Aridis Pharmaceuticals (ARDS) 10-K 13 Apr 22 2021 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Apr. 11, 2022	Jun. 30, 2021
Cover [Abstract]
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2021
Document Transition Report	false
Entity File Number	001-38630
Entity Registrant Name	Aridis Pharmaceuticals, Inc.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	47-2641188
Entity Address, Address Line One	983 University Avenue, Bldg. B
Entity Address, City or Town	Los Gatos
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	95032
City Area Code	408
Local Phone Number	385-1742
Title of 12(b) Security	Common Stock, par value $0.0001 per share
Trading Symbol	ARDS
Security Exchange Name	NASDAQ
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Small Business	true
Entity Emerging Growth Company	true
Entity Ex Transition Period	false
Entity Shell Company	false
Entity Filer Category	Non-accelerated Filer
Entity Interactive Data Current	Yes
Entity Public Float			$ 72.5
Entity Common Stock, Shares Outstanding		17,701,592
Entity Well-known Seasoned Issuer	No
Entity Central Index Key	0001614067
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	FY
Auditor Name	Mayer Hoffman McCann P.C.
Auditor Firm ID	199
Auditor Location	San Diego, California
Amendment Flag	false

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($)	Dec. 31, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 18,098,000	$ 8,232,000
Restricted cash	1,388,000
Accounts receivable	0	0
Other receivables	237,000	368,000
Contract costs	1,967,000	1,973,000
Prepaid asset	2,700,000	2,182,000
Total current assets	24,390,000	12,755,000
Property and equipment, net	1,357,000	1,258,000
Intangible assets, net	22,000	27,000
Restricted cash, non-current	500,000	500,000
Contract costs, non-current	96,000	90,000
Equity Method Investments	0
Other assets	431,000	487,000
Total assets	26,796,000	15,117,000
Current liabilities:
Accounts payable	5,240,000	1,886,000
Accrued liabilities	6,464,000	1,330,000
Deferred revenue	20,838,000	18,748,000
Note payable	696,000	439,000
Other liabilities	110,000	37,000
Total current liabilities	33,348,000	22,440,000
Deferred revenue, non-current	913,000	854,000
Note payable, non-current	5,282,000	276,000
Other liabilities	363,000	228,000
Total liabilities	39,906,000	23,798,000
Commitments and contingencies (Note 13)
Stockholders' equity (deficit):
Preferred stock (par value $0.0001; 60,000,000 shares authorized; zero shares issued and outstanding as of December 31, 2021 and 2020, respectively)
Common stock (par value $0.0001; 100,000,000 shares authorized; shares issued and outstanding: 17,701,592 and 10,065,727 as of December 31, 2021 and 2020, respectively)	2,000	1,000
Additional paid-in capital	152,183,000	114,420,000
Accumulated deficit	(165,295,000)	(123,102,000)
Total stockholders' deficit	(13,110,000)	(8,681,000)
Total liabilities and stockholders' deficit	$ 26,796,000	$ 15,117,000

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Parenthetical) - $ / shares	Dec. 31, 2021	Dec. 31, 2020
Condensed Consolidated Balance Sheets
Preferred stock, par value (in dollars per share)	$ 0.0001
Preferred stock, shares authorized (in shares)	60,000,000
Preferred stock, shares issued (in shares)	0
Preferred stock, shares outstanding (in shares)	0
Common stock, par value (in dollars per share)	$ 0.0001
Common stock, shares authorized (in shares)	100,000,000
Common stock, shares issued (in shares)	17,701,592	10,065,727
Common stock, shares outstanding (in shares)	17,701,592	10,065,727

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Revenue:
Revenue	$ 1,535	$ 1,000
Operating expenses:
Research and development	36,936	16,956
General and administrative	7,310	6,445
Total operating expenses	44,246	23,401
Loss from operations	(42,711)	(22,401)
Other income (expense):
Interest (expense) income, net	(245)	77
Other income	74
Gain on extinguishment of Paycheck Protection Program loan	722
Change in fair value of note payable	(33)
Share of loss from equity method investment		(9)
Net loss	(42,193)	(22,333)
Deemed dividends	(4,127)
Net loss available to common stockholders	$ (46,320)	$ (22,333)
Weighted-average common shares outstanding used in computing net loss per share available to common stockholders, basic	12,291,600	9,168,744
Weighted-average common shares outstanding used in computing net loss per share available to common stockholders, diluted	12,291,600	9,168,744
Net loss per share to common stockholders, basic	$ (3.77)	$ (2.44)
Net loss per share to common stockholders, diluted	$ (3.77)	$ (2.44)

Consolidated Statements of Chan

Consolidated Statements of Changes in Stockholders' Equity (Deficit) - USD ($) $ in Thousands	Common Stock MemberPrivate placement	Common Stock MemberATM offering Agreement	Common Stock Member	Additional Paid-In CapitalPrivate placement	Additional Paid-In CapitalATM offering Agreement	Additional Paid-In Capital	Accumulated Deficit	Private placement	ATM offering Agreement	Total
Balances at the beginning of the period at Dec. 31, 2019			$ 1			$ 104,404	$ (100,769)			$ 3,636
Balances at the beginning of the period (in shares) at Dec. 31, 2019			8,918,461
Changes in equity
Issuance of common stock				$ 5,807	$ 62			$ 5,807	$ 62
Issuance of common stock (in shares)	1,134,470	7,883
Issuance of common stock warrants in registered direct offering, net of issuance costs						2,005				2,005
Exercise of stock options						14				14
Exercise of stock options (in shares)			4,913
Stock-based compensation						2,128				2,128
Net loss							(22,333)			(22,333)
Balances at the end of the period at Dec. 31, 2020			$ 1			114,420	(123,102)			(8,681)
Balances at the end of the period (shares) at Dec. 31, 2020			10,065,727
Changes in equity
Issuance of common stock			$ 0			29,011				29,011
Issuance of common stock (in shares)			2,337,405						7,883
Issuance of common stock in connection with license agreement						6,460				6,460
Issuance of common stock in connection with license agreement (in shares)			884,956
Issuance of common stock for consulting services						33				33
Issuance of common stock for consulting services (in shares)			5,000
Issuance of common stock upon exercise of warrants			$ 1			3				4
Issuance of common stock upon exercise of warrants (in shares)			3,647,556
Deemed dividends (in shares)			759,389
Exercise of stock options						5				$ 5
Exercise of stock options (in shares)			1,559							1,559
Stock-based compensation						2,251				$ 2,251
Net loss							(42,193)			(42,193)
Balances at the end of the period at Dec. 31, 2021			$ 2			$ 152,183	$ (165,295)			$ (13,110)
Balances at the end of the period (shares) at Dec. 31, 2021			17,701,592

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Cash flows from operating activities:
Net loss	$ (42,193)	$ (22,333)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	435	337
Stock-based compensation expense	2,251	2,128
Issuance of common stock for licensing activities	6,460
Issuance of shares in exchange for consulting services	33
Gain on extinguishment of Paycheck Protection Program loan	(722)
Non-cash debt issuance expense	250
Change in fair value of note payable	33
Share of loss from equity method investment		9
Changes in operating assets and liabilities:
Other receivables	131	(144)
Prepaid asset	178	808
Contract costs		(488)
Other assets	56	46
Accounts payable	2,654	(83)
Accrued liabilities and other liabilities	5,349	(756)
Deferred revenue	2,149
Net cash used in operating activities	(22,936)	(20,476)
Cash flows from investing activities:
Purchase of property and equipment	(530)	(367)
Net cash used in investing activities	(530)	(367)
Cash flows from financing activities:
Proceeds from note payable	5,000	715
Proceeds from issuance of common stock and warrants, net	29,715	7,949
Proceeds from stock option exercises	5	14
Net cash provided by financing activities	34,720	8,678
Net increase (decrease) in cash, cash equivalents and restricted cash	11,254	(12,165)
Cash, cash equivalents and restricted cash at:
Beginning of period	8,732	20,897
End of period	19,986	8,732
Supplemental cash flow disclosures:
Cash paid for taxes	2	2
Property and equipment additions		$ 230
Supplemental noncash investing and financing activities:
Financed insurance premiums, net	696
Deemed dividends	$ 4,127

Description of Business and Bas

Description of Business and Basis of Presentation	12 Months Ended
	Dec. 31, 2021
Description of Business and Basis of Presentation
Description of Business and Basis of Presentation	1. Description of Business and Basis of Presentation Organization Aridis Pharmaceuticals, Inc. (the “Company” or “we” or “our” or “us”) was established as a California limited liability corporation in 2003. The Company converted to a Delaware C corporation on May 21, 2014. Our principal place of business is in Los Gatos, California. We are a late-stage biopharmaceutical Company focused on developing new breakthrough therapies for infectious diseases and addressing the growing problem of antibiotic resistance. The Company has a deep, diversified portfolio of clinical and pre-clinical stage non-antibiotic anti-infective product candidates that are complimented by a fully human monoclonal antibody discovery platform technology. The Company’s suite of anti-infective monoclonal antibodies offers opportunities to profoundly alter the current trajectory of increasing antibiotic resistance and improve the health outcome of many of the most serious life-threatening infections particularly in hospital settings. Basis of Presentation and Consolidation The accompanying consolidated financial statements have been prepared in accordance with the United States generally accepted accounting principles, or GAAP. The consolidated financial statements include the accounts of the Company and its two wholly-owned subsidiaries, Aridis Biopharmaceuticals, LLC and Aridis Pharmaceuticals, C.V. All intercompany balances and transactions have been eliminated in consolidation. The Company operates in one segment. Management uses one measurement of profitability and does not segregate its business for internal reporting. COVID-19 The COVID-19 outbreak in the United States has caused business disruption. The extent of the impact of COVID-19 on the Company’s operational and financial performance will depend on certain developments, including the duration and spread of the outbreak, and impact on the Company’s clinical trials, employees and vendors, all of which are uncertain and cannot be predicted. At this point, the extent to which COVID-19 may impact the Company’s financial condition or results of operations is uncertain. Going Concern The Company had recurring losses from operations since inception and negative cash flows from operating activities during the years ended December 31, 2021 and 2020. Management expects to incur operating losses and negative cash flows from operations in the foreseeable future as the Company continues its product development programs. The forecasted outflow of cash for at least a one-year period from the expected financial statement issuance date, is in excess of the cash available on-hand. In February 2022, the Company received additional gross proceeds of $5.0 million from debt financing (see Note 14). The Company’s research and development expenses and resulting cash burn during the year ended December 31, 2021, were largely due to costs associated with the Phase 3 study of AR-301 for the treatment of ventilator associated pneumonia (“VAP”) caused by the Staphylococcus aureus (S. aureus) bacteria, the Phase 1/2 study of AR-501 for the treatment of chronic lung infections associated with cystic fibrosis, the pre-launch activities associated with the Phase 3 study of AR-320 for the prevention of S. aureus VAP, and the preclinical development of AR-712 COVID-19 monoclonal antibodies (mAbs). Current development activities are focused on AR-301, AR-320, AR-501 and AR-712. We expect our expenses to continue in connection with our ongoing development activities, particularly as we continue the research, development and clinical trials of, and seek regulatory approval for, our therapeutic candidates The on-going COVID-19 pandemic is affecting the United States and global economies. The pandemic has affected the Company and is likely to continue to affect the Company and its third parties, on which the Company relies, by causing disruptions in the clinical trial supplies for the product candidates and the conduct of current and future clinical trials. Additionally, as the duration of the COVID-19 pandemic is difficult to assess or predict, the impact of the COVID-19 pandemic on the global financial markets may reduce our ability to access capital, which could negatively impact the Company’s short-term and long-term liquidity. Additionally, the AR-301 clinical trial currently has sites enrolling in Russia, Ukraine and Belarus. To the extent the conflict between Ukraine and Russia adversely impacts our ability to enroll patients or complete enrollments in process or adversely impacts the ability of our suppliers to produce and distribute the supplies we need for our AR-301 clinical trial, the timing for completing our AR-301 trial may be adversely impacted. These effects could have a material impact on the Company’s liquidity, capital resources, operations and business and those of the third parties on which the Company relies. The Company plans to fund its cash flow needs through current cash on hand and future debt and equity financings which we may obtain through one or more public or private equity offerings, debt financings, government or other third-party funding, strategic alliances and licensing or collaboration arrangements. If the Company is unable to obtain funding, the Company could be forced to delay, reduce or eliminate its research and development programs or future commercialization efforts, which could adversely affect its future business prospects and its ability to continue as a going concern. The Company believes that its current available cash and cash equivalents, including cash received in February 2022 from debt proceeds, will not be sufficient to fund its planned expenditures and meet the Company’s obligations for at least the one-year period following its consolidated financial statement issuance date. The accompanying consolidated financial statements have been prepared on a going concern basis that contemplates the realization of assets and discharge of liabilities in their normal course of business. There is substantial doubt about the Company’s ability to continue as a going concern for one year after the date that these consolidated financial statements are issued. These consolidated financial statements do not include any adjustments that might be necessary from the outcome of this uncertainty.

