ContraFect (CFRXQ) 10-K 31 Mar 23 2022 FY Annual report Financial data

Cover Page

Cover Page - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Mar. 24, 2023	Jun. 30, 2022
Cover [Abstract]
Document Type	10-K
Amendment Flag	false
Entity Interactive Data Current	Yes
Document Period End Date	Dec. 31, 2022
Document Fiscal Year Focus	2022
Document Fiscal Period Focus	FY
Trading Symbol	CFRX
Entity Registrant Name	ContraFect Corporation
Entity Central Index Key	0001478069
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Current Reporting Status	Yes
Entity Emerging Growth Company	false
Entity Public Float			$ 120.8
Title of 12(b) Security	Common Stock, Par Value $0.0001 per share
Security Exchange Name	NASDAQ
Entity Shell Company	false
Entity File Number	001-36577
Entity Tax Identification Number	39-2072586
Entity Incorporation, State or Country Code	DE
Entity Address, Address Line One	28 Wells Avenue
Entity Address, Address Line Two	3rd Floor
Entity Address, City or Town	Yonkers
Entity Address, State or Province	NY
Entity Address, Postal Zip Code	10701
City Area Code	914
Local Phone Number	207-2300
Entity Common Stock, Shares Outstanding		1,565,920
Document Annual Report	true
Document Transition Report	false
ICFR Auditor Attestation Flag	false
Auditor Name	Ernst & Young, LLP
Auditor Firm ID	42
Auditor Location	Hartford, Connecticut

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Current assets:
Cash and cash equivalents	$ 8,907	$ 16,654
Marketable securities	4,775	37,631
Prepaid expenses	1,382	4,439
Other current assets	2,642	4,140
Total current assets	17,706	62,864
Property and equipment, net	627	741
Operating lease right-of-use assets	2,241	2,544
Other assets	105	613
Total assets	20,679	66,762
Current liabilities:
Accounts payable	13,671	2,389
Accrued and other current liabilities	6,498	9,128
Current portion of lease liabilities	671	657
Total current liabilities	20,840	12,174
Warrant liabilities	9,299	2,530
Long-term portion of lease liabilities	2,210	2,609
Other liabilities	182	73
Total liabilities	32,531	17,386
Commitments and contingencies (Note 8)
Stockholders' (deficit) equity:
Preferred stock, $0.0001 par value, 25,000,000 shares authorized and none issued or outstanding at December 31, 2022 and 2021
Common stock, $0.0001 par value, 125,000,000 shares authorized; 594,983 and 491,626 shares issued and outstanding at December 31, 2022 and 2021	1	1
Additional paid-in capital	313,884	310,011
Accumulated other comprehensive loss	(32)	(84)
Accumulated deficit	(325,705)	(260,552)
Total stockholders' (deficit) equity	(11,852)	49,376
Total liabilities and stockholders' (deficit) equity	$ 20,679	$ 66,762

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - $ / shares	Dec. 31, 2022	Dec. 31, 2021
Statement of Financial Position [Abstract]
Preferred stock, par value	$ 0.0001	$ 0.0001
Preferred stock, shares authorized	25,000,000	25,000,000
Preferred stock, shares outstanding	0	0
Preferred stock, shares issued	0	0
Common stock, par value	$ 0.0001	$ 0.0001
Common stock, shares authorized	125,000,000	125,000,000
Common stock, shares issued	594,983	491,626
Common stock, shares outstanding	594,983	491,626

Consolidated Statements of Oper

Consolidated Statements of Operations - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Operating expenses:
Research and development, including stock-based compensation of $1,027, $933 and $655, respectively	$ 44,738	$ 35,508	$ 22,614
General and administrative, including stock-based compensation of $2,845, $2,261 and $1,921, respectively	12,151	11,757	11,625
Restructuring	7,719
Total operating expenses	64,608	47,265	34,239
Loss from operations	(64,608)	(47,265)	(34,239)
Other (expense) income:
Interest income	81	109	192
Other expense	(4,813)		(2,165)
Change in fair value of warrant liabilities	4,187	26,874	8,056
Total other (expense) income, net	(545)	26,983	6,083
Net loss	$ (65,153)	$ (20,282)	$ (28,156)
Basic net loss per share	$ (124.97)	$ (44.12)	$ (98.95)
Shares used in computing basic net loss per share	521,359	459,699	284,544
Diluted net loss per share	$ (124.97)	$ (44.12)	$ (98.95)
Shares used in computing diluted net loss per share	521,359	459,699	284,544

Consolidated Statements of Op_2

Consolidated Statements of Operations (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Stock-based compensation expense	$ 3,873	$ 3,194	$ 2,576
Research and Development Expense [Member]
Stock-based compensation expense	1,027	933	655
General and Administrative Expense [Member]
Stock-based compensation expense	$ 2,845	$ 2,261	$ 1,921

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Loss - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Statement of Comprehensive Income [Abstract]
Net loss	$ (65,153)	$ (20,282)	$ (28,156)
Other comprehensive gain (loss):
Unrealized gain (loss) on available-for-sale securities	52	(63)	(21)
Comprehensive loss	$ (65,101)	$ (20,345)	$ (28,177)

Consolidated Statements of Stoc

Consolidated Statements of Stockholders' (Deficit) Equity - USD ($) $ in Thousands	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Other Comprehensive Loss [Member]	Accumulated Deficit [Member]
Beginning Balance at Dec. 31, 2019	$ 15,546	$ 1	$ 227,659	$ 0	$ (212,114)
Beginning Balance, Shares at Dec. 31, 2019		191,619
Issuance of securities in registered offerings	21,108		21,108
Issuance of securities in registered offerings, Shares		147,471
Issuance of securities in private placement	3,000		3,000
Issuance of securities in private placement, Shares		8,427
Financing cost of sale of securities	(1,462)		(1,462)
Issuance of common stock for exercise of warrants	$ 29		29
Issuance of common stock for exercise of warrants, Shares	73	73
Stock-based compensation	$ 2,576		2,576
Unrealized loss on marketable securities	(21)			(21)
Issuance of common stock for exercise of options, Shares		4
Net loss	(28,156)				(28,156)
Ending balance at Dec. 31, 2020	12,620	$ 1	252,910	(21)	(240,270)
Ending balance, Shares at Dec. 31, 2020		347,594
Issuance of securities in registered offerings	57,500		57,500
Issuance of securities in registered offerings, Shares		143,750
Financing cost of sale of securities	(3,703)		(3,703)
Issuance of common stock for exercise of warrants	$ 110		110
Issuance of common stock for exercise of warrants, Shares	282	282
Stock-based compensation	$ 3,194		3,194
Unrealized loss on marketable securities	(63)			(63)
Net loss	(20,282)				(20,282)
Ending balance at Dec. 31, 2021	49,376	$ 1	310,011	(84)	(260,552)
Ending balance, Shares at Dec. 31, 2021		491,626
Issuance of securities in registered offerings, Shares		54,375
Issuance of common stock for exercise of pre-funded warrants, Shares		48,982
Stock-based compensation	3,873		3,873
Unrealized loss on marketable securities	$ 52			52
Issuance of common stock for exercise of options, Shares	0
Net loss	$ (65,153)				(65,153)
Ending balance at Dec. 31, 2022	$ (11,852)	$ 1	$ 313,884	$ (32)	$ (325,705)
Ending balance, Shares at Dec. 31, 2022		594,983

Statements of Cash Flows

Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Cash flows from operating activities
Net loss	$ (65,153)	$ (20,282)	$ (28,156)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation	154	148	168
Stock-based compensation expense	3,873	3,194	2,576
Fair value of warrants issued in excess of proceeds received	3,961
Issuance costs allocated to warrants	851		2,175
Change in fair value of warrant liabilities	(4,187)	(26,874)	(8,056)
Net amortization of premium paid on marketable securities	763	924	378
Changes in operating assets and liabilities:
Decrease (increase) in prepaid expenses and other current and non-current assets	5,003	(4,336)	1,738
Increase (decrease) in accounts payable, accrued liabilities and other liabilities	8,761	6,101	(4,010)
Net cash used in operating activities	(45,974)	(41,125)	(33,187)
Cash flows from investing activities
Purchases of marketable securities		(48,698)	(47,555)
Sales of marketable securities	5,525
Proceeds from maturities of marketable securities	26,620	37,085	20,151
Purchases of property and equipment	(62)
Net cash provided by (used in) investing activities	32,083	(11,613)	(27,404)
Cash flows from financing activities
Proceeds from issuance of equity securities	6,995	57,500	55,500
Payment of financing costs of securities sold	(851)	(3,703)	(3,637)
Proceeds from exercise of warrants		110	29
Net cash provided by financing activities	6,144	53,907	51,892
Net (decrease) increase in cash and cash equivalents	(7,747)	1,169	(8,699)
Cash and cash equivalents at beginning of period	16,654	15,485	24,184
Cash and cash equivalents at end of period	8,907	$ 16,654	15,485
Supplemental disclosures of cash flow information:
Issuance of warrants to purchase common stock	$ 10,956		$ 31,391

Organization and Description of

Organization and Description of Business	12 Months Ended
	Dec. 31, 2022
Accounting Policies [Abstract]
Organization and Description of Business	1. Organization and Description of Business Organization and Business ContraFect Corporation (the “Company”) is a clinical-stage biotechnology company focused on the discovery and development of direct lytic agents (“DLAs”), including lysins and amurin peptides, as new medical modalities for the treatment of life-threatening, antibiotic-resistant infections. The Company intends to address antibiotic-resistant infections using product candidates from our lysin and amurin peptide platforms. DLAs are fundamentally different than antibiotics and offer a potential paradigm shift in the treatment of antibiotic-resistant infections. The Company’s most advanced product candidate is exebacase, a lysin which targets S. aureus S. aureus Exebacase was being studied in a pivotal Phase 3 superiority study (the “DISRUPT study”) to evaluate the safety, tolerability, efficacy and pharmacokinetics of intravenous (“IV”) exebacase when used in addition to background standard of care antibiotic therapy for the treatment of S. aureus pre-specified follow-up On July 29, 2022, the Company initiated a restructuring plan resulting in a reduction in workforce. The restructuring plan was designed to reduce costs and align resources with the Company’s anticipated product development milestones for exebacase and CF-370 write-off The Company has incurred recurring losses since inception as a research and development organization and has an accumulated deficit of $325.7 million as of December 31, 2022. For the year ended December 31, 2022, the Company used $46.0 million of cash in operations. The Company has relied on its ability to fund its operations through public and private debt and equity financings, and, to a lesser extent, grant funding and government contracts. The Company expects operating losses and negative cash flows to continue at significant levels in the future as it continues to advance its programs. As of December 31, 2022, the Company had $13.7 million in cash, cash equivalents and marketable securities, which, without additional funding, the Company believes will not be sufficient to meet its obligations within the next twelve months from the date of issuance of these consolidated financial statements. The Company plans to continue to fund its operations through public or private debt and equity financings, but there can be no assurances that such financing will continue to be available to the Company on satisfactory terms, or at all, particularly in light of the Trial Closure. As such, management has not considered the potential for future capital raises in its assessment of the Company’s ability to meet its obligations for the next twelve months, and substantial doubt exists about the Company’s ability to continue as a going concern for twelve months from the date the financial statements were issued. If the Company is unable to obtain funding, the Company would be forced to delay, further reduce its workforce or reduce or eliminate its research and development programs, which could adversely affect its business prospects, or the Company may be unable to continue operations or continue as a going concern and may be forced to sell or liquidate the business. The consolidated financial statements have been prepared assuming that the Company will continue as a going concern, which contemplates continuity of operations, the realization of assets and the satisfaction of liabilities and commitments in the normal course of business. On March 22, 2021, the Company completed an underwritten public offering under the Company’s registration statement on Form S-3 (Reg. No. 333-246359) (the “Form-S-3”). The Form S-3 was declared effective by the SEC on August 31, 2020 and allows the Company to offer and sell from time-to-time up to $ million of common stock, preferred stock, debt securities, warrants or units comprised of any combination of these securities. The Company issued 143,750 shares of its common stock, including shares sold pursuant to the fully exercised overallotment option granted to the underwriters in connection with the offering, at a public offering price of $400.00 per share, resulting in net proceeds to the Company of $53.8 million after underwriting discounts and commissions and offering expenses payable by the Company. On December 15, 2022, the Company completed (i) a registered direct offering under the Form S-3 of 54,375 shares of its common stock and a pre-funded warrant to purchase 623,919 shares of common stock (the “Pre-Funded Warrant”) and (ii) a concurrent private placement in which the Company issued a Class A warrant to purchase up to an aggregate of 1,356,589 shares of common stock (the “Class A Warrant”) and a Class B warrant to purchase up to an aggregate of 678,294 shares of common stock (the “Class B Warrant”) (collectively, the “2022 Offering”). All shares of common stock, the Pre-Funded Warrant, the Class A Warrant and the Class B Warrant were issued together to a single accredited investor purchaser for consideration equating to $10.32 share of common stock (or Pre-Funded Warrant to purchase one share of common stock, less a nominal exercise price), together with a Class A Warrant to purchase two shares of common stock and a Class B warrant to purchase one share of common stock, in the case of each of the Class A Warrant and Class B Warrant, for no additional consideration but each with an exercise price per share of $10.32, for aggregate net proceeds to the Company of $6.1 million after placement agent fees and offering expenses payable by the Company. On March 2, 2023, the Company completed (i) a registered direct offering under the Form S-3 of shares of its common stock and a pre-funded warrant to purchase shares of common stock and (ii) a concurrent private placement in which the Company issued a warrant to purchase up to an aggregate of shares of common stock (collectively, the “2023 Offering”). All securities in the 2023 Offering were issued to the same single accredited investor purchaser as in the 2022 Offering for consideration equating to $ share of common stock, less a nominal exercise price), together with a warrant to purchase The significant changes in common stock outstanding are expected to impact the year-over-year comparability one-for-eighty

