [Line Items]
Milestone payment related to regulatory and clinical development events	$ 4,000,000.0
ISU Abxis \| Amended and Restated License Agreement
Revenue Recognition Multiple Deliverable Arrangements [Line Items]
Regulatory and development milestone payment				$ 2,500,000	0
ISU Abxis \| Maximum \| Amended and Restated License Agreement
Revenue Recognition Multiple Deliverable Arrangements [Line Items]
Milestone payment				19,500,000	0
Commercial milestone payments				$ 17,000,000.0	0
Biogen
Revenue Recognition Multiple Deliverable Arrangements [Line Items]
License and collaboration revenue					0	0
Biogen \| Collaboration \| Reimbursable Out-of-Pocket and Personnel Costs Incurred Related to Research Services
Revenue Recognition Multiple Deliverable Arrangements [Line Items]
License and collaboration revenue					800,000	$ 7,300,000
Biogen \| Exclusive License
Revenue Recognition Multiple Deliverable Arrangements [Line Items]
Up-front payments received			$ 15,000,000.0
Biogen \| Termination Agreement
Revenue Recognition Multiple Deliverable Arrangements [Line Items]
Forgiveness of accounts receivable, net		$ 600,000
Payments to cash		$ 10,000
Biogen \| Termination Agreement \| General and Administrative
Revenue Recognition Multiple Deliverable Arrangements [Line Items]
Settlement expense					$ 600,000
Biogen \| Maximum \| Exclusive License
Revenue Recognition Multiple Deliverable Arrangements [Line Items]
Development and sales milestone payments			$ 340,000,000.0

Interest and Other Income (Expense), Net - Detail of Interest and Other Income (Expense), Net (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Other Income And Expenses [Abstract]
Interest income	$ 537	$ 39
Gain from extinguishment of liability	180
Other		(78)
Total interest and other income (expense), net	$ 717	$ (39)

Stockholders' Equity - Additional Information (Detail) - USD ($)		12 Months Ended
	Oct. 15, 2021	Dec. 31, 2022	Mar. 24, 2023	Dec. 31, 2021
Stockholders Equity Disclosure [Line Items]
Common stock, shares authorized		100,000,000		100,000,000
Common stock, par value		$ 0.001		$ 0.001
Common Stock, voting rights		one vote
Common stock issued		37,756,574		31,409,707
Common stock outstanding		37,756,574		31,409,707
Preferred stock shares authorized		5,000,000
Preferred stock par value per share		$ 0.001
Redeemable Convertible Preferred Stock
Stockholders Equity Disclosure [Line Items]
Preferred stock shares authorized		123,418
Preferred stock shares issued		12,340
Preferred stock, shares outstanding		12,340
Preferred stock, shares issued upon conversion of common stock		10,000
Temporary equity,par value		$ 0.001		$ 0.001
Affiliates beneficial own shares specified percentage		9.99%
Redeemable Convertible Preferred Stock \| Subsequent Event
Stockholders Equity Disclosure [Line Items]
Conversion of outstanding preferred stock redeemed for cash			$ 25,700,000
Temporary equity,par value			$ 0.21
Redeemable Convertible Preferred Stock \| Maximum
Stockholders Equity Disclosure [Line Items]
Preferred stock shares issued		12,340
Affiliates beneficial own shares percentage		19.99%
Redeemable Convertible Preferred Stock \| Maximum \| F351 Agreement
Stockholders Equity Disclosure [Line Items]
Preferred stock shares issued		111,078
Redeemable Convertible Preferred Stock \| Minimum
Stockholders Equity Disclosure [Line Items]
Affiliates beneficial own shares percentage		4.99%
2021 ATM Program
Stockholders Equity Disclosure [Line Items]
Common stock, par value	$ 0.001
Proceeds from Issuance	$ 50,000,000.0
Percentage of commission for shares sold	3.00%
Legal expenses incurred	$ 50,000
Warrants
Stockholders Equity Disclosure [Line Items]
Common stock issued		0		85
Common stock outstanding		0		85
Warrants exercise price per share		$ 392.70		$ 392.70
Warrant expiration month and year		2022-08

Net Loss per Share Attributable to Common Stockholders - Anti-dilutive Security not Included In Diluted per Share Calculations (Detail) - shares

12 Months Ended

Dec. 31, 2022

Dec. 31, 2021

Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]

Anti dilutive securities

132,078,767

2,603,715

Options To Purchase Common Stock

Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]

Anti dilutive securities

8,678,767

2,603,630

Common Stock Warrants

Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]

Anti dilutive securities

Redeemable Convertible Preferred Stock

Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]

Anti dilutive securities

^[1]

123,400,000

[1]	(1) Shown as common stock equivalents

Restructuring - Additional Information (Detail) $ in Thousands		1 Months Ended		3 Months Ended	12 Months Ended
	Nov. 30, 2021	May 31, 2022 USD ($)	Mar. 31, 2022 Employee	Mar. 31, 2022 USD ($)	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)
Restructuring Cost And Reserve [Line Items]
Percent of employees terminated	35.00%
Severance costs and expenses						$ 400
Charges related to write off of prepaid manufacturing cost						3,800
Restructuring liability						$ 200
Number of employees terminated \| Employee			22
Remaining number of full time employees \| Employee			5
Gain (loss) on disposal					$ 57,186
Proceeds from the sale of complement portfolio to Vertex					55,000
Dren Bio, Inc. and Copia Scientific, LLC
Restructuring Cost And Reserve [Line Items]
Total consideration for sales agreements					500
Gain (loss) on disposal					(200)
Vertex Pharmaceuticals Incorporated
Restructuring Cost And Reserve [Line Items]
Gain (loss) on disposal		$ 57,400
Proceeds from the sale of complement portfolio to Vertex		60,000
Upfront payment received		55,000
Post closing indemnification obligation		$ 5,000
Transaction costs					$ 2,600
Operating Expense
Restructuring Cost And Reserve [Line Items]
Severance and other charges				$ 1,000

Restructuring - Summary of Restructuring Charges Recorded in Component of Operating Expenses (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Restructuring Cost And Reserve [Line Items]
Total restructuring charges	$ 1,011	$ 4,168
Research and Development Expense
Restructuring Cost And Reserve [Line Items]
Total restructuring charges	609	4,025
General and Administrative
Restructuring Cost And Reserve [Line Items]
Total restructuring charges	$ 402	$ 143

Subsequent Events - Additional Information (Detail) $ / shares in Units, $ in Thousands						1 Months Ended	12 Months Ended
	Mar. 10, 2023 USD ($) Account	Feb. 27, 2023 USD ($)	Jan. 12, 2023 USD ($) $ / shares	Dec. 27, 2022 USD ($)	Sep. 20, 2022 USD ($) $ / shares	Mar. 31, 2023 USD ($)	Dec. 31, 2022 USD ($) $ / shares
Subsequent Event [Line Items]
Dividend declared \| $ / shares					$ 1.43		$ 1.43
Aggregate amount of special dividend payment				$ 7,600	$ 45,000
Common stock, dividend payable, date of record				Jan. 05, 2022	Sep. 06, 2022
Proceeds from the sale of complement portfolio to Vertex							$ 55,000
Subsequent Event
Subsequent Event [Line Items]
Dividends Payable, date declared			Jan. 12, 2023
Dividend declared \| $ / shares			$ 0.24
Aggregate amount of special dividend payment			$ 7,600
Common stock, dividend payable, date of record			Jan. 05, 2023
Number of bank accounts \| Account	2
Cash deposit	$ 9,000
Subsequent Event \| GC Biopharma Corp
Subsequent Event [Line Items]
Proceeds from the sale of complement portfolio to Vertex		$ 6,000
Upfront payment received		1,000				$ 200
Post closing indemnification obligation		$ 5,000