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2021
Summary of Significant Accounting Policies
Summary of Significant Accounting Policies	2. Summary of Significant Accounting Policies Use of Estimates The preparation of the consolidated financial statements requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities as of the date of the consolidated financial statements and the reported amounts of expenses during the reporting period. Such estimates include those related to the evaluation of our ability to continue as a going concern, best estimate of standalone selling price of revenue deliverables, useful life of long-lived assets, classification of deferred revenue, income taxes, assumptions used in the Black-Scholes-Merton (“BSM”) model to calculate the fair value of stock-based compensation, deferred tax asset valuation allowances, and preclinical study and clinical trial accruals. Actual results could differ from those estimates. Concentrations Credit Risk The Company’s cash and cash equivalents are maintained at financial institutions in the United States of America. Deposits held by these institutions may exceed the amount of insurance provided on such deposits. Customer Risk For the year ended December 31, 2021, three customers, each individually being 34%, 36% and 30% accounted for 100% of total revenue and for the year ended December 31, 2020, one customer accounted for 100% of total revenue. The customers are located in the United States. As of December 31, 2021 and 2020, there were no accounts receivable. Cash, Cash Equivalents and Restricted Cash The Company considers all highly liquid investments purchased with an original maturity of three months or less to be cash equivalents. Cash equivalents consist primarily of checking account and money market fund account balances. The following table provides a reconciliation of cash, cash equivalents and restricted cash within the consolidated balance sheets which, in aggregate, represent the amount reported in the consolidated statements of cash flows (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, ​ ​ 2021 ​ 2020 Cash and cash equivalents $ 18,098 ​ $ 8,232 Restricted cash ​ 1,888 ​ 500 Total cash, cash equivalents and restricted cash ​ $ 19,986 ​ $ 8,732 ​ Restricted cash consists of deposits for a letter of credit that the Company has provided to secure its obligations under its facility lease and cash received from the Gates Foundation restricted specifically to research associated with the grant. Restricted cash is classified as current when the Company expects to fulfill the obligation within one year or less. ​ Accounts Receivable and Allowance for Doubtful Accounts Accounts receivable are recorded at the invoiced amount and do not bear interest. The Company considers the credit worthiness of its customers but does not require collateral in advance of a sale. The Company evaluates collectability and maintains an allowance for doubtful accounts for estimated losses inherent in its accounts receivable portfolio when necessary. The allowance is based on the Company’s best estimate of the amount of losses in the Company’s existing accounts receivable, which is based on customer creditworthiness, facts and circumstances specific to outstanding balances, and payment terms. Account balances are charged off against the allowance after all means of collection have been exhausted and the potential for recovery is considered remote. As of December 31, 2021 and 2020, there were no allowances for doubtful accounts. Operating Leases The Company evaluates leases at their inception as either operating or capital leases, and may receive renewal or expansion options, rent holidays, leasehold improvement allowances and other incentives on such lease agreements. The Company recognizes operating lease costs on a straight-line basis over the term of the agreement. ​ Property and Equipment Property and equipment are stated at cost less accumulated depreciation. Depreciation and amortization is computed using the straight-line method over the estimated useful lives of the assets, generally between three Intangible Assets Intangible assets are recorded at cost and amortized over the estimated useful life of the asset. Intangible assets consist of licenses with various institutions whereby the Company has rights to use intangible property obtained from such institutions. 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. Recoverability is measured by comparison of the carrying amount to the future undiscounted net cash flows which the assets are expected to generate. If such assets are considered to be impaired, the impairment is measured by the excess of the carrying amount of the assets over fair value less the costs to sell the assets, generally determined using the projected discounted future net cash flows arising from the asset. There have been no such impairments of long-lived assets as of December 31, 2021 and 2020. Revenue Recognition The Company recognizes revenue based on Accounting Standards Codification (“ASC”) 606, Revenue from Contracts with Customers To determine revenue recognition for arrangements that the Company determines are within the scope of ASC 606, the Company performs the following five steps: (i) identify the contract(s) with a customer; (ii) identify the performance obligations in the contract; (iii) determine the transaction price; (iv) allocate the transaction price to the performance obligations in the contract; and (v) recognize revenue at a point in time, or over time, as the entity satisfies performance obligations. The Company only applies the five-step model to contracts when it is probable that it will collect the consideration it is entitled to in exchange for the goods or services it transfers to the customer. At contract inception, once the contract is determined to be within the scope of ASC 606, the Company assesses the goods or services promised within each contract, determines those that are performance obligations, and assesses whether each promised good or service is distinct. The Company then recognizes as revenue the amount of the transaction price that is allocated to the respective performance obligation when (or as) the performance obligation is satisfied. As part of the accounting for customer arrangements, the Company must use judgment to determine: a) the number of performance obligations based on the determination under step (ii) above; b) the transaction price under step (iii) above; and c) the standalone selling price for each performance obligation identified in the contract for the allocation of the transaction price in step (iv) above. The Company uses judgment to determine whether milestones or other variable consideration should be included in the transaction price. The transaction price is allocated to each performance obligation on a relative standalone selling price basis. In developing the standalone price for a performance obligation, the Company considers applicable market conditions and relevant entity-specific factors, including factors that were contemplated in negotiating the agreement with the customer and estimated costs. The Company recognizes revenue as or when the performance obligations under the contract are satisfied. The Company receives payments from its customers based on payment schedules established in each contract. The Company records any amounts received prior to satisfying the revenue recognition criteria as deferred revenue on its consolidated balance sheets. Amounts recognized as revenue, but not yet received or invoiced are recorded within other receivables on the consolidated balance sheet. Amounts are recorded as other receivables on the consolidated balance sheet when our right to consideration is unconditional. The Company does not assess whether a contract has a significant financing component if the expectation at contract inception is such that the period between payment by the customer and the transfer of a majority of the promised goods or services to the customer will be one year or less. Contract Assets The incremental costs of obtaining a contract under ASC 606 (i.e. costs that would not have been incurred if the contract had not been obtained) are recognized as an asset in the Company’s consolidated balance sheets if the Company expects to recover them (see Note 6). Capitalized costs will be amortized to the respective expenses using a systematic basis that mirrors the pattern in which the Company transfers control of the goods and service to the customer. At each reporting date, the Company determines whether or not the capitalized costs to obtain a contract are impaired by comparing the carrying amount of the asset to the remaining amount of consideration that the Company received and expects to receive less the costs that relate to providing services under the relevant contract. For the years ended December 31, 2021 and 2020, there was no amortization of the contract assets and there have been no impairments as of December 31, 2021 and 2020. Deferred Revenue Amounts received prior to satisfying the above revenue recognition criteria, or in which the Company has an unconditional right to payment, are recorded as deferred revenue in the Company’s consolidated balance sheets. The Company has estimated the classification between current and noncurrent deferred revenue related to the respective license agreement within its consolidated balance sheets at December 31, 2021 and 2020 (see Note 6). Research and Development Research and development costs are expensed to operations as incurred. Our research and development expenses consist primarily of: ● salaries and related overhead expenses, which include stock-based compensation and benefits for personnel in research and development functions; ● fees paid to consultants and contract research organizations, or CROs, including in connection with our preclinical studies and clinical trials and other related clinical trial fees, such as for investigator grants, patient screening, laboratory work, clinical trial material management and statistical compilation and analyses; ● costs related to acquiring and manufacturing clinical trial materials; ● costs related to compliance with regulatory requirements; and ● payments related to licensed products and technologies. Costs for certain development activities are recognized based on an evaluation of the progress to completion of specific tasks using information and data provided to us by our vendors and clinical sites. Nonrefundable advance payments for goods or services to be received in future periods for use in research and development activities are deferred and capitalized. The capitalized amounts are then expensed as the related goods are delivered or when the services are performed. Stock-Based Compensation The Company recognizes compensation expense for all stock-based awards based on the grant-date estimated fair values, which the Company determines using the BSM option pricing model, on a straight-line basis over the requisite service period for the award. The Company accounts for forfeitures as they occur. The BSM option pricing model incorporates various highly sensitive assumptions, including the fair value of our common stock, expected volatility, expected term and risk-free interest rates. The weighted average expected life of options was calculated using the simplified method as prescribed by the SEC’s Staff Accounting Bulletin, Topic 14 (“SAB Topic 14”). This decision was based on the lack of relevant historical data due to our limited historical experience. In addition, due to our limited historical data, the estimated volatility also reflects the application of SAB Topic 14, incorporating the historical volatility of comparable companies whose stock prices are publicly available. The risk-free interest rate for the periods within the expected term of the option is based on the U.S. Treasury yield in effect at the time of grant. The dividend yield was zero, as we have never declared or paid dividends and have no plans to do so in the foreseeable future. Income Taxes The Company accounts for income taxes under the liability method. Under this method, deferred tax assets and liabilities are determined based on the difference between the financial statement and tax basis of assets and liabilities using enacted tax rates in effect for the year in which the differences are expected to affect taxable income. Valuation allowances are established when necessary to reduce deferred tax assets to the amounts expected to be realized. The Company assesses all material positions taken in any income tax return, including all significant uncertain positions, in all tax years that are still subject to assessment or challenge by the relevant taxing authorities. Assessing an uncertain tax position begins with the initial determination of the position’s sustainability and is measured at the largest amount of benefit that is greater than 50% likely of being realized upon ultimate settlement. At each balance sheet date, unresolved uncertain tax positions must be reassessed, and the Company will determine whether (i) the factors underlying the sustainability assertion have changed and (ii) the amount of the recognized benefit is still appropriate. The recognition and measurement of tax benefits requires significant judgment. Judgments concerning the recognition and measurement of a tax benefit might change as new information becomes available. The Company’s policy is to recognize interest or penalties related to income tax matters in income tax expense. Comprehensive Loss The Company has no items of comprehensive income or loss other than net loss. Loss Per Share Basic loss per share is calculated by dividing net loss for the period by the weighted-average number of common shares outstanding during the period, without consideration for potentially dilutive securities. Diluted net loss per share is computed by dividing the net loss by the weighted-average number of common shares and potentially dilutive securities outstanding for the period. In March 2021 and in August 2021, the Company issued 124,789 and 634,600 dividend shares, respectively, to certain common stockholders with a fair value of approximately $986,000 and approximately $3.1 million, respectively, (see Note 9) which is included in the net loss available to common stockholders for the year ended December 31, 2021 in the below table. For the years ended December 31, 2021 and 2020, there is no difference in the number of shares used to compute basic and diluted net loss per share due to the Company’s net loss position. The following tables presents the computation of the basic and diluted net loss per share (in thousands, except share and per share data): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year Ended ​ ​ December 31, ​ 2021 2020 Numerator: ​ ​ ​ ​ Net loss available to common stockholders ​ $ (46,320) ​ $ (22,333) ​ ​ ​ ​ ​ ​ ​ Denominator: ​ ​ ​ Weighted-average common shares outstanding used in computing net loss per share available to common stockholders, basic and diluted ​ 12,291,600 ​ 9,168,744 Basic and diluted net loss per share ​ $ (3.77) ​ $ (2.44) ​ The following potentially dilutive securities were excluded from the computation of diluted net loss per share for the periods presented because including them would have been antidilutive: ​ ​ ​ ​ ​ ​ ​ ​ Year Ended ​ ​ December 31, ​ 2021 ​ 2020 Stock options to purchase common stock 1,905,459 ​ 1,550,956 Common stock warrants 3,592,905 ​ 2,052,128 ​ 5,498,364 ​ 3,603,084 ​ JOBS Act Accounting Election The JOBS Act permits an “emerging growth company” such as us to take advantage of an extended transition period to comply with new or revised accounting standards applicable to public companies. We are choosing to take advantage of this provision and, as a result, we will adopt the extended transition period available under the JOBS Act until the earlier of the date we (i) are no longer an emerging growth company or (ii) affirmatively and irrevocably opt out of the extended transition period provided under the JOBS Act. Recently Issued Accounting Pronouncements not yet adopted as of December 31, 2021 Accounting Standards Update 2016-02, 2018-11 and 2019-01 In February 2016, the FASB issued ASU 2016-02, Leases (ASC 842) Leases off-balance sheet financing. Initial guidance required the adoption of the new lease standard using the modified retrospective transition method. In July 2018, the FASB issued ASU 2018-11, Leases (ASC 842)-Targeted Improvements Codification improvements Accounting Standards Update 2016-13 In June 2016, the FASB issued ASU 2016-13, “ Financial Instruments- Credit Losses (ASC 326) Accounting Standards Update 2019-12 In December 2019, the FASB issued ASU 2019-12, “ Simplifying the Accounting for Income Taxes (ASC 740)

Fair Value Disclosure

Fair Value Disclosure	12 Months Ended
	Dec. 31, 2021
Fair Value Disclosure
Fair Value Disclosure	3. Fair Value Disclosure Fair value is defined as the exchange price that would be received for an asset or an exit price paid to transfer a liability in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. Valuation techniques used to measure fair value must maximize the use of observable inputs and minimize the use of unobservable inputs. The fair value hierarchy defines a three-level valuation hierarchy for disclosure of fair value measurements as follows: ​ ​ Level 1 Unadjusted quoted prices in active markets for identical assets or liabilities; ​ ​ Level 2 Inputs other than quoted prices included within Level 1 that are observable, unadjusted quoted prices in markets that are not active, or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the related assets or liabilities; and ​ ​ Level 3 Unobservable inputs that are supported by little or no market activity for the related assets or liabilities. ​ The categorization of a financial instrument within the valuation hierarchy is based upon the lowest level of input that is significant to the fair value measurement. The carrying value of the Company’s cash and cash equivalents, restricted cash, prepaid expenses and other current assets, other assets, accounts payable, accrued liabilities, and insurance financing note payable approximate fair value due to the short-term nature of these items. ​

