Gyre Therapeutics (GYRE) 10-Q 12 Nov 21 2021 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2021	Nov. 08, 2021
Cover [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2021
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q3
Trading Symbol	CBIO
Entity Registrant Name	Catalyst Biosciences, Inc.
Entity Central Index Key	0001124105
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	false
Entity Common Stock, Shares Outstanding		31,409,707
Entity Current Reporting Status	Yes
Entity Shell Company	false
Entity File Number	000-51173
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
Entity Interactive Data Current	Yes
Security Exchange Name	NASDAQ
Entity Incorporation, State or Country Code	DE
Document Quarterly Report	true
Document Transition Report	false
Title of 12(b) Security	Common Stock

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 59,157	$ 30,360
Short-term investments	5,371	48,994
Accounts receivable	1,114	3,313
Prepaid and other current assets	8,322	6,843
Total current assets	73,964	89,510
Long-term investments		2,543
Other assets, noncurrent	869	528
Right-of-use assets	2,613	1,832
Property and equipment, net	1,091	433
Total assets	78,537	94,846
Current liabilities:
Accounts payable	3,862	5,931
Accrued compensation	2,548	2,476
Deferred revenue	853	1,983
Other accrued liabilities	8,144	6,743
Operating lease liability	1,844	663
Total current liabilities	17,251	17,796
Operating lease liability, noncurrent	550	981
Total liabilities	17,801	18,777
Commitments and contingencies (Note 10)
Stockholders’ equity:
Preferred stock, $0.001 par value, 5,000,000 shares authorized; zero shares issued and outstanding
Common stock, $0.001 par value, 100,000,000 shares authorized; 31,392,618 and 22,097,820 shares issued and outstanding at September 30, 2021 and December 31, 2020, respectively	31	22
Additional paid-in capital	443,069	390,803
Accumulated other comprehensive income	1	5
Accumulated deficit	(382,365)	(314,761)
Total stockholders’ equity	60,736	76,069
Total liabilities and stockholders’ equity	$ 78,537	$ 94,846

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Parenthetical) - $ / shares	Sep. 30, 2021	Dec. 31, 2020
Statement Of Financial Position [Abstract]
Preferred stock, par value	$ 0.001	$ 0.001
Preferred stock, shares authorized	5,000,000	5,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value	$ 0.001	$ 0.001
Common stock, shares authorized	100,000,000	100,000,000
Common stock, shares issued	31,392,618	31,392,618
Common stock, shares outstanding	22,097,820	22,097,820

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Revenue:
License and collaboration revenue	$ 2,299	$ 893	$ 4,898	$ 18,917
Operating expenses:
Research and development	20,352	12,249	52,754	38,419
General and administrative	4,869	3,833	14,799	11,895
Total operating expenses	27,528	16,993	72,479	57,446
Loss from operations	(25,229)	(16,100)	(67,581)	(38,529)
Interest and other income (expense), net	(9)	67	(23)	1,195
Net loss	$ (25,238)	$ (16,033)	$ (67,604)	$ (37,334)
Net loss per share attributable to common stockholders, basic and diluted	$ (0.80)	$ (0.73)	$ (2.23)	$ (2.05)
Shares used to compute net loss per share attributable to common stockholders, basic and diluted	31,379,755	22,072,243	30,382,231	18,199,575
License
Revenue:
License and collaboration revenue		$ 32		$ 15,100
Collaboration
Revenue:
License and collaboration revenue	$ 2,299	861	$ 4,898	3,817
Cost of license
Operating expenses:
Cost of license and collaboration		32		3,102
Cost of collaboration
Operating expenses:
Cost of license and collaboration	$ 2,307	$ 879	$ 4,926	$ 4,030

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Comprehensive Loss (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Statement Of Income And Comprehensive Income [Abstract]
Net loss	$ (25,238)	$ (16,033)	$ (67,604)	$ (37,334)
Other comprehensive loss:
Unrealized loss on available-for-sale debt securities	(1)	(33)	(4)	(26)
Total comprehensive loss	$ (25,239)	$ (16,066)	$ (67,608)	$ (37,360)

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Stockholders' Equity (Unaudited) - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-In Capital	Accumulated Other Comprehensive Income (Loss)	Accumulated Deficit
Balance at Dec. 31, 2019	$ 68,336	$ 12	$ 326,810	$ 34	$ (258,520)
Balance (in shares) at Dec. 31, 2019		12,040,835
Stock-based compensation expense	805		805
Stock-based compensation expense, shares		7,817
Issuance of common stock from stock grants and option exercises	339		339
Issuance of common stock from stock grants and option exercises, shares		62,969
Issuance of common stock for public offering, net of issuance costs	31,986	$ 5	31,981
Issuance of common stock for public offering, net of issuance costs, shares		5,307,692
Unrealized loss on available-for-sale debt securities	106			106
Net loss	(4,053)				(4,053)
Balance at Mar. 31, 2020	97,519	$ 17	359,935	140	(262,573)
Balance (in shares) at Mar. 31, 2020		17,419,313
Balance at Dec. 31, 2019	68,336	$ 12	326,810	34	(258,520)
Balance (in shares) at Dec. 31, 2019		12,040,835
Unrealized loss on available-for-sale debt securities	(26)
Net loss	(37,334)
Balance at Sep. 30, 2020	94,059	$ 22	389,883	8	(295,854)
Balance (in shares) at Sep. 30, 2020		22,082,924
Balance at Mar. 31, 2020	97,519	$ 17	359,935	140	(262,573)
Balance (in shares) at Mar. 31, 2020		17,419,313
Stock-based compensation expense	834		834
Stock-based compensation expense, shares		16,048
Issuance of common stock for public offering, net of issuance costs	27,955	$ 5	27,950
Issuance of common stock for public offering, net of issuance costs, shares		4,615,384
Unrealized loss on available-for-sale debt securities	(99)			(99)
Net loss	(17,248)				(17,248)
Balance at Jun. 30, 2020	108,961	$ 22	388,719	41	(279,821)
Balance (in shares) at Jun. 30, 2020		22,050,745
Stock-based compensation expense	1,068		1,068
Stock-based compensation expense, shares		12,295
Issuance of common stock from stock grants and option exercises	96		96
Issuance of common stock from stock grants and option exercises, shares		19,884
Unrealized loss on available-for-sale debt securities	(33)			(33)
Net loss	(16,033)				(16,033)
Balance at Sep. 30, 2020	94,059	$ 22	389,883	8	(295,854)
Balance (in shares) at Sep. 30, 2020		22,082,924
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	1,026		1,026
Stock-based compensation expense, shares		10,149
Issuance of common stock from stock grants and option exercises	182		182
Issuance of common stock from stock grants and option exercises, shares		38,058
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
Net loss	(22,438)				(22,438)
Balance at Mar. 31, 2021	104,089	$ 31	441,252	5	(337,199)
Balance (in shares) at Mar. 31, 2021		31,331,027
Balance at Dec. 31, 2020	76,069	$ 22	390,803	5	(314,761)
Balance (in shares) at Dec. 31, 2020		22,097,820
Unrealized loss on available-for-sale debt securities	(4)
Net loss	(67,604)
Balance at Sep. 30, 2021	60,736	$ 31	443,069	1	(382,365)
Balance (in shares) at Sep. 30, 2021		31,392,618
Balance at Mar. 31, 2021	104,089	$ 31	441,252	5	(337,199)
Balance (in shares) at Mar. 31, 2021		31,331,027
Stock-based compensation expense	983		983
Stock-based compensation expense, shares		13,713
Issuance of common stock from stock grants and option exercises	23		23
Issuance of common stock from stock grants and option exercises, shares		5,000
Unrealized loss on available-for-sale debt securities	(3)			(3)
Net loss	(19,928)				(19,928)
Balance at Jun. 30, 2021	85,164	$ 31	442,258	2	(357,127)
Balance (in shares) at Jun. 30, 2021		31,349,740
Stock-based compensation expense	713		713
Stock-based compensation expense, shares		15,961
Issuance of common stock from stock grants and option exercises	98		98
Issuance of common stock from stock grants and option exercises, shares		26,917
Unrealized loss on available-for-sale debt securities	(1)			(1)
Net loss	(25,238)				(25,238)
Balance at Sep. 30, 2021	$ 60,736	$ 31	$ 443,069	$ 1	$ (382,365)
Balance (in shares) at Sep. 30, 2021		31,392,618