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2022
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	2. Summary of significant accounting policies Basis of Presentation The accompanying financial information has been prepared in accordance with U.S. generally accepted accounting principles (“U.S. GAAP”). Principles of Consolidation The Company has a wholly-owned subsidiary, ContraFect International Limited, in Scotland that establishes legal status for interactions with the European Economic Area. This subsidiary is dormant or is otherwise non-operative. Segment and Geographic Information Operating segments are identified as components of an enterprise about which separate discrete financial information is available for evaluation by the chief operating decision maker, or decision-making group, in making decisions on how to allocate resources and assess performance. The Company’s chief operating decision maker is the chief executive officer. The Company and the chief decision maker view the Company’s operations and manage its business as one operating segment. The Company operates in only one geographic segment. Significant Risks and Uncertainties The Company’s operations are subject to a number of factors that can affect its operating results and financial condition. Such factors include, but are not limited to, the results of clinical testing and trial activities of the Company’s products, the Company’s ability to obtain regulatory approval to market its products, competition from products manufactured and sold or being developed by other companies, the price of, and demand for, the Company’s products, the Company’s ability to negotiate favorable licensing or other manufacturing and marketing agreements for its products, the Company’s ability to raise capital and the effects of COVID-19 The Company currently relies on a single manufacturer of drug substance for each of its product candidates and two manufacturers of drug product, one located in the United States and one in Western Europe, and there are no long-term supply agreements in place. A sustained disruption in the operations of any of these manufacturers, or in the event the Company would need to change to a new supplier, could result in a significant delay in the ability of the Company to complete any associated activities. Use of Estimates The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of expenses during the reporting period. The Company bases estimates and assumptions on historical experience when available and on various factors that it believes to be reasonable under the circumstances. On an ongoing basis, the Company evaluates its estimates and assumptions, including those related to stock-based compensation, warrant valuation, research and development accruals and prepaid expenses and realization of net deferred income tax assets. The Company’s actual results may differ from these estimates under different assumptions or conditions. There have been no significant changes from the Company’s original estimates in any periods presented. Concentrations of Credit Risk Financial instruments which potentially subject the Company to credit risk consist primarily of cash, cash equivalents and marketable securities. The Company holds these investments in highly rated financial institutions, and, by policy, limits the amounts of credit exposure to any one financial institution. These amounts at times may exceed federally insured limits. The Company’s accounts at Silicon Valley Bank have not experienced any credit losses and the Company does not believe it has material exposure to any significant credit risk on these funds. The Company maintains the majority of its cash, cash equivalents and marketable securities at other financial institutions. The Company has no off-balance Cash and Cash Equivalents The Company considers all highly liquid investments with maturities at the date Marketable Securities Marketable securities consists of investments in corporate debt securities. Management determines the appropriate of realized losses on sales of marketable securities for the year ended December , and realized gains or losses on sales of marketable securities for the year ended December , . There were $ of realized gains on sales of marketable securities for the year ended December , . There were marketable securities that had been in an unrealized loss position for more than months as of December , or . The Company reviews marketable securities for other-than-temporary impairment whenever the fair value of a marketable security is less than the amortized cost and evidence indicates that a marketable security’s carrying amount is not recoverable within a reasonable period of time. Other-than-temporary impairments of investments are recognized in the consolidated statements of operations if the Company has experienced a credit loss, has the intent to sell the marketable security, or if it is more likely than not that the Company will be required to sell the marketable security before recovery of the amortized cost basis. Evidence considered in this assessment includes reasons for the impairment, compliance with the Company’s investment policy, the severity and the duration of the impairment and changes in value subsequent to the end of the period. Fair Value of Financial Instruments The Company’s financial instruments consist of cash and cash equivalents, marketable securities, accounts payable, accrued liabilities and warrant liabilities. Fair value estimates of these instruments are made at a specific point in time, based on relevant market information. These estimates may be subjective in nature and involve uncertainties and matters of judgment and therefore cannot be determined with precision. The fair value of the Company’s warrant liabilities is based upon unobservable inputs, as described further below. The Company discloses information on all assets and liabilities reported at fair value using a hierarchy of inputs used in measuring fair value that maximizes the use of observable inputs and minimizes the use of unobservable inputs by requiring that the observable inputs be used when available. Observable inputs are inputs that market participants would use in pricing the asset or liability based on market data obtained from sources independent of the Company. Unobservable inputs are inputs that reflect the Company’s assumptions about the inputs that market participants would use in pricing the asset or liability, and are developed based on the best information available in the circumstances. The fair value hierarchy applies only to the valuation inputs used in determining the reported fair value of the investments and is not a measure of the investment credit quality. The three levels of the fair value hierarchy are described below: Level 1—Valuations based on unadjusted quoted prices in active markets for identical assets or liabilities that the Company has the ability to access at the measurement date. Level 2—Valuations based on quoted prices for similar assets or liabilities in markets that are not active or for which all significant inputs are observable, either directly or indirectly. Level 3—Valuations that require inputs that reflect the Company’s own assumptions that are both significant to the fair value measurement and unobservable. To the extent that valuation is based on models or inputs that are less observable or unobservable in the market, the determination of fair value requires more judgment. Accordingly, the degree of judgment exercised by the Company in determining fair value is greatest for instruments categorized in Level 3. A financial instrument’s level within the fair value hierarchy is based on the lowest level of any input that is significant to the fair value measurement. The Company had no liabilities classified as Level 1 or Level 2. The carrying amounts reported in the accompanying financial statements for accounts payable and accrued expenses approximate their respective fair values due to their short-term maturities. The fair value of the warrant liabilities is discussed in Note 4, “Fair Value Measurements.” Property, Office Equipment, and Leasehold Improvements Property and equipment are recorded at cost less accumulated depreciation. Depreciation of property and equipment is provided by the straight-line method over their estimated useful lives, ranging from three Leasehold improvements are amortized on a straight-line basis over the useful life of the improvement or the initial lease term, whichever is shorter. Costs for normal repair and maintenance are charged to expense as incurred. Impairment of Long-lived Assets The Company reviews long-lived assets for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable. An impairment loss would be recognized when estimated undiscounted future cash flows expected to result from the use of the asset and its eventual disposition is less than its carrying amount. During the periods ended December 31, 2022 and 2021, impairment of long-lived assets occurred. Research and Development Costs Research and development costs are charged to expense as incurred and are typically made up of salaries and benefits, clinical trial activities, drug development and manufacturing costs, and third-party service fees, including for clinical research organizations and investigative sites. Costs for certain development activities, such as clinical trials, are recognized based on an evaluation of the progress to completion of specific tasks using data such as patient enrollment, clinical site activations, or information provided by vendors on their actual costs incurred. Payments for these activities are based on the terms of the individual arrangements, which may differ from the pattern of costs incurred, and are reflected in the financial statements as prepaid expenses or accrued liabilities. Stock-based Compensation Stock-based compensation is measured and recognized as compensation expense for all stock-based payment awards made to employees, directors, and non-employees, Compensation expense based on the grant date fair value is generally amortized over the requisite service period of the award on a straight-line basis. The fair value of options is calculated using the Black-Scholes option pricing model on the date of grant based on key assumptions such as stock price, risk free interest rates, expected volatility, expected term, and expected dividend yield. The Company’s estimates of these assumptions are based on historical data and judgment regarding future trends and factors. Income Taxes The Company uses the asset and liability method to calculate deferred tax assets and liabilities. Deferred taxes are recognized based on the differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases using enacted tax rates expected to apply to taxable income in the years in which those differences are expected to be recovered or settled. The Company records a valuation allowance against a deferred tax asset when it is more-likely-than-not The Company is subject to federal, state and local taxes and follows a recognition threshold and measurement attribute for the financial statement recognition and measurement of a tax position taken or expected to be taken in a tax return. The Company recognizes tax benefits or expenses of uncertain tax positions in the year such determination is made when the position is “more likely than not” to be sustained assuming examination by tax authorities. Management has reviewed the Company’s tax positions for all open tax years (tax years ended December 31, 2011 through December 31, 2022) and concluded that provision for unrecognized tax benefits or expense is required in these financial statements. There are no income tax audits in progress as of December 31, 2022. Government Contracts and Grant Agreements On March 10, 2021, the Company entered into a cost-share contract (the “BARDA Contract”) with BARDA, a division of the U.S. Department of Health and Human Services’ Office of the Assistant Secretary for Preparedness and Response. The base period for the BARDA Contract included government funding of up to $9.8 million to reimburse expenses to support the conduct of the Phase 3 DISRUPT study and futility analysis. In connection with the Trial Closure, the BARDA Contract was modified to provide for up to $6.6 million in funding to support a futility outcome root-cause analysis and the close-out of the Phase 3 DISRUPT study of exebacase. The Company recognizes a receivable in other current assets with a related reduction in its research and development expenses when the actual reimbursable costs have been incurred and the Company has complied with the conditions of the applicable government contract or grant agreement and the amounts will be received. The Company recognized a reduction to its research and development expense in the amount of $ million, $ million and $ million for the years ended December 31, 2022, 2021 and 2020 respectively. The receivable for government contracts and grant agreements as of December 31, 2022 and 2021 was $ million and $ million, respectively. The Company has $ million of committed government contract and grant agreement funding remaining as of December 31, 2022. Restructuring The Company has made estimates and judgments regarding the amount and timing Net Loss per Share Applicable to Common Stockholders Basic net loss per share applicable to common stockholders is calculated by dividing net loss applicable to common stockholders by the weighted average shares outstanding during the period, without consideration for common stock equivalents. Diluted net loss per share applicable to common stockholders is calculated by adjusting weighted average shares outstanding for the dilutive effect of common stock equivalents outstanding for the period, determined using the treasury-stock method. For purposes of the dilutive net loss per share applicable to common stockholders’ calculation, stock options and warrants are considered to be common stock equivalents but are excluded from the calculation of diluted net loss per share applicable to common stockholders, as their effect would be anti-dilutive; therefore, basic and diluted net loss per share applicable to common stockholders were the same for all periods presented. Recently Adopted Accounting Pronouncements Government Assistance On January 1, 2022, the Company adopted Accounting Standards Update No. 2021-10, Disclosure by Business Entities about Government Assistance (ASU 2021-10) 2021-10 Income Taxes On January 1, 2021, the Company adopted Accounting Standards Update No. 2019-12, Income Taxes (Topic 740) Recently Issued Accounting Pronouncements Not Yet Adopted In June 2016, the FASB issued a new Accounting Standards Update, Financial Instruments-Credit Losses (ASU 2016-13). 2016-13 available-for-sale disclosures.

Marketable Securities

Marketable Securities	12 Months Ended
	Dec. 31, 2022
Investments, Debt and Equity Securities [Abstract]
Marketable Securities	3. Marketable Securities Marketable securities at December 31, 2022 consisted of the following (in thousands): Marketable Securities Amortized Cost Unrealized Unrealized Fair Current: Corporate debt $ 4,807 $ — $ (32 ) $ 4,775 Marketable securities at December 31, 2021 consisted of the following (in thousands): Marketable Securities Amortized Cost Unrealized Unrealized Fair Current: Corporate debt $ 37,715 $ — $ (84 ) $ 37,631 Corporate debt includes obligations issued by investment-grade corporations. At December 31, 2022, the Company held only investments that have maturities of less than one year. At December 31, 2022 and 2021, the Company held debt securities, respectively, that individually and in total were in an immaterial unrealized loss position for . The aggregate fair value of debt securities in an unrealized loss position at December 31, 2022 and 2021 was $ million and million, respectively. The Company evaluated its securities for other-than-temporary impairment and considered the decline in market value for the securities to be primarily attributable to current economic and market conditions. It was not more likely than not that the Company would have been required to sell the securities prior to the recovery of the amortized cost basis. Based on this analysis, these marketable securities were not considered to be other-than-temporarily impaired as of December 31, 2022 and 2021.