Balance Sheet Components

Balance Sheet Components	12 Months Ended
	Dec. 31, 2021
Balance Sheet Components
Balance Sheet Components	4. Balance Sheet Components Property and Equipment, net Property and equipment, net consist of the following (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, ​ December 31, ​ 2021 ​ 2020 Lab equipment ​ $ 2,390 ​ $ 2,200 Computer equipment and software ​ ​ 25 ​ 25 Construction in progress ​ ​ — ​ ​ 188 Leasehold improvements ​ ​ 527 ​ ​ — Total property and equipment ​ ​ 2,942 ​ 2,413 Less: Accumulated depreciation ​ (1,585) ​ (1,155) Property and equipment, net ​ $ 1,357 ​ $ 1,258 ​ Depreciation expense was approximately $430,000 and $332,000 for years ended December 31, 2021 and 2020. In October 2020, the Company entered into a lease agreement for its new headquarters facility in Los Gatos, California (see Note 13). The Company moved into the new facility in December 2020 and recorded approximately $188,000 in construction in progress related to leasehold improvements made by the Company related to the new facility. The Company substantially completed construction in progress related to leasehold improvements made by the Company related to the new facility. As a result, approximately $527,000 was recorded to leasehold improvements including approximately $188,000 of construction in progress that had been recorded in 2020. Intangible Assets, net Intangible assets, net consist of the following (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, ​ December 31, ​ 2021 ​ 2020 Licenses ​ $ 81 ​ $ 81 Less: Accumulated amortization ​ ​ (59) ​ (54) Intangible assets, net ​ $ 22 ​ $ 27 ​ Amortization expense was approximately $5,000 for both years ended December 31, 2021 and 2020, respectively. The estimated acquired intangible amortization expense for the next five fiscal years is as follows (in thousands): ​ ​ ​ ​ Year ending December 31, ​ 2022 ​ $ 5 2023 ​ 5 2024 ​ ​ 5 2025 ​ ​ 5 2026 ​ ​ 2 Total ​ $ 22 ​ Licenses University Licensing Agreements The University of Chicago-Exclusive Patent License Agreement We are party to an exclusive licensing agreement with The University of Chicago (UOC), a non-profit university. This agreement granted to us an exclusive, royalty-bearing license for staph alpha toxin technology. The UOC agreement also granted to us the right to sublicense. UOC retained the non-transferrable right to use such patent rights for academic and research purposes, and also to certain pre-existing rights of the U.S. government. We paid upfront fees upon the execution of the agreement and are obligated to pay an annual maintenance fee. We also are obligated to pay UOC low single digit percentage royalties on net sales from our and our sublicensee’s sale of any commercialized licensed product or process, and certain other payments, subject to a minimum amount. The aggregate milestone payments under the UOC agreement potentially total up to $1.6 million. No milestones were met or accrued for during 2021. A $100,000 milestone was accrued for at December 31, 2020. We are responsible for our pro rata share of patent expenses. The agreement provides that we have certain obligations to conduct further research and development, and are obligated to utilize reasonable efforts to commercialize, either directly or through a sublicensee, the licensed UOC patent rights as licensed products or processes. The term of the agreement continues until all patents and filed patent applications, included within the licensed UOC patents, have expired or been abandoned, or until the agreement is earlier terminated. We may terminate the agreement on prior written notice to UOC. Each party has the right to terminate the agreement for the other party’s uncured material breach of obligations under the agreement. The Brigham and Women’s Hospital, Inc.-Exclusive Patent License Agreement We are party to an exclusive licensing agreement with The Brigham and Women’s Hospital, Inc. (BWH), a non-profit corporation. This agreement granted to us an exclusive, royalty-bearing license under its and Beth Israel Deaconess Medical Center’s (BIDMC) rights in methods and composition relating to specific binding peptides to P. aeruginosa The agreement provides that we have certain obligations to conduct further research and development, and are obligated to utilize reasonable efforts to commercialize, either directly or through a sublicensee, the licensed BWH patent rights as licensed products or processes. The term of the agreement continues until all patents and filed patent applications, included within the licensed BWH patents, have expired or been abandoned, or until the agreement is earlier terminated. We may terminate the agreement on prior written notice to BWH. Each party has the right to terminate the agreement for the other party’s uncured material breach of obligations under the agreement. The University of Iowa Research Foundation-Exclusive Patent License Agreement We are party to an exclusive licensing agreement with The University of Iowa Research Foundation (UIRF). The UIRF agreement granted to us an exclusive, royalty-bearing license under its rights in methods relating to gallium containing compounds for the treatment of infections to make, use and sell products that are covered by such patent rights. The UIRF agreement also granted to us the right to sublicense. UIRF retained the right and ability to grant right to use such patent rights for academic and research purposes, and also to certain pre-existing rights of the U.S. government including the United States Department of Veterans Affairs. We also are obligated to pay UIRF low single digit percentage royalties on net sales from our and our sublicensee’s sale of any commercialized licensed product or process, and certain other payments. The aggregate milestone payments under the UIRF agreement potentially total up to $712,500. No milestones were met or accrued for during 2020. A milestone was met and $75,000 was accrued for as of December 31, 2021. We are responsible for diligently prosecuting and maintaining the licensed UIRF patent rights, at our sole cost and expense. The agreement provides that we have certain obligations to conduct further research and development, and are obligated to utilize reasonable efforts to commercialize, either directly or through a sublicensee, the licensed UIRF patent rights as licensed products or processes. The term of the agreement continues until the expiration of the last to expire patents, included within the licensed UIRF patents, or until the agreement is earlier terminated. We may terminate the agreement on prior written notice to UIRF. Each party has the right to terminate the agreement for the other party’s uncured material breach of obligations under the agreement. Brigham Young University-Exclusive Patent License Agreement We are party to an exclusive licensing agreement with Brigham Young University (BYU). This agreement granted to us an exclusive, royalty-bearing license under its rights in stabilization of biological agents methods relating to human vaccines to make, use and sell products that are covered by such patent rights. The agreement also granted to us the right to sublicense. BYU and the Church of Jesus Christ of Latter-day Saints and the Church Education System retained the right and ability to use such patent rights for academic and ecclesiastical purposes and also to purchase products using such patents rights at a discounted price. We also are obligated to pay BYU low single digit percentage royalties on net sales from our and our sublicensee’s sale of any commercialized licensed product, and certain other payments. The aggregate milestone payments under the BYU agreement potentially total up to $400,000. No milestones were met or accrued for during 2021 or 2020. BYU is responsible for diligently prosecuting and maintaining the licensed BYU patent rights and we reimburse them for one- third The agreement provides that we have certain obligations to conduct further research and development, and are obligated to utilize reasonable efforts to commercialize, either directly or through a sublicensee, the licensed BYU patent rights as licensed products or processes. The term of this agreement continues until the expiration of the last to expire patents, included within the licensed BYU patents, or until the agreement is earlier terminated. We may terminate the agreement on prior written notice to BYU. Each party has the right to terminate the agreement for the other party’s uncured material breach of obligations under the agreement. The University of Alabama at Birmingham Research Foundation — Exclusive Patent License Agreement In September 2020, the Company entered into an exclusive licensing agreement with the University of Alabama at Birmingham The Company has agreed to provide at least $50,000 in research funding to each of the two lead inventor’s research programs. This funding was supplied under research agreements between the Company, UABRF and Texas Biomed, and the intellectual property resulting from such research shall be included under this exclusive license agreement. The potential development and commercialization milestone payments under the UABRF agreement total up to approximately $5.5 million. No milestones were met or accrued for as of December 31, 2021 and 2020. The Company is also obligated to pay UABRF single digit percentage royalties on net sales from us and our sublicensee’s sale of any commercialized licensed product or process, subject to minimum annual amounts starting in 2026. The Company is obligated to pay UABRF double digit percentage royalties on non-royalty income received during the term of the license agreement, and payments will be reduced by one The term of the license agreement continues until all patents and filed patent applications, included within the licensed UABRF patents, have expired, or been abandoned, or until the agreement is earlier terminated. The Company may terminate the license agreement by giving no less than ninety ( 90 Broad Institute of MIT and Harvard — Non-Exclusive Manufacturing License Agreement We entered into a non-exclusive manufacturing licensing agreement with the Broad Institute of MIT and Harvard (the “Broad Institute”) to make and manufacture CRISPR Modified Cell Lines, CRISPR Modified Animals and CRISPR Modified Plants. These license rights permit the non-exclusive use of the CRISPR Technology for the creation of and improvement of yield from protein and mAb production cell lines, which is one of the core components of the PEXTM mAb discovery and manufacturing production technology. We are obligated to pay to the Broad Institute an issue fee of $25,000, an annual license maintenance fee of $50,000 in 2022, and fees of $100,000 in 2023 Non-Profit Licensing Agreements Program for Appropriate Technology in Health and PATH Vaccine Solutions We granted the Program for Appropriate Technology in Health (PATH), a global non-profit organization, and the PATH Vaccine Solutions a non-exclusive license, with right to sublicense formulations, for use with the measles, rotavirus, live-attenuated influenza, pneumococcal and enteric vaccines only for sale in developing countries. We have also agreed to provide rotavirus vaccines to public sector purchasers in developing countries at a preferential price relative to private sector purchasers in developing countries where the rotavirus vaccine utilizing the enabling formulation technology is offered for sale. Corporate Licensing Agreements MedImmune Limited - License Agreement In July 2021, the Company executed a license agreement effective July 12, 2021 and entered into an amendment to the license agreement on August 9, 2021 (collectively the “MedImmune License Agreement”) with MedImmune Limited (“MedImmune”), pursuant to which MedImmune granted the Company an exclusive worldwide license for the development and commercialization of suvratoxumab, a Phase 3 ready fully human monoclonal antibody targeting the staphylococcus aureus alpha toxin (the “Licensed Product”). As consideration for the MedImmune License Agreement, the Company issued 884,956 shares of its common stock to MedImmune and a $5.0 million cash payment is due to MedImmune upon the earlier of (i) a registered direct offering in which the Company receives third-party funding or (ii) December 31, 2021. The $5.0 million liability has not been paid and therefore has been included in accrued liabilities within the Company’s consolidated balance sheet at December 31, 2021, and recorded as research and development expense within its consolidated statement of operations for the year ended December 31, 2021. The fair value of the 884,956 shares of the Company’s common stock issued in connection with the MedImmune License agreement is approximately $6.5 million (see Note 9) which the Company recognized as research and development expense within its consolidated statement of operations and additional paid-in capital within equity in its consolidated balance sheet during the year ended December 31, 2021. As additional consideration, the Company will pay MedImmune milestone payments upon the achievement of certain regulatory approvals, for one licensed product, up to a total aggregate amount of $30.0 million and sales related milestone payments of up to $85.0 million. There are no development milestone payments. MedImmune is entitled to royalty payments based on aggregate net sales ranging from 12.5% to 15% dependent on net sales volume. Further, until delivery of an interim data readout, or an interim futility analysis, from the first Phase 3 clinical study for any indication, MedImmune has a right of first negotiation regarding any commercial rights that the Company intends to sub-license. The term of the MedImmune License Agreement continues until the expiration of the last royalty term for the last licensed product as defined in the license agreement. Kenta Biotech Ltd. We are party to an asset purchase agreement with Kenta Biotech Ltd. (Kenta), a for profit corporation (Aktiengesellschaft) duly incorporated in Schlieren (Canton of Zurich, Switzerland), registered under the identification number CH-035.3.035.876-2. The agreement assigned and transferred certain of Kenta’s physical assets, contracts and technology to us. The physical assets included all physical assets owned or controlled by Kenta, including but not limited to cell lines, genes, antibodies, diagnostic assays and related documentation, which were related to Kenta’s MabIgX technology platform for hybridoma generation and its mAb targeting S. aureus P. aeruginosa A. baumannii S. aureus P. aeruginosa . baumannii We were obligated to pay Kenta a fixed purchase price, which was fully paid during 2013 and 2014, and a declining scale of low double digit to low single digit percentage royalties on gross licensing revenues from either our licensing of the assets or net sales revenues actually received by us up to a maximum of $50 million. As of December 31, 2021 and 2020, no royalty obligation was due to Kenta. Emergent Product Development Gaithersburg Inc. We are party to a license agreement with Emergent Product Development Gaithersburg Inc. (Emergent). We granted Emergent an exclusive, perpetual, royalty-bearing license to use certain of our patents and related know how for the prevention or treatment of infection or illness caused by biodefense pathogens. We also granted a non-exclusive, royalty-bearing license to use certain of our patents and related know how for the prevention or treatment of tularemia and viral hemorrhagic fever indications. Emergent is obligated to pay us low single digit percentage royalties on net sales from their and their sublicensee’s sale of any commercialized licensed product, and certain other payments. The aggregate milestone payments that the Company could receive under the Emergent agreement amount to $2.8 million. The Company is not aware of Emergent achieving any milestones under the agreement and has not received any milestone payments. The Company has certain diligence obligations to conduct further research and development, and to exploit licensed products. Accrued Liabilities Accrued liabilities consist of the following (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, ​ December 31, ​ 2021 ​ 2020 ​ ​ ​ ​ ​ ​ ​ Research and development services ​ $ 5,939 ​ $ 872 Payroll related expenses ​ ​ 416 ​ 279 Professional services and other ​ ​ 109 ​ 179 Accrued liabilities ​ $ 6,464 ​ $ 1,330 ​

Equity Method Investment

Equity Method Investment	12 Months Ended
	Dec. 31, 2021
Equity Method Investment
Equity Method Investment	5. Equity Method Investment On February 11, 2018, the Company entered into a joint venture agreement (the “JV Agreement”) with Shenzhen Hepalink Pharmaceutical Group Co., Ltd., a related party, principal shareholder of the Company, and a Chinese entity (“Hepalink”), to develop and commercialize products for infectious diseases. Under the terms of the JV Agreement, the Company contributed $1.0 million and the license of its technology relating to the Company’s AR-101 and AR-301 product candidates for use in the joint venture company named Shenzhen Arimab BioPharmaceuticals Co., Ltd. (the “JV Entity”) in the territories of the Republic of China, Hong Kong, Macau and Taiwan (the “Territory”) and initially owns 49% of the JV Entity. On July 2, 2018, the JV Entity received final approval from the government of the Peoples Republic of China. It was agreed by the parties that the Company shall be reimbursed for certain legal and contract manufacturing expenses related to the clinical drug supply for a Phase 3 clinical study of AR-301 and the clinical drug supply for a clinical study of AR-105 (see Note 12). On August 6, 2018, the Company entered into an amendment to the JV Agreement with Hepalink whereby the Company agreed to additionally contribute an exclusive, revocable, and royalty-free right and license to its AR-105 product candidate in the Territory. Pursuant to the JV Agreement and the amendment, Hepalink initially owns 51% of the JV Entity and is obligated to contribute the equivalent of $7.2 million to the JV Entity. Additionally, Hepalink is obligated to make an additional equity investment of $10.8 million or more at the time of the JV Entity’s first future financing. The Company evaluated the accounting for the JV Agreement entered into noting that it did not meet the accounting definition of a joint venture and instead meets the definition of a variable interest entity. The Company concluded that it is not the primary beneficiary of the JV Entity and therefore is not required to consolidate the entity. This conclusion was based on the fact that the equity-at-risk is insufficient to support operations without additional investment and that the Company does not hold decision-making power over activities that significantly impact the JV Entity’s operations. The Company accounted for its investment in the JV Entity as an equity method investment. The Company recorded the equity method investment at $1.0 million which represents the Company’s contribution into the JV Entity. The Company’s license contributed to the JV Entity was recorded at its carryover basis of $0. For the years ended December 31, 2021 and 2020, the Company recognized approximately $0 and $9,000 in losses from the operations of the JV Entity, respectively. As of December 31, 2021 and 2020, the Company’s equity method investment in the JV Entity was $0.