Condensed Consolidated Statem_4

Condensed Consolidated Statements of Stockholders' Equity (Unaudited) (Parenthetical) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Jun. 30, 2020	Mar. 31, 2020
Statement Of Stockholders Equity [Abstract]
Issuance costs of issuance of common stock for public offering	$ 3,563	$ 2,045	$ 2,514

Condensed Consolidated Statem_5

Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Operating Activities
Net loss	$ (67,604)	$ (37,334)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation expense	2,722	2,707
Depreciation and amortization	175	93
Changes in operating assets and liabilities:
Accounts receivable	2,199	13,445
Prepaid and other assets	(2,028)	225
Accounts payable	(2,063)	(35)
Accrued compensation and other accrued liabilities	1,473	2,156
Operating lease liability and right-of-use asset	177	45
Deferred revenue	(1,130)	(14,236)
Net cash flows used in operating activities	(66,079)	(32,934)
Investing Activities
Proceeds from maturities of short-term investments	46,162	74,082
Purchase of short-term investments		(91,742)
Purchases of property and equipment	(839)	(228)
Net cash flows provided by (used in) investing activities	45,323	(17,888)
Financing Activities
Issuance of common stock for public offering, net of issuance costs	49,250	59,941
Issuance of common stock from stock grants and option exercises	303	435
Net cash flow provided by financing activities	49,553	60,376
Net increase in cash and cash equivalents	28,797	9,554
Cash and cash equivalents at beginning of the period	30,360	15,369
Cash and cash equivalents at end of the period	59,157	$ 24,923
Supplemental Disclosure of Non-Cash Investing and Financing Activities:
Right-of-use assets obtained in exchange for operating lease liabilities	$ 1,850

Nature of Operations and Liquid

Nature of Operations and Liquidity	9 Months Ended
	Sep. 30, 2021
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Nature of Operations and Liquidity	1. Catalyst Biosciences, Inc. and its subsidiary (the “Company” or “Catalyst”) is a fully integrated research and clinical development biopharmaceutical company with expertise in protease engineering, discovery, translational research, clinical development, and manufacturing. The Company is focused on advancing its protease product candidates in the fields of hemostasis and complement regulation. The Company had a net loss of $67.6 million for the nine months ended September 30, 2021 and an accumulated deficit of $382.4 million as of September 30, 2021. The Company expects to continue to incur losses for the next several years. As of September 30, 2021, the Company had $64.5 million of cash, cash equivalents and short-term investments. Its primary uses of cash are to fund operating expenses, including research and development expenditures and general and administrative expenditures. Based on the current status of its research and development plans, the Company believes that its existing cash, cash equivalents and short-term investments as of September 30, 2021 will be sufficient to fund its cash requirements for at least the next 12 months from the date of the filing of this quarterly report. If, at any time, the Company’s prospects for financing its research and development programs decline, the Company may decide to reduce research and development expenses by delaying, discontinuing or reducing its funding of one or more of its research or development programs. Alternatively, the Company might raise funds through strategic collaborations, public or private financings or other arrangements. Such funding, if needed, may not be available on favorable terms, or at all.

Summary of Significant Accounti

Summary of Significant Accounting Policies	9 Months Ended
	Sep. 30, 2021
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	2. Basis of Presentation The Company’s condensed consolidated financial statements have been prepared in accordance with U.S. generally accepted accounting principles (“GAAP”) and following the requirements of the Securities and Exchange Commission (the “SEC”) for interim reporting. As permitted under those rules, certain footnotes or other financial information that are normally required by GAAP can be condensed or omitted. These financial statements have been prepared on the same basis as the Company’s annual financial statements and, in the opinion of management, reflect all adjustments, consisting only of normal recurring adjustments, which are necessary for a fair presentation of the Company’s financial information. These interim results and cash flows for any interim period are not necessarily indicative of the results to be expected for the year ending December 31, 2021, or for any other future annual or interim period. The accompanying condensed consolidated financial statements and related financial information should be read in conjunction with the consolidated financial statements filed with the Company’s Annual Report on Form 10-K for the year ended December 31, 2020 (“Annual Report”). Accounting Pronouncements Recently Adopted In December 2019, the FASB issued ASU 2019-12, Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes. New Accounting Pronouncements Recently Issued But Not Yet Adopted In June 2016, the FASB issued ASU 2016-13, Measurement of Credit Losses on Financial Instruments is permitted. The Company plans to adopt ASU 2016-13 and related updates as of January 1, 2023. The Company will assess the impact of adoption of this standard on its condensed consolidated financial statements. In May 2021, the FASB issued 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 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. The Company recorded $1.9 million and $0.8 million during the three months ended September 30, 2021 and 2020, respectively, and $4.3 million and $3.8 million during the nine months ended September 30, 2021 and 2020, respectively, of research and development expense as cost of collaboration revenue related to the collaboration agreement with Biogen signed in December 2019. 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.

Fair Value Measurements

Fair Value Measurements	9 Months Ended
	Sep. 30, 2021
Fair Value Disclosures [Abstract]
Fair Value Measurements	3. For a description of the fair value hierarchy and the Company’s fair value methodology, see “ Part II - Item 8 - Financial Statements and Supplementary Data - Note 3 – Summary of Significant Accounting Policies The following tables present the fair value hierarchy for assets and liabilities measured at fair value on a recurring basis as of September 30, 2021 and December 31, 2020 ( in thousands September 30, 2021 Level 1 Level 2 Level 3 Total Financial assets: Money market funds (1) $ 59,157 $ — $ — $ 59,157 U.S. government agency securities (2) 2,514 — — 2,514 Federal agency securities (2) — 2,857 — 2,857 Total financial assets $ 61,671 $ 2,857 $ — $ 64,528 December 31, 2020 Level 1 Level 2 Level 3 Total Financial assets: Money market funds (1) $ 30,360 $ — $ — $ 30,360 U.S. government agency securities (2) 37,837 — — 37,837 Federal agency securities (2) — 13,700 — 13,700 Total financial assets $ 68,197 $ 13,700 $ — $ 81,897 (1) Included in cash and cash equivalents on the accompanying condensed consolidated balance sheets. ( 2 ) Included in short-term investments on the accompanying condensed consolidated balance sheets and classified as available-for-sale debt securities. $2.5 million of U.S. government agency securities as of December 31, 2020 are included in long-term investments on the accompanying condensed consolidated balance sheets due to the maturity being more than 12 months.

Financial Instruments

Financial Instruments	9 Months Ended
	Sep. 30, 2021
Investments All Other Investments [Abstract]
Financial Instruments	4. Cash equivalents and investments (debt securities) which are classified as available-for-sale securities, consisted of the following ( in thousands September 30, 2021 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value Money market funds (cash equivalents) $ 59,157 $ — $ — $ 59,157 U.S. government agency securities 2,513 1 — 2,514 Federal agency securities 2,857 — — 2,857 Total financial assets $ 64,527 $ 1 $ — $ 64,528 Classified as: Cash and cash equivalents $ 59,157 Short-term investments 5,371 Total financial assets $ 64,528 December 31, 2020 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value Money market funds (cash equivalents) $ 30,360 $ — $ — $ 30,360 U.S. government agency securities 37,835 2 — 37,837 Federal agency securities 13,697 3 — 13,700 Total financial assets $ 81,892 $ 5 $ — $ 81,897 Classified as: Cash and cash equivalents $ 30,360 Short-term investments 48,994 Long-term investments 2,543 Total financial assets $ 81,897 There have been no material realized gains or losses on available-for-sale debt securities for the periods presented. As of September 30, 2021, the remaining contractual maturities of $5.4 million of available-for-sale debt securities were less than one year. The carrying amounts of cash and cash equivalents, accounts receivable, accounts payable, and other accrued liabilities approximate their fair values due to the short-term maturity of these instruments.

Lease

Lease	9 Months Ended
	Sep. 30, 2021
Lessee Disclosure [Abstract]
Lease	5. 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. 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 . 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 has an original lease term of one year and a renewal period of six months. This License Agreement commenced during the second quarter of 2021. For the three and nine months ended September 30, 2021, the Company’s operating lease expense was $0.5 million and $1.1 million, respectively. For the three and nine months ended September 30, 2020, the Company’s operating lease expense was $0.2 million and $0.6 million, respectively. September 30, December 31, 2021 2020 Weighted-average remaining lease term 1.3 years 2.3 years Weighted-average discount rate 4.9 % 5.7 % The maturity of the Company’s operating lease liabilities as of September 30, 2021 were as follows (in thousands) Year Ending December 31, Amount Remaining in 2021 $ 498 2022 1,719 2023 259 Total undiscounted lease payments 2,476 Less imputed interest (82 ) Total operating lease liability $ 2,394 Supplemental cash flow information related to operating leases was as follows (in thousands) Nine Months Ended September 30, 2021 2020 Cash paid for amounts included in the measurement of lease liabilities $ 977 $ 433 Prepaid cash payment for lease liabilities 208 — Cash paid for operating leases that were included in operating cash outflows $ 1,185 $ 433

Stock Based Compensation

Stock Based Compensation	9 Months Ended
	Sep. 30, 2021
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Stock Based Compensation	6. 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 to the 2018 Plan to increase the number of shares of common stock reserved for issuance by 2,500,000 shares to a total of 5,300,000 shares. The amendment became effective immediately upon stockholder approval. Performance-Based Stock Option Grants In February 2021, the Committee approved the issuance of option grants to purchase 647,000 shares of common stock for executive officers pursuant to the 2018 Plan, which will vest upon (a) the achievement of specified performance goals and (b) the grantees’ continued employment during the service period specified in each grant. 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) Outstanding — December 31, 2020 2,355,615 $ 8.59 8.0 Options granted 1,301,238 $ 5.73 Options exercised (5,000 ) $ 4.63 Options forfeited (631,827 ) $ 6.73 Options expired (569 ) $ 582.27 Outstanding — September 30, 2021 3,019,457 $ 7.65 7.9 Exercisable — September 30, 2021 1,468,499 $ 9.39 Valuation Assumptions The Company estimated the fair value of stock options granted using the Black-Scholes option-pricing model and a single option award approach. Due to its limited history as a public company and limited number of sales of its common stock, 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 operating 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: Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 Employee Stock Options: Risk-free rate 0.91% 0.39% 0.76% 0.96% Expected term (in years) 6.0 6.1 6.0 5.8 Dividend yield 0.00% 0.00% 0.00% 0.00% Volatility 90.95% 115.62% 93.34% 112.87% Weighted-average fair value of stock options granted $ 3.23 $ 4.61 $ 4.31 $ 5.17 Total stock-based compensation expense recognized was as follows ( in thousands Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 Research and development $ 158 $ 493 $ 921 $ 1,151 General and administrative (1) 555 575 1,801 1,556 Total stock-based compensation expense $ 713 $ 1,068 $ 2,722 $ 2,707 (1) Included in general and administrative for the three and nine months ended September 30, 2021 is stock-based compensation expense related to 15,961 shares and 39,823 shares, respectively, of common stock issued to certain board members in lieu of their cash compensation. As of September 30, 2021, 3,037,815 shares of common stock were available for future grant and 3,019,457

Collaborations

Collaborations	9 Months Ended
	Sep. 30, 2021
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Collaborations	7. 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 entered into two amendments to the Mosaic research collaboration agreements in December 2019 and May 2020. See Note 11, Related Parties ISU Abxis In December 2018, the Company entered into an amended and restated license agreement with ISU Abxis (the “A&R ISU Abxis Agreement”), which amended and restated its previous license and collaboration agreement with ISU Abxis previously entered into in September 2013, as subsequently amended in October 2014 and December 2016 (the “Original 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 eliminates the profit-sharing arrangement in the Original ISU Abxis Agreement and rovides 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 , 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 September 30, 2021, no milestones have been met. Biogen On December 18, 2019, the Company and Biogen International GmbH (“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 age-related macular degeneration (“ twelve-month 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 is eligible to receive development milestones and sales milestones of up to $340.0 million. In addition, the Company is 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 will also receive 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. The Biogen Agreement will continue on a product-by-product and country-by-country basis until the tenth anniversary of the first commercial sale of the first product in a country, unless terminated earlier by either party as specified under the agreement. For the nine months ended September 30, 2021, the Company recognized no license revenue from the Biogen Agreement. For the nine months ended September 30, 2020, the Company recognized $15.0 million in license revenue upon the transfer of the Exclusive License and the related know-how, and $0.1 million in license revenue for reimbursable out-of-pocket costs incurred. The Company recognized $2.3 million and $0.9 million for the three months ended September 30, 2021 and 2020, respectively, and $4.9 million and $3.8 million for the nine months ended September 30, 2021 and 2020, respectively, in collaboration revenue for reimbursable third-party vendor, out-of-pocket and personnel costs incurred related to Research Services. For the nine months ended September 30, 2021, the Company recognized $ 1.6 million in collaboration revenue from the beginning of period d eferred revenue balance.

Net Loss per Share Attributable

Net Loss per Share Attributable to Common Stockholders	9 Months Ended
	Sep. 30, 2021
Earnings Per Share [Abstract]
Net Loss per Share Attributable to Common Stockholders	8. 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 on an as-if converted basis that were not included in the diluted per share calculations because they would be anti-dilutive were as follows: September 30, 2021 2020 Options to purchase common stock 3,019,457 2,264,141 Common stock warrants 85 722 Total 3,019,542 2,264,863

Stockholders' Equity

Stockholders' Equity	9 Months Ended
	Sep. 30, 2021
Equity [Abstract]
Stockholders' Equity	9. Stockholders’ Equity In the first quarter of 2021, the Company issued and sold an aggregate of 9,185,000 registered shares of its common stock (including 485,000 shares sold pursuant to the exercise of the underwriters’ overallotment option) at a price of $5.75 per share. The net proceeds to the Company, after deducting $3.6 million in underwriting discounts and commissions, and offering expenses, were approximately $49.3 million.

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2021
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	10. Commitments and Contingencies Manufacturing Agreements On May 20, 2016, the Company signed a development and manufacturing services agreement with AGC Biologics, Inc. (“AGC”), pursuant to which AGC will conduct manufacturing development of agreed upon product candidates. The Company currently has firm work orders with AGC to manufacture MarzAA and DalcA to support its clinical trials totaling $16.5 million and the payment obligations remaining as of September 30, 2021 were $3.6 million. In July 2021, the Company entered into two separate agreements, one for additional clinical trial services for MarzAA, and another for the Company’s screening and natural history of disease clinical studies related to CFI deficiency, with total payments of up to $3.2 million and $6.5 million, respectively. The Company can terminate these agreements at its discretion and upon termination will be responsible to pay for those services incurred prior to termination plus reasonable wind-down expenses. On September 16, 2021, the Company signed a Manufacturing and Research and Development Studies Agreement to support the lyophilized drug product, CB4332. The agreement will cover analytical method qualification to support GMP manufacturing. The Company currently has firm work orders related to this agreement totaling $0.3 million and the payment obligations remaining as of September 30, 2021 were $0.3 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, potential trial participants 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 operations of the Company’s manufacturers or disrupt supply logistics, which could impact the timing of deliveries and potentially increase expenses under the Company’s agreements. The Company is actively monitoring the impact of COVID-19 and the possible effects on its financial condition, liquidity, operations, clinical trials, suppliers, industry and workforce

Related Parties

Related Parties	9 Months Ended
	Sep. 30, 2021
Related Party Transactions [Abstract]
Related Parties	11. Related Parties On October 24, 2017, the Company announced a strategic research collaboration with Mosaic to develop intravitreal anti-complement factor C3 products for the treatment of dry AMD and other retinal diseases. Dr. Usman, the Company’s Chief Executive Officer and a member of the Company’s board of directors, and Mr. Lawlor, a member of the Company’s board of directors, were also members of the board of directors of Mosaic. On December 21, 2018, the Company amended its collaboration agreement with Mosaic to, among other things, include certain additional products. According to the Mosaic collaboration agreement, as amended, the Company and Mosaic co-funded certain research. On December 18, 2019, the Company entered into the second amendment to the Mosaic collaboration agreement following completion of the co-funded research. Pursuant to the second amendment, any future services provided by Mosaic will be performed on a fee-for-service basis. In connection with the Biogen Agreement, the Company received a $15.0 million upfront license fee on January 10, 2020, see Note 7, Collaborations On May 8, 2020, the Company entered into a subsequent amendment to the Mosaic collaboration agreement. As part of this amendment, the Company paid a one-time $0.8 million cash payment to Mosaic, and 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 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. The Company now owns one hundred percent of all future payment streams related to these product candidates. As of June 30, 2020, Mosaic was no longer a related party.

Interest and Other Income (Expe

Interest and Other Income (Expense), Net	9 Months Ended
	Sep. 30, 2021
Other Income And Expenses [Abstract]
Interest and Other Income (Expense), Net	12. Interest and Other Income (Expense), Net The following table shows the detail of interest and other income (expense), net as follows ( in thousands Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 Interest income $ 7 $ 74 $ 35 $ 536 Miscellaneous income (expense) (3 ) — 8 679 Other (13 ) (7 ) (66 ) (20 ) Total interest and other income (expense), net $ (9 ) $ 67 $ (23 ) $ 1,195

Subsequent Event

Subsequent Event	9 Months Ended
	Sep. 30, 2021
Subsequent Events [Abstract]
Subsequent Event	13. Subsequent Events Lease Amendment In October 2021, the Company amended the License Agreement entered into in April 2021 to extend the lease term for a period of 12 months. April 2023 At-the-Market Equity Offering On October 15, 2021, the Company entered into an Equity Distribution Agreement (the “ATM Agreement”) with Piper Sandler & Co. (“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 an “at the market” equity offering 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 Agreement 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. Other Event On November 11, 2021, the Company made a strategic decision to stop the clinical development of MarzAA and focus solely on its complement programs and protease medicines platform. The strategic shift from late-stage hemophilia to earlier-stage complement development offers the Company a path forward for long-term success. The Company implemented a restructuring plan under which it provided or will provide employees one-time severance payments upon termination, continued benefits for a specific period, and outplacement services. The Company expects to incur total expenses of approximately $0.6 million. The Company expects that the cash payments due under this restructuring will be approximately $0.4 million and $0.2 million in the fourth quarter of 2021 and first quarter of 2022, respectively. In the first quarter of 2022, the Company may also occur other charges or cash expenditures not currently contemplated due to events that occur as a result of, or associated with, the decision to stop clinical development of MarzAA.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2021
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The Company’s condensed consolidated financial statements have been prepared in accordance with U.S. generally accepted accounting principles (“GAAP”) and following the requirements of the Securities and Exchange Commission (the “SEC”) for interim reporting. As permitted under those rules, certain footnotes or other financial information that are normally required by GAAP can be condensed or omitted. These financial statements have been prepared on the same basis as the Company’s annual financial statements and, in the opinion of management, reflect all adjustments, consisting only of normal recurring adjustments, which are necessary for a fair presentation of the Company’s financial information. These interim results and cash flows for any interim period are not necessarily indicative of the results to be expected for the year ending December 31, 2021, or for any other future annual or interim period. The accompanying condensed consolidated financial statements and related financial information should be read in conjunction with the consolidated financial statements filed with the Company’s Annual Report on Form 10-K for the year ended December 31, 2020 (“Annual Report”).
Accounting Pronouncements Recently Adopted	Accounting Pronouncements Recently Adopted In December 2019, the FASB issued ASU 2019-12, Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes. New Accounting Pronouncements Recently Issued But Not Yet Adopted In June 2016, the FASB issued ASU 2016-13, Measurement of Credit Losses on Financial Instruments is permitted. The Company plans to adopt ASU 2016-13 and related updates as of January 1, 2023. The Company will assess the impact of adoption of this standard on its condensed consolidated financial statements. In May 2021, the FASB issued 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
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. The Company recorded $1.9 million and $0.8 million during the three months ended September 30, 2021 and 2020, respectively, and $4.3 million and $3.8 million during the nine months ended September 30, 2021 and 2020, respectively, of research and development expense as cost of collaboration revenue related to the collaboration agreement with Biogen signed in December 2019.
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.

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	9 Months Ended
	Sep. 30, 2021
Fair Value Disclosures [Abstract]
Assets and Liabilities Measured at Fair Value on a Recurring Basis	The following tables present the fair value hierarchy for assets and liabilities measured at fair value on a recurring basis as of September 30, 2021 and December 31, 2020 ( in thousands September 30, 2021 Level 1 Level 2 Level 3 Total Financial assets: Money market funds (1) $ 59,157 $ — $ — $ 59,157 U.S. government agency securities (2) 2,514 — — 2,514 Federal agency securities (2) — 2,857 — 2,857 Total financial assets $ 61,671 $ 2,857 $ — $ 64,528 December 31, 2020 Level 1 Level 2 Level 3 Total Financial assets: Money market funds (1) $ 30,360 $ — $ — $ 30,360 U.S. government agency securities (2) 37,837 — — 37,837 Federal agency securities (2) — 13,700 — 13,700 Total financial assets $ 68,197 $ 13,700 $ — $ 81,897 (1) Included in cash and cash equivalents on the accompanying condensed consolidated balance sheets. ( 2 ) Included in short-term investments on the accompanying condensed consolidated balance sheets and classified as available-for-sale debt securities. $2.5 million of U.S. government agency securities as of December 31, 2020 are included in long-term investments on the accompanying condensed consolidated balance sheets due to the maturity being more than 12 months.

Financial Instruments (Tables)

Financial Instruments (Tables)	9 Months Ended
	Sep. 30, 2021
Investments All Other Investments [Abstract]
Cash Equivalents, Restricted Cash and Short-Term Investments 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 September 30, 2021 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value Money market funds (cash equivalents) $ 59,157 $ — $ — $ 59,157 U.S. government agency securities 2,513 1 — 2,514 Federal agency securities 2,857 — — 2,857 Total financial assets $ 64,527 $ 1 $ — $ 64,528 Classified as: Cash and cash equivalents $ 59,157 Short-term investments 5,371 Total financial assets $ 64,528 December 31, 2020 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value Money market funds (cash equivalents) $ 30,360 $ — $ — $ 30,360 U.S. government agency securities 37,835 2 — 37,837 Federal agency securities 13,697 3 — 13,700 Total financial assets $ 81,892 $ 5 $ — $ 81,897 Classified as: Cash and cash equivalents $ 30,360 Short-term investments 48,994 Long-term investments 2,543 Total financial assets $ 81,897

Lease (Tables)

Lease (Tables)	9 Months Ended
	Sep. 30, 2021
Lessee Disclosure [Abstract]
Summary of Present Value Assumptions used in Calculating Present Value of Lease Payments	For the three and nine months ended September 30, 2020, the Company’s operating lease expense was $0.2 million and $0.6 million, respectively. September 30, December 31, 2021 2020 Weighted-average remaining lease term 1.3 years 2.3 years Weighted-average discount rate 4.9 % 5.7 %
Schedule of Maturity of Operating Lease Liabilities	The maturity of the Company’s operating lease liabilities as of September 30, 2021 were as follows (in thousands) Year Ending December 31, Amount Remaining in 2021 $ 498 2022 1,719 2023 259 Total undiscounted lease payments 2,476 Less imputed interest (82 ) Total operating lease liability $ 2,394
Schedule of Supplemental Cash Flow Information	Supplemental cash flow information related to operating leases was as follows (in thousands) Nine Months Ended September 30, 2021 2020 Cash paid for amounts included in the measurement of lease liabilities $ 977 $ 433 Prepaid cash payment for lease liabilities 208 — Cash paid for operating leases that were included in operating cash outflows $ 1,185 $ 433

Stock Based Compensation (Table

Stock Based Compensation (Tables)	9 Months Ended
	Sep. 30, 2021
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) Outstanding — December 31, 2020 2,355,615 $ 8.59 8.0 Options granted 1,301,238 $ 5.73 Options exercised (5,000 ) $ 4.63 Options forfeited (631,827 ) $ 6.73 Options expired (569 ) $ 582.27 Outstanding — September 30, 2021 3,019,457 $ 7.65 7.9 Exercisable — September 30, 2021 1,468,499 $ 9.39
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: Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 Employee Stock Options: Risk-free rate 0.91% 0.39% 0.76% 0.96% Expected term (in years) 6.0 6.1 6.0 5.8 Dividend yield 0.00% 0.00% 0.00% 0.00% Volatility 90.95% 115.62% 93.34% 112.87% Weighted-average fair value of stock options granted $ 3.23 $ 4.61 $ 4.31 $ 5.17
Summary of Stock-Based Compensation Expense Recognized	Total stock-based compensation expense recognized was as follows ( in thousands Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 Research and development $ 158 $ 493 $ 921 $ 1,151 General and administrative (1) 555 575 1,801 1,556 Total stock-based compensation expense $ 713 $ 1,068 $ 2,722 $ 2,707 (1) Included in general and administrative for the three and nine months ended September 30, 2021 is stock-based compensation expense related to 15,961 shares and 39,823 shares, respectively, of common stock issued to certain board members in lieu of their cash compensation.

Net Loss per Share Attributab_2

Net Loss per Share Attributable to Common Stockholders (Tables)	9 Months Ended
	Sep. 30, 2021
Earnings Per Share [Abstract]
Anti-dilutive Security not Included In Diluted per Share Calculations	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 on an as-if converted basis that were not included in the diluted per share calculations because they would be anti-dilutive were as follows: September 30, 2021 2020 Options to purchase common stock 3,019,457 2,264,141 Common stock warrants 85 722 Total 3,019,542 2,264,863

Interest and Other Income, Net

Interest and Other Income, Net (Tables)	9 Months Ended
	Sep. 30, 2021
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 Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 Interest income $ 7 $ 74 $ 35 $ 536 Miscellaneous income (expense) (3 ) — 8 679 Other (13 ) (7 ) (66 ) (20 ) Total interest and other income (expense), net $ (9 ) $ 67 $ (23 ) $ 1,195

Nature of Operations and Liqu_2

Nature of Operations and Liquidity - Additional Information (Detail) $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2021USD ($)	Jun. 30, 2021USD ($)	Mar. 31, 2021USD ($)	Sep. 30, 2020USD ($)	Jun. 30, 2020USD ($)	Mar. 31, 2020USD ($)	Sep. 30, 2021USD ($)Segment	Sep. 30, 2020USD ($)	Dec. 31, 2020USD ($)
Accounting Policies [Abstract]
Number of operating segment | Segment							1
Net loss	$ 25,238	$ 19,928	$ 22,438	$ 16,033	$ 17,248	$ 4,053	$ 67,604	$ 37,334
Accumulated deficit	382,365						382,365		$ 314,761
Cash, cash equivalents and short-term investments	$ 64,500						$ 64,500

Summary of Significant Accoun_3

Summary of Significant Accounting Policies - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Research and Development Expense
Summary Of Significant Accounting Policies [Line Items]
Cost of collaboration revenue	$ 1.9	$ 0.8	$ 4.3	$ 3.8

Assets and Liabilities Measured

Assets and Liabilities Measured at Fair Value (Detail) - USD ($) $ in Thousands		Sep. 30, 2021	Dec. 31, 2020
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, fair value		$ 64,528	$ 81,897
Money Market Funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, fair value	[1]	59,157	30,360
U.S. Government Agency Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, fair value	[2]	2,514	37,837
Federal Agency Securities | Short-Term Investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, fair value	[2]	2,857	13,700
Fair Value, Inputs, Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, fair value		61,671	68,197
Fair Value, Inputs, Level 1 | Money Market Funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, fair value	[1]	59,157	30,360
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	[2]	2,514	37,837
Fair Value, Inputs, Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, fair value		2,857	13,700
Fair Value, Inputs, Level 2 | Federal Agency Securities | Short-Term Investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, fair value	[2]	$ 2,857	$ 13,700
[1]	Included in cash and cash equivalents on the accompanying condensed consolidated balance sheets.
[2]	Included in short-term investments on the accompanying condensed consolidated balance sheets and classified as available-for-sale debt securities. $2.5 million of U.S. government agency securities as of December 31, 2020 are included in long-term investments on the accompanying condensed consolidated balance sheets due to the maturity being more than 12 months.

Assets and Liabilities Measur_2

Assets and Liabilities Measured at Fair Value - Additional Information (Detail) $ in Millions	Dec. 31, 2020USD ($)
Long Term Investments | U.S. Government Agency Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale, debt securities	$ 2.5

Cash Equivalents and Short-Term

Cash Equivalents and Short-Term Investments Classified as Available-for-sale Securities (Detail) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	$ 64,527	$ 81,892
Gross Unrealized Gains	1	5
Estimated Fair Value	64,528	81,897
Money Market Funds | Cash Equivalents
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	59,157	30,360
Estimated Fair Value	59,157	30,360
U.S. Government Agency Securities
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	2,513	37,835
Gross Unrealized Gains	1	2
Estimated Fair Value	2,514	37,837
Cash and Cash Equivalents
Schedule Of Available For Sale Securities [Line Items]
Estimated Fair Value	59,157	30,360
Short-Term Investments
Schedule Of Available For Sale Securities [Line Items]
Estimated Fair Value	5,371	48,994
Long Term Investments
Schedule Of Available For Sale Securities [Line Items]
Estimated Fair Value		2,543
Federal Agency Securities
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	2,857	13,697
Gross Unrealized Gains		3
Estimated Fair Value	$ 2,857	$ 13,700

Financial Instruments - Additio

Financial Instruments - Additional Information (Detail)	9 Months Ended
	Sep. 30, 2021USD ($)
Financial Instrument [Line Items]
Material realized gains or losses on available-for-sale securities	$ 0
Available-for-sale debt securities current	$ 5,400,000
Maximum
Financial Instrument [Line Items]
Available for sale debt securities contractual maturities	1 year

Lease - Additional Information

Lease - Additional Information (Detail) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended		9 Months Ended
	Apr. 30, 2021	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Lessee Lease Description [Line Items]
Lease expiration date				Apr. 30, 2023
Lessee operating lease renewal term description				no stated renewal options
Undiscounted future payment		$ 2,476		$ 2,476
Operating lease expense		$ 500	$ 200	$ 1,100	$ 600
Lease Lab and Office Space | Sublease Arrangement
Lessee Lease Description [Line Items]
Undiscounted future payment	$ 1,900
Lease term	1 year
Operating lease, option to extend	This License Agreement has an original lease term of one year and a renewal period of six months.
Operating lease commenced description	commenced during the second quarter of 2021.

Summary of Present Value Assump

Summary of Present Value Assumptions used in Calculating Present Value of Lease Payments (Detail)	Sep. 30, 2021	Dec. 31, 2020
Lessee Disclosure [Abstract]
Weighted-average remaining lease term	1 year 3 months 18 days	2 years 3 months 18 days
Weighted-average discount rate	4.90%	5.70%

Schedule of Maturity of Operati

Schedule of Maturity of Operating Lease Liabilities (Detail) $ in Thousands	Sep. 30, 2021USD ($)
Operating Lease Liabilities Payments Due [Abstract]
Remaining in 2021	$ 498
2022	1,719
2023	259
Total undiscounted lease payments	2,476
Less imputed interest	(82)
Total operating lease liability	$ 2,394

Schedule of Supplemental Cash F

Schedule of Supplemental Cash Flow Information (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Operating Lease Liabilities Payments Due [Abstract]
Cash paid for amounts included in the measurement of lease liabilities	$ 977	$ 433
Prepaid cash payment for lease liabilities	208
Cash paid for operating leases that were included in operating cash outflows	$ 1,185	$ 433

Stock Based Compensation - Addi

Stock Based Compensation - Additional Information (Detail) - USD ($) $ in Millions	Jun. 09, 2021	Sep. 30, 2021	Feb. 28, 2021	Dec. 31, 2020
Schedule Of Share Based Compensation Arrangements By Share Based Payment Award [Table]
Number of common stock available for future grant		3,037,815
Shares remaining outstanding		3,019,457		2,355,615
Employee Stock Option
Schedule Of Share Based Compensation Arrangements By Share Based Payment Award [Table]
Unrecognized employee stock based compensation expense		$ 5.3
Unrecognized employee stock based compensation expense, period for recognition		2 years 7 months 6 days
2018 Omnibus Incentive Plan
Schedule Of Share Based Compensation Arrangements By Share Based Payment Award [Table]
Increase in number of shares of common stock reserved for issuance.	2,500,000
Common Stock, Capital Shares Reserved for Future Issuance	5,300,000
2018 Omnibus Incentive Plan | Performance-Based Stock Option Grants
Schedule Of Share Based Compensation Arrangements By Share Based Payment Award [Table]
Issuance of option grants to purchase common stock shares			647,000

Summary of Option Activity Unde

Summary of Option Activity Under Company's 2018 Plan (Detail) - $ / shares	9 Months Ended	12 Months Ended
	Sep. 30, 2021	Dec. 31, 2020
Number of Shares Underlying Outstanding Options
Number of Shares Underlying Outstanding Options, Beginning Balance	2,355,615
Number of Shares Underlying Outstanding Options, Options granted	1,301,238
Number of Shares Underlying Outstanding Options, Options exercised	(5,000)
Number of Shares Underlying Outstanding Options, Options forfeited	(631,827)
Number of Shares Underlying Outstanding Options, Options expired	(569)
Number of Shares Underlying Outstanding Options, Ending Balance	3,019,457	2,355,615
Number of Shares Underlying Outstanding Options, Exercisable - September 30, 2021	1,468,499
Weighted- Average Exercise Price
Weighted- Average Exercise Price, Beginning Balance	$ 8.59
Weighted- Average Exercise Price, Options granted	5.73
Weighted- Average Exercise Price, Options exercised	4.63
Weighted- Average Exercise Price, Options forfeited	6.73
Weighted- Average Exercise Price, Options expired	582.27
Weighted- Average Exercise Price, Ending Balance	7.65	$ 8.59
Weighted- Average Exercise Price, Exercisable - September 30, 2021	$ 9.39
Weighted-Average Remaining Contractual Term (Years)
Weighted-Average Remaining Contractual Term (Years), Outstanding Balance	7 years 10 months 24 days	8 years

Fair Values of Stock Options Es

Fair Values of Stock Options Estimated Using Black-Scholes Valuation Model (Detail) - Employee Stock Option - $ / shares	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions Black Scholes Method Used [Line Items]
Risk-free rate	0.91%	0.39%	0.76%	0.96%
Expected term (in years)	6 years	6 years 1 month 6 days	6 years	5 years 9 months 18 days
Dividend yield	0.00%	0.00%	0.00%	0.00%
Volatility	90.95%	115.62%	93.34%	112.87%
Weighted-average fair value of stock options granted	$ 3.23	$ 4.61	$ 4.31	$ 5.17

Summary of Stock-Based Compensa

Summary of Stock-Based Compensation Expense Recognized (Detail) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation expense		$ 713	$ 1,068	$ 2,722	$ 2,707
Research and development
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation expense		158	493	921	1,151
General and Administrative
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation expense	[1]	$ 555	$ 575	$ 1,801	$ 1,556
[1]	Included in general and administrative for the three and nine months ended September 30, 2021 is stock-based compensation expense related to 15,961 shares and 39,823 shares, respectively, of common stock issued to certain board members in lieu of their cash compensation.

Summary of Stock-Based Compen_2

Summary of Stock-Based Compensation Expense Recognized (Parenthetical) (Detail) - shares	3 Months Ended	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2021
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Number of shares of common stock issued to certain board members in lieu of cash compensation	15,961	39,823

Collaborations - Additional Inf

Collaborations - Additional Information (Detail) - USD ($)	1 Months Ended		3 Months Ended		9 Months Ended
	Jan. 31, 2020	Dec. 31, 2018	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Revenue Recognition Multiple Deliverable Arrangements [Line Items]
License and collaboration revenue			$ 2,299,000	$ 893,000	$ 4,898,000	$ 18,917,000
Deferred revenue, recognized					1,600,000
License
Revenue Recognition Multiple Deliverable Arrangements [Line Items]
License and collaboration revenue				32,000		15,100,000
License | Transfer of Exclusive License and Related Know-How
Revenue Recognition Multiple Deliverable Arrangements [Line Items]
License and collaboration revenue						15,000,000
Exclusive License
Revenue Recognition Multiple Deliverable Arrangements [Line Items]
License and collaboration revenue						100,000
Collaboration
Revenue Recognition Multiple Deliverable Arrangements [Line Items]
License and collaboration revenue			2,299,000	861,000	4,898,000	3,817,000
Collaboration | Reimbursable Out-of-Pocket and Personnel Costs Incurred Related to Research Services
Revenue Recognition Multiple Deliverable Arrangements [Line Items]
License and collaboration revenue			$ 2,300,000	$ 900,000	4,900,000	$ 3,800,000
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 | Amended and Restated License Agreement | Maximum
Revenue Recognition Multiple Deliverable Arrangements [Line Items]
Milestone payment		19,500,000			0
Commercial milestone payments		$ 17,000,000			0
Biogen
Revenue Recognition Multiple Deliverable Arrangements [Line Items]
License and collaboration revenue					$ 0
Biogen | License and Collaboration Agreement (the “Biogen Agreement”)
Revenue Recognition Multiple Deliverable Arrangements [Line Items]
Research services					30 months
Research services option to extend					12 months
Biogen | Exclusive License
Revenue Recognition Multiple Deliverable Arrangements [Line Items]
Up-front payments received	$ 15,000,000
Biogen | Exclusive License | Maximum
Revenue Recognition Multiple Deliverable Arrangements [Line Items]
Development and sales milestone payments	$ 340,000,000

Anti-dilutive Security not Incl

Anti-dilutive Security not Included In Diluted per Share Calculations (Detail) - shares	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti dilutive securities	3,019,542	2,264,863
Options To Purchase Common Stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti dilutive securities	3,019,457	2,264,141
Common Stock Warrants
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti dilutive securities	85	722

Stockholders' Equity - Addition

Stockholders' Equity - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended
	Mar. 31, 2021	Jun. 30, 2020	Mar. 31, 2020	Feb. 29, 2020
Stockholders Equity Disclosure [Line Items]
Net proceeds from sale of common stock after deducting underwriting commissions and offering expenses	$ 49.3
Underwriting discounts, commissions and offering expenses payable	$ 3.6
Common Stock
Stockholders Equity Disclosure [Line Items]
Issuance of common stock for public offering, net of issuance costs of $2,514 and $3,536, shares	9,185,000	4,615,384	5,307,692
Common stock price, per share				$ 5.75
Common Stock | Underwriters' Overallotment Option
Stockholders Equity Disclosure [Line Items]
Issuance of common stock for public offering, net of issuance costs of $2,514 and $3,536, shares	485,000

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Detail) - USD ($) $ in Millions	Sep. 30, 2021	Jul. 31, 2021
Marzeptacog Alfa Activated | Maximum | Service Agreements
Commitments And Contingencies Disclosure [Line Items]
Cost of services as per agreement		$ 3.2
Dalcinonacog Alfa | Maximum | Service Agreements
Commitments And Contingencies Disclosure [Line Items]
Cost of services as per agreement		$ 6.5
AGC Biologics, Inc | Marzeptacog Alfa Activated and Dalcinonacog Alfa
Commitments And Contingencies Disclosure [Line Items]
Firm work order supporting clinical trials	$ 16.5
Contractual obligation payments	3.6
Integrity Bio | GMP
Commitments And Contingencies Disclosure [Line Items]
Firm work order supporting clinical trials	0.3
Contractual obligation payments	$ 0.3

Related Parties - Additional In

Related Parties - Additional Information (Detail) - USD ($) $ in Millions	May 08, 2020	Sep. 30, 2020	Jan. 10, 2020
License and Collaboration Agreement (the “Biogen Agreement”)
Related Party Transaction [Line Items]
Upfront license fee received from collaboration agreement			$ 15
Mosaic Biosciences Inc
Related Party Transaction [Line Items]
Sublicence Fee		$ 3
One time expense related to collaboration	$ 0.8
Mosaic Biosciences Inc | Maximum
Related Party Transaction [Line Items]
Milestone payments , clinical development events		$ 4

Detail of Interest and Other In

Detail of Interest and Other Income (Expense), Net (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Other Income And Expenses [Abstract]
Interest income	$ 7	$ 74	$ 35	$ 536
Miscellaneous income (expense)	(3)		8	679
Other	(13)	(7)	(66)	(20)
Total interest and other income (expense), net	$ (9)	$ 67	$ (23)	$ 1,195

Subsequent Events - Additional

Subsequent Events - Additional Information (Detail) - USD ($)	Nov. 11, 2021	Oct. 15, 2021	Oct. 30, 2021	Apr. 30, 2021	Mar. 31, 2022	Dec. 31, 2021	Sep. 30, 2021	Dec. 31, 2020
Subsequent Event [Line Items]
Lease expiration date							Apr. 30, 2023
Common stock, par value							$ 0.001	$ 0.001
Sublease Arrangement | Lease Lab and Office Space
Subsequent Event [Line Items]
Operating lease, option to extend				This License Agreement has an original lease term of one year and a renewal period of six months.
Subsequent Event
Subsequent Event [Line Items]
Total expenses	$ 600,000
Cash payments Due					$ 200,000	$ 400,000
Subsequent Event | At-the-Market Equity Offering [Member]
Subsequent Event [Line Items]
Common stock, par value		$ 0.001
Percentage of commission for shares sold		3.00%
Subsequent Event | At-the-Market Equity Offering [Member] | Maximum
Subsequent Event [Line Items]
Gross sales proceeds		$ 50,000,000
Legal expenses incurred		$ 50,000
Subsequent Event | Sublease Arrangement | Lease Lab and Office Space
Subsequent Event [Line Items]
Operating lease, option to extend			In October 2021, the Company amended the License Agreement entered into in April 2021 to extend the lease term for a period of 12 months.
Operating Leases Monthly Payment			$ 100,000
Lease expiration date			Apr. 30, 2023