Fair Value Measurements

Fair Value Measurements	12 Months Ended
	Dec. 31, 2022
Fair Value Disclosures [Abstract]
Fair Value Measurements	4. Fair Value Measurements The following fair value hierarchy table presents information about the Company’s financial assets and liabilities measured at fair value on a recurring basis as of December 31, 2022 and 2021 (in thousands): Fair Value Measurement as of December 31, 2022 Quoted Prices Significant (Level 2) Significant (Level 3) Cash equivalents $ 7,596 $ — $ — Marketable securities 4,775 — — Warrant liabilities — — 9,229 Total $ 12,371 $ — $ 9,229 Fair Value Measurement as of December 31, 2021 Quoted Prices Significant (Level 2) Significant (Level 3) Cash equivalents $ 7,734 $ — $ — Marketable securities 37,631 — — Warrant liabilities — — 2,530 Total $ 45,365 $ — $ 2,530 The Company issued warrants to the purchasers of its 2017 Offering (the “2017 Warrants”). The Company determined that these warrants should be classified as a liability and considered as a Level 3 financial instrument (see also Note 10, “Capital Structure”). The 2017 Warrants are re-measured As of Expected volatility 56.5 % Remaining contractual term (in years) 0.58 Risk-free interest rate 0.19 % Expected dividend yield — % The Company issued warrants to the purchasers of its 2020 Offering (the “2020 Warrants”). The Company determined that these warrants should be classified as a liability and considered as a Level 3 financial instrument (see also Note 10, “Capital Structure”). The 2020 Warrants are re-measured As of As of Expected volatility 80.2 % 61.9 % Remaining contractual term (in years) 0.42 1.42 Risk-free interest rate 4.76 % 0.56 % Expected dividend yield — % — % The Company issued Class A and Class B warrants to the purchaser of its 2022 Offering (together, the “2022 Warrants”). The Company determined that these warrants should be classified as a liability and considered as a Level 3 financial instrument (see also Note 10, “Capital Structure”). The 2022 Warrants are re-measured Class A Warrants Class B Warrants As of At Issuance As of At Issuance Expected volatility 99.8 % 99.4 % 140.3 % 141.6 % Remaining contractual term (in years) 5.08 5.13 0.58 0.63 Risk-free interest rate 3.99 % 3.62 % 4.76 % 4.70 % Expected dividend yield — % — % — % — % The following tables present a reconciliation of the Company’s financial liabilities measured at fair value on a recurring basis using significant unobservable inputs (Level 3) for the years ended December 31, 2022, 2021 and 2020 (in thousands): Warrant liabilities Year Ended December 31, 2022 2021 2020 Balance at beginning of period $ 2,530 $ 29,404 $ 6,069 Issuance of 2020 Warrants — — 31,391 Issuance of 2022 Warrants 10,956 Change in fair value (4,187 ) (26,874 ) (8,056 ) Balance at end of period $ 9,299 $ 2,530 $ 29,404 The key inputs into the Black-Scholes option pricing model are the per share value and the expected volatility of the Company’s common stock. Significant changes in these inputs will directly increase or decrease the estimated fair value of the Company’s warrant liability.

Property, Equipment, and Leaseh

Property, Equipment, and Leasehold Improvements	12 Months Ended
	Dec. 31, 2022
Property, Plant and Equipment [Abstract]
Property, Equipment, and Leasehold Improvements	5. Property, Equipment, and Leasehold Improvements Property, equipment, and leasehold improvements, at cost, consisted of the following for the years ended December 31, 2022 and 2021 (in thousands): December 31, 2022 2021 Computer equipment $ 63 $ 20 Furniture 435 435 Lab equipment 1,883 1,864 Leasehold improvements 1,963 1,985 4,344 4,304 Less: accumulated depreciation and amortization (3,717 ) (3,563 ) $ 627 $ 741 Depreciation expense was $154, $148 and $168 for the years ended December 31, 2022, 2021 and 2020, respectively.

Accrued and Other Current Liabi

Accrued and Other Current Liabilities	12 Months Ended
	Dec. 31, 2022
Payables and Accruals [Abstract]
Accrued and Other Current Liabilities	6. Accrued and Other Current Liabilities Accrued and other current liabilities consisted of the following for the years ended December 31, 2022 and 2021 (in thousands): December 31, 2022 2021 Accrued research and clinical development service fees $ 3,443 $ 5,641 Accrued compensation costs 1,676 2,215 Accrued professional fees 970 819 Accrued facilities operation expenses 252 307 Other accrued expenses 157 146 $ 6,498 $ 9,128

Net Loss Per Share of Common St

Net Loss Per Share of Common Stock	12 Months Ended
	Dec. 31, 2022
Earnings Per Share [Abstract]
Net Loss Per Share of Common Stock	7. Net Loss Per Share of Common Stock Diluted loss per share is the same as basic loss per share for all periods presented because the effects of potentially dilutive items were anti-dilutive given the Company’s net loss. Basic loss per share is computed by dividing net loss available to common stockholders by the weighted-average number of common shares outstanding, including the weighted average effect of the Pre-Funded common shares underlying the Pre-Funded The following table sets forth the computation of basic and diluted loss per share for common stockholders (in thousands, except share and per share data): Year Ended December 31, 2022 2021 2020 Net loss applicable to common stockholders $ (65,153 ) $ (20,282 ) $ (28,156 ) Weighted average shares of common stock outstanding 521,359 459,699 284,544 Net loss per share of common stock—basic and diluted $ (124.97 ) $ (44.12 ) $ (98.95 ) The following potentially dilutive securities outstanding at December 31, 2022, 2021 and 2020 have been excluded from the computation of diluted weighted average shares outstanding, as they would have been antidilutive given the Company’s net loss: December 31, 2022 2021 2020 Options to purchase common stock 55,565 36,246 23,173 Warrants to purchase common stock 2,151,451 136,580 154,378 2,207,016 172,826 177,551

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2022
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	8. Commitments and Contingencies Operating Leases In December 2010, the Company entered into a non-cancellable In January 2012, the Company entered into a non-cancellable The balance sheet classification of the Company’s lease liabilities was as follows (in thousands): December 31, Description 2022 2021 Operating lease liabilities: Current portion of lease liabilities $ 671 $ 657 Long-term portion of lease liabilities $ 2,210 $ 2,609 The Company adopted Topic 842 in accounting for its lease liabilities as of January 1, 2019. Operating lease liabilities are based on the net present value of the remaining lease payments over the remaining lease term. In determining the present value of lease payments, the Company used a discount rate of 9.93%, which was an estimate of its incremental borrowing rate based on the information available at the adoption date. The leases are renewable at the end of the lease term at the Company’s option. For the purposes of determining the remaining lease term in contemplation of available extensions, the Company did not consider either renewal to be probable and therefore the remaining lease term used to determine the operating lease liability was 9.0 years at the adoption date. As of December 31, 2022, the maturities of the Company’s operating lease liabilities were as follows (in thousands): Amount Year ending December 31: 2023 $ 707 2024 721 2025 736 2026 750 2027 702 Total lease payments 3,616 Less: Present value adjustment (735 ) Operating lease liabilities $ 2,881 Lease costs under the terms of the Company’s leases for the years ended December 31, 2022 and 2021 are as follows (in thousands): Year Ended 2022 2021 Operating lease cost (1) $ 615 $ 616 Variable lease costs (2) 176 148 Total lease cost $ 791 $ 764 (1) Operating lease payments included in the measurement of the Company’s lease liabilities are comprised of fixed payments according to the terms of the Company’s leases. (2) Variable lease payments consist of the Company’s utility costs billed by and paid to its landlord. Variable lease payments are presented as operating expenses in the Company’s Consolidated Statement of Operations in the same line item as expense arising from fixed lease payments and in net cash used in operating activities in the Company’s Statement of Cash Flows. Rockefeller University License Agreements The Company has entered into the following license agreements with The Rockefeller University: • On July 12, 2011, the Company entered into a license agreement for the worldwide, exclusive right to a patent covering the composition of matter for the lysin PlySS2 for the treatment and prevention of diseases caused by gram-positive bacteria (the “CF-301 CF-301 • On June 1, 2011, the Company entered into a license agreement for the exclusive rights to The Rockefeller University’s interest in a joint patent application covering the method of delivering antibodies through the cell wall of gram-positive bacteria to the periplasmic space. This intellectual property was developed as a result of the sponsored research agreement between the Company and The Rockefeller University and was jointly discovered and filed by the two parties. • On September 23, 2010, the Company entered into a license agreement for the worldwide, exclusive right to develop, make, have made, use, import, lease, sell, and offer for sale products that would otherwise infringe a claim of the suite of patents and patent applications covering the composition of matter for eight individual lysin molecules for the treatment and prevention of diseases caused by gram-positive bacteria. The lysins in this suite have activity against Group B Streptococci Staphylococcus aureus, Streptococcus pneumonia, Bacillus anthracis, Enterococcus faecalis and Enterococcus faecium In consideration for the licenses, the Company paid Rockefeller license initiation fees in cash and stock. The Company is currently $0.2 million milestone, royalty or sublicense payments made during the years ended December 31, 2022, 2021 or 2020. The Company has made total milestone payments under the CF-301 million as of December 31, 2022. Each license agreement terminates upon the later of (i) the expiration or abandonment of the last licensed patent under the license agreement to expire or become abandoned, or (ii) 10 years after the first commercial sale of the first licensed product. The Rockefeller University may terminate any license agreement in the event of a breach of such agreement by the Company or if the Company challenges the validity or enforceability of the underlying patent rights. The Company may terminate any license agreement at any time on 60 days’ notice. Legal Contingencies From time to time, the Company may be involved in disputes and legal proceedings in the ordinary course of its business. These proceedings may include allegations of infringement of intellectual property, employment or other matters. The Company records a liability in its financial statements for these matters when a loss is known or considered probable and the amount can be reasonably estimated. The Company reviews these estimates each accounting period as additional information is known and adjusts the loss provision when appropriate. If a matter is both probable to result in a liability and the amounts of loss can be reasonably estimated, the Company estimates and discloses the possible loss or range of loss to the extent necessary to make the financial statements not misleading. If the loss is not probable or cannot be reasonably estimated, a liability is not recorded in the Company’s financial statements. The Company currently has no legal proceedings ongoing that management estimates could have a material effect on the Company’s financial statements.

Restructuring

Restructuring	12 Months Ended
	Dec. 31, 2022
Restructuring and Related Activities [Abstract]
Restructuring	9. Restructuring On July 29, 2022, the Company initiated a restructuring plan resulting in a reduction in workforce. The restructuring plan was designed to reduce costs and align resources with the Company’s anticipated product development milestones for exebacase and CF-370 million, including $ million related to employee termination costs, including severance, health benefits and other related expenses from the workforce reduction, and $ million from the write-off of prepaid manufacturing costs following the suspension of IV exebacase manufacturing activities. The restructuring costs were included in accounts payable, accrued and other current liabilities and other liabilities. Activity for the year ended December 31, 2022 is summarized as follows (in thousands): As of Balance at beginning of period $ — Charge to expense 7,719 Payments made (576 ) Balance at end of period $ 7,143 As of December 31, 2022, the Company had $7.0 million remaining in accounts payable and accrued and other current liabilities and $0.1 million

Capital Structure

Capital Structure	12 Months Ended
	Dec. 31, 2022
Federal Home Loan Banks [Abstract]
Capital Structure	10. Capital Structure Common Stock As of December 31, 2022, the Company was authorized to issue 125,000,000 shares of common stock at $0.0001 par value per share. Follow-on On December 15, 2022, the Company completed the 2022 Offering. All shares of common stock, the Pre-Funded Warrant, the Class A Warrant and the Class B Warrant were issued together to a single accredited investor purchaser for consideration equating to $10.32 share of common stock (or Pre-Funded , for aggregate net proceeds to the Company of after placement agent fees and offering expenses payable by the Company. As of December 31, 2022, 48,982 shares of common stock had been purchased through the partial exercise of the Pre-Funded Warrant. At issuance, the 2022 Warrants were not exercisable and would only become exercisable following (i) stockholder approval of (and the effectiveness of) an amendment to the Company’s certificate of incorporation that either combines outstanding shares of common stock with such combination ratio as determined by the Company’s board of directors and/or authorizes additional shares of common stock to such number as determined by the Company’s board of directors, in each case, so as to enable the issuance of the number of shares of common stock underlying the 2022 Warrants (disregarding any limitations on the exercise thereof), and (ii) the issuance of all shares of common stock issued in, or issuable pursuant to the exercise of the Pre-Funded Warrant or 2022 Warrants issued in, the 2022 Offering was required by the applicable rules and regulations of the Nasdaq Stock Market (or any successor entity). On March 22, 2021, the Company completed an underwritten public offering under the Form S-3 of shares of its common stock, including shares sold pursuant to the fully exercised overallotment option granted to the underwriters in connection with the offering, at a public offering price of $ per share, resulting in net proceeds to the Company of $ million after underwriting discounts and commissions and offering expenses payable by the Company. On May 27, 2020, the Company completed an underwritten public offering of 147,471 shares of its common stock and warrants to purchase an additional 110,603 shares of its common stock at an exercise price of $392.00 per share. The public offering price was $356.00 for one share of common stock and an accompanying warrant to purchase 0.75 shares of common stock, resulting in net proceeds to the Company of $48.9 million after underwriting discounts and commissions and offering expenses payable by the Company. The Company completed a concurrent private placement to Pfizer of 8,427 shares of common stock and an accompanying warrant to purchase an additional 6,320 shares of its common stock at an exercise price of $392.00 per share at a price of $356.00 for one share of common stock and an accompanying warrant to purchase 0.75 shares of common stock, resulting in net proceeds to the Company of $3.0 m The Company issued warrants in its 2022, 2020 and 2017 offerings of securities. These warrants contain certain terms within the fundamental transaction provision that the Company determined requires classification as liabilities in accordance with ASC 815. At issuance, the Company determined the fair value of the 2022 Warrants, the 2020 Warrants and the 2017 Warrants to be $ million, respectively, and recorded these balances as warrant liabilities, and reducing the amount of net proceeds recorded as additional paid-in-capital. The fair value of the 2022 Warrants exceeded the proceeds received in the 2022 Offering and the excess of $4.0 million was expensed as other expense. The Company consummated the 2022 Offering on market terms available at the time of the transaction to provide additional funding to advance its product candidates. The fair value of these warrants is re-measured at each reporting period and changes in fair value are recognized in the consolidated statement of operations (see Note 4, “Fair Value Measurements”). Additionally, the Company allocated $ million of issuance costs to the 2022 Warrants, the 2020 Warrants and the 2017 Warrants, respectively, based on the proportion of the proceeds allocated to the fair value of the warrants. The allocated issuance costs were expensed as other expense. On , the 2017 Warrants expired in accordance with their terms and are no longer exercisable. The Pfizer Warrant does not contain the same fundamental transaction provision and therefore the Company determined that the Pfizer Warrant should be classified as equity in the Company’s consolidated balance sheet. Voting The holders of shares of common stock are entitled to one vote for each share of common stock held at all meetings of stockholders and written actions in lieu of meetings. Dividends The holders of shares of common stock are entitled to receive dividends, if and when declared by the board of directors. As of December 31, 2022, no dividends have been declared or paid on the Company’s common stock since inception. Reserved for Future Issuance The Company has reserved for future issuance the following number of shares of common stock as of December 31, 2022 and 2021: December 31, 2022 2021 Outstanding pre-funded warrants to purchase common stoc k 574,937 — Outstanding options to purchase common stock 55,565 36,246 Outstanding warrants to purchase common stock 2,151,451 136,580 For future issuance under the 2014 Omnibus Incentive Plan 1,317 970 For future issuance under the 2021 Employment Inducement Plan 12,375 12,500 2,795,645 186,296

Stock Warrants

Stock Warrants	12 Months Ended
	Dec. 31, 2022
Text Block [Abstract]
Stock Warrants	11. Stock Warrants As of December 31, 2022 and 2021, the Company had warrants outstanding to purchase the underlying number of shares of common stock as shown in the table below. December 31, 2022 2021 2022 Warrants 2,034,883 — 2020 Warrants 110,248 110,248 2017 Warrants — 19,996 Pfizer Warrant 6,320 6,320 Other warrants (1) — 16 Warrants to purchase common stock 2,151,451 136,580 Weighted-average exercise price per share $ 31.00 $ 517.60 (1) Other warrants are comprised of warrants issued prior to the Company’s IPO, generally in exchange for services rendered to the Company. The following table summarizes information regarding the Company’s warrants outstanding and the corresponding exercise price at December 31, 2022: Exercise Prices Shares Expiration Date $10.32 678,294 August 14, 2023 $10.32 1,356,589 February 14, 2028 $392.00 116,568 May 27, 2023 2,151,451

Stock Option and Incentive Plan

Stock Option and Incentive Plans	12 Months Ended
	Dec. 31, 2022
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stock Option and Incentive Plans	12. Stock Option and Incentive Plans Amended and Restated 2008 Equity Incentive Plan In July 2008, the Company adopted the 2008 Equity Incentive Plan (the “Plan”). On February 26, 2013, the board of directors approved an amended and restated plan (the “Amended Plan”) under which the number of shares of common stock available for issuance was 1,964. For new awards, the period that vested awards would remain exercisable upon termination of service was reduced from ten years to two years. The board of directors also increased the number of shares of common stock available under the Company’s Amended Plan on February 24, 2014 and April 29, 2014 to 2,321 and 2,946, respectively. As of the closing of the Company’s IPO, there were no further grants made under the Amended Plan. 2014 Omnibus Incentive Plan In April 2014, the Company’s board of directors adopted the 2014 Omnibus Incentive Plan (the “2014 Plan”). The 2014 Plan was approved by the Company’s shareholders on July 3, 2014. The 2014 Plan allows for the granting of incentive and non-qualified 2021 Employment Inducement Omnibus Incentive Plan In September 2021, the Company’s board of directors adopted the 2021 Employment Inducement Omnibus Incentive Plan (the “2021 Plan”), under which the number of shares of common stock reserved for issuance was 12,500. The 2021 Plan allows for the granting of non-qualified 2022 Employee Stock Purchase Plan In March 2022, the Company’s board of directors adopted the 2022 Employee Stock Purchase Plan (the “2022 ESPP”). The 2022 ESPP was approved by the Company’s shareholders on May 17, 2022. The 2022 ESPP allows employees to buy Company stock through after-tax payroll deductions at a discount from market value. One component of the 2022 ESPP is intended to qualify as an “employee stock purchase plan” under Section 423 of the Internal Revenue Code, whereas the other component authorizes the grant of rights which need not qualify as rights granted pursuant to an “employee stock purchase plan” under Section 423. The number of shares of common stock initially available for issuance under the 2022 ESPP was shares of common stock. As of December 31, 2022, purchase rights were outstanding under the 2022 ESPP. Under the 2022 ESPP, employees may purchase common stock through after-tax payroll deductions. In the absence of a contrary designation, the purchase price will be 85% of the lower of the fair market value of our common stock on the first trading day of an offering period or the last trading day of an offering period. The Company recognizes compensation expense for stock-based compensation based on the fair value of the underlying instrument. The fair value of each stock option grant is estimated on the date of grant using the Black-Scholes option-pricing model. Stock option activity for the year ended December 31, 2022, is summarized as follows: Number of Options Weighted Weighted (in years) Aggregate Intrinsic Value Options outstanding at 36,246 $ 729.60 Granted 22,925 $ 245.14 Exercised — — Expired (848 ) $ 783.53 Forfeited (2,758 ) $ 328.84 Options outstanding at December 31, 2022 55,565 $ 548.79 7.97 $ — Vested and exercisable at December 31, 2022 31,757 $ 729.10 6.87 $ — The fair value of each option grant is estimated on the date of the grant using the Black-Scholes option-pricing model. The weighted average grant date fair value of options granted during the years ended December 31, 2022, 2021 and 2020 was $245.14, $344.80 and $773.60, respectively. Total compensation expense recognized amounted to $3.9 million, $3.2 million and $2.6 million for the years ended December 31, 2022, 2021 and 2020, respectively. As of December 31, 2022, the total remaining unrecognized compensation cost related to unvested stock options was $4.6 million which will be recognized over a weighted average period of approximately 2.00 years. The following weighted average assumptions were used to compute the fair value of stock option grants: Year Ended December 31, 2022 2021 2020 Risk free interest rate 2.23 % 0.83 % 1.14 % Expected dividend yield — — — Expected term (in years) 5.91 5.99 6.03 Expected volatility 91.9 % 94.5 % 94.6 % Expected volatility— Expected term— Risk-free interest rate— Expected dividend yield—

401k Savings Plan

401k Savings Plan	12 Months Ended
	Dec. 31, 2022
Retirement Benefits [Abstract]
401k Savings Plan	13. 401k Savings Plan In 2010, the Company established a defined-contribution savings plan under Section 401(k) of the Internal Revenue Code (the 401(k) Plan). The 401(k) Plan covers all employees who meet defined minimum age and service requirements and allows participants to defer a portion of their annual compensation on a pre-tax

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2022
Income Tax Disclosure [Abstract]
Income Taxes	14. Income Taxes The Company has available $ $ The Internal Revenue Code of 1986, as amended (the “Code”) provides for a limitation of the annual use of net operating losses and other tax attributes (such as research and development tax credit carryforwards) following certain ownership changes (as defined by the Code) that could limit the Company’s ability to utilize these carryforwards. At this time, the Company has not completed a study to assess whether an ownership change under Section 382 of the Code has occurred, or whether there have been multiple ownership changes since the Company’s formation, due to the costs and complexities associated with such a study. The Company may have experienced various ownership changes, as defined by the Code, as a result of past financing transactions. Accordingly, the Company’s ability to utilize the aforementioned carryforwards may be limited. Additionally, U.S. tax laws limit the time during which these carryforwards may be applied against future taxes. Therefore, the Company may not be able to take full advantage of these carryforwards for federal or state income tax purposes. The Company’s reserves related to taxes are based on a determination of whether and how much of a tax benefit taken by the Company in its tax filings or positions is more likely than not to be realized following resolution of any potential contingencies present related to the tax benefit. For the three years ended December 31, 2022, the Company had no unrecognized tax benefits or related interest and penalties accrued. The Company has not, as yet, conducted a study of R&D credit carryforwards. This study may result in an adjustment to the Company’s R&D credit carryforwards; however, until a study is completed and any adjustment is known, no amounts are being presented as an uncertain tax position. A full valuation allowance has been provided against the Company’s R&D credits and, if an adjustment is required, this adjustment would be offset by an adjustment to the valuation allowance. Thus, there would be no impact to the consolidated balance sheet or statement of operations if an adjustment were required. The Company would recognize both accrued interest and penalties related to unrecognized benefits in income tax expense. The Company’s uncertain tax positions are related to years that remain subject to examination by relevant tax authorities. Since the Company is in a loss carryforward position, the Company is generally subject to examination by the U.S. federal, state and local income tax authorities for all tax years in which a loss carryforward is available. The principal components of the Company’s deferred tax assets and liabilities are as follows (in thousands): December 31, 2022 2021 Deferred tax assets: Net operating loss carryovers $ 79,694 $ 77,431 Stock-based compensation 3,295 2,457 R&D capitalization 14,610 — R&D tax credits 8,196 5,031 Accrued compensation and severance 451 563 Lease liability 801 911 Intangible assets 77 88 Total deferred tax assets $ 107,124 $ 86,481 Valuation allowance (106,366 ) (85,613 ) Total deferred tax assets net of valuation allowance $ 758 $ 868 Deferred tax liabilities: Right-of-use (654 ) (746 ) Depreciation (104 ) (122 ) Total deferred tax liabilities $ (758 ) $ (868 ) Net deferred tax asset (liability) $ — $ — A reconciliation of the statutory U.S. Federal rate to the company’s effective tax rate is as follows: Year Ended December 31, 2022 2021 2020 Federal income tax benefit at statutory rate (21.00 )% (21.00 )% (21.00 )% State income tax, net of federal benefit (6.57 ) (14.41 ) (9.09 ) Permanent items including change in fair value of warrants 0.55 (26.27 ) (5.35 ) Change in valuation allowance 31.83 63.08 37.88 R&D tax credits (4.86 ) (5.89 ) (2.43 ) Other (0.05 ) 4.49 (0.01 ) Effective income tax (benefit) expense rate 0 % 0 % 0 %

Subsequent Events

Subsequent Events	12 Months Ended
	Dec. 31, 2022
Subsequent Events [Abstract]
Subsequent Events	15. Subsequent Events On February 10, 2023, the stockholders of the Company approved a reverse stock-split of the Company’s outstanding shares of common stock at a ratio ranging from any whole number between 1-for-10 and 1-for-80 , as determined by the Board of Directors in its discretion. The Board subsequently determined to implement a reverse stock split at a ratio of 1-for-80. The stock split became effective on February 14, 2023. Accordingly, all share and per share amounts for all periods presented in the accompanying financial statements and notes thereto have been retroactively adjusted, where applicable, to reflect this reverse stock split. Shares of common stock underlying outstanding stock options and other equity instruments were proportionately decreased and the respective per share value and exercise prices, if applicable, were proportionately increased in accordance with the terms of the agreements governing such securities. In addition, the stockholders of the Company approved the issuance of all shares of common stock issued in, or issuable pursuant to the exercise of the Pre-Funded Warrant or 2022 Warrants issued in, the 2022 Offering as may be required by the applicable rules and regulations of the Nasdaq Stock Market, the approval of which, together with the approval and effectiveness of the 1-for-80 reverse stock-split effected on February 14, 2023, commenced the exercisability of the 2022 Warrants as of February 14, 2023. The resulting expiration dates of the 2022 Warrants have been reflected, where applicable, in the accompanying financial statements and notes thereto. On March 2, 2023, the Company completed 2023 Offering. All securities in the 2023 Offering were issued the same single accredited investor purchaser as in the 2022 Offering for consideration equating to $4.00 per share of common stock (or pre-funded

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2022
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The accompanying financial information has been prepared in accordance with U.S. generally accepted accounting principles (“U.S. GAAP”).
Principles of Consolidation	Principles of Consolidation The Company has a wholly-owned subsidiary, ContraFect International Limited, in Scotland that establishes legal status for interactions with the European Economic Area. This subsidiary is dormant or is otherwise non-operative.
Segment and Geographic Information	Segment and Geographic Information Operating segments are identified as components of an enterprise about which separate discrete financial information is available for evaluation by the chief operating decision maker, or decision-making group, in making decisions on how to allocate resources and assess performance. The Company’s chief operating decision maker is the chief executive officer. The Company and the chief decision maker view the Company’s operations and manage its business as one operating segment. The Company operates in only one geographic segment.
Significant Risks and Uncertainties	Significant Risks and Uncertainties The Company’s operations are subject to a number of factors that can affect its operating results and financial condition. Such factors include, but are not limited to, the results of clinical testing and trial activities of the Company’s products, the Company’s ability to obtain regulatory approval to market its products, competition from products manufactured and sold or being developed by other companies, the price of, and demand for, the Company’s products, the Company’s ability to negotiate favorable licensing or other manufacturing and marketing agreements for its products, the Company’s ability to raise capital and the effects of COVID-19 The Company currently relies on a single manufacturer of drug substance for each of its product candidates and two manufacturers of drug product, one located in the United States and one in Western Europe, and there are no long-term supply agreements in place. A sustained disruption in the operations of any of these manufacturers, or in the event the Company would need to change to a new supplier, could result in a significant delay in the ability of the Company to complete any associated activities.
Use of Estimates	Use of Estimates The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of expenses during the reporting period. The Company bases estimates and assumptions on historical experience when available and on various factors that it believes to be reasonable under the circumstances. On an ongoing basis, the Company evaluates its estimates and assumptions, including those related to stock-based compensation, warrant valuation, research and development accruals and prepaid expenses and realization of net deferred income tax assets. The Company’s actual results may differ from these estimates under different assumptions or conditions. There have been no significant changes from the Company’s original estimates in any periods presented.
Concentrations of Credit Risk	Concentrations of Credit Risk Financial instruments which potentially subject the Company to credit risk consist primarily of cash, cash equivalents and marketable securities. The Company holds these investments in highly rated financial institutions, and, by policy, limits the amounts of credit exposure to any one financial institution. These amounts at times may exceed federally insured limits. The Company’s accounts at Silicon Valley Bank have not experienced any credit losses and the Company does not believe it has material exposure to any significant credit risk on these funds. The Company maintains the majority of its cash, cash equivalents and marketable securities at other financial institutions. The Company has no off-balance
Cash and Cash Equivalents	Cash and Cash Equivalents The Company considers all highly liquid investments with maturities at the date
Marketable Securities	Marketable Securities Marketable securities consists of investments in corporate debt securities. Management determines the appropriate of realized losses on sales of marketable securities for the year ended December , and realized gains or losses on sales of marketable securities for the year ended December , . There were $ of realized gains on sales of marketable securities for the year ended December , . There were marketable securities that had been in an unrealized loss position for more than months as of December , or . The Company reviews marketable securities for other-than-temporary impairment whenever the fair value of a marketable security is less than the amortized cost and evidence indicates that a marketable security’s carrying amount is not recoverable within a reasonable period of time. Other-than-temporary impairments of investments are recognized in the consolidated statements of operations if the Company has experienced a credit loss, has the intent to sell the marketable security, or if it is more likely than not that the Company will be required to sell the marketable security before recovery of the amortized cost basis. Evidence considered in this assessment includes reasons for the impairment, compliance with the Company’s investment policy, the severity and the duration of the impairment and changes in value subsequent to the end of the period.
Fair Value of Financial Instruments	Fair Value of Financial Instruments The Company’s financial instruments consist of cash and cash equivalents, marketable securities, accounts payable, accrued liabilities and warrant liabilities. Fair value estimates of these instruments are made at a specific point in time, based on relevant market information. These estimates may be subjective in nature and involve uncertainties and matters of judgment and therefore cannot be determined with precision. The fair value of the Company’s warrant liabilities is based upon unobservable inputs, as described further below. The Company discloses information on all assets and liabilities reported at fair value using a hierarchy of inputs used in measuring fair value that maximizes the use of observable inputs and minimizes the use of unobservable inputs by requiring that the observable inputs be used when available. Observable inputs are inputs that market participants would use in pricing the asset or liability based on market data obtained from sources independent of the Company. Unobservable inputs are inputs that reflect the Company’s assumptions about the inputs that market participants would use in pricing the asset or liability, and are developed based on the best information available in the circumstances. The fair value hierarchy applies only to the valuation inputs used in determining the reported fair value of the investments and is not a measure of the investment credit quality. The three levels of the fair value hierarchy are described below: Level 1—Valuations based on unadjusted quoted prices in active markets for identical assets or liabilities that the Company has the ability to access at the measurement date. Level 2—Valuations based on quoted prices for similar assets or liabilities in markets that are not active or for which all significant inputs are observable, either directly or indirectly. Level 3—Valuations that require inputs that reflect the Company’s own assumptions that are both significant to the fair value measurement and unobservable. To the extent that valuation is based on models or inputs that are less observable or unobservable in the market, the determination of fair value requires more judgment. Accordingly, the degree of judgment exercised by the Company in determining fair value is greatest for instruments categorized in Level 3. A financial instrument’s level within the fair value hierarchy is based on the lowest level of any input that is significant to the fair value measurement. The Company had no liabilities classified as Level 1 or Level 2. The carrying amounts reported in the accompanying financial statements for accounts payable and accrued expenses approximate their respective fair values due to their short-term maturities. The fair value of the warrant liabilities is discussed in Note 4, “Fair Value Measurements.”
Property, Office Equipment, and Leasehold Improvements	Property, Office Equipment, and Leasehold Improvements Property and equipment are recorded at cost less accumulated depreciation. Depreciation of property and equipment is provided by the straight-line method over their estimated useful lives, ranging from three Leasehold improvements are amortized on a straight-line basis over the useful life of the improvement or the initial lease term, whichever is shorter. Costs for normal repair and maintenance are charged to expense as incurred.
Impairment of Long-lived Assets	Impairment of Long-lived Assets The Company reviews long-lived assets for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable. An impairment loss would be recognized when estimated undiscounted future cash flows expected to result from the use of the asset and its eventual disposition is less than its carrying amount. During the periods ended December 31, 2022 and 2021, impairment of long-lived assets occurred.
Research and Development Costs	Research and Development Costs Research and development costs are charged to expense as incurred and are typically made up of salaries and benefits, clinical trial activities, drug development and manufacturing costs, and third-party service fees, including for clinical research organizations and investigative sites. Costs for certain development activities, such as clinical trials, are recognized based on an evaluation of the progress to completion of specific tasks using data such as patient enrollment, clinical site activations, or information provided by vendors on their actual costs incurred. Payments for these activities are based on the terms of the individual arrangements, which may differ from the pattern of costs incurred, and are reflected in the financial statements as prepaid expenses or accrued liabilities.
Stock-based Compensation	Stock-based Compensation Stock-based compensation is measured and recognized as compensation expense for all stock-based payment awards made to employees, directors, and non-employees, Compensation expense based on the grant date fair value is generally amortized over the requisite service period of the award on a straight-line basis. The fair value of options is calculated using the Black-Scholes option pricing model on the date of grant based on key assumptions such as stock price, risk free interest rates, expected volatility, expected term, and expected dividend yield. The Company’s estimates of these assumptions are based on historical data and judgment regarding future trends and factors.
Income Taxes	Income Taxes The Company uses the asset and liability method to calculate deferred tax assets and liabilities. Deferred taxes are recognized based on the differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases using enacted tax rates expected to apply to taxable income in the years in which those differences are expected to be recovered or settled. The Company records a valuation allowance against a deferred tax asset when it is more-likely-than-not The Company is subject to federal, state and local taxes and follows a recognition threshold and measurement attribute for the financial statement recognition and measurement of a tax position taken or expected to be taken in a tax return. The Company recognizes tax benefits or expenses of uncertain tax positions in the year such determination is made when the position is “more likely than not” to be sustained assuming examination by tax authorities. Management has reviewed the Company’s tax positions for all open tax years (tax years ended December 31, 2011 through December 31, 2022) and concluded that provision for unrecognized tax benefits or expense is required in these financial statements. There are no income tax audits in progress as of December 31, 2022.
Government Contracts and Grant Agreements	Government Contracts and Grant Agreements On March 10, 2021, the Company entered into a cost-share contract (the “BARDA Contract”) with BARDA, a division of the U.S. Department of Health and Human Services’ Office of the Assistant Secretary for Preparedness and Response. The base period for the BARDA Contract included government funding of up to $9.8 million to reimburse expenses to support the conduct of the Phase 3 DISRUPT study and futility analysis. In connection with the Trial Closure, the BARDA Contract was modified to provide for up to $6.6 million in funding to support a futility outcome root-cause analysis and the close-out of the Phase 3 DISRUPT study of exebacase. The Company recognizes a receivable in other current assets with a related reduction in its research and development expenses when the actual reimbursable costs have been incurred and the Company has complied with the conditions of the applicable government contract or grant agreement and the amounts will be received. The Company recognized a reduction to its research and development expense in the amount of $ million, $ million and $ million for the years ended December 31, 2022, 2021 and 2020 respectively. The receivable for government contracts and grant agreements as of December 31, 2022 and 2021 was $ million and $ million, respectively. The Company has $ million of committed government contract and grant agreement funding remaining as of December 31, 2022.
Restructuring	Restructuring The Company has made estimates and judgments regarding the amount and timing
Net Loss per Share Applicable to Common Stockholders	Net Loss per Share Applicable to Common Stockholders Basic net loss per share applicable to common stockholders is calculated by dividing net loss applicable to common stockholders by the weighted average shares outstanding during the period, without consideration for common stock equivalents. Diluted net loss per share applicable to common stockholders is calculated by adjusting weighted average shares outstanding for the dilutive effect of common stock equivalents outstanding for the period, determined using the treasury-stock method. For purposes of the dilutive net loss per share applicable to common stockholders’ calculation, stock options and warrants are considered to be common stock equivalents but are excluded from the calculation of diluted net loss per share applicable to common stockholders, as their effect would be anti-dilutive; therefore, basic and diluted net loss per share applicable to common stockholders were the same for all periods presented.
Recently Adopted Accounting Pronouncements and Recent Accounting Pronouncements Not Yet Adopted	Recently Adopted Accounting Pronouncements Government Assistance On January 1, 2022, the Company adopted Accounting Standards Update No. 2021-10, Disclosure by Business Entities about Government Assistance (ASU 2021-10) 2021-10 Income Taxes On January 1, 2021, the Company adopted Accounting Standards Update No. 2019-12, Income Taxes (Topic 740) Recently Issued Accounting Pronouncements Not Yet Adopted In June 2016, the FASB issued a new Accounting Standards Update, Financial Instruments-Credit Losses (ASU 2016-13). 2016-13 available-for-sale disclosures.

Marketable Securities (Tables)

Marketable Securities (Tables)	12 Months Ended
	Dec. 31, 2022
Investments, Debt and Equity Securities [Abstract]
Schedule of Marketable Securities	Marketable securities at December 31, 2022 consisted of the following (in thousands): Marketable Securities Amortized Cost Unrealized Unrealized Fair Current: Corporate debt $ 4,807 $ — $ (32 ) $ 4,775 Marketable securities at December 31, 2021 consisted of the following (in thousands): Marketable Securities Amortized Cost Unrealized Unrealized Fair Current: Corporate debt $ 37,715 $ — $ (84 ) $ 37,631

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2022
Information about Company's Financial Assets and Liabilities Measured at Fair Value on Recurring Basis	The following fair value hierarchy table presents information about the Company’s financial assets and liabilities measured at fair value on a recurring basis as of December 31, 2022 and 2021 (in thousands): Fair Value Measurement as of December 31, 2022 Quoted Prices Significant (Level 2) Significant (Level 3) Cash equivalents $ 7,596 $ — $ — Marketable securities 4,775 — — Warrant liabilities — — 9,229 Total $ 12,371 $ — $ 9,229 Fair Value Measurement as of December 31, 2021 Quoted Prices Significant (Level 2) Significant (Level 3) Cash equivalents $ 7,734 $ — $ — Marketable securities 37,631 — — Warrant liabilities — — 2,530 Total $ 45,365 $ — $ 2,530
Reconciliation of Company's Financial Liabilities Measured at Fair Value on Recurring Basis Using Significant Unobservable Inputs (Level 3)	The following tables present a reconciliation of the Company’s financial liabilities measured at fair value on a recurring basis using significant unobservable inputs (Level 3) for the years ended December 31, 2022, 2021 and 2020 (in thousands): Warrant liabilities Year Ended December 31, 2022 2021 2020 Balance at beginning of period $ 2,530 $ 29,404 $ 6,069 Issuance of 2020 Warrants — — 31,391 Issuance of 2022 Warrants 10,956 Change in fair value (4,187 ) (26,874 ) (8,056 ) Balance at end of period $ 9,299 $ 2,530 $ 29,404
2017 Warrants [Member]
Assumption Used to Determine Fair Value of Warrant Liability	The following assumptions were used in a Black-Scholes option-pricing model to determine the fair value of the warrant liability: As of Expected volatility 56.5 % Remaining contractual term (in years) 0.58 Risk-free interest rate 0.19 % Expected dividend yield — %
2020 Warrants [Member]
Assumption Used to Determine Fair Value of Warrant Liability	The following assumptions were used in a Black-Scholes option-pricing model to determine the fair value of the warrant liability: As of As of Expected volatility 80.2 % 61.9 % Remaining contractual term (in years) 0.42 1.42 Risk-free interest rate 4.76 % 0.56 % Expected dividend yield — % — %
2022 Warrants [Member]
Assumption Used to Determine Fair Value of Warrant Liability	The following assumptions were used in a Black-Scholes option-pricing model to determine the fair value of the warrant liability: Class A Warrants Class B Warrants As of At Issuance As of At Issuance Expected volatility 99.8 % 99.4 % 140.3 % 141.6 % Remaining contractual term (in years) 5.08 5.13 0.58 0.63 Risk-free interest rate 3.99 % 3.62 % 4.76 % 4.70 % Expected dividend yield — % — % — % — %

Property, Equipment, and Leas_2

Property, Equipment, and Leasehold Improvements (Tables)	12 Months Ended
	Dec. 31, 2022
Property, Plant and Equipment [Abstract]
Schedule of Property, Equipment and Leasehold Improvements, at Cost	Property, equipment, and leasehold improvements, at cost, consisted of the following for the years ended December 31, 2022 and 2021 (in thousands): December 31, 2022 2021 Computer equipment $ 63 $ 20 Furniture 435 435 Lab equipment 1,883 1,864 Leasehold improvements 1,963 1,985 4,344 4,304 Less: accumulated depreciation and amortization (3,717 ) (3,563 ) $ 627 $ 741

Accrued and Other Current Lia_2

Accrued and Other Current Liabilities (Tables)	12 Months Ended
	Dec. 31, 2022
Payables and Accruals [Abstract]
Summary of Accrued Liabilities	Accrued and other current liabilities consisted of the following for the years ended December 31, 2022 and 2021 (in thousands): December 31, 2022 2021 Accrued research and clinical development service fees $ 3,443 $ 5,641 Accrued compensation costs 1,676 2,215 Accrued professional fees 970 819 Accrued facilities operation expenses 252 307 Other accrued expenses 157 146 $ 6,498 $ 9,128

Net Loss Per Share of Common _2

Net Loss Per Share of Common Stock (Tables)	12 Months Ended
	Dec. 31, 2022
Earnings Per Share [Abstract]
Schedule of Computation of Basic and Diluted Loss Per Share for Common Stockholders	The following table sets forth the computation of basic and diluted loss per share for common stockholders (in thousands, except share and per share data): Year Ended December 31, 2022 2021 2020 Net loss applicable to common stockholders $ (65,153 ) $ (20,282 ) $ (28,156 ) Weighted average shares of common stock outstanding 521,359 459,699 284,544 Net loss per share of common stock—basic and diluted $ (124.97 ) $ (44.12 ) $ (98.95 )
Schedule of Antidilutive Securities Excluded from Computation of Diluted Weighted Average Shares Outstanding	The following potentially dilutive securities outstanding at December 31, 2022, 2021 and 2020 have been excluded from the computation of diluted weighted average shares outstanding, as they would have been antidilutive given the Company’s net loss: December 31, 2022 2021 2020 Options to purchase common stock 55,565 36,246 23,173 Warrants to purchase common stock 2,151,451 136,580 154,378 2,207,016 172,826 177,551

Commitments and Contingencies (

Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2022
Commitments and Contingencies Disclosure [Abstract]
Schedule of Classification of Lease Liabilities	The balance sheet classification of the Company’s lease liabilities was as follows (in thousands): December 31, Description 2022 2021 Operating lease liabilities: Current portion of lease liabilities $ 671 $ 657 Long-term portion of lease liabilities $ 2,210 $ 2,609
Summary of Future Minimum Lease Payments	As of December 31, 2022, the maturities of the Company’s operating lease liabilities were as follows (in thousands): Amount Year ending December 31: 2023 $ 707 2024 721 2025 736 2026 750 2027 702 Total lease payments 3,616 Less: Present value adjustment (735 ) Operating lease liabilities $ 2,881
Lease, Cost	Lease costs under the terms of the Company’s leases for the years ended December 31, 2022 and 2021 are as follows (in thousands): Year Ended 2022 2021 Operating lease cost (1) $ 615 $ 616 Variable lease costs (2) 176 148 Total lease cost $ 791 $ 764 (1) Operating lease payments included in the measurement of the Company’s lease liabilities are comprised of fixed payments according to the terms of the Company’s leases. (2) Variable lease payments consist of the Company’s utility costs billed by and paid to its landlord. Variable lease payments are presented as operating expenses in the Company’s Consolidated Statement of Operations in the same line item as expense arising from fixed lease payments and in net cash used in operating activities in the Company’s Statement of Cash Flows.

Restructuring (Tables)

Restructuring (Tables)	12 Months Ended
	Dec. 31, 2022
Restructuring and Related Activities [Abstract]
Schedule of Restructuring Reserve by Type of Cost	The restructuring costs were included in accounts payable, accrued and other current liabilities and other liabilities. Activity for the year ended December 31, 2022 is summarized as follows (in thousands): As of Balance at beginning of period $ — Charge to expense 7,719 Payments made (576 ) Balance at end of period $ 7,143

Capital Structure (Tables)

Capital Structure (Tables)	12 Months Ended
	Dec. 31, 2022
Stockholders Equity Reverse Stock Split [Abstract]
Summary of Common Stock Reserved for Future Issuance	The Company has reserved for future issuance the following number of shares of common stock as of December 31, 2022 and 2021: December 31, 2022 2021 Outstanding pre-funded warrants to purchase common stoc k 574,937 — Outstanding options to purchase common stock 55,565 36,246 Outstanding warrants to purchase common stock 2,151,451 136,580 For future issuance under the 2014 Omnibus Incentive Plan 1,317 970 For future issuance under the 2021 Employment Inducement Plan 12,375 12,500 2,795,645 186,296

Stock Warrants (Tables)

Stock Warrants (Tables)	12 Months Ended
	Dec. 31, 2022
Warrants and Rights Note Disclosure [Abstract]
Schedule of Warrants Outstanding	As of December 31, 2022 and 2021, the Company had warrants outstanding to purchase the underlying number of shares of common stock as shown in the table below. December 31, 2022 2021 2022 Warrants 2,034,883 — 2020 Warrants 110,248 110,248 2017 Warrants — 19,996 Pfizer Warrant 6,320 6,320 Other warrants (1) — 16 Warrants to purchase common stock 2,151,451 136,580 Weighted-average exercise price per share $ 31.00 $ 517.60 (1) Other warrants are comprised of warrants issued prior to the Company’s IPO, generally in exchange for services rendered to the Company. The following table summarizes information regarding the Company’s warrants outstanding and the corresponding exercise price at December 31, 2022: Exercise Prices Shares Expiration Date $10.32 678,294 August 14, 2023 $10.32 1,356,589 February 14, 2028 $392.00 116,568 May 27, 2023 2,151,451

Stock Option and Incentive Pl_2

Stock Option and Incentive Plans (Tables)	12 Months Ended
	Dec. 31, 2022
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Summary of Stock Option Activity	Stock option activity for the year ended December 31, 2022, is summarized as follows: Number of Options Weighted Weighted (in years) Aggregate Intrinsic Value Options outstanding at 36,246 $ 729.60 Granted 22,925 $ 245.14 Exercised — — Expired (848 ) $ 783.53 Forfeited (2,758 ) $ 328.84 Options outstanding at December 31, 2022 55,565 $ 548.79 7.97 $ — Vested and exercisable at December 31, 2022 31,757 $ 729.10 6.87 $ —
Assumptions to Compute Fair Value of Stock Option Grants	The following weighted average assumptions were used to compute the fair value of stock option grants: Year Ended December 31, 2022 2021 2020 Risk free interest rate 2.23 % 0.83 % 1.14 % Expected dividend yield — — — Expected term (in years) 5.91 5.99 6.03 Expected volatility 91.9 % 94.5 % 94.6 %

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2022
Income Tax Disclosure [Abstract]
Components of Deferred Tax Assets and Liabilities	The principal components of the Company’s deferred tax assets and liabilities are as follows (in thousands): December 31, 2022 2021 Deferred tax assets: Net operating loss carryovers $ 79,694 $ 77,431 Stock-based compensation 3,295 2,457 R&D capitalization 14,610 — R&D tax credits 8,196 5,031 Accrued compensation and severance 451 563 Lease liability 801 911 Intangible assets 77 88 Total deferred tax assets $ 107,124 $ 86,481 Valuation allowance (106,366 ) (85,613 ) Total deferred tax assets net of valuation allowance $ 758 $ 868 Deferred tax liabilities: Right-of-use (654 ) (746 ) Depreciation (104 ) (122 ) Total deferred tax liabilities $ (758 ) $ (868 ) Net deferred tax asset (liability) $ — $ —
Summary of Reconciliation of Statutory U.S. Federal Rate to Company's Effective Tax Rate	A reconciliation of the statutory U.S. Federal rate to the company’s effective tax rate is as follows: Year Ended December 31, 2022 2021 2020 Federal income tax benefit at statutory rate (21.00 )% (21.00 )% (21.00 )% State income tax, net of federal benefit (6.57 ) (14.41 ) (9.09 ) Permanent items including change in fair value of warrants 0.55 (26.27 ) (5.35 ) Change in valuation allowance 31.83 63.08 37.88 R&D tax credits (4.86 ) (5.89 ) (2.43 ) Other (0.05 ) 4.49 (0.01 ) Effective income tax (benefit) expense rate 0 % 0 % 0 %

Organization and Description _2

Organization and Description of Business - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands							12 Months Ended
	Mar. 02, 2023	Dec. 15, 2022	Aug. 15, 2022	Jul. 29, 2022	Mar. 22, 2021	May 27, 2020	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Organization And Description Of Business [Line Items]
Accumulated deficit							$ 325,705	$ 260,552
Net cash used in operating activities							(45,974)	$ (41,125)	$ (33,187)
Number of shares issued						147,471
Cash Cash Equivalents And Marketable Securities							13,700
Restructuring charge			$ 7,700	$ 7,700			$ 7,719
Labor and Related Expense			1,600	1,600
Write-off of prepaid manufacturing costs			$ 6,100	$ 6,100
Common Stock [Member]
Organization And Description Of Business [Line Items]
Number of shares issued		54,375
Subsequent Event [Member] | Common Stock [Member]
Organization And Description Of Business [Line Items]
Number of shares issued	128,000
Class of warrant or right, issued	5,000,000
Sale of stock, price per share	$ 4
Prefunded Warrants [Member]
Organization And Description Of Business [Line Items]
Class of warrant or right, issued		623,919
Prefunded Warrants [Member] | Subsequent Event [Member]
Organization And Description Of Business [Line Items]
Class of warrant or right, issued	2,372,000
Follow-on Offering [Member]
Organization And Description Of Business [Line Items]
Exercise Price of Warrants or Rights						$ 392
Public offering price, per unit						$ 356
Stock issued during period, value					$ 150,000
Over-Allotment Option [Member]
Organization And Description Of Business [Line Items]
Number of shares issued					143,750
Public offering price, per unit					$ 400
Proceeds from initial public offer					$ 53,800
Sale of stock, price per share					$ 400
Pre Funded Warrants and Common Stock [Member]
Organization And Description Of Business [Line Items]
Proceeds from issuance or sale of equity		$ 6,100
Pre Funded Warrants and Common Stock [Member] | Subsequent Event [Member]
Organization And Description Of Business [Line Items]
Proceeds from issuance or sale of equity	$ 9,200
Class A warrants [Member] | Common Stock [Member]
Organization And Description Of Business [Line Items]
Class of warrant or right, issued		1,356,589
Class B warrants [Member] | Common Stock [Member]
Organization And Description Of Business [Line Items]
Class of warrant or right, issued		678,294
Class A warrant and Class B warrant [Member]
Organization And Description Of Business [Line Items]
Sale of stock, price per share		$ 10.32
Two Thousand and Twenty Three Offering [Member] | Subsequent Event [Member]
Organization And Description Of Business [Line Items]
Exercise Price of Warrants or Rights	$ 4
Number of common stock Called by each warrant or right	2
Two Thousand and Twenty Three Offering [Member] | Prefunded Warrants [Member] | Subsequent Event [Member]
Organization And Description Of Business [Line Items]
Number of common stock Called by each warrant or right	1
Two Thousand And Twenty Two Offering [Member]
Organization And Description Of Business [Line Items]
Exercise Price of Warrants or Rights		10.32
Sale of stock, price per share		$ 10.32
Two Thousand And Twenty Two Offering [Member] | Subsequent Event [Member]
Organization And Description Of Business [Line Items]
Exercise Price of Warrants or Rights	$ 4
Sale of stock, price per share	$ 4
Proceeds from issuance or sale of equity	$ 9,200
Number of common stock Called by each warrant or right	2
Two Thousand And Twenty Two Offering [Member] | Prefunded Warrants [Member] | Subsequent Event [Member]
Organization And Description Of Business [Line Items]
Number of common stock Called by each warrant or right	1
Two Thousand And Twenty Two Offering [Member] | ClassA Warrant [Member]
Organization And Description Of Business [Line Items]
Number of common stock Called by each warrant or right		1
Two Thousand And Twenty Two Offering [Member] | ClassB Warrant [Member]
Organization And Description Of Business [Line Items]
Number of common stock Called by each warrant or right		2

Summary of Significant Accoun_3

Summary of Significant Accounting Policies - Additional Information (Detail)		12 Months Ended
	Mar. 10, 2021 USD ($)	Dec. 31, 2022 USD ($) Segment	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)
Summary Of Significant Accounting Policies [Line Items]
Number of operating segment | Segment		1
Number of geographic segment | Segment		1
Maturity period of highly liquid investments		three months or less
Realized gains or losses on marketable securities		$ 23,128	$ 0	$ 9,609
Number of securities in unrealized loss position for more than 12 months		0	0
Impairment of long-lived assets		$ 0	$ 0
Provision for unrecognized tax benefits or expense		0
Grants receivable recognized		8,600,000	10,500,000	$ 4,200,000
Grants receivable		2,600,000	$ 4,100,000
Grants remaining to be awarded		5,100,000
BARDA Contract [Member] | Base Period BARDA Funding [Member]
Summary Of Significant Accounting Policies [Line Items]
Total funding receives in future	$ 9,800,000
Barda Extended Contract [Member] | Base Period BARDA Funding [Member]
Summary Of Significant Accounting Policies [Line Items]
Total funding receives in future		$ 6,600,000
Earliest Tax Year [Member]
Summary Of Significant Accounting Policies [Line Items]
Tax position for all open tax years		2011
Latest Tax Year [Member]
Summary Of Significant Accounting Policies [Line Items]
Tax position for all open tax years		2022
Minimum [Member]
Summary Of Significant Accounting Policies [Line Items]
Property and equipment, estimated useful lives		3 years
Maximum [Member]
Summary Of Significant Accounting Policies [Line Items]
Property and equipment, estimated useful lives		5 years
Level 1 [Member]
Summary Of Significant Accounting Policies [Line Items]
Liabilities		$ 0
Level 2 [Member]
Summary Of Significant Accounting Policies [Line Items]
Liabilities		$ 0

Marketable Securities - Schedul

Marketable Securities - Schedule of Marketable Securities (Detail) - Corporate debt [Member] - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Schedule of Available-for-sale Securities [Line Items]
Marketable Securities, Amortized Cost	$ 4,807	$ 37,715
Marketable Securities, Unrealized Gains	0	0
Marketable Securities, Unrealized Losses	(32)	(84)
Marketable Securities, Fair Value	$ 4,775	$ 37,631

Marketable Securities - Additio

Marketable Securities - Additional Information (Detail) $ in Thousands	12 Months Ended
	Dec. 31, 2022 USD ($) Security	Dec. 31, 2021 USD ($) Security
Marketable Securities [Abstract]
Marketable securities	$ 0	$ 0
Maturity period classified current investments	less than one year
Number of securities in unrealized loss position for less than one year | Security	3	23
Aggregate fair value of debt securities	$ 4,800	$ 37,600

Fair Value Measurements - Infor

Fair Value Measurements - Information about Company's Financial Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	$ 4,775	$ 37,631
Warrant liabilities	(9,299)	(2,530)
Fair Value, Measurements, Recurring [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	7,596	7,734
Marketable securities	4,775	37,631
Total	12,371	45,365
Fair Value, Measurements, Recurring [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Warrant liabilities	9,229	2,530
Total	$ 9,229	$ 2,530

Fair Value Measurements - Assum

Fair Value Measurements - Assumption Used to Determine Fair Value of Warrant Liability (Detail)	Dec. 31, 2022 yr	Dec. 15, 2022 yr	Dec. 31, 2021 yr
2017 Warrants [Member] | Expected Volatility [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair value of warrant liability			0.565
2017 Warrants [Member] | Remaining Contractual term (in years) [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair value of warrant liability			0.58
2017 Warrants [Member] | Risk-free Interest Rate [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair value of warrant liability			0.0019
2020 Warrants [Member] | Expected Volatility [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair value of warrant liability	0.802		0.619
2020 Warrants [Member] | Remaining Contractual term (in years) [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair value of warrant liability	0.42		1.42
2020 Warrants [Member] | Risk-free Interest Rate [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair value of warrant liability	0.0476		0.0056
2022 Warrants [Member] | Expected Volatility [Member] | Class A warrants [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair value of warrant liability	0.998	0.994
2022 Warrants [Member] | Expected Volatility [Member] | Class B warrants [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair value of warrant liability	1.403	1.416
2022 Warrants [Member] | Remaining Contractual term (in years) [Member] | Class A warrants [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair value of warrant liability	5.08	5.13
2022 Warrants [Member] | Remaining Contractual term (in years) [Member] | Class B warrants [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair value of warrant liability	0.58	0.63
2022 Warrants [Member] | Risk-free Interest Rate [Member] | Class A warrants [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair value of warrant liability	0.0399	0.0362
2022 Warrants [Member] | Risk-free Interest Rate [Member] | Class B warrants [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair value of warrant liability	0.0476	0.047

Fair Value Measurements - Recon

Fair Value Measurements - Reconciliation of Company's Financial Liabilities Measured at Fair Value on Recurring Basis Using Significant Unobservable Inputs (Level 3) (Detail) - Warrant Liabilities [Member] - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Balance at beginning of period	$ 2,530	$ 29,404	$ 6,069
Issuance of Warrants	10,956	0	31,391
Change in fair value	(4,187)	(26,874)	(8,056)
Balance at end of period	$ 9,299	$ 2,530	$ 29,404

Fair Value Measurements - Addit

Fair Value Measurements - Additional Information (Detail)	Dec. 31, 2022	Jul. 25, 2022
2017 Warrants [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Warrants And Rights Expiry Date	Jul. 25, 2022	Jul. 25, 2022

Property, Equipment, and Leas_3

Property, Equipment, and Leasehold Improvements - Schedule of Property, Equipment and Leasehold Improvements, at Cost (Detail) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Property, Plant and Equipment [Line Items]
Property, equipment, and leasehold improvements, at cost, gross	$ 4,344	$ 4,304
Less: accumulated depreciation and amortization	(3,717)	(3,563)
Property, equipment, and leasehold improvements, at cost, net	627	741
Computer Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, equipment, and leasehold improvements, at cost, gross	63	20
Furniture [Member]
Property, Plant and Equipment [Line Items]
Property, equipment, and leasehold improvements, at cost, gross	435	435
Lab Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, equipment, and leasehold improvements, at cost, gross	1,883	1,864
Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Property, equipment, and leasehold improvements, at cost, gross	$ 1,963	$ 1,985

Property, Equipment, and Leas_4

Property, Equipment, and Leasehold Improvements - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Property, Plant and Equipment [Abstract]
Depreciation expense	$ 154	$ 148	$ 168

Accrued and Other Current Lia_3

Accrued and Other Current Liabilities - Summary of Accrued Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Payables and Accruals [Abstract]
Accrued research and clinical development service fees	$ 3,443	$ 5,641
Accrued compensation costs	1,676	2,215
Accrued professional fees	970	819
Accrued facilities operation expenses	252	307
Other accrued expenses	157	146
Total accrued expenses	$ 6,498	$ 9,128

Net Loss Per Share of Common _3

Net Loss Per Share of Common Stock - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2022 shares
Common Stock [Member] | Prefunded Warrants [Member]
Share-based compensation arrangement by share-based payment award, non-option equity instruments, exercised	574,937

Net Loss Per Share of Common _4

Net Loss Per Share of Common Stock - Schedule of Computation of Basic and Diluted Loss Per Share for Common Stockholders (Detail) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Earnings Per Share [Abstract]
Net loss applicable to common stockholders	$ (65,153)	$ (20,282)	$ (28,156)
Shares used in computing basic net loss per share	521,359	459,699	284,544
Basic net loss per share	$ (124.97)	$ (44.12)	$ (98.95)
Shares used in computing diluted net loss per share	521,359	459,699	284,544
Diluted net loss per share	$ (124.97)	$ (44.12)	$ (98.95)

Net Loss Per Share of Common _5

Net Loss Per Share of Common Stock - Schedule of Antidilutive Securities Excluded from Computation of Diluted Weighted Average Shares Outstanding (Detail) - shares	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potentially antidilutive securities outstanding excluded from the computation of diluted weighted average shares	2,207,016	172,826	177,551
Employee Stock Options [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potentially antidilutive securities outstanding excluded from the computation of diluted weighted average shares	55,565	36,246	23,173
Warrants [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potentially antidilutive securities outstanding excluded from the computation of diluted weighted average shares	2,151,451	136,580	154,378

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Detail)	1 Months Ended			12 Months Ended
	Jan. 31, 2012 ft² ExtensionOptions	Dec. 31, 2011 ExtensionOptions	Dec. 31, 2010	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)	Jan. 01, 2019
Loss Contingencies [Line Items]
Non-cancellable operating lease, expiration date	2027-12		2025-12
Extended lease agreement, date		2027-12
Number of lease extension options | ExtensionOptions	2	2
Lease renewal termination period	5 years	5 years
Area of space relinquished from lease agreement | ft²	10,912
Milestone payment				$ 800,000
Operating lease, remaining lease term								9 years
Operating lease, discount rate, percent								9.93%
Rockefeller University [Member]
Loss Contingencies [Line Items]
Annual maintenance fees payable after 2018				$ 200,000	$ 200,000	$ 200,000
Percentage of royalty on net sales					5%	5%	5%
Regulatory milestone payment					$ 5,000,000	$ 5,000,000	$ 5,000,000
Royalty or sublicense payment					$ 0	$ 0
License agreement termination notice period				60 days
Period of termination after first commercial sale of first licensed product				10 years
License agreement termination description				Each license agreement terminates upon the later of (i) the expiration or abandonment of the last licensed patent under the license agreement to expire or become abandoned, or (ii) 10 years after the first commercial sale of the first licensed product. The Rockefeller University may terminate any license agreement in the event of a breach of such agreement by the Company or if the Company challenges the validity or enforceability of the underlying patent rights. The Company may terminate any license agreement at any time on 60 days’ notice.

Commitments and Contingencies_2

Commitments and Contingencies - Schedule of Classification of Lease Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Operating lease liabilities:
Current portion of lease liabilities	$ 671	$ 657
Long-term portion of lease liabilities	$ 2,210	$ 2,609

Commitments and Contingencies_3

Commitments and Contingencies - Maturities of Operating Lease Liabilities (Detail) $ in Thousands	Dec. 31, 2022 USD ($)
Commitments and Contingencies Disclosure [Abstract]
2023	$ 707
2024	721
2025	736
2026	750
2027	702
Total lease payments	3,616
Less: Present value adjustment	(735)
Operating lease liabilities	$ 2,881

Commitments and Contingencies_4

Commitments and Contingencies - Lease Cost (Detail) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2022	Dec. 31, 2021
Disclosure of Lease of Cost [Abstract]
Operating lease cost	[1]	$ 615	$ 616
Variable lease costs	[2]	176	148
Total lease cost		$ 791	$ 764
[1]Operating lease payments included in the measurement of the Company’s lease liabilities are comprised of fixed payments according to the terms of the Company’s leases.[2]Variable lease payments consist of the Company’s utility costs billed by and paid to its landlord. Variable lease payments are presented as operating expenses in the Company’s Consolidated Statement of Operations in the same line item as expense arising from fixed lease payments and in net cash used in operating activities in the Company’s Statement of Cash Flows.

Restructuring - Schedule of Re

Restructuring - Schedule of Restructuring Reserve by Type of Cost (Detail) - USD ($) $ in Thousands			12 Months Ended
	Aug. 15, 2022	Jul. 29, 2022	Dec. 31, 2022
Restructuring Cost and Reserve [Line Items]
Balance at beginning of period			$ 0
Charge to expense	$ 7,700	$ 7,700	7,719
Payments made			(576)
Balance at end of period			$ 7,143

Restructuring - Additional Info

Restructuring - Additional Information (Detail) - USD ($) $ in Thousands			12 Months Ended
	Aug. 15, 2022	Jul. 29, 2022	Dec. 31, 2022
Restructuring and Related Activities [Abstract]
Restructuring Charges	$ 7,700	$ 7,700	$ 7,719
Labor and Related Expense	1,600	1,600
Write-off of prepaid manufacturing costs	$ 6,100	$ 6,100
Accounts Payable and Accrued Liabilities, Current			7,000
Other liabilities			$ 100

Capital Structure - Additional

Capital Structure - Additional Information (Detail) $ / shares in Units, $ in Thousands						12 Months Ended
	Dec. 15, 2022 USD ($) $ / shares shares	Mar. 22, 2021 USD ($) $ / shares shares	May 27, 2020 USD ($) $ / shares shares	Jul. 25, 2017 USD ($)	Jul. 27, 2016 USD ($)	Dec. 31, 2022 USD ($) $ / shares shares	Dec. 31, 2021 USD ($) $ / shares shares	Dec. 31, 2020 USD ($) shares	Jul. 25, 2022
Class of Stock [Line Items]
Common stock, shares authorized | shares						125,000,000
Common stock, par value | $ / shares						$ 0.0001	$ 0.0001
Number of shares issued | shares			147,471
Net proceeds received			$ 48,900
Gross Proceed			$ 3,000
Dividends declared or paid						$ 0
Issuance costs allocated to warrants						$ 851		$ 2,175
Common stock, voting rights						The holders of shares of common stock are entitled to one vote for each share of common stock held at all meetings of stockholders and written actions in lieu of meetings.
Issuance of common stock for exercise of warrants, Shares | shares							282	73
Fair value adjustment of warrants						$ (4,187)	$ (26,874)	$ (8,056)
Other Expense [Member]
Class of Stock [Line Items]
Fair value adjustment of warrants						$ 4,000
2017 Warrants [Member]
Class of Stock [Line Items]
Warrants And Rights Expiry Date						Jul. 25, 2022			Jul. 25, 2022
Class Of Warrant Or Rights Exercisable | shares						0
Private Placement [Member]
Class of Stock [Line Items]
Public offering price, per unit | $ / shares			$ 356
Issuance of securities in private placement, Shares | shares			8,427
Follow-on Offering [Member]
Class of Stock [Line Items]
Public offering price, per unit | $ / shares			$ 356
Warrants to purchase shares of common stock | shares			110,603
Warrant exercise price per share | $ / shares			$ 392
Conversion ratio of common stock							0.75	0.75
Follow-on Offering [Member] | 2017 Warrants [Member]
Class of Stock [Line Items]
Fair value of warrants					$ 12,400
Issuance costs allocated to warrants					$ 900
Follow-on Offering [Member] | 2020 Warrants [Member]
Class of Stock [Line Items]
Fair value of warrants				$ 31,400
Issuance costs allocated to warrants				$ 2,200
Follow-on Offering [Member] | 2022 Warrants [Member]
Class of Stock [Line Items]
Fair value of warrants			$ 11,000
Issuance costs allocated to warrants			$ 900
Over-Allotment Option [Member]
Class of Stock [Line Items]
Number of shares issued | shares		143,750
Public offering price, per unit | $ / shares		$ 400
Sale of stock, price per share | $ / shares		$ 400
Proceeds from Issuance Initial Public Offering		$ 53,800
Class A Warrant and Class B Warrant [Member]
Class of Stock [Line Items]
Sale of stock, price per share | $ / shares	$ 10.32
Pre Funded Warrants and Common Stock [Member]
Class of Stock [Line Items]
Proceeds from issuance or sale of equity	$ 6,100
Two Thousand And Twenty Two Offering [Member]
Class of Stock [Line Items]
Warrant exercise price per share | $ / shares	$ 10.32
Sale of stock, price per share | $ / shares	$ 10.32
Pfizer Warrants [Member]
Class of Stock [Line Items]
Warrants to purchase shares of common stock | shares			6,320
Warrant exercise price per share | $ / shares			$ 392
Class A warrants [Member] | Two Thousand And Twenty Two Offering [Member]
Class of Stock [Line Items]
Number of common stock Called by each warrant or right | shares	2
Class B warrants [Member] | Two Thousand And Twenty Two Offering [Member]
Class of Stock [Line Items]
Number of common stock Called by each warrant or right | shares	1
CFRX Prefunded Warrants [Member] | Follow-on Offering [Member]
Class of Stock [Line Items]
Warrants to purchase shares of common stock | shares						48,982

Capital Structure - Summary of

Capital Structure - Summary of Common Stock Reserved for Future Issuance (Detail) - shares	Dec. 31, 2022	Dec. 31, 2021
Class of Stock [Line Items]
Common Stock reserved for future issuance	2,795,645	186,296
Two Thousand Fourteen Omnibus Incentive Plan [Member]
Class of Stock [Line Items]
Common Stock reserved for future issuance	1,317	970
Two Thousand Twenty One Employment Inducement Plan [Member]
Class of Stock [Line Items]
Common Stock reserved for future issuance	12,375	12,500
Stock Options [Member]
Class of Stock [Line Items]
Common Stock reserved for future issuance	55,565	36,246
Warrants [Member]
Class of Stock [Line Items]
Common Stock reserved for future issuance	2,151,451	136,580
CFRX Prefunded Warrants [Member]
Class of Stock [Line Items]
Common Stock reserved for future issuance	574,937	0

Stock Warrants - Schedule of Wa

Stock Warrants - Schedule of Warrants Outstanding (Detail) - $ / shares	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	May 27, 2020
Class of Warrant or Right [Line Items]
Shares Underlying Outstanding Warrants	2,151,451	136,580
Weighted-average exercise price per share	$ 31	$ 517.6
Pfizer Warrants [Member]
Class of Warrant or Right [Line Items]
Shares Underlying Outstanding Warrants	6,320	6,320
Exercise Prices			$ 392
Other Warrants [Member]
Class of Warrant or Right [Line Items]
Shares Underlying Outstanding Warrants	0	16
Exercise Price Ten Point Three Two [Member]
Class of Warrant or Right [Line Items]
Shares Underlying Outstanding Warrants	678,294
Expiration Start Date	Aug. 14, 2023
Exercise One At Price Ten Point Three Two [Member]
Class of Warrant or Right [Line Items]
Shares Underlying Outstanding Warrants	1,356,589
Exercise Prices	$ 10.32
Expiration Start Date	Feb. 14, 2028
Exercise Price Three Nine Two Point Zero Zero [Member]
Class of Warrant or Right [Line Items]
Shares Underlying Outstanding Warrants	116,568
Exercise Prices	$ 392
Expiration Start Date	May 27, 2023
Minimum [Member] | Exercise Price Ten Point Three Two [Member]
Class of Warrant or Right [Line Items]
Exercise Prices	$ 10.32
2017 Warrants [Member]
Class of Warrant or Right [Line Items]
Shares Underlying Outstanding Warrants	0	19,996
2020 Warrants [Member]
Class of Warrant or Right [Line Items]
Shares Underlying Outstanding Warrants	110,248	110,248
2022 Warrants [Member]
Class of Warrant or Right [Line Items]
Shares Underlying Outstanding Warrants	2,034,883	0

Stock Option and Incentive Pl_3

Stock Option and Incentive Plans - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Millions			12 Months Ended
	Dec. 31, 2022	Dec. 31, 2015	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	May 17, 2022	Sep. 30, 2021	Jul. 28, 2014	Apr. 29, 2014	Feb. 24, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares of common stock reserved pursuant to the plan	2,795,645		2,795,645	186,296
Number of common stock shares outstanding	55,565		55,565	36,246
Weighted average grant date fair value of options			$ 245.14	$ 344.8	$ 773.6
Unrecognized compensation cost related to unvested stock options	$ 4.6		$ 4.6
Weighted average period of unvested stock options			2 years
Employee Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation expense recognized			$ 3.9	$ 3.2	$ 2.6
Amended and Restated 2008 Equity Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Termination of service, Period			2 years
2008 Equity Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares of common stock reserved pursuant to the plan									2,946	2,321
Termination of service, Period			10 years
2014 Omnibus Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares of common stock reserved pursuant to the plan								715
Number of additional shares increases of common stock reserved pursuant to the plan	53,358
2014 Omnibus Incentive Plan [Member] | Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Annual increase of plan, percentage of common stock shares outstanding		4%
2021 Employment Inducement Omnibus Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares of common stock reserved pursuant to the plan							12,500
Two Thousand and Twenty Two Employee Stock Purchase Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares of common stock reserved pursuant to the plan						10,000
Number of common stock shares outstanding						0
Discount rate from fair value on offering date that participants pay for shares.			85%

Stock Option and Incentive Pl_4

Stock Option and Incentive Plans - Summary of Stock Option Activity (Detail)	12 Months Ended
	Dec. 31, 2022 USD ($) $ / shares shares
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Number of Options, Options outstanding, Beginning balance | shares	36,246
Number of Options, Granted | shares	22,925
Number of Options, Exercised | shares	0
Number of Options, Expired | shares	(848)
Number of Options, Forfeited | shares	(2,758)
Number of Options, Options outstanding, Ending balance | shares	55,565
Number of Options, Vested and exercisable, Ending Balance | shares	31,757
Weighted Average Exercise Price, Options outstanding, Beginning balance | $ / shares	$ 729.6
Weighted Average Exercise Price, Granted | $ / shares	245.14
Weighted Average Exercise Price, Exercised | $ / shares	0
Weighted Average Exercise Price, Expired | $ / shares	783.53
Weighted Average Exercise Price, Forfeited | $ / shares	328.84
Weighted Average Exercise Price, Options outstanding, Ending balance | $ / shares	548.79
Weighted Average Exercise Price, Vested and exercisable, Ending balance | $ / shares	$ 729.1
Weighted Average Remaining Contractual Life (in years), Options outstanding	7 years 11 months 19 days
Weighted Average Remaining Contractual Life (in years), Vested and exercisable	6 years 10 months 13 days
Aggregate Intrinsic value, Options outstanding | $	$ 0
Aggregate Intrinsic value, Vested and exercisable | $	$ 0

Stock Option and Incentive Pl_5

Stock Option and Incentive Plans - Assumptions to Compute Fair Value of Stock Option Grants (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Risk free interest rate	2.23%	0.83%	1.14%
Expected dividend yield	$ 0	$ 0	$ 0
Expected term (in years)	5 years 10 months 28 days	5 years 11 months 26 days	6 years 10 days
Expected volatility	91.90%	94.50%	94.60%

401k Savings Plan - Additional

401k Savings Plan - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
401k Savings Plan [Member]
Defined Contribution Plan Disclosure [Line Items]
Expense for matching contributions	$ 0.2	$ 0.2	$ 0.1

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Income Tax Contingency [Line Items]
Unused operating loss carryforwards for federal tax purposes	$ 283,700,000
Unused operating loss carryforwards for state tax purposes	$ 302,000,000
Net operating loss carryforwards, expiration year	2028
Deferred tax valuation allowance	$ 106,366,000	$ 85,613,000
Increase (decrease) in valuation allowance	20,800,000	$ 12,800,000
Unrecognized tax benefits	0
Unrecognized interest	0
Unrecognized penalties accrued	$ 0
Research and development credit carry forwards expiration year	2031

Income Taxes - Components of De

Income Taxes - Components of Deferred Tax Assets and Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Deferred tax assets:
Net operating loss carryovers	$ 79,694	$ 77,431
Stock-based compensation	3,295	2,457
R&D capitalization	14,610	0
R&D tax credits	8,196	5,031
Accrued compensation and severance	451	563
Lease liability	801	911
Intangible assets	77	88
Total deferred tax assets	107,124	86,481
Valuation allowance	(106,366)	(85,613)
Total deferred tax assets net of valuation allowance	758	868
Deferred tax liabilities:
Right-of-use asset	(654)	(746)
Depreciation	(104)	(122)
Total deferred tax liabilities	(758)	(868)
Net deferred tax asset (liability)	$ 0	$ 0

Income Taxes - Summary of Recon

Income Taxes - Summary of Reconciliation of Statutory U.S. Federal Rate to Company's Effective Tax Rate (Detail)	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Income Tax Disclosure [Abstract]
Federal income tax benefit at statutory rate	(21.00%)	(21.00%)	(21.00%)
State income tax, net of federal benefit	(6.57%)	(14.41%)	(9.09%)
Permanent items including change in fair value of warrants	0.55%	(26.27%)	(5.35%)
Change in valuation allowance	31.83%	63.08%	37.88%
R&D tax credits	(4.86%)	(5.89%)	(2.43%)
Other	(0.05%)	4.49%	(0.01%)
Effective income tax (benefit) expense rate	0%	0%	0%

Subsequent Events - Additional

Subsequent Events - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Millions	Mar. 02, 2023	Feb. 10, 2023	Dec. 15, 2022
Two Thousand And Twenty Two Offering [Member]
Subsequent Event [Line Items]
Sale of stock, price per share			$ 10.32
Exercise Prices			$ 10.32
Subsequent Event [Member]
Subsequent Event [Line Items]
Stockholders' Equity, Reverse Stock Split		1-for-80
Subsequent Event [Member] | Minimum [Member]
Subsequent Event [Line Items]
Stockholders' Equity, Reverse Stock Split		1-for-10
Subsequent Event [Member] | Maximum [Member]
Subsequent Event [Line Items]
Stockholders' Equity, Reverse Stock Split		1-for-80
Subsequent Event [Member] | Two Thousand And Twenty Two Offering [Member]
Subsequent Event [Line Items]
Sale of stock, price per share	$ 4
Stockholders' Equity, Reverse Stock Split		1-for-80
Proceeds from Issuance or Sale of Equity	$ 9.2
Number of common stock Called by each warrant or right	2
Exercise Prices	$ 4
Subsequent Event [Member] | Two Thousand And Twenty Two Offering [Member] | Pre-Funded Warrants
Subsequent Event [Line Items]
Number of common stock Called by each warrant or right	1