Collaboration, Development and

Collaboration, Development and License Agreements	12 Months Ended
	Dec. 31, 2021
Collaboration, Development and License Agreements
Collaboration, Development and License Agreements	6. Collaboration, Development and License Agreements Cystic Fibrosis Foundation Development Agreement In December 2016, the Company received an award from the Cystic Fibrosis Foundation (“CFF”), which was executed under the Development Program Letter Agreement (the “CFF Agreement”), for approximately $2.9 million. Under the CFF Agreement, CFF made an upfront payment of $200,000 and will make milestone payments to the Company as certain milestones defined in the agreement are met. The milestones relate to pre-clinical and clinical research activities. The agreement also specifies that we are obligated to cumulatively spend on the development program at least an equal amount that the Company receives from the CFF. In the event that we do not spend as much as we received under the agreement, we are obligated to return any overage to the CFF. In November 2018, the CFF increased the award to approximately $7.5 million. As of the adoption date of ASC 606 on January 1, 2019 (the “Adoption Date”), the Company identified the following promises with regards to the clinical research activities under the CFF Agreement that represent an initial contract of: a) Phase 1 single ascending dose (“SAD”) clinical trial, which consists of the satisfied development-based milestones and one development-based milestone in progress which was accounted for as a single performance obligation; and contingent promises of: b) Phase 1 multiple ascending dose (“MAD”) clinical trial, which consists of one development-based milestone that had not yet been started, and c) Phase 2a clinical trial, which consists of four development-based milestones that had not yet been started. Of these promises, the Phase 1 SAD clinical trial was determined to be a distinct performance obligation as of the Adoption Date. For the clinical research activities related to the Phase 1 MAD clinical trial and the Phase 2a clinical trial that had not yet been started, the Company was contingently obligated to perform these clinical research activities only after the previous milestones, which achievement was uncertain, had been met. The clinical research activities related to the Phase 1 MAD clinical trial and the Phase 2a clinical trial that had not been started were evaluated to determine if they should be considered variable consideration or contingent promises akin to optional purchases under ASC 606. The Company concluded that these two promises that have not been started are contingent promises because there is substantive uncertainty about the contingent event occurring (i.e. milestones being achieved) and the contingent event requires additional distinct services and incremental payments from the CFF. The Company determined that these contingent promises did not provide the CFF with any material rights. The Phase 1 MAD clinical trial and the Phase 2a clinical trial will be accounted for as separate contracts at the time the Company is obligated to perform the underlying clinical research activities. The Company determined that the consideration for the Phase 1 SAD clinical trial contract included several development-based milestones, which had been achieved as of the Adoption Date, totaling approximately $1.7 million, and the one development-based milestone in progress as of the Adoption Date of $1.0 million became probable during the quarter ended March 31, 2019. Prior to March 31, 2019, the amount of the one development-based milestone in progress as of the Adoption Date could not be included in the transaction price as it was contingent on successful completion of Phase 1 SAD clinical trial, and it was not probable that significant reversal of cumulative revenue recognized would not occur if this milestone were included in the transaction price. The Company determined the consideration for the Phase 1 MAD clinical trial contract included one development-based milestone of $1.0 million which became probable of achievement and was achieved during the quarter ended June 30, 2020. Prior to June 30, 2020, the amount of the one development-based milestone could not be included in the transaction price for this contract as it was contingent on successful completion of the Phase 1 MAD clinical trial, and it was not probable that a significant reversal of cumulative revenue recognized would not occur if this milestone were included in the transaction price. The Company determined the consideration for the Phase 2a clinical trial contract totals approximately $3.8 million which includes four development-based milestones. The Company determined as of December 31, 2021, the transaction price for the Phase 2a clinical trial contract was $1.0 million as the first of the four development-based milestones was achieved during the year ended December 31, 2021. As of December 31, 2021, the amount of the remaining three development-based milestones could not be included in the transaction price for this contract as it was contingent on successful completion of the remaining three milestones, and it was not probable that a significant reversal of cumulative revenue recognized would not occur if those milestones were included in the transaction price. The milestones under the CFF Agreement are development-based milestones related to pre-clinical and clinical research activities and the realization of or recognition of revenue associated with the milestones as determined by the completion of the milestones and, if applicable, review and approval of the achievement by the CFF. Each development-based milestone payment has specific criteria that needs to be met, some examples of which include, the completion of certain study activities and approval to move to the next activity. At every reporting period, the Company evaluates the individual facts and circumstances of the development-based milestone to assess whether the revenue attributable to the development-based milestone in progress should be constrained. The constraint assessment by the Company includes an analysis of the key judgements and considerations used for each milestone which include, but are not limited to, the nature and amount of work to be performed, if the work is subject to the approval of the CFF, clinical data and uncertainty with regards to the results of the clinical studies, and the probability of successful clinical studies. The constraint will be removed once the Company achieves the development-based milestone or has determined that there is probable completion of the development-based milestone, and it has also concluded that it is not probable that revenue recognized attributable to the development-based milestone will result in a significant reversal of revenue in the future. The Company determined that the clinical research activities under the CFF Agreement should be recognized over time by calculating the amount of revenue to recognize in any given period by accumulating the total related costs incurred for the respective clinical research activities related to that distinct performance obligation using the input method (cost-to-cost) and applies that percentage of completion to the transaction price at each reporting period. The Company believes this method best depicts the transfer of control to the customer, which occurs as the costs related to the clinical research activities are incurred. For the year ended December 31, 2021, the Company recognized revenue of approximately $524,000 from the CFF Agreement, mainly due to the achievement of the first of four development-based milestones related to the Phase 2a clinical trial in 2021. The Company recorded a contract liability for the remaining consideration for achieving the first milestone of approximately $476,000 to deferred revenue, current, on its consolidated balance sheet as of December 31, 2021. For the year ended December 31, 2020, the Company recognized $1.0 million in revenue from the CFF Agreement, mainly due to the achievement in 2020 of one development-based milestone related to the Phase 1 MAD clinical trial. Gates Foundation Grant Agreement On October 15, 2021, the Company entered into an agreement with the Bill and Melinda Gates Foundation (“Gates Foundation” or “BMGF”) by executing a Grant Agreement identified as Investment ID INV-033376 (“Grant”). The goal of the Grant Agreement, is to develop durable approaches to block the infection and transmission of pathogens. For providing research and development services under the Grant Agreement, the Gates Foundation has agreed to compensate the Company $1.93 million due upon execution of the Grant Agreement. In return, we agreed to conduct a proof-of-concept study seeking to demonstrate that inhaled neutralizing antibodies are effective for preventing viral infection and transmission. We are required to ensure global access which means that the knowledge and information gained from the project will be promptly and broadly disseminated, and that the products, technologies, materials, processes and other intellectual property resulting from the proof-of-concept study (collectively referred to as the Funded Developments) will be made available and accessible at an affordable price (i) to people most in need within developing countries or (ii) in support of the U.S. educational system and public libraries. Consistent with our Global Access commitments, if the project description specifies publication or publication is otherwise requested by the Gates Foundation, the Company will seek prompt Publication of any Funded Developments consisting of data and results. These obligations survive any expiration or termination of the grant agreement. Under the Grant Agreement, the Gates Foundation made an upfront payment of $1.93 million. The Agreement specifies that we may not use funds provided under the Grant Agreement for any purpose other than the project. The Company is required to repay any portion of the funds used or committed in material breach of the Grant Agreement. Any grant funds, plus any income, that have not been used for, or committed to, the Project upon expiration or termination of the Agreement, must be returned promptly to the Gates Foundation. The Company is required to maintain grant funds in a physically separate bank account or a separate bookkeeping account maintained as part of the Company’s financial records and dedicated to the project. The Company will conduct research and development services up until the proof-of-concept study is completed, at which point the Gates Foundation will determine whether to approve further grant funding for transmission studies or end the study in which case the Company will no longer provide any significant goods or services. The Company will partner with three main subcontractors to deliver the scope of work described in the investment document. The Gates Foundation’s role is limited to advisory participation and participation in review meetings. If the Gates Foundation decides not to proceed with the transmission studies described in the Investment Document, the Company will not undertake any additional activities or incur any substantial costs outside the Grant Agreement. The Grant Agreement is considered within the scope of ASC 606 as the parties have a customer/vendor relationship and are not exposed equally to the risks and rewards of the research and development services contemplated in the Grant Agreement. The Company identified the following promises under the Agreement: 1) research and development services, 2) global access commitment, 3) humanitarian license, 4) publication if requested by the Gates Foundation, and 5) intellectual property reporting upon request. The Company determined that these promises are not distinct from each other, and therefore represent one performance obligation. Since the Company is required to update the Gates Foundation on technical progress during each stage of the Funded Development, the ability to access research and development results represents the Gates Foundation’s consumption of the benefits from the Company’s research and development activities. As such, research and development services revenue is recognized over time. At each reporting period, the amount of revenue to recognize is calculated using the input method (cost-to-cost), by comparing cumulative costs incurred to the total estimated costs to perform the research and development services and applying that percentage of completion to the transaction price. The Company believes this method best depicts the transfer of control to the customer, which occurs as the costs related to the research and development services are incurred. For the year ended December 31, 2021, the Company recognized revenue of approximately $546,000 from the Grant Agreement, based on expenses incurred and paid to partners to assist with the research and development services. The Company recorded a contract liability for the remaining consideration of approximately $1,387,000 to deferred revenue, current, on its consolidated balance sheet as of December 31, 2021. Serum License Agreement In July 2019, the Company and Serum International B.V. (“SIBV”), an affiliate of Serum Institute of India Private Limited, entered into an option agreement which granted SIBV the option to license multiple programs from the Company and access the Company’s MabIgX® platform technology for asset identification and selection. The Company received an upfront cash payment of $5 million upon execution of this option agreement. In connection with the option agreement, SIBV made an equity investment whereby the Company issued 801,820 shares of its restricted common stock in a private placement to SIBV for total gross proceeds of $10 million. As a result of this transaction, SIBV and its affiliates, are considered related parties to the Company. In September 2019, the Company and Serum AMR Products (“SAMR”), a party under common ownership of SIBV, entered into a License, Development and Commercialization Agreement (the “License Agreement”). Pursuant to the License Agreement, the Company granted to SAMR exclusive licenses, and rights to sublicense, certain patent rights and technology related know-how to the Company’s products AR-301, AR-105, AR-101 (i.e. exclusive rights to, among other things, develop, distribute, market, promote, sell, import and otherwise commercialize) in (a) the country of India, and (b) all other countries of the world except the USA, Canada, EU Territory, UK, China, Australia, South Korea, Brazil, New Zealand, and Japan (products AR-105 and AR-101 countries do not exclude South Korea and Brazil) (the “Limited Territory”); and AR-201 (i.e. exclusive rights to, among other things, develop, manufacture, make, distribute, market, promote, sell, import and otherwise commercialize) in all countries of the world except China, Hong Kong, Macau and Taiwan (the “Worldwide Territory”) (the “licenses and know-how”). Further, the License Agreement grants SAMR an option for the Company to provide research services using its MabIgX® platform technology for the identification of up to five (5) candidates including product development of these identified candidates and an exclusive license to develop, manufacture, make, distribute, market, promote, sell, import and otherwise commercialize these development products in the Worldwide Territory (the “research and development option”). Pursuant to the License Agreement, the Company will provide development support related to the licensed products above in order to assist SAMR in its efforts to develop, receive regulatory approval, and manufacture and sell the licensed products in SAMR’s authorized territories which will be performed under the direction of a Joint Steering Committee (“JSC”) which the Company will participate in (collectively “development support services”). In addition, under the License Agreement, SAMR was granted an exclusive manufacturing license option as the initial license granted above for AR-301, AR-105 and AR-101 does not allow for manufacturing. This manufacturing option provides incremental rights related to these products beyond what is granted as part of the licensing discussed above (the “manufacturing rights option”). If this option is exercised, after SAMR has met certain requirements to exercise the option as defined in the License Agreement, it would provide for an exclusive license for use by SAMR to manufacture and supply the products for SAMR’s own use in the Limited Territory and to manufacture and supply these products to the Company, or their affiliates, for the Company’s use outside the Limited Territory. Should SAMR exercise the development and research option or the manufacturing rights option discussed above, SAMR and the Company shall negotiate in good faith the economic terms around these arrangements. If a third-party sublicensee of AR-301, AR-105 and AR-101 wishes to manufacture these products by itself for the territory for which it has a license from the Company, then the Company shall have the right to buy back the manufacturing rights for all territories outside of the Limited Territory by paying to SAMR $5 million. Under the License Agreement, the Company received upfront payments totaling $15 million, of which $5 million was received in July 2019 through the option agreement referred to above. The Company is also entitled to additional payments from SAMR of up to $42.5 million, conditioned upon the achievement of specified milestones related to completion of certain trials and regulatory approvals as defined in the License Agreement. Further, the Company may receive additional royalty-based payments from SAMR if certain sales levels on licensed products are achieved as defined in the License Agreement. Given the equity investment by SIBV was negotiated in conjunction with the option agreement, which resulted in the execution of the License Agreement, all arrangements were evaluated as a single agreement and amounts were allocated to the elements of the arrangement based on their fair value. The Company recorded approximately $5.0 million, which represented the fair value of the restricted common stock issued of $5.4 million, net of $441,000 of issuance costs, to stockholders’ equity within the Company’s consolidated balance sheet as of December 31, 2019. The Company allocated the net $4.6 million from the equity investment, after deducting commissions and offering costs, to the License Agreement. Therefore, the Company recorded approximately $19.6 million to deferred revenue based on the $15.0 million from upfront payments under the License Agreement and approximately $4.6 million from the equity allocation. The License Agreement is determined to be within the scope of ASC 606, as the transaction represents a contract with a customer where the participants function in a customer/vendor relationship and are not exposed equally to the risks and rewards of the activities contemplated under the License Agreement. Using the concepts of ASC 606, the Company identified the following performance obligations under the License Agreement: 1) the transfer of licenses of the intellectual property for AR-301, AR-101, AR-105 and AR-201, inclusive of the related technology know-how conveyance (referred to as the license and know-how above); and 2) the Company to deliver ongoing development support services related to the licensed products and the Company’s participation in the JSC (referred to as the development support services above); and identified the following material promises under the License Agreement: 3) SAMR was granted a research and development option of up to five identified product candidates for the Company to perform including specific development services (the research and development option referred to above); and 4) SAMR was granted an exclusive manufacturing license option which would provide for incremental manufacturing rights related to AR-301, AR-105 and AR-101 beyond what is granted in the License Agreement (the manufacturing rights option referred to above). The Company concluded that the performance obligations and material promises identified are separate and distinct from each other. The Company is also entitled to additional payments from SAMR of up to $42.5 million, conditioned upon the achievement of specified milestones related to completion of certain trials and regulatory approvals as defined in the License Agreement. Further, the Company may receive additional royalty-based payments from SAMR if certain sales levels on licensed products are achieved as defined in the License Agreement. The Company concluded that these milestones and royalty payments each contain a significant uncertainty associated with a future event. As such, these milestone and royalty payments are constrained at contract inception and are not included in the transaction price as the Company could not conclude that it is probable a significant reversal in the amount of cumulative revenue recognized will not occur surrounding these payments. At the end of each reporting period, the Company will update its assessment of whether the milestone and royalty payments are constrained by considering both the likelihood and magnitude of the potential revenue reversal. At December 31, 2021 and 2020 the Company performed an assessment and determined that these milestone and royalty payments are constrained. The Company determined that the transaction price under the License Agreement was $19.6 million, consisting of the $15.0 million from upfront payments under the License Agreement and approximately $4.6 million from the equity allocation as noted above, which was allocated among the performance obligations and material promises based on their respective related standalone selling prices. The Company allocated the $19.6 million transaction price to the following: approximately $14.5 million to the licenses and know-how; approximately $79,000 to the development support services; approximately $892,000 to the research and development option; and approximately $4.1 million to the manufacturing rights option. The Company determined that the intellectual property licensed under the License Agreement represents functional intellectual property and it has significant standalone functionality and therefore should be recognized at a point in time upon satisfying the performance obligations. The Company will satisfy the performance obligations upon transfer of the licenses and know-how to SAMR, and expects to satisfy these performance obligations by the end of the third quarter of 2022. The Company determined that no performance obligations or material promises were satisfied as of December 31, 2021, and therefore, no revenue related to the License Agreement was recognized for the years ended December 31, 2021 and 2020. The Company has recorded contract liabilities resulting from the License Agreement of approximately $18.6 million and $18.7 million to deferred revenue, current, and approximately $913,000 and $854,000 to deferred revenue, noncurrent, on its consolidated balance sheets as of December 31, 2021 and 2020, respectively. The Company capitalized a contract asset resulting from the License Agreement of approximately $2.1 million related to the incremental costs of obtaining the License Agreement on its consolidated balance sheets, of which approximately $2.0 million and $2.0 million is classified as current, and approximately $96,000 and $90,000 is classified as noncurrent, as of December 31, 2021 and December 31, 2020, respectively. Kermode Licensing and Product Discovery Agreement In February 2021, the Company entered into an out-licensing and product discovery agreement, and a statement of work (collectively, the “Kermode Agreement”) with Kermode Biotechnologies, Inc. (“Kermode”). Under the terms of this agreement, Kermode will fund for one year the discovery of product candidates for African Swine Fever Virus (“ASFV”) with an option to include the discovery of product candidates for swine influenza virus (“SIV”). Kermode also received exclusive rights to all mAbs and vaccines discovered for veterinary uses and rights to a non-exclusive license to use the Company’s ʎPEX technology platform for further development activities. The Company retained exclusive rights to mAbs and vaccines discovered for human uses. In March 2021, the Company received a nonrefundable upfront payment of $500,000 and received one milestone payment of $250,000 in December 2021. The Company will receive one more milestone payment of $250,000 from Kermode after certain research and development phases in the agreement are completed. The Kermode Agreement defines four phases of research and development activities. The Company is also entitled to royalty payments based on future net sales if Kermode is ultimately successful in commercializing product candidates. The Kermode Agreement is within the scope of ASC 606 as the parties have a customer/vendor relationship and are not exposed equally to the risks and rewards of the activities contemplated in the Kermode Agreement. The Company identified the following promises under the Kermode Agreement: 1) research and development services, and 2) license rights of the ʎPEX Platform and mAbs and vaccines (“Program IP”). The Company determined that these promises are not distinct from each other, and therefore represent one performance obligation. As of December 31, 2021, the transaction price of the Kermode Agreement was $750,000, consisting of the nonrefundable upfront payment and one milestone payment. Another milestone payment of $250,000, and potential royalty payments were not included in the transaction price, as it was not probable that a significant reversal of cumulative revenue recognized would not occur if these amounts were included. At the end of each reporting period, the Company will update its assessment of whether the milestone payment and royalties are constrained by considering both the likelihood and magnitude of the potential revenue reversal. The Company determined that the one performance obligation under the Kermode Agreement should be recognized over time. At each reporting period, the amount of revenue to recognize will be calculated using the input method (cost-to-cost), by comparing cumulative costs incurred to the total estimated costs to perform all four phases of the research and development activities, and applying that percentage of completion to the transaction price. The Company believes this method best depicts the transfer of control to the customer, which occurs as the costs related to the research and development activities are incurred. For year ended December 31, 2021, the Company recognized approximately $465,000 in revenue related to the Kermode Agreement. The Company has recorded the remaining portion of the nonrefundable upfront payment as a contract liability of approximately $285,000 to deferred revenue, current, as of December 31, 2021.

Notes Payable

Notes Payable	12 Months Ended
	Dec. 31, 2021
Notes Payable
Notes Payable	7. Notes Payable Note Purchase Agreement On November 23, 2021, the Company entered into an agreement (“Note Purchase Agreement”) with Streeterville Capital, LLC (Lender), pursuant to which we issued to the Lender a secured promissory note (Note) in the aggregate principal amount of $5,250,000. Closing occurred on November 23, 2021 (Issuance Date). The Note carries an original issue discount of $250,000. The Note bears interest at the rate of 6% per annum and matures on November 23, 2023. Beginning on May 23, 2022, the Lender has the right to redeem all or any portion of the Note up to the Maximum Monthly Redemption Amount which is $450,000. Payments of each redemption amount must be made in cash. Pursuant to the Note, the Company can defer all redemption payments that the Lender could otherwise elect to make during any calendar month on three (3) separate occasions by providing written notice to Lender at least three (3) trading days prior to the first day of each such calendar month for which it wishes to defer redemptions for that month. In the event the Company elects to defer, the aggregate principal amount plus accrued but unpaid interest (Outstanding Amount) shall automatically be increased by (a) 0.5% for the first exercise; (b) 1% for the second exercise and (c) 1.5% for the third exercise. The Company can prepay all or any portion of the Outstanding Amount at a rate of (a) 105% of the portion of the Outstanding Balance the Company elects to prepay if prepayment occurs on or before the three-month anniversary of the Issuance Date; (b) 107.5% of the portion of the Outstanding Balance the Company elects to prepay if prepayment occurs after the three-month anniversary of the Issuance Date but on or before the six-month anniversary of the Issuance Date and (c) 110% of the Outstanding Balance if the prepayment occurs after the six-month anniversary of the Issuance Date. Pursuant to the Note Purchase Agreement, we are subject to certain covenants, including the obligations to: (i) timely file all reports required to be filed under Sections 13 or 15(d) of the Securities Exchange Act of 1934, as amended (the “Exchange Act”) and not terminate its status as an issuer required to file reports under the Exchange Act; (ii) maintain listing of our common stock on a securities exchange; and (iii) avoid trading in our common stock from being suspended, halted, chilled, frozen or otherwise ceased. The Note is secured by the Company’s MabIgX assets. The Company elected to apply the fair value option to the measurement of this note. The total initial fair value at issuance was $5,250,000. The Company remeasured the fair value as of December 31, 2021 and recognized an expense of $33,000 as the fair value of note had increased. The fair value measurement includes the accrued interest and interest expense, at the stated rate, and thus separate amount is not reflected in the consolidated statement of operations. For the year ended December 31, 2021, the Company recognized approximately $250,000 in interest expense for the issuance discount related to the note. . The Company has recorded a liability of approximately $5,282,000 to Note Payable, non-current, as of December 31, 2021. The note matures on November 23, 2023. Insurance Financing The Company obtained financing for certain Director & Officer liability insurance policy premiums. The agreement assigns First Insurance Funding (Lender) a first priority lien on and security interest in the financed policies and any additional premium required in the financed policies including (a) all returned or unearned premiums, (b) all additional cash contributions or collateral amounts assessed by the insurance companies in relation to the financed policies and financed by Lender, (c) any credits generated by the financed policies, (d) dividend payments, and (e) loss payments which reduce unearned premiums. If any circumstances exist in which premiums related to any Financed Policy could become fully earned in the event of loss, Lender shall be named a loss-payee with respect to such policy. The total premiums, taxes and fees financed is approximately $1,645,000 with an annual interest rate of 3.67%. In consideration of the premium payment by Lender to the insurance companies or the Agent or Broker, the Company unconditionally promises to pay Lender the amount Financed plus interest and other charges permitted under the Agreement. At December 31, 2021 the Company recognized approximately $696,000 as insurance financing note payable in its consolidated balance sheet. The Company will pay the insurance financing through installment payments with the last payment being on May 14, 2022. Paycheck Protection Program Loan The Company applied for and received a loan, which is in the form of a note dated May 1, 2020, from Silicon Valley Bank (“SVB”) in the aggregate amount of approximately $715,000 (the “Loan”), pursuant to the Paycheck Protection Program (the “PPP”). The PPP, established as part of the Coronavirus Aid, Relief and Economic Security Act (“CARES Act”), provides for loans to qualifying businesses for amounts up to 2.5 times of the average monthly payroll expenses of the qualifying business. In May 2021, the Company received confirmation that the PPP Loan was forgiven by the SBA and was legally released from its financial obligation by the lender, SVB. As such, for the year ended December 31, 2021, the Company recognized in its consolidated statement of operations a gain on extinguishment of PPP Loan of approximately $722,000, which includes the PPP Loan principal of approximately $715,000 and accrued interest of approximately $7,000. At December 31, 2021, the Company had no liabilities related to the PPP Loan recorded in its consolidated balance sheet. ​

Warrants

Warrants	12 Months Ended
	Dec. 31, 2021
Warrants
Warrants	8. Warrants In August 2021, the Company entered into a Securities Purchase Agreement (the “August 2021 Securities Purchase Agreement”) with an institutional investor, pursuant to which the Company agreed to offer, issue and sell to this investor, in a registered direct offering, 1,300,000 shares of its Common Stock, pre-funded warrants to purchase up to an aggregate of 3,647,556 shares of Common Stock (the “Pre-Funded Warrants”), and warrants to purchase up to 2,473,778 shares of Common Stock (the “Warrants”). The combined purchase price of each share of Common Stock and accompanying Warrants is $5.053 per share. The combined purchase price of each Pre-Funded Warrant and accompanying Warrant is $5.052 (equal to the combined purchase price per share of Common Stock and accompanying Warrant, minus $0.001). The Company received gross proceeds of approximately $25.0 million, and after deducting the placement agent fees and expenses and offering costs, net proceeds were approximately $22.6 million (see Note 9). one one The Company measured the fair value of the Common Stock and Pre-Funded Warrants based on the Company’s closing stock price on the date the August 2021 Purchase Agreement was entered into and the fair value of the Warrants was based upon a BSM valuation model. The BSM valuation model used the following assumptions: expected term of seven In December 2021, all of the Pre-Funded Warrants were exercised. A total of 3,647,556 shares of Common Stock were issued in exchange for approximately $4,000 in cash as a result of the exercise. Warrants Issued in Private Placement In October 2020, the Company entered into a Securities Purchase Agreement (the “October 2020 Purchase Agreement”) in which the Company agreed to offer, issue and sell (i) in a registered direct offering, an aggregate of 1,134,470 shares (the “Shares”) of common stock, par value $0.0001 per share (“Common Stock”) and (ii) in a concurrent private placement, Series A warrants (the “Series A Warrants”) and Series B warrants (the “Series B Warrants” and collectively, with the Series A Warrants, the “Warrants”) to purchase up to an aggregate 567,234 shares (the “Warrant Shares”) of common stock, for aggregate gross proceeds to the Company of approximately $8.5 million, and after deducting commissions and offering costs, net proceeds were approximately $7.8 million (See Note 9). The combined purchase price for each Share, together with one Series A Warrant and one Series B Warrant, is $7.4925. The Series A Warrants have an exercise price of $7.43 per share, are exercisable six months from the date of issuance, and expire three three The Company measured the fair value of the Common Stock Shares based on the Company’s closing stock price on the date the October 2020 Purchase Agreement was entered into and the fair value of the Warrant Shares was based upon a Black-Scholes valuation. The Black-Scholes valuation used the following assumptions: expected term of four years, expected volatility of 104%, risk-free interest rate of 0.25%, and dividend yield of 0%. The Company used the relative fair value method to allocate the net proceeds received from the sale of the Common Stock Shares and the Warrants Shares of approximately $7.8 million. The Company recorded approximately $5.8 million and $2.0 million, which represented the relative fair value of the Common Stock Shares and Warrant Shares, respectively, to stockholders’ equity (deficit) within the Company’s consolidated balance sheet. ​

Common Stock

Common Stock	12 Months Ended
	Dec. 31, 2021
Common Stock
Common Stock	9. Common Stock As of December 31, 2021, the Company had reserved the following common stock for future issuance: ​ ​ ​ ​ Shares reserved for exercise of outstanding warrants to purchase common stock 3,592,905 Shares reserved for exercise of outstanding options to purchase common stock ​ 1,905,459 Shares reserved for issuance of future options ​ 228,099 Total 5,726,463 ​ March 2021 Securities Purchase Agreement In March 2021, the Company entered into a Securities Purchase Agreement (the “March 2021 Securities Purchase Agreement”) with certain institutional and individual investors (the “Purchasers”), pursuant to which the Company agreed to offer, issue and sell to the Purchasers, in a registered direct offering, an aggregate of 1,037,405 shares (the “Shares”) of the Company’s common stock, par value $0.0001 per share (“Common Stock”) for aggregate gross proceeds to the Company of approximately $7.0 million, and after deducting commissions and offering costs, net proceeds were approximately $6.4 million. ​ In October 2020, shares of Common Stock were sold in a registered direct offering in which each share contains a price based anti-dilution rights. If the Company issues additional securities at a purchase price less than the purchase price paid by these respective holders, the Company shall issue additional common shares equal to the difference of the number of common shares that each respective shareholder would have received if they paid the subsequent lower price, and the number of shares each respective shareholder originally received. As a result of the March 2021 registered direct offering price per share being less than the October 2020 registered direct offering price per share, the Company was obligated to issue an additional 124,789 shares of unregistered Common Stock to the investors in the Company’s October 2020 registered direct offering pursuant to the anti-dilutive provisions of the October 2020 Securities Purchase Agreement. In March 2021, the Company issued 124,789 dividend shares to certain common stockholders with a fair value of approximately $986,000, which the Company recorded as a credit to additional paid-in capital, and since the Company has an accumulated deficit, the corresponding debit to additional paid-in capital, resulting in no dollar impact within the Company’s consolidated statement of changes in stockholders’ equity (deficit) for the year ended December 31, 2021. MedImmune Limited License Agreement Effective July 12, 2021, the Company entered into the MedImmune License Agreement, pursuant to which MedImmune granted the Company an exclusive worldwide license for the development and commercialization of suvratoxumab, a Phase 3 ready fully human monoclonal antibody targeting staphylococcus aureus alpha toxin (see Note 4). As part of the consideration for the MedImmune License Agreement, the Company issued 884,956 shares of its’s common stock to MedImmune. The fair value of the 884,956 shares of the Company’s common stock issued in connection with the MedImmune License agreement is approximately $6.5 million. The Company measured the fair value of the common stock issued to MedImmune based on the Company’s closing stock price on the effective date of the MedImmune License Agreement. The Company recognized the $6.5 million as research and development expense within its consolidated statement of operations and additional paid-in capital within equity in its consolidated balance sheet for the year ended December 31, 2021. August 2021 Securities Purchase Agreement In August 2021, the Company entered into a Securities Purchase Agreement (the “August 2021 Securities Purchase Agreement”) with an institutional investor, pursuant to which the Company agreed to offer, issue and sell to this investor, in a registered direct offering, 1,300,000 shares of its Common Stock, pre-funded warrants to purchase up to an aggregate of 3,647,556 shares of Common Stock (the “Pre-Funded Warrants”), and warrants to purchase up to 2,473,778 shares of Common Stock (the “Warrants”). The combined purchase price of each share of Common Stock and accompanying Warrants is $5.053 per share. The combined purchase price of each Pre-Funded Warrant and accompanying Warrant is $5.052 (equal to the combined purchase price per share of Common Stock and accompanying Warrant, minus $0.001). The Company received gross proceeds of approximately $25.0 million, and after deducting the placement agent fees and expenses and offering costs, net proceeds were approximately $22.6 million (see Note 8). As a result of this registered direct offering price per share being less than the October 2020 and March 2021 registered direct offerings price per share, the Company was obligated to issue an additional 634,600 shares of unregistered Common Stock to the investors in the Company’s October 2020 and March 2021 registered direct offerings pursuant to the anti-dilutive provisions of the October 2020 and March 2021 Securities Purchase Agreements. In August 2021, the Company issued 634,600 dividend shares to certain common stockholders with a fair value of approximately $3.1 million, which the Company recorded as a credit to additional paid-in capital, and since the Company has an accumulated deficit, the corresponding debit to additional paid-in capital, resulting in no dollar impact within the Company’s consolidated statement of changes in stockholders’ equity (deficit) for the year ended December 31, 2021. ATM Agreement In September 2019, the Company entered into a Common Stock Sales Agreement (the “ATM Agreement”) with Cantor Fitzgerald & Co. (“Cantor”) under which the Company may offer and sell, from time to time, at its sole discretion, shares of common stock having an aggregate offering price of up to $25.0 million through Cantor as our sales agent. The Company’s registration statement on Form S-3 contemplated under the ATM Agreement was declared effective by the SEC on September 5, 2019. The registration statement on Form S-3 includes a base prospectus covering the offering of up to $100 million in aggregate shares of securities as defined within the prospectus and a prospectus supplement of up to a maximum aggregate offering of $25 million in common stock in accordance with the ATM Agreement. Cantor may sell common stock under the ATM Agreement by any method permitted by law deemed to be an “at the market offering” as defined in Rule 415 of the Securities Act of 1933, as amended (the “Securities Act”), including without limitation sales made by means of ordinary brokers’ transactions on the Nasdaq Global Market or otherwise at market prices prevailing at the time of sale, in block transactions, or as otherwise directed by the Company. Cantor will use commercially reasonable efforts to sell the common stock from time to time, based upon instructions from the Company (including any price, time or size limits or other customary parameters or conditions the Company may impose). The Company will pay Cantor a commission of up to three percent (3.0%) of the gross sales proceeds of any common stock sold through Cantor under the ATM Agreement, and also has provided Cantor with customary indemnification rights. The Company is not obligated to make any sales of common stock under the ATM Agreement. The offering of shares of common stock pursuant to the ATM Agreement will terminate upon the earlier of (i) the sale of all common stock subject to the ATM Agreement, or (ii) termination of the ATM Agreement in accordance with its terms. As a result of the limitations of General Instruction I.B.6 of Form S-3, and in accordance with the terms of the ATM Agreement, the Company filed a prospectus supplement on May 14, 2020 that registered the offer and sale of shares of its common stock having an aggregate offering price of up to $22.0 million from time to time through Cantor. During the year ended December 31, 2021, the Company had not sold any shares of common stock under the ATM Agreement. During the year ended December 31, 2020, the Company had sold 7,883 shares of common stock under the ATM Agreement for gross proceeds of approximately $64,000, and after deducting commissions, net proceeds were approximately $62,000. On January 10, 2022, the Company notified Cantor of its intent to terminate, which became effective on January 18, 2022, the Controlled Equity Offering Sales Agreement dated as of September 3, 2019 between the Company and Cantor in connection with the Company’s at-the-market offering of up to $25.0 million. On January 19, 2022, the Company entered into an At-the-Market Sales Agreement (“Sales Agreement”) with Virtu Americas LLC (“Virtu”), as sales agent. Pursuant to the terms of the Sales Agreement, the Company may issue and sell from time to time shares of its common stock, par value $0.0001 per share, through Virtu, acting as its sales agent, or directly to Virtu, acting as principal. Pursuant to the Company’s prospectus supplement filed on January 19, 2022, the Company may issue and sell shares of its common stock having an aggregate offering price of up to $25.0 million. Under the Sales Agreement, Shares will be offered and sold pursuant to the Company’s shelf registration statement on Form S-3 (File No. 333-233601) filed with the Securities and Exchange Commission (the “SEC”) on September 3, 2019, declared effective by the SEC on September 5, 2019. In addition, under the Sales Agreement, sales of Shares may be made by any method permitted by law deemed to be an “at the market offering” as defined in Rule 415(a)(4) under the Securities Act of 1933, as amended. The Company will pay Virtu a commission rate of up to 3.0% of the gross proceeds from each sale of Shares and has agreed to provide Virtu with customary indemnification and contribution rights. The Company will also reimburse Virtu for certain specified expenses in connection with entering into the Sales Agreement. The Company has no obligation to sell any of the Shares under the Sales Agreement and may at any time suspend the offering of its common stock upon notice and subject to other conditions. The Sales Agreement contains customary representations, warranties and agreements by the Company, other obligations of the parties and termination provisions. The Company intends to use the net proceeds from the sale of any Shares sold under the Sales Agreement for general corporate purposes, which may include, among other things, increasing the Company’s working capital, financing ongoing operating expenses and overhead, funding capital expenditures, repayment of debt, acquisitions, and investments in the Company’s subsidiaries. Securities Purchase Agreement In October 2020, the Company entered into the October 2020 Purchase Agreement with certain institutional investors (the “Purchasers”), pursuant to which the Company agreed to offer, issue and sell to the Purchasers, (i) in a registered direct offering, an aggregate of 1,134,470 shares of common stock, par value $0.0001 per share and (ii) in a concurrent private placement, Series A warrants and Series B warrants to purchase up to an aggregate 567,234 shares of Common Stock, for aggregate gross proceeds to the Company of approximately $8.5 million, and after deducting commissions and offering costs, net proceeds were approximately $7.8 million (see Note 8). In October 2020, the Company paid Arcadia Securities, LLC a fee equal to 3.5% of the aggregate purchase price of the shares of its common stock sold in the offering to certain of the investors. In addition, in October 2020, the Company paid Cantor a fee equal to 3.5% of the aggregate purchase price of the shares of its common stock sold in the offering.

Stock-Based Compensation

Stock-Based Compensation	12 Months Ended
	Dec. 31, 2021
Stock-Based Compensation
Stock-Based Compensation	10. Stock-Based Compensation Equity Incentive Plan In May 2014, the Company adopted and the shareholders approved the 2014 Equity Incentive Plan (the 2014 Plan). Under the 2014 Plan, 233,722 shares of the Company’s common stock were initially reserved for the issuance of stock options to employees, directors, and consultants, under terms and provisions established by the Board of Directors. Under the terms of the 2014 Plan, options may be granted at an exercise price not less than fair market value. For employees holding more than 10% of the voting rights of all classes of stock, the exercise prices for incentive stock options may not be less than 110% of fair market value, as determined by the Board of Directors. The terms of options granted under the 2014 Plan may not exceed ten years. In June 2020, the adoption of an amendment to the 2014 Plan to eliminate the evergreen provision and set the number of shares of common stock reserved for issuance thereunder to 2,183,692 shares was approved by the Company’s stockholders. The additional shares reserved in the below stock option activity table includes 162,736 shares reserved pursuant to the evergreen provision and 400,000 shares reserved pursuant to the amendment to the 2014 Plan. Stock Options The number of shares, terms, and vesting periods are determined by the Company’s Board of Directors or a committee thereof on an option by option basis. Options generally vest ratably over service periods of up to four years and expire ten years from the date of grant. Stock option activity for the year ended December 31, 2021 is represented in the following table: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Options Outstanding ​ Shares ​ Weighted- ​ ​ Available ​ Number of ​ Average ​ ​ for Grant ​ Shares ​ Exercise Price Balances at December 31, 2020 584,161 1,550,956 ​ $ 9.43 Options granted ​ (493,440) ​ 493,440 ​ $ 5.04 Options exercised — (1,559) ​ $ 2.89 Options cancelled ​ 137,378 ​ (137,378) ​ $ 7.05 Balances at December 31, 2021 228,099 1,905,459 ​ $ 8.47 ​ Additional information related to the status of options as of December 31, 2021 is summarized as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted- ​ ​ ​ ​ ​ ​ ​ Weighted- ​ Average ​ Aggregate ​ ​ Number of ​ Average ​ Contractual ​ Intrinsic ​ Options Exercise Price Term (Years) Value ​ ​ ​ ​ ​ ​ ​ ​ ​ (in thousands) Options outstanding ​ 1,905,459 ​ $ 8.47 ​ 6.97 ​ $ 13 Options vested and exercisable ​ 1,287,094 ​ $ 9.70 ​ 6.11 ​ $ — ​ The Company estimated the fair value of options using the BSM option valuation model. The fair value of options is being amortized on a straight-line basis over the requisite service period of the awards. The fair value of the options granted during the years ended December 31, 2021 and 2020 were estimated using the following assumptions: ​ ​ ​ ​ ​ ​ ​ ​ ​ Years Ended ​ ​ ​ December 31, ​ ​ 2021 2020 ​ Expected term (in years) 6.00 ​ 6.00 ​ Expected volatility 99% - 100% ​ 84% - 100% ​ Risk-free interest rate 0.8% - 1.17% ​ 0.38% - 1.73% ​ Dividend yield 0% ​ 0% ​ ​ During the years ended December 31, 2021 and 2020, the Company granted options to purchase 493,440 and 207,155 shares with a weighted-average grant date fair value of $3.68 and $4.72 per share, respectively. There were 1,559 and 4,913 options exercised during the years ended December 31, 2021 and 2020, respectively. The aggregate intrinsic value of options exercised during the years ended December 31, 2021 and 2020 was approximately $5,000 and $17,000, respectively. Stock-Based Compensation The following table presents stock-based compensation expense related to stock options (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Years Ended ​ ​ December 31, ​ 2021 ​ 2020 Research and development ​ $ 687 ​ $ 590 General and administrative ​ ​ 1,564 ​ ​ 1,538 Total ​ $ 2,251 ​ $ 2,128 ​ As of December 31, 2021, total unrecognized stock-based compensation expenses related to unvested stock options was approximately $2.5 million, which is expected to be recognized on a straight-line basis over a weighted-average period of approximately 2.42 years.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2021
Income Taxes
Income Taxes	11. Income Taxes The Company has accumulated net losses since inception and has not recorded an income tax provision or benefit during the years ended December 31, 2021 and 2020. A reconciliation between the statutory U.S. federal rate and the Company’s effective tax rate is as follows (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ Year Ended ​ ​ December 31, ​ 2021 ​ 2020 Federal income tax at statutory rate ​ $ (8,860) ​ $ (4,690) State income tax, net of federal benefit ​ (759) ​ (36) Foreign tax differential ​ 1,345 ​ 1,906 State Rate change ​ ​ (346) ​ ​ 287 Permanent differences ​ 66 ​ 1,088 Tax credits generated in current year ​ (894) ​ (649) Uncertain tax position change ​ ​ 224 ​ ​ 162 Other ​ ​ 28 ​ (92) Valuation allowance change ​ 9,196 ​ 2,024 ​ ​ $ — ​ ​ — ​ Deferred income taxes reflect the net tax effects of temporary differences between the carrying amounts of assets and liabilities for financial reporting purposes and the amounts used for income tax purposes. Significant components of our Net deferred tax assets (in thousands) are as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ Year Ended ​ December 31, ​ 2021 ​ 2020 Net operating loss carryforwards ​ $ 22,603 ​ $ 14,793 Accruals and reserves ​ 175 ​ 39 Stock based compensations ​ ​ 1,607 ​ ​ 1,153 Research and development credits ​ 2,692 ​ 2,021 Deferred revenue ​ ​ 1,454 ​ ​ 1,338 Depreciation and amortization ​ — ​ (9) Total ​ 28,531 ​ 19,335 Valuation allowance change ​ (28,531) ​ (19,335) Net deferred tax assets (liabilities) ​ $ — ​ $ — ​ A reconciliation of the beginning and ending amount of the Company’s liability for uncertain tax positions (in thousands) is as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, ​ 2021 ​ 2020 Balance at the beginning of the year ​ $ 705 ​ $ 534 Increase/(decrease) based on current year tax positions ​ 235 ​ 171 Increase/(decrease) for prior year tax positions ​ — ​ — Balance at the end of the year ​ $ 940 ​ $ 705 ​ Due to the existence of the valuation allowance, future changes in the Company’s liability for uncertain tax positions will not impact the Company’s effective tax rate. The Company does not anticipate that there will be a substantial change in its liability for uncertain tax positions in the next twelve months. Tax Legislation subjects a U.S. shareholder to tax on Global Intangible Low-Taxed Income (“GILTI”) earned by certain foreign subsidiaries. The FASB Staff Q&A, Topic 740, No. 5, Accounting for Global Intangible Low-Taxed Income, states that an entity can make an accounting policy election to either recognize deferred taxes for temporary basis differences expected to reverse as GILTI in future years or to provide for the tax expense related to GILTI in the year the tax is incurred as a period expense only. The Company has elected to account for GILTI in the year the tax is incurred. The Company does not have a GILTI inclusion as the foreign subsidiaries are in loss positions in 2021. Based on the available objective evidence, management believes it is more-likely-than-not that the deferred tax assets were not fully realizable as of December 31, 2021 and 2020. Accordingly, the Company has established a full valuation allowance against its deferred tax assets. The net change in the valuation allowance for the years ended December 31, 2021 and 2020 was approximately $9.2 million and $2.0 million, respectively. At December 31, 2021, the Company had federal net operating loss carryforwards of approximately $19.5 million that begin to expire in 2034. The Company also has federal net operating losses of approximately $66.5 million that arose after the 2017 tax year and will carryforward indefinitely. The Company has state net operating loss carryforwards of approximately $69.2 million that will begin to expire in 2034. At December 31, 2021, the Company has research credit carryforwards of approximately $2.9 million and approximately $814,000 for federal and California state income tax purposes, respectively. The federal credits begin to expire in 2034 and the state credits can be carried forward indefinitely. Under the Internal Revenue Code (“IRC”) Sections 382 and 383, annual use of the Company’s net operating loss and research tax credit carryforwards to offset taxable income may be limited based on cumulative changes in ownership. The Company has not completed an analysis to determine whether any such limitations have been triggered as of December 31, 2021. The Company has no income tax affect due to the recognition of a full valuation allowance on the expected tax benefits of future loss carry forwards based on uncertainty surrounding realization of such assets. Any annual limitation may result in the expiration of net operating losses and credits before utilization. The Company may continue to experience ownership changes in the future as a result of the Company’s future expected equity financings and subsequent shifts in its stock ownership, some of which may be outside of its control. The Company is subject to taxation in the United States, California, the Netherlands and China, and remains subject to possible examination by tax authorities in these jurisdictions for tax years dating back to 2014. The Company became subject to taxation in Maryland and North Carolina starting tax year 2020 , and becomes subject to taxation in Colorado, Pennsylvania and South Carolina starting tax year 2021. The Company does not have any pending tax examinations. Following the Company’s adoption of ASC 740-10 regarding accounting for uncertainty in income taxes, the Company made a comprehensive review of its portfolio of uncertain tax positions in accordance with the guidance. In this regard, an uncertain tax position represents the Company’s expected treatment of a tax position taken in a filed tax return, or planned to be taken in a future tax return, that has not been reflected in measuring income tax expense for financial reporting purposes. As a result of that review, the Company concluded there were no uncertain tax positions and no cumulative effect on retained earnings at the time of adoption.

Related Parties

Related Parties	12 Months Ended
	Dec. 31, 2021
Related Parties
Related Parties	12. Related Parties Joint Venture On February 11, 2018, the Company entered into a Joint Venture (“JV”) Agreement with Hepalink which is a related party and principal shareholder in the Company, pursuant to which the Company formed a JV Entity for developing and commercializing products for infectious diseases in the greater China territories. It was agreed by the parties that the Company shall be reimbursed for certain legal and contract manufacturing expenses related to the clinical drug supply for a Phase 3 clinical study of AR-301 and the clinical drug supply for a clinical study of AR-105. For the years ended December 31, 2021 and 2020, the Company recorded approximately $75,000 and $188,000, respectively, as a reduction to operating expenses in the consolidated statements of operations for amounts reimbursed to the Company by the JV Entity under this arrangement. As of December 31, 2021 and 2020, the Company recorded approximately $43,000 and $3,000, respectively, in other receivables on the consolidated balance sheets for amounts owed to the Company by the JV Entity under this arrangement and the Company expects the amounts to be collectable and as a result, no reserve for uncollectability was established. Serum International B.V. In July 2019, the Company issued 801,820 shares of its restricted common stock in a private placement to Serum International B.V. (“SIBV”), an affiliate of Serum Institute of India Private Limited, for total gross proceeds of $10 million (see Note 9). As a result of this transaction, SIBV and its affiliates, are considered related parties to the Company. In September 2019, the Company and Serum AMR Products (“SAMR”), a party under common ownership of SIBV, entered into a License, Development and Commercialization Agreement (“ License Agreement”) (see Note 6). The Company determined that no performance obligations were satisfied as of December 31, 2021 and 2020. Therefore, no revenue related to the License Agreement was recognized during the years ended December 31, 2021 and 2020. The Company has recorded contract liabilities resulting from the License Agreement of approximately $18.7 million and $18.7 million to deferred revenue, current, and approximately $913,000 and $854,000 to deferred revenue, noncurrent, on its consolidated balance sheets at December 31, 2021 and 2020, respectively. The Company capitalized a contract asset resulting from the License Agreement of approximately $2.1 million related to the incremental costs of obtaining the License Agreement on its consolidated balance sheets, of which approximately $2.0 million and $2.0 million is classified as current, and approximately $96,000 and $90,000 is classified as noncurrent, as of December 31, 2021 and 2020, respectively.

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2021
Commitments and Contingencies
Commitments and Contingencies	13. Commitments and Contingencies Facility Lease The Company previously leased office and lab space in San Jose, California under an operating lease arrangement which terminated in December 2020. In October 2020, the Company entered into a new lease agreement (the “Lease Agreement”) with Boccardo Corporation (the “Landlord”) pursuant to which the Company leased approximately 15,129 square feet of office and laboratory space in Los Gatos, California. In December 2020, the Company moved into the new facility which serves as the Company’s corporate headquarters and the Company has made leasehold improvements to the new facility of which approximately $378,000 may be reimbursed by the Landlord as certain criteria are met as defined in the Lease Agreement. The lease commenced in December 2020 and has an approximate five year term with a three year renewal option. Rental payments by the Company commenced on February 1, 2021. In connection with the Lease Agreement, the Company was required to deliver a security deposit in the form of a letter of credit of $500,000 to the Landlord which is classified as restricted cash, noncurrent, in the Company’s consolidated balance sheet. The future minimum lease payments for the new facility as of December 31, 2021 are as follows (in thousands): ​ ​ ​ ​ Year ending December 31, ​ 2022 ​ $ 610 2023 ​ 628 2024 ​ 646 2025 ​ 666 2026 ​ ​ 57 Total ​ $ 2,607 ​ Rent expense for leases was approximately $630,000 and $529,000 for the years ended December 31, 2021 and 2020, respectively. Indemnification In the normal course of business, the Company enters into contracts and agreements that contain a variety of representations and warranties and provide for general indemnifications. The Company’s exposure under these agreements is unknown because it involves claims that may be made against the Company in the future but have not yet been made. To date, the Company has not paid any claims or been required to defend any action related to its indemnification obligations. However, the Company may incur charges in the future as a result of these indemnification obligations. License Agreements The Company has entered into various collaboration and licensing agreements that provide it with access to certain technology and patent rights. Under the terms of the agreements, the Company may be required to make milestone payments upon achievement of certain development and regulatory activities. See further disclosure related to these agreements in Note 4. Contingencies From time to time, the Company may have certain contingent liabilities that arise in the ordinary course of its business activities. The Company accrues a liability for such matters when it is probable that a potential loss will be incurred and such amount can be reasonably estimated. As of December 31, 2021 and 2020, no accruals have been made related to contingencies. From time to time, the Company may be involved in various legal proceedings, claims and litigation arising in the ordinary course of business. See below Legal Proceedings for legal complaints filed during the years ended December 31, 2021 and 2020. Legal Proceedings A complaint was filed in February 2020 in the New York State Supreme Court against the Company by an investor who invested in the Company’s preferred stock in July 2017 prior to the Company’s IPO in August 2018. The complaint alleges, among other things, that the Company breached its contract and fiduciary duty, by not issuing additional securities to the investor as a result of the Company’s IPO. The plaintiff is asking for approximately $277,000 in compensatory damages. The parties are currently in fact discovery. The Company believes that the claims in this complaint are without merit and intends to defend vigorously against them. The Company accrues a liability for such matters when it is probable that future expenditures will be made, and such expenditures can be reasonably estimated. As of December 31, 2021 and 2020, no liability recognized related to this matter. In September 2021, Cantor filed a complaint in the New York State Supreme Court against the Company alleging that it breached a letter agreement with Cantor and owes Cantor approximately $1.8 million, including attorney’s fees for a financing fee related to the Company’s equity offering in August 2021. The parties entered into a settlement agreement and release on December 15, 2021. The settlement amount is included in accounts payable on the consolidated balance sheet as of December 31, 2021. The Company submitted a complaint in Superior Court of the State of California, County of Santa Clara, against its former landlord on October 22, 2021, asserting claims for breach of contract, breach of the covenant of good faith and fair dealing, unjust enrichment and violation of the unfair competition law. The claims arise from rent increases and the termination of the tenancy the Company allege were not permitted by the agreement with the landlord. The Company seeks to recover rent paid under protest, its deposit, moving and relocation expenses and consequential damages arising from disruption to its operations. The Company will account for any possible gain that may result from this complaint upon resolution. Grant Income The Company receives various grants that are subject to audit by the grantors or their representatives. Such audits could result in requests for reimbursement for expenditures disallowed under the terms of the grant; however, management believes that these disallowances, if any, would be immaterial. Cystic Fibrosis Foundation Agreement In December 2016, the Company received an award for up to $2.9 million from the CFF to advance research on potential drugs utilizing inhaled gallium citrate anti-infective. In November 2018, the CFF increased the award to $7.5 million. Under the award agreement, the CFF will make payments to the Company as certain milestones are met. The award agreement also contains a provision whereby if the Company spends less on developing a potential drug utilizing inhaled gallium citrate anti-infective than the Company actually receives under this award agreement, the Company will be required to return the excess portion of the award to the CFF. At the end of any reporting period, if the Company determines that the cumulative amount spent on this program is less than the cumulative cash received from the CFF, the Company will record the excess amount received as a liability. No liability related to this excess amount was recorded by the Company as of December 31, 2021 and 2020. In the event that development efforts are successful and the Company commercializes a drug from these related development efforts, the Company will be subject to paying to CFF a one-time amount over time equal to nine times the actual net award received from CFF. Such amount shall be paid in not more than five annual installments, as follows: within ninety days of the end of the calendar year in which the first commercial sale occurs, and within ninety days of the end of each subsequent calendar year until the net amount received from CFF is repaid. The Company shall pay 15% of net sales for that calendar year up to the amount of the net award received from CFF (except that in the fifth installment, if any, the Company shall pay the remaining unpaid portion of the net award received from CFF). In the event that the Company licenses rights to the product in the field to a third-party, sells the product, or consummates a change of control transaction prior to the first commercial sale, the Company shall pay to CFF an amount equal to 15% of the amounts received by the Company and its shareholders in connection with such disposition (whether paid upfront or in accordance with subsequent milestones and whether paid in cash or property) up to nine times the actual net award received from CFF. The payment shall be made within sixty days after the closing of such a transaction. In the event that the development efforts are delayed, which result from events within the Company’s control, for more than one hundred eighty (180) consecutive days at any time before the first commercialization of the drug from the related development efforts, the CFF may provide an interruption notice to the Company, or in lieu of the interruption license, pay to the CFF an amount greater than two times the award received plus interest up to the time of such election. The Company then has thirty (30) days to respond to such notice. If the Company does not respond within thirty (30) days, an interruption license shall be effective. The interruption license to the CFF is an exclusive, worldwide license under the development program technology to manufacture, have manufactured, license, use, sell, offer to sell, and support the product in the field and includes financial conditions for both parties. None of these events have occurred as of December 31, 2021. ​ Kermode Agreement In February 2021, the Company entered into the Kermode Agreement, in which the Company received an upfront payment. Since then one milestone payment has been received in December 2021. The Company will receive additional milestone payments from Kermode as certain phases defined in the agreement are completed. The Company is also entitled to additional payments from Kermode for royalty payments on future net sales (see Note 6). In the event that the research and development efforts under the agreement are successful and if the Company elects to develop and commercialize products under certain provisions contained in the agreement, the Company shall pay to Kermode a 5% royalty of net sales from those products. None of these events occurred as of December 31, 2021. MedImmune Limited License Agreement In July 2021, the Company executed the MedImmune License Agreement (see Note 4). As additional consideration under this agreement, the Company will pay MedImmune milestone payments upon the achievement of certain regulatory approvals, for one licensed product, up to a total aggregate amount of $30.0 million and sales related milestone payments of up to $85.0 million. There are no development milestone payments. MedImmune is entitled to royalty payments based on aggregate net sales ranging from 12.5% to 15% dependent on net sales volume. Further, until delivery of an interim data readout, or an interim futility analysis, from the first Phase 3 clinical study for any indication, MedImmune has a right of first negotiation regarding any commercial rights that the Company intends to sub-license. None of these events occurred as of December 31, 2021.

Subsequent Events

Subsequent Events	12 Months Ended
	Dec. 31, 2021
Subsequent Events
Subsequent Events	14. Subsequent Events ATM Agreement On January 10, 2022, the Company notified Cantor of its intent to terminate, which became effective on January 18, 2022, the Controlled Equity Offering Sales Agreement dated as of September 3, 2019 between the Company and Cantor in connection with the Company’s at-the-market offering of up to $25.0 million. On January 19, 2022, the Company entered into an At-the-Market Sales Agreement (“Sales Agreement”) with Virtu Americas LLC (“Virtu”), as sales agent. Pursuant to the terms of the Sales Agreement, the Company may issue and sell from time to time shares of its common stock, par value $0.0001 per share, through Virtu, acting as its sales agent, or directly to Virtu, acting as principal. Pursuant to the Company’s prospectus supplement filed on January 19, 2022, the Company may issue and sell shares of its common stock having an aggregate offering price of up to $25.0 million. The Company will pay Virtu a commission rate of up to 3.0% of the gross proceeds from each sale of Shares and has agreed to provide Virtu with customary indemnification and contribution rights. The Company will also reimburse Virtu for certain specified expenses in connection with entering into the Sales Agreement. Legal proceedings The Company submitted an amended complaint in Superior Court of the State of California, County of Santa Clara, against our former landlord on February 4, 2022, asserting claims for breach of contract, breach of the covenant of good faith and fair dealing, wrongful eviction/constructive eviction and unjust enrichment and violation of the unfair competition law. The claims arise from rent increases and the termination of the tenancy that we allege were not permitted by the agreement with the landlord. We seek to recover rent paid under protest, our deposit, moving and relocation expenses and consequential damages arising from disruption to our operations. The landlord has filed a cross-complaint for damage to property and attorneys’ fees. Note Purchase Agreement Pursuant to the terms agreed in the Note Purchase Agreement with Streeterville Capital, LLC, the Company issued a second Note to the Lender on February 21, 2022 in the aggregate principal amount of $5,250,000 which are substantially similar to the first Note except the maturity date is February 21, 2024.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2021
Summary of Significant Accounting Policies
Use of Estimates	Use of Estimates The preparation of the consolidated financial statements requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities as of the date of the consolidated financial statements and the reported amounts of expenses during the reporting period. Such estimates include those related to the evaluation of our ability to continue as a going concern, best estimate of standalone selling price of revenue deliverables, useful life of long-lived assets, classification of deferred revenue, income taxes, assumptions used in the Black-Scholes-Merton (“BSM”) model to calculate the fair value of stock-based compensation, deferred tax asset valuation allowances, and preclinical study and clinical trial accruals. Actual results could differ from those estimates.
Concentration of Risk	Concentrations Credit Risk The Company’s cash and cash equivalents are maintained at financial institutions in the United States of America. Deposits held by these institutions may exceed the amount of insurance provided on such deposits. Customer Risk For the year ended December 31, 2021, three customers, each individually being 34%, 36% and 30% accounted for 100% of total revenue and for the year ended December 31, 2020, one customer accounted for 100% of total revenue. The customers are located in the United States. As of December 31, 2021 and 2020, there were no accounts receivable.
Cash, Cash Equivalents and Restricted Cash	Cash, Cash Equivalents and Restricted Cash The Company considers all highly liquid investments purchased with an original maturity of three months or less to be cash equivalents. Cash equivalents consist primarily of checking account and money market fund account balances. The following table provides a reconciliation of cash, cash equivalents and restricted cash within the consolidated balance sheets which, in aggregate, represent the amount reported in the consolidated statements of cash flows (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, ​ ​ 2021 ​ 2020 Cash and cash equivalents $ 18,098 ​ $ 8,232 Restricted cash ​ 1,888 ​ 500 Total cash, cash equivalents and restricted cash ​ $ 19,986 ​ $ 8,732 ​ Restricted cash consists of deposits for a letter of credit that the Company has provided to secure its obligations under its facility lease and cash received from the Gates Foundation restricted specifically to research associated with the grant. Restricted cash is classified as current when the Company expects to fulfill the obligation within one year or less. ​
Accounts Receivable and Allowance for Doubtful Accounts	Accounts Receivable and Allowance for Doubtful Accounts Accounts receivable are recorded at the invoiced amount and do not bear interest. The Company considers the credit worthiness of its customers but does not require collateral in advance of a sale. The Company evaluates collectability and maintains an allowance for doubtful accounts for estimated losses inherent in its accounts receivable portfolio when necessary. The allowance is based on the Company’s best estimate of the amount of losses in the Company’s existing accounts receivable, which is based on customer creditworthiness, facts and circumstances specific to outstanding balances, and payment terms. Account balances are charged off against the allowance after all means of collection have been exhausted and the potential for recovery is considered remote. As of December 31, 2021 and 2020, there were no allowances for doubtful accounts.
Operating Leases	Operating Leases The Company evaluates leases at their inception as either operating or capital leases, and may receive renewal or expansion options, rent holidays, leasehold improvement allowances and other incentives on such lease agreements. The Company recognizes operating lease costs on a straight-line basis over the term of the agreement. ​
Property and Equipment	Property and Equipment Property and equipment are stated at cost less accumulated depreciation. Depreciation and amortization is computed using the straight-line method over the estimated useful lives of the assets, generally between three
Intangible Assets	Intangible Assets Intangible assets are recorded at cost and amortized over the estimated useful life of the asset. Intangible assets consist of licenses with various institutions whereby the Company has rights to use intangible property obtained from such institutions.
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. Recoverability is measured by comparison of the carrying amount to the future undiscounted net cash flows which the assets are expected to generate. If such assets are considered to be impaired, the impairment is measured by the excess of the carrying amount of the assets over fair value less the costs to sell the assets, generally determined using the projected discounted future net cash flows arising from the asset. There have been no such impairments of long-lived assets as of December 31, 2021 and 2020.
Revenue Recognition	Revenue Recognition The Company recognizes revenue based on Accounting Standards Codification (“ASC”) 606, Revenue from Contracts with Customers To determine revenue recognition for arrangements that the Company determines are within the scope of ASC 606, the Company performs the following five steps: (i) identify the contract(s) with a customer; (ii) identify the performance obligations in the contract; (iii) determine the transaction price; (iv) allocate the transaction price to the performance obligations in the contract; and (v) recognize revenue at a point in time, or over time, as the entity satisfies performance obligations. The Company only applies the five-step model to contracts when it is probable that it will collect the consideration it is entitled to in exchange for the goods or services it transfers to the customer. At contract inception, once the contract is determined to be within the scope of ASC 606, the Company assesses the goods or services promised within each contract, determines those that are performance obligations, and assesses whether each promised good or service is distinct. The Company then recognizes as revenue the amount of the transaction price that is allocated to the respective performance obligation when (or as) the performance obligation is satisfied. As part of the accounting for customer arrangements, the Company must use judgment to determine: a) the number of performance obligations based on the determination under step (ii) above; b) the transaction price under step (iii) above; and c) the standalone selling price for each performance obligation identified in the contract for the allocation of the transaction price in step (iv) above. The Company uses judgment to determine whether milestones or other variable consideration should be included in the transaction price. The transaction price is allocated to each performance obligation on a relative standalone selling price basis. In developing the standalone price for a performance obligation, the Company considers applicable market conditions and relevant entity-specific factors, including factors that were contemplated in negotiating the agreement with the customer and estimated costs. The Company recognizes revenue as or when the performance obligations under the contract are satisfied. The Company receives payments from its customers based on payment schedules established in each contract. The Company records any amounts received prior to satisfying the revenue recognition criteria as deferred revenue on its consolidated balance sheets. Amounts recognized as revenue, but not yet received or invoiced are recorded within other receivables on the consolidated balance sheet. Amounts are recorded as other receivables on the consolidated balance sheet when our right to consideration is unconditional. The Company does not assess whether a contract has a significant financing component if the expectation at contract inception is such that the period between payment by the customer and the transfer of a majority of the promised goods or services to the customer will be one year or less. Contract Assets The incremental costs of obtaining a contract under ASC 606 (i.e. costs that would not have been incurred if the contract had not been obtained) are recognized as an asset in the Company’s consolidated balance sheets if the Company expects to recover them (see Note 6). Capitalized costs will be amortized to the respective expenses using a systematic basis that mirrors the pattern in which the Company transfers control of the goods and service to the customer. At each reporting date, the Company determines whether or not the capitalized costs to obtain a contract are impaired by comparing the carrying amount of the asset to the remaining amount of consideration that the Company received and expects to receive less the costs that relate to providing services under the relevant contract. For the years ended December 31, 2021 and 2020, there was no amortization of the contract assets and there have been no impairments as of December 31, 2021 and 2020. Deferred Revenue Amounts received prior to satisfying the above revenue recognition criteria, or in which the Company has an unconditional right to payment, are recorded as deferred revenue in the Company’s consolidated balance sheets. The Company has estimated the classification between current and noncurrent deferred revenue related to the respective license agreement within its consolidated balance sheets at December 31, 2021 and 2020 (see Note 6).
Research and Development	Research and Development Research and development costs are expensed to operations as incurred. Our research and development expenses consist primarily of: ● salaries and related overhead expenses, which include stock-based compensation and benefits for personnel in research and development functions; ● fees paid to consultants and contract research organizations, or CROs, including in connection with our preclinical studies and clinical trials and other related clinical trial fees, such as for investigator grants, patient screening, laboratory work, clinical trial material management and statistical compilation and analyses; ● costs related to acquiring and manufacturing clinical trial materials; ● costs related to compliance with regulatory requirements; and ● payments related to licensed products and technologies. Costs for certain development activities are recognized based on an evaluation of the progress to completion of specific tasks using information and data provided to us by our vendors and clinical sites. Nonrefundable advance payments for goods or services to be received in future periods for use in research and development activities are deferred and capitalized. The capitalized amounts are then expensed as the related goods are delivered or when the services are performed.
Stock-Based Compensation	Stock-Based Compensation The Company recognizes compensation expense for all stock-based awards based on the grant-date estimated fair values, which the Company determines using the BSM option pricing model, on a straight-line basis over the requisite service period for the award. The Company accounts for forfeitures as they occur. The BSM option pricing model incorporates various highly sensitive assumptions, including the fair value of our common stock, expected volatility, expected term and risk-free interest rates. The weighted average expected life of options was calculated using the simplified method as prescribed by the SEC’s Staff Accounting Bulletin, Topic 14 (“SAB Topic 14”). This decision was based on the lack of relevant historical data due to our limited historical experience. In addition, due to our limited historical data, the estimated volatility also reflects the application of SAB Topic 14, incorporating the historical volatility of comparable companies whose stock prices are publicly available. The risk-free interest rate for the periods within the expected term of the option is based on the U.S. Treasury yield in effect at the time of grant. The dividend yield was zero, as we have never declared or paid dividends and have no plans to do so in the foreseeable future.
Income Taxes	Income Taxes The Company accounts for income taxes under the liability method. Under this method, deferred tax assets and liabilities are determined based on the difference between the financial statement and tax basis of assets and liabilities using enacted tax rates in effect for the year in which the differences are expected to affect taxable income. Valuation allowances are established when necessary to reduce deferred tax assets to the amounts expected to be realized. The Company assesses all material positions taken in any income tax return, including all significant uncertain positions, in all tax years that are still subject to assessment or challenge by the relevant taxing authorities. Assessing an uncertain tax position begins with the initial determination of the position’s sustainability and is measured at the largest amount of benefit that is greater than 50% likely of being realized upon ultimate settlement. At each balance sheet date, unresolved uncertain tax positions must be reassessed, and the Company will determine whether (i) the factors underlying the sustainability assertion have changed and (ii) the amount of the recognized benefit is still appropriate. The recognition and measurement of tax benefits requires significant judgment. Judgments concerning the recognition and measurement of a tax benefit might change as new information becomes available. The Company’s policy is to recognize interest or penalties related to income tax matters in income tax expense.
Comprehensive Loss	Comprehensive Loss The Company has no items of comprehensive income or loss other than net loss.
Loss Per Share	Loss Per Share Basic loss per share is calculated by dividing net loss for the period by the weighted-average number of common shares outstanding during the period, without consideration for potentially dilutive securities. Diluted net loss per share is computed by dividing the net loss by the weighted-average number of common shares and potentially dilutive securities outstanding for the period. In March 2021 and in August 2021, the Company issued 124,789 and 634,600 dividend shares, respectively, to certain common stockholders with a fair value of approximately $986,000 and approximately $3.1 million, respectively, (see Note 9) which is included in the net loss available to common stockholders for the year ended December 31, 2021 in the below table. For the years ended December 31, 2021 and 2020, there is no difference in the number of shares used to compute basic and diluted net loss per share due to the Company’s net loss position. The following tables presents the computation of the basic and diluted net loss per share (in thousands, except share and per share data): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year Ended ​ ​ December 31, ​ 2021 2020 Numerator: ​ ​ ​ ​ Net loss available to common stockholders ​ $ (46,320) ​ $ (22,333) ​ ​ ​ ​ ​ ​ ​ Denominator: ​ ​ ​ Weighted-average common shares outstanding used in computing net loss per share available to common stockholders, basic and diluted ​ 12,291,600 ​ 9,168,744 Basic and diluted net loss per share ​ $ (3.77) ​ $ (2.44) ​ The following potentially dilutive securities were excluded from the computation of diluted net loss per share for the periods presented because including them would have been antidilutive: ​ ​ ​ ​ ​ ​ ​ ​ Year Ended ​ ​ December 31, ​ 2021 ​ 2020 Stock options to purchase common stock 1,905,459 ​ 1,550,956 Common stock warrants 3,592,905 ​ 2,052,128 ​ 5,498,364 ​ 3,603,084 ​
JOBS Act Accounting Election	JOBS Act Accounting Election The JOBS Act permits an “emerging growth company” such as us to take advantage of an extended transition period to comply with new or revised accounting standards applicable to public companies. We are choosing to take advantage of this provision and, as a result, we will adopt the extended transition period available under the JOBS Act until the earlier of the date we (i) are no longer an emerging growth company or (ii) affirmatively and irrevocably opt out of the extended transition period provided under the JOBS Act.
Recently Issued Accounting Pronouncements not yet adopted as of June 30, 2021	Recently Issued Accounting Pronouncements not yet adopted as of December 31, 2021 Accounting Standards Update 2016-02, 2018-11 and 2019-01 In February 2016, the FASB issued ASU 2016-02, Leases (ASC 842) Leases off-balance sheet financing. Initial guidance required the adoption of the new lease standard using the modified retrospective transition method. In July 2018, the FASB issued ASU 2018-11, Leases (ASC 842)-Targeted Improvements Codification improvements Accounting Standards Update 2016-13 In June 2016, the FASB issued ASU 2016-13, “ Financial Instruments- Credit Losses (ASC 326) Accounting Standards Update 2019-12 In December 2019, the FASB issued ASU 2019-12, “ Simplifying the Accounting for Income Taxes (ASC 740)

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2021
Summary of Significant Accounting Policies
Reconciliation schedule of cash, cash equivalents and restricted cash	The following table provides a reconciliation of cash, cash equivalents and restricted cash within the consolidated balance sheets which, in aggregate, represent the amount reported in the consolidated statements of cash flows (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, ​ ​ 2021 ​ 2020 Cash and cash equivalents $ 18,098 ​ $ 8,232 Restricted cash ​ 1,888 ​ 500 Total cash, cash equivalents and restricted cash ​ $ 19,986 ​ $ 8,732
Schedule of computation of the basic and diluted net loss per share	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year Ended ​ ​ December 31, ​ 2021 2020 Numerator: ​ ​ ​ ​ Net loss available to common stockholders ​ $ (46,320) ​ $ (22,333) ​ ​ ​ ​ ​ ​ ​ Denominator: ​ ​ ​ Weighted-average common shares outstanding used in computing net loss per share available to common stockholders, basic and diluted ​ 12,291,600 ​ 9,168,744 Basic and diluted net loss per share ​ $ (3.77) ​ $ (2.44)
Schedule of potentially dilutive securities were excluded from the computation of diluted net loss per share	​ ​ ​ ​ ​ ​ ​ ​ Year Ended ​ ​ December 31, ​ 2021 ​ 2020 Stock options to purchase common stock 1,905,459 ​ 1,550,956 Common stock warrants 3,592,905 ​ 2,052,128 ​ 5,498,364 ​ 3,603,084

Balance Sheet Components (Table

Balance Sheet Components (Tables)	12 Months Ended
	Dec. 31, 2021
Balance Sheet Components
Schedule of property and equipment, net	Property and equipment, net consist of the following (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, ​ December 31, ​ 2021 ​ 2020 Lab equipment ​ $ 2,390 ​ $ 2,200 Computer equipment and software ​ ​ 25 ​ 25 Construction in progress ​ ​ — ​ ​ 188 Leasehold improvements ​ ​ 527 ​ ​ — Total property and equipment ​ ​ 2,942 ​ 2,413 Less: Accumulated depreciation ​ (1,585) ​ (1,155) Property and equipment, net ​ $ 1,357 ​ $ 1,258 ​
Schedule of intangible assets, net	Intangible assets, net consist of the following (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, ​ December 31, ​ 2021 ​ 2020 Licenses ​ $ 81 ​ $ 81 Less: Accumulated amortization ​ ​ (59) ​ (54) Intangible assets, net ​ $ 22 ​ $ 27 ​
Schedule of estimated acquired intangible amortization expense	The estimated acquired intangible amortization expense for the next five fiscal years is as follows (in thousands): ​ ​ ​ ​ Year ending December 31, ​ 2022 ​ $ 5 2023 ​ 5 2024 ​ ​ 5 2025 ​ ​ 5 2026 ​ ​ 2 Total ​ $ 22 ​
Schedule of accrued liabilities	Accrued liabilities consist of the following (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, ​ December 31, ​ 2021 ​ 2020 ​ ​ ​ ​ ​ ​ ​ Research and development services ​ $ 5,939 ​ $ 872 Payroll related expenses ​ ​ 416 ​ 279 Professional services and other ​ ​ 109 ​ 179 Accrued liabilities ​ $ 6,464 ​ $ 1,330

Common Stock (Tables)

Common Stock (Tables)	12 Months Ended
	Dec. 31, 2021
Common Stock
Schedule of company reserved common stock for future issuance	​ ​ ​ ​ Shares reserved for exercise of outstanding warrants to purchase common stock 3,592,905 Shares reserved for exercise of outstanding options to purchase common stock ​ 1,905,459 Shares reserved for issuance of future options ​ 228,099 Total 5,726,463

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	12 Months Ended
	Dec. 31, 2021
Stock-Based Compensation
Schedule of stock option activity	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Options Outstanding ​ Shares ​ Weighted- ​ ​ Available ​ Number of ​ Average ​ ​ for Grant ​ Shares ​ Exercise Price Balances at December 31, 2020 584,161 1,550,956 ​ $ 9.43 Options granted ​ (493,440) ​ 493,440 ​ $ 5.04 Options exercised — (1,559) ​ $ 2.89 Options cancelled ​ 137,378 ​ (137,378) ​ $ 7.05 Balances at December 31, 2021 228,099 1,905,459 ​ $ 8.47
Schedule of stock-based compensation expense related to stock options	The following table presents stock-based compensation expense related to stock options (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Years Ended ​ ​ December 31, ​ 2021 ​ 2020 Research and development ​ $ 687 ​ $ 590 General and administrative ​ ​ 1,564 ​ ​ 1,538 Total ​ $ 2,251 ​ $ 2,128
Schedule of the status of options	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted- ​ ​ ​ ​ ​ ​ ​ Weighted- ​ Average ​ Aggregate ​ ​ Number of ​ Average ​ Contractual ​ Intrinsic ​ Options Exercise Price Term (Years) Value ​ ​ ​ ​ ​ ​ ​ ​ ​ (in thousands) Options outstanding ​ 1,905,459 ​ $ 8.47 ​ 6.97 ​ $ 13 Options vested and exercisable ​ 1,287,094 ​ $ 9.70 ​ 6.11 ​ $ —
Options
Stock-Based Compensation
Schedule of fair value of the options granted estimated using assumptions	​ ​ ​ ​ ​ ​ ​ ​ ​ Years Ended ​ ​ ​ December 31, ​ ​ 2021 2020 ​ Expected term (in years) 6.00 ​ 6.00 ​ Expected volatility 99% - 100% ​ 84% - 100% ​ Risk-free interest rate 0.8% - 1.17% ​ 0.38% - 1.73% ​ Dividend yield 0% ​ 0% ​

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2021
Income Taxes
Schedule of the difference between income tax expense and the amount computed by applying the statutory federal income tax rate to income before income tax	A reconciliation between the statutory U.S. federal rate and the Company’s effective tax rate is as follows (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ Year Ended ​ ​ December 31, ​ 2021 ​ 2020 Federal income tax at statutory rate ​ $ (8,860) ​ $ (4,690) State income tax, net of federal benefit ​ (759) ​ (36) Foreign tax differential ​ 1,345 ​ 1,906 State Rate change ​ ​ (346) ​ ​ 287 Permanent differences ​ 66 ​ 1,088 Tax credits generated in current year ​ (894) ​ (649) Uncertain tax position change ​ ​ 224 ​ ​ 162 Other ​ ​ 28 ​ (92) Valuation allowance change ​ 9,196 ​ 2,024 ​ ​ $ — ​ ​ — ​
Significant components of deferred tax assets	​ ​ ​ ​ ​ ​ ​ ​ ​ Year Ended ​ December 31, ​ 2021 ​ 2020 Net operating loss carryforwards ​ $ 22,603 ​ $ 14,793 Accruals and reserves ​ 175 ​ 39 Stock based compensations ​ ​ 1,607 ​ ​ 1,153 Research and development credits ​ 2,692 ​ 2,021 Deferred revenue ​ ​ 1,454 ​ ​ 1,338 Depreciation and amortization ​ — ​ (9) Total ​ 28,531 ​ 19,335 Valuation allowance change ​ (28,531) ​ (19,335) Net deferred tax assets (liabilities) ​ $ — ​ $ —
Schedule of reconciliation of the beginning and ending amount of the Company's liability for uncertain tax positions	A reconciliation of the beginning and ending amount of the Company’s liability for uncertain tax positions (in thousands) is as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, ​ 2021 ​ 2020 Balance at the beginning of the year ​ $ 705 ​ $ 534 Increase/(decrease) based on current year tax positions ​ 235 ​ 171 Increase/(decrease) for prior year tax positions ​ — ​ — Balance at the end of the year ​ $ 940 ​ $ 705

Commitments and Contingencies (

Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2021
Commitments and Contingencies
Schedule of future minimum lease payments for the new facility	The future minimum lease payments for the new facility as of December 31, 2021 are as follows (in thousands): ​ ​ ​ ​ Year ending December 31, ​ 2022 ​ $ 610 2023 ​ 628 2024 ​ 646 2025 ​ 666 2026 ​ ​ 57 Total ​ $ 2,607

Description of Business and B_2

Description of Business and Basis of Presentation (Details)	12 Months Ended
	Dec. 31, 2021segmentsubsidiary
Description of Business and Basis of Presentation
Subsidiaries (in subsidiaries) | subsidiary	2
Operating segments (in segments)	1
Reporting segments (in segments)	1

Summary of Significant Accoun_4

Summary of Significant Accounting Policies - Concentrations (Details)	12 Months Ended
	Dec. 31, 2021USD ($)customer	Dec. 31, 2020USD ($)
Summary of Significant Accounting Policies
Accounts receivable	$ 0	$ 0
Contract revenue | Customer risk
Summary of Significant Accounting Policies
Number of customers	3	1
Contract revenue | Customer | Customer risk
Summary of Significant Accounting Policies
Concentration risk percentage	100.00%	100.00%
Contract revenue | Customer 1 | Customer risk
Summary of Significant Accounting Policies
Concentration risk percentage	34.00%
Contract revenue | Customer 2 | Customer risk
Summary of Significant Accounting Policies
Concentration risk percentage	36.00%
Contract revenue | Customer 3 | Customer risk
Summary of Significant Accounting Policies
Concentration risk percentage	30.00%

Summary of Significant Accoun_5

Summary of Significant Accounting Policies - Cash, Cash Equivalents and Restricted Cash (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Summary of Significant Accounting Policies
Cash and cash equivalents	$ 18,098	$ 8,232
Restricted cash	1,888	500
Total cash, cash equivalents and restricted cash	$ 19,986	$ 8,732	$ 20,897

Summary of Significant Accoun_6

Summary of Significant Accounting Policies - Accounts Receivable and Allowance for Doubtful Accounts (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Summary of Significant Accounting Policies
Accounts receivable	$ 0	$ 0
Allowance for doubtful accounts	$ 0	$ 0

Summary of Significant Accoun_7

Summary of Significant Accounting Policies - Property and Equipment and Impairment of Long-Lived Assets (Details)	12 Months Ended
	Dec. 31, 2021
Minimum
Property and Equipment, net
Estimated useful life (in years)	3 years
Maximum
Property and Equipment, net
Estimated useful life (in years)	5 years

Summary of Significant Accoun_8

Summary of Significant Accounting Policies - Impairment of Long-Lived Assets (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Summary of Significant Accounting Policies
Impairments of long-lived assets	$ 0	$ 0

Summary of Significant Accoun_9

Summary of Significant Accounting Policies - Revenue Recognition (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Summary of Significant Accounting Policies
Amortization of contract assets	$ 0	$ 0
Impairments of contract assets	$ 0

Summary of Significant Accou_10

Summary of Significant Accounting Policies - Stock-Based Compensation (Details)	12 Months Ended
	Dec. 31, 2021
Summary of Significant Accounting Policies
Dividend yield (in percent)	0.00%

Summary of Significant Accou_11

Summary of Significant Accounting Policies - Loss Per Share (Details) - USD ($)	1 Months Ended		12 Months Ended
	Aug. 31, 2021	Mar. 31, 2021	Dec. 31, 2021	Dec. 31, 2020
Summary of Significant Accounting Policies
Preferred Stock Dividends and Other Adjustments			$ 4,127,000
Numerator:
Net loss available to common stockholders			$ (46,320,000)	$ (22,333,000)
Denominator:
Weighted-average common shares outstanding used in computing net loss per share available to common stockholders, basic			12,291,600	9,168,744
Weighted-average common shares outstanding used in computing net loss per share available to common stockholders, diluted			12,291,600	9,168,744
Net loss per share to common stockholders, basic			$ (3.77)	$ (2.44)
Net loss per share to common stockholders, diluted			$ (3.77)	$ (2.44)
Potentially dilutive securities excluded from computation of diluted net loss per share			5,498,364	3,603,084
Common Stock Member
Summary of Significant Accounting Policies
Dividend shares to its common stock stockholders	634,600	124,789
Fair value of dividend shares issued to common stockholders	$ 3,100,000	$ 986,000
Options
Denominator:
Potentially dilutive securