0001564590-21-041373 | 10-Q | XBRL Viewer

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Document and Entity Information - shares	6 Months Ended
Document and Entity Information - shares	Jun. 30, 2021	Jul. 30, 2021
Cover [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Jun. 30, 2021
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q2
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		31,365,701
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 Sheets - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 73,621	$ 30,360
Short-term investments	12,902	48,994
Accounts receivable	1,971	3,313
Prepaid and other current assets	8,332	6,843
Total current assets	96,826	89,510
Long-term investments		2,543
Other assets, noncurrent	1,169	528
Right-of-use assets	3,107	1,832
Property and equipment, net	684	433
Total assets	101,786	94,846
Current liabilities:
Accounts payable	1,834	5,931
Accrued compensation	2,516	2,476
Deferred revenue	2,038	1,983
Other accrued liabilities	7,366	6,743
Operating lease liability	1,814	663
Total current liabilities	15,568	17,796
Operating lease liability, noncurrent	1,054	981
Total liabilities	16,622	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; 31,349,740 and 22,097,820 shares issued and outstanding at June 30, 2021 and December 31, 2020, respectively	31	22
Additional paid-in capital	442,258	390,803
Accumulated other comprehensive income	2	5
Accumulated deficit	(357,127)	(314,761)
Total stockholders’ equity	85,164	76,069
Total liabilities and stockholders’ equity	$ 101,786	$ 94,846

Condensed Consolidated Balance Sheets (Parenthetical) - $ / shares	Jun. 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	31,349,740	22,097,820
Common stock, shares outstanding	31,349,740	22,097,820

Condensed Consolidated Statements of Operations (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Revenue:
License and collaboration revenue	$ 1,132	$ 1,658	$ 2,599	$ 18,024
Operating expenses:
Research and development	15,389	12,906	32,402	26,170
General and administrative	4,518	4,371	9,930	8,062
Total operating expenses	21,046	19,019	44,951	40,453
Loss from operations	(19,914)	(17,361)	(42,352)	(22,429)
Interest and other income (expense), net	(14)	113	(14)	1,128
Net loss	$ (19,928)	$ (17,248)	$ (42,366)	$ (21,301)
Net loss per share attributable to common stockholders, basic and diluted	$ (0.64)	$ (0.96)	$ (1.42)	$ (1.31)
Shares used to compute net loss per share attributable to common stockholders, basic and diluted	31,348,602	17,891,475	29,875,202	16,241,963
License
Revenue:
License and collaboration revenue		$ 23		$ 15,068
Collaboration
Revenue:
License and collaboration revenue	$ 1,132	1,635	$ 2,599	2,956
Cost of license
Operating expenses:
Cost of license and collaboration		23		3,070
Cost of collaboration
Operating expenses:
Cost of license and collaboration	$ 1,139	$ 1,719	$ 2,619	$ 3,151

Condensed Consolidated Statements of Comprehensive Loss (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Statement Of Income And Comprehensive Income [Abstract]
Net loss	$ (19,928)	$ (17,248)	$ (42,366)	$ (21,301)
Other comprehensive (loss) income:
Unrealized (loss) gain on available-for-sale debt securities	(3)	(99)	(3)	7
Total comprehensive loss	$ (19,931)	$ (17,347)	$ (42,369)	$ (21,294)

- Definition

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

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+ Details

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		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) gain 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) gain on available-for-sale debt securities	7
Net loss	(21,301)
Balance at Jun. 30, 2020	108,961	$ 22	388,719	41	(279,821)
Balance (in shares) at Jun. 30, 2020		22,050,745
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		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) gain 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
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		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) gain on available-for-sale debt securities	(3)
Net loss	(42,366)
Balance at Jun. 30, 2021	85,164	$ 31	442,258	2	(357,127)
Balance (in shares) at Jun. 30, 2021		31,349,740
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		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) gain 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

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 Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020
Operating Activities
Net loss	$ (42,366)	$ (21,301)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation expense	2,009	1,639
Depreciation and amortization	90	51
Changes in operating assets and liabilities:
Accounts receivable	1,342	13,012
Prepaid and other assets	(2,338)	2,267
Accounts payable	(4,091)	(2,780)
Accrued compensation and other accrued liabilities	663	1,825
Operating lease liability and right-of-use asset	157	31
Deferred revenue	55	(14,670)
Net cash flows used in operating activities	(44,479)	(19,926)
Investing Activities
Proceeds from maturities of short-term investments	38,632	50,493
Purchase of short-term investments		(47,081)
Purchases of property and equipment	(347)	(33)
Net cash flows provided by investing activities	38,285	3,379
Financing Activities
Issuance of common stock for public offering, net of issuance costs	49,250	60,112
Issuance of common stock from stock grants and option exercises	205	339
Net cash flow provided by financing activities	49,455	60,451
Net increase in cash and cash equivalents	43,261	43,904
Cash and cash equivalents at beginning of the period	30,360	15,369
Cash and cash equivalents at end of the period	73,621	$ 59,273
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 Liquidity

6 Months Ended

Jun. 30, 2021

Organization Consolidation And Presentation Of Financial Statements [Abstract]

Nature of Operations and Liquidity

1.	Nature of Operations and Liquidity

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 is located in South San Francisco, California and operates in one segment.

The Company had a net loss of $42.4 million for the six months ended June 30, 2021 and an accumulated deficit of $357.1 million as of June 30, 2021. The Company expects to continue to incur losses for the next several years. As of June 30, 2021, the Company had $86.5 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 June 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 Accounting Policies

6 Months Ended

Jun. 30, 2021

Accounting Policies [Abstract]

Summary of Significant Accounting Policies

2.	Summary of Significant Accounting Policies

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. The amendments in ASU 2019-12 are intended to simplify various aspects related to accounting for income taxes. ASU 2019-12 removes certain exceptions to the general principles in Topic 740 and also clarifies and amends existing guidance to improve consistent application. The Company adopted ASU 2019-12 as of January 1, 2021, on a prospective transition basis. The adoption of ASU 2019-12 did not have a material impact on the Company’s condensed consolidated financial statements.

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 (“ASU 2016-13”). 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. Subsequent to issuing ASU 2016-13, the FASB issued ASU 2018-19, Codification Improvements to Topic 326, Financial Instruments – Credit Losses, for the purpose of clarifying certain aspects of ASU 2016-13. In May 2019, the FASB issued ASU 2019-05, Financial Instruments – Credit Losses (Topic 326): Targeted Transition Relief, to provide entities with more flexibility in applying the fair value option on adoption of the credit impairment standard.

ASU 2018-19 and ASU 2019-05 have the same effective date and transition requirements as ASU 2016-13. 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. Early adoption 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 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. The amendments in ASU No. 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 No. 2021-04 are effective for all entities for fiscal years beginning after December 15, 2021, and interim periods within those fiscal years, with early adoption permitted, including interim periods within those fiscal years. The Company plans to adopt ASU 2021-04 and related updates on January 1, 2022. The Company is currently evaluating the impact of adopting this ASU on its condensed consolidated financial statements.

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 $1.1 million and $1.7 million during the three months ended June 30, 2021 and 2020, respectively, and $2.6 million and $3.2 million during the six months ended June 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

6 Months Ended

Jun. 30, 2021

Fair Value Disclosures [Abstract]

Fair Value Measurements

3.	Fair Value Measurements

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” in the Company’s Annual Report. There were no significant changes in these methodologies during the six months ended June 30, 2021.

There were no transfers in or out of Level 1 or 2 during the periods presented. The following tables present the fair value hierarchy for assets and liabilities measured at fair value on a recurring basis as of June 30, 2021 and December 31, 2020 (in thousands):

	June 30, 2021
	Level 1		Level 2		Level 3		Total
Financial assets:
Money market funds⁽¹⁾	$	73,621	$	—	$	—	$	73,621
U.S. government agency securities⁽²⁾		7,779		—		—		7,779
Federal agency securities⁽²⁾		—		5,123		—		5,123
Total financial assets	$	81,400	$	5,123	$	—	$	86,523

(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.

	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.

- 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

6 Months Ended

Jun. 30, 2021

Investments All Other Investments [Abstract]

Financial Instruments

4.	Financial Instruments

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

June 30, 2021	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Estimated Fair Value
Money market funds (cash equivalents)	$	73,621	$	—	$	—	$	73,621
U.S. government agency securities		7,778		1		—		7,779
Federal agency securities		5,122		1		—		5,123
Total financial assets	$	86,521	$	2	$	—	$	86,523
Classified as:
Cash and cash equivalents							$	73,621
Short-term investments								12,902
Total financial assets							$	86,523

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 June 30, 2021, the remaining contractual maturities of $12.9 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

6 Months Ended

Jun. 30, 2021

Lessee Disclosure [Abstract]

Lease

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 commenced during the second quarter of 2021.

For the three and six months ended June 30, 2021, the Company’s operating lease expense was $0.4 million and $0.6 million, respectively. For the three and six months ended June 30, 2020, the Company’s operating lease expense was $0.2 million and $0.4 million, respectively. The present value assumptions used in calculating the present value of the lease payments were as follows:

	June 30,			December 31,
	2021			2020
Weighted-average remaining lease term	1.6 years			2.3 years
Weighted-average discount rate		4.9	%		5.7	%

The maturity of the Company’s operating lease liabilities as of June 30, 2021 were as follows (in thousands):

Year	Undiscounted lease payments
Remaining in 2021	$	1,003
2022		1,719
2023		260
Total undiscounted lease payments		2,982
Less imputed interest		(114	)
Total operating lease liability	$	2,868

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

Six Months Ended June 30,

2021

2020

Cash paid for leases that were

included in operating cash

outflows

680

288

Stock Based Compensation

6 Months Ended

Jun. 30, 2021

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Stock Based Compensation

6.	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 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		1,157,488		$	5.90
Options exercised		(5,000	)	$	4.63
Options forfeited		(270,942	)	$	7.12
Options expired		(569	)	$	582.27
Outstanding — June 30, 2021		3,236,592		$	7.66		8.2
Exercisable — June 30, 2021		1,338,239		$	9.65

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 June 30,				Six Months Ended June 30,
	2021		2020		2021		2020
Employee Stock Options:
Risk-free rate	0.96%		0.40%		0.74%		1.29%
Expected term (in years)		5.7		5.9		6.0		5.6
Dividend yield	0.00%		0.00%		0.00%		0.00%
Volatility	92.79%		115.20%		93.64%		111.27%
Weighted-average fair value of stock options granted	$	3.37	$	5.25	$	4.45	$	5.50

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

	Three Months Ended June 30,				Six Months Ended June 30,
	2021		2020		2021		2020
Research and development	$	394	$	314	$	763	$	658
General and administrative⁽¹⁾		589		520		1,246		981
Total stock-based compensation expense	$	983	$	834	$	2,009	$	1,639

(1)	Included in general and administrative for the three and six months ended June 30, 2021 is stock-based compensation expense related to 13,713 shares and 23,862 shares, respectively, of common stock issued to certain board members in lieu of their cash compensation.

As of June 30, 2021, 2,842,373 shares of common stock were available for future grant and 3,236,592 options to purchase shares of common stock were outstanding. As of June 30, 2021, the Company had unrecognized employee stock-based compensation expense of $7.1 million, related to unvested stock awards, which is expected to be recognized over an estimated weighted-average period of 2.7 years.

Collaborations

6 Months Ended

Jun. 30, 2021

Organization Consolidation And Presentation Of Financial Statements [Abstract]

Collaborations

7.	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 entered into two amendments to the Mosaic research collaboration agreements in December 2019 and May 2020. See Note 11.

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”). 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 eliminates the profit-sharing arrangement in the Original ISU Abxis Agreement and 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 June 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 (“AMD”) and other disorders. Pursuant to the Biogen Agreement, the Company will perform certain pre-clinical and manufacturing activities (“Research Services”), and Biogen will be solely responsible for funding the pre-clinical and manufacturing activities and performing IND-enabling activities, worldwide clinical development, and commercialization. The Company will provide the Research Services over a term of thirty months with Biogen having the option to extend the term for two additional twelve-month periods.

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 six months ended June 30, 2021, the Company recognized no license revenue from the Biogen Agreement. For the six months ended June 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 $1.1 million and $1.6 million for the three months ended June 30, 2021 and 2020, respectively, and $2.6 million and $3.0 million for the six months ended June 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 six months ended June 30, 2021, the Company recognized $1.3 million in collaboration revenue from the beginning of period deferred revenue balance.

Net Loss per Share Attributable to Common Stockholders

6 Months Ended

Jun. 30, 2021

Earnings Per Share [Abstract]

Net Loss per Share Attributable to Common Stockholders

8.	Net Loss per Share Attributable to Common Stockholders

The following table sets forth the computation of the basic and diluted net loss per common share as follows (in thousands, except share and per share data):

	Three Months Ended June 30,						Six Months Ended June 30,
	2021			2020			2021			2020
Net loss attributable to common stockholders	$	(19,928	)	$	(17,248	)	$	(42,366	)	$	(21,301	)
Weighted-average number of shares used in computing net loss per share, basic and diluted		31,348,602			17,891,475			29,875,202			16,241,963
Net loss available for common stockholders per share, basic and diluted	$	(0.64	)	$	(0.96	)	$	(1.42	)	$	(1.31	)

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:

	June 30,
	2021		2020
Options to purchase common stock		3,236,592		2,010,315
Common stock warrants		85		722
Total		3,236,677		2,011,037

Stockholders' Equity

6 Months Ended

Jun. 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

6 Months Ended

Jun. 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”), formerly known as CMC ICOS Biologics, Inc., 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 $19.7 million and the payment obligations remaining as of June 30, 2021 were $7.0 million.

COVID-19

The current COVID-19 pandemic has presented a substantial public health and economic challenge around the world and is affecting our employees, potential trial participants and business operations. The full extent to which the COVID-19 pandemic will directly or indirectly impact our 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 our agreements. We are actively monitoring the impact of COVID-19 and the possible effects on our financial condition, liquidity, operations, clinical trials, suppliers, industry and workforce. All required MarzAA supplies for the MAA-304 and MAA-202 studies have been manufactured.

Related Parties

6 Months Ended

Jun. 30, 2021

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.

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 (Expense), Net

6 Months Ended

Jun. 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 June 30,						Six Months Ended June 30,
	2021			2020			2021			2020
Interest income	$	11		$	128		$	28		$	462
Miscellaneous income		2			—			11			679
Other		(27	)		(15	)		(53	)		(13	)
Total interest and other income (expense), net	$	(14	)	$	113		$	(14	)	$	1,128

Subsequent Event

6 Months Ended

Jun. 30, 2021

Subsequent Events [Abstract]

Subsequent Event

13.	Subsequent Event

In July 2021, we entered into agreements for additional clinical trial services for MarzAA and for our 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. We can terminate these agreements at our discretion and upon termination will be responsible to pay for those services incurred prior to termination plus reasonable wind-down expenses.

Summary of Significant Accounting Policies (Policies)	6 Months Ended
Summary of Significant Accounting Policies (Policies)	Jun. 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. The amendments in ASU 2019-12 are intended to simplify various aspects related to accounting for income taxes. ASU 2019-12 removes certain exceptions to the general principles in Topic 740 and also clarifies and amends existing guidance to improve consistent application. The Company adopted ASU 2019-12 as of January 1, 2021, on a prospective transition basis. The adoption of ASU 2019-12 did not have a material impact on the Company’s condensed consolidated financial statements. 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 (“ASU 2016-13”). 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. Subsequent to issuing ASU 2016-13, the FASB issued ASU 2018-19, Codification Improvements to Topic 326, Financial Instruments – Credit Losses, for the purpose of clarifying certain aspects of ASU 2016-13. In May 2019, the FASB issued ASU 2019-05, Financial Instruments – Credit Losses (Topic 326): Targeted Transition Relief, to provide entities with more flexibility in applying the fair value option on adoption of the credit impairment standard. ASU 2018-19 and ASU 2019-05 have the same effective date and transition requirements as ASU 2016-13. 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. Early adoption 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 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. The amendments in ASU No. 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 No. 2021-04 are effective for all entities for fiscal years beginning after December 15, 2021, and interim periods within those fiscal years, with early adoption permitted, including interim periods within those fiscal years. The Company plans to adopt ASU 2021-04 and related updates on January 1, 2022. The Company is currently evaluating the impact of adopting this ASU on its condensed consolidated financial statements.
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 $1.1 million and $1.7 million during the three months ended June 30, 2021 and 2020, respectively, and $2.6 million and $3.2 million during the six months ended June 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)

6 Months Ended

Jun. 30, 2021

Fair Value Disclosures [Abstract]

Assets and Liabilities Measured at Fair Value on a Recurring Basis

	June 30, 2021
	Level 1		Level 2		Level 3		Total
Financial assets:
Money market funds⁽¹⁾	$	73,621	$	—	$	—	$	73,621
U.S. government agency securities⁽²⁾		7,779		—		—		7,779
Federal agency securities⁽²⁾		—		5,123		—		5,123
Total financial assets	$	81,400	$	5,123	$	—	$	86,523

(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.

	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)

Financial Instruments (Tables)

6 Months Ended

Jun. 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):

June 30, 2021	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Estimated Fair Value
Money market funds (cash equivalents)	$	73,621	$	—	$	—	$	73,621
U.S. government agency securities		7,778		1		—		7,779
Federal agency securities		5,122		1		—		5,123
Total financial assets	$	86,521	$	2	$	—	$	86,523
Classified as:
Cash and cash equivalents							$	73,621
Short-term investments								12,902
Total financial assets							$	86,523

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)

6 Months Ended

Jun. 30, 2021

Lessee Disclosure [Abstract]

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

For the three and six months ended June 30, 2020, the Company’s operating lease expense was $0.2 million and $0.4 million, respectively. The present value assumptions used in calculating the present value of the lease payments were as follows:

	June 30,			December 31,
	2021			2020
Weighted-average remaining lease term	1.6 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 June 30, 2021 were as follows (in thousands):

Year	Undiscounted lease payments
Remaining in 2021	$	1,003
2022		1,719
2023		260
Total undiscounted lease payments		2,982
Less imputed interest		(114	)
Total operating lease liability	$	2,868

Schedule of Supplemental Cash Flow Information

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

Six Months Ended June 30,

2021

2020

Cash paid for leases that were

included in operating cash

outflows

680

288

Stock Based Compensation (Tables)

6 Months Ended

Jun. 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		1,157,488		$	5.90
Options exercised		(5,000	)	$	4.63
Options forfeited		(270,942	)	$	7.12
Options expired		(569	)	$	582.27
Outstanding — June 30, 2021		3,236,592		$	7.66		8.2
Exercisable — June 30, 2021		1,338,239		$	9.65

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 June 30,				Six Months Ended June 30,
	2021		2020		2021		2020
Employee Stock Options:
Risk-free rate	0.96%		0.40%		0.74%		1.29%
Expected term (in years)		5.7		5.9		6.0		5.6
Dividend yield	0.00%		0.00%		0.00%		0.00%
Volatility	92.79%		115.20%		93.64%		111.27%
Weighted-average fair value of stock options granted	$	3.37	$	5.25	$	4.45	$	5.50

Summary of Stock-Based Compensation Expense Recognized

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

	Three Months Ended June 30,				Six Months Ended June 30,
	2021		2020		2021		2020
Research and development	$	394	$	314	$	763	$	658
General and administrative⁽¹⁾		589		520		1,246		981
Total stock-based compensation expense	$	983	$	834	$	2,009	$	1,639

(1)	Included in general and administrative for the three and six months ended June 30, 2021 is stock-based compensation expense related to 13,713 shares and 23,862 shares, respectively, of common stock issued to certain board members in lieu of their cash compensation.

Net Loss per Share Attributable to Common Stockholders (Tables)

6 Months Ended

Jun. 30, 2021

Earnings Per Share [Abstract]

Basic and Diluted Net Loss Per Common Share

The following table sets forth the computation of the basic and diluted net loss per common share as follows (in thousands, except share and per share data):

	Three Months Ended June 30,						Six Months Ended June 30,
	2021			2020			2021			2020
Net loss attributable to common stockholders	$	(19,928	)	$	(17,248	)	$	(42,366	)	$	(21,301	)
Weighted-average number of shares used in computing net loss per share, basic and diluted		31,348,602			17,891,475			29,875,202			16,241,963
Net loss available for common stockholders per share, basic and diluted	$	(0.64	)	$	(0.96	)	$	(1.42	)	$	(1.31	)

Anti-dilutive Security not Included In Diluted per Share Calculations

	June 30,
	2021		2020
Options to purchase common stock		3,236,592		2,010,315
Common stock warrants		85		722
Total		3,236,677		2,011,037

Interest and Other Income, Net (Tables)

6 Months Ended

Jun. 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 June 30,						Six Months Ended June 30,
	2021			2020			2021			2020
Interest income	$	11		$	128		$	28		$	462
Miscellaneous income		2			—			11			679
Other		(27	)		(15	)		(53	)		(13	)
Total interest and other income (expense), net	$	(14	)	$	113		$	(14	)	$	1,128

Nature of Operations and Liquidity - Additional Information (Detail) $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2021 USD ($)	Mar. 31, 2021 USD ($)	Jun. 30, 2020 USD ($)	Mar. 31, 2020 USD ($)	Jun. 30, 2021 USD ($) Segment	Jun. 30, 2020 USD ($)	Dec. 31, 2020 USD ($)
Accounting Policies [Abstract]
Number of operating segment \| Segment					1
Net loss	$ 19,928	$ 22,438	$ 17,248	$ 4,053	$ 42,366	$ 21,301
Accumulated deficit	357,127				357,127		$ 314,761
Cash, cash equivalents and short-term investments	$ 86,500				$ 86,500

- Definition

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

+ References

+ Details

Summary of Significant Accounting Policies - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Research and Development Expense
Summary Of Significant Accounting Policies [Line Items]
Cost of collaboration revenue	$ 1.1	$ 1.7	$ 2.6	$ 3.2

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

Jun. 30, 2021

Dec. 31, 2020

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

Assets, fair value

$ 86,523

$ 81,897

Money Market Funds

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

Assets, fair value

^[1]

73,621

30,360

U.S. Government Agency Securities

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

Assets, fair value

7,779

^[2]

37,837

^[3]

Federal Agency Securities | Short-Term Investments

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

Assets, fair value

5,123

^[2]

13,700

^[3]

Fair Value, Inputs, Level 1

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

Assets, fair value

81,400

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]

73,621

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

7,779

^[2]

37,837

^[3]

Fair Value, Inputs, Level 2

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

Assets, fair value

5,123

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

$ 5,123

^[2]

$ 13,700

^[3]

[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.
[3]	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 Measured at Fair Value - Additional Information (Detail) $ in Millions	Dec. 31, 2020 USD ($)
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 Investments Classified as Available-for-sale Securities (Detail) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	$ 86,521	$ 81,892
Gross Unrealized Gains	2	5
Estimated Fair Value	86,523	81,897
Money Market Funds \| Cash Equivalents
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	73,621	30,360
Estimated Fair Value	73,621	30,360
U.S. Government Agency Securities
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	7,778	37,835
Gross Unrealized Gains	1	2
Estimated Fair Value	7,779	37,837
Cash and Cash Equivalents
Schedule Of Available For Sale Securities [Line Items]
Estimated Fair Value	73,621	30,360
Short-Term Investments
Schedule Of Available For Sale Securities [Line Items]
Estimated Fair Value	12,902	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	5,122	13,697
Gross Unrealized Gains	1	3
Estimated Fair Value	$ 5,123	$ 13,700

Financial Instruments - Additional Information (Detail)	6 Months Ended
Financial Instruments - Additional Information (Detail)	Jun. 30, 2021 USD ($)
Financial Instrument [Line Items]
Material realized gains or losses on available-for-sale securities	$ 0
Available-for-sale debt securities current	$ 12,900,000
Maximum
Financial Instrument [Line Items]
Available for sale debt securities contractual maturities	1 year

Lease - Additional Information (Detail) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended		6 Months Ended
	Apr. 30, 2021	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 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		$ 2,982		$ 2,982
Operating lease expense		$ 400	$ 200	$ 600	$ 400
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 not yet commenced description	commenced during the second quarter of 2021.

Summary of Present Value Assumptions used in Calculating Present Value of Lease Payments (Detail)	Jun. 30, 2021	Dec. 31, 2020
Lessee Disclosure [Abstract]
Weighted-average remaining lease term	1 year 7 months 6 days	2 years 3 months 18 days
Weighted-average discount rate	4.90%	5.70%

Schedule of Maturity of Operating Lease Liabilities (Detail) $ in Thousands	Jun. 30, 2021 USD ($)
Operating Lease Liabilities Payments Due [Abstract]
Remaining in 2021	$ 1,003
2022	1,719
2023	260
Total undiscounted lease payments	2,982
Less imputed interest	(114)
Total operating lease liability	$ 2,868

Schedule of Supplemental Cash Flow Information (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020
Operating Lease Liabilities Payments Due [Abstract]
Cash paid for leases that were included in operating cash outflows	$ 680	$ 288

Stock Based Compensation - Additional Information (Detail) - USD ($) $ in Millions		6 Months Ended
	Jun. 09, 2021	Jun. 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		2,842,373
Shares remaining outstanding		3,236,592		2,355,615
Employee Stock Option
Schedule Of Share Based Compensation Arrangements By Share Based Payment Award [Table]
Unrecognized employee stock based compensation expense		$ 7.1
Unrecognized employee stock based compensation expense, period for recognition		2 years 8 months 12 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 Under Company's 2018 Plan (Detail) - $ / shares	6 Months Ended	12 Months Ended
	Jun. 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	1,157,488
Number of Shares Underlying Outstanding Options, Options exercised	(5,000)
Number of Shares Underlying Outstanding Options, Options forfeited	(270,942)
Number of Shares Underlying Outstanding Options, Options expired	(569)
Number of Shares Underlying Outstanding Options, Ending Balance	3,236,592	2,355,615
Number of Shares Underlying Outstanding Options, Exercisable - June 30, 2020	1,338,239
Weighted- Average Exercise Price
Weighted- Average Exercise Price, Beginning Balance	$ 8.59
Weighted- Average Exercise Price, Options granted	5.90
Weighted- Average Exercise Price, Options exercised	4.63
Weighted- Average Exercise Price, Options forfeited	7.12
Weighted- Average Exercise Price, Options expired	582.27
Weighted- Average Exercise Price, Ending Balance	7.66	$ 8.59
Weighted- Average Exercise Price, Exercisable - June 30, 2020	$ 9.65
Weighted-Average Remaining Contractual Term (Years)
Weighted-Average Remaining Contractual Term (Years), Outstanding Balance	8 years 2 months 12 days	8 years

Fair Values of Stock Options Estimated Using Black-Scholes Valuation Model (Detail) - Employee Stock Option - $ / shares	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions Black Scholes Method Used [Line Items]
Risk-free rate	0.96%	0.40%	0.74%	1.29%
Expected term (in years)	5 years 8 months 12 days	5 years 10 months 24 days	6 years	5 years 7 months 6 days
Dividend yield	0.00%	0.00%	0.00%	0.00%
Volatility	92.79%	115.20%	93.64%	111.27%
Weighted-average fair value of stock options granted	$ 3.37	$ 5.25	$ 4.45	$ 5.50

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

3 Months Ended

6 Months Ended

Jun. 30, 2021

Jun. 30, 2020

Jun. 30, 2021

Jun. 30, 2020

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

Total stock-based compensation expense

$ 983

$ 834

$ 2,009

$ 1,639

Research and development

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

Total stock-based compensation expense

394

314

763

658

General and Administrative

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

Total stock-based compensation expense

^[1]

$ 589

$ 520

$ 1,246

$ 981

[1]	Included in general and administrative for the three and six months ended June 30, 2021 is stock-based compensation expense related to 13,713 shares and 23,862 shares, respectively, of common stock issued to certain board members in lieu of their cash compensation.

Summary of Stock-Based Compensation Expense Recognized (Parenthetical) (Detail) - shares	3 Months Ended	6 Months Ended
	Jun. 30, 2021	Jun. 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	13,713	23,862

Collaborations - Additional Information (Detail) - USD ($)	1 Months Ended		3 Months Ended		6 Months Ended
	Jan. 31, 2020	Dec. 31, 2018	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Revenue Recognition Multiple Deliverable Arrangements [Line Items]
License and collaboration revenue			$ 1,132,000	$ 1,658,000	$ 2,599,000	$ 18,024,000
Deferred revenue, recognized					1,300
License
Revenue Recognition Multiple Deliverable Arrangements [Line Items]
License and collaboration revenue				23,000		15,068,000
License \| Transfer of Exclusive License and Related Know-How
Revenue Recognition Multiple Deliverable Arrangements [Line Items]
License and collaboration revenue						15,000,000.0
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			1,132,000	1,635,000	2,599,000	2,956,000
Collaboration \| Reimbursable Out-of-Pocket and Personnel Costs Incurred Related to Research Services
Revenue Recognition Multiple Deliverable Arrangements [Line Items]
License and collaboration revenue			$ 1,100,000	$ 1,600,000	2,600,000	$ 3,000,000.0
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 \| 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			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	$ 15,000,000.0
Biogen \| Exclusive License \| Maximum
Revenue Recognition Multiple Deliverable Arrangements [Line Items]
Development and sales milestone payments	$ 340,000,000.0

Basic and Diluted Net Loss Per Common Share (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Earnings Per Share [Abstract]
Net loss attributable to common stockholders	$ (19,928)	$ (17,248)	$ (42,366)	$ (21,301)
Weighted-average number of shares used in computing net loss per share, basic and diluted	31,348,602	17,891,475	29,875,202	16,241,963
Net loss available for common stockholders per share, basic and diluted	$ (0.64)	$ (0.96)	$ (1.42)	$ (1.31)

- Definition

Amount, after deduction of tax, noncontrolling interests, dividends on preferred stock and participating securities; of income (loss) available to common shareholders.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
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-SubTopic 10
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Reference 2: http://www.xbrl.org/2003/role/disclosureRef
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-Name Accounting Standards Codification
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Reference 3: http://www.xbrl.org/2003/role/disclosureRef
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-Name Accounting Standards Codification
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+ Details

Anti-dilutive Security not Included In Diluted per Share Calculations (Detail) - shares	6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti dilutive securities	3,236,677	2,011,037
Options To Purchase Common Stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti dilutive securities	3,236,592	2,010,315
Common Stock Warrants
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti dilutive securities	85	722

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 - Additional Information (Detail) - AGC Biologics, Inc - Marzeptacog Alfa Activated and Dalcinonacog Alfa $ in Millions	Jun. 30, 2021 USD ($)
Commitments And Contingencies Disclosure [Line Items]
Firm work order supporting clinical trials	$ 19.7
Contractual obligation payments	$ 7.0

Related Parties - Additional Information (Detail) - USD ($) $ in Millions		6 Months Ended
	May 08, 2020	Jun. 30, 2020	Jan. 10, 2020
License and Collaboration Agreement (the “Biogen Agreement”)
Related Party Transaction [Line Items]
Upfront license fee received from collaboration agreement			$ 15.0
Mosaic Biosciences Inc
Related Party Transaction [Line Items]
One time expense related to collaboration	$ 0.8
Mosaic Biosciences Inc \| Maximum
Related Party Transaction [Line Items]
Milestone payments , clinical development events		$ 4.0

Detail of Interest and Other Income (Expense), Net (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Other Income And Expenses [Abstract]
Interest income	$ 11	$ 128	$ 28	$ 462
Miscellaneous income	2		11	679
Other	(27)	(15)	(53)	(13)
Interest and other income (expense), net	$ (14)	$ 113	$ (14)	$ 1,128

Subsequent Event - Additional Information (Detail) - Service Agreements - Subsequent Event - Maximum $ in Millions	Jul. 31, 2021 USD ($)
Marzeptacog Alfa Activated
Subsequent Event [Line Items]
Cost of services as per agreement	$ 3.2
Dalcinonacog Alfa
Subsequent Event [Line Items]
Cost of services as per agreement	$ 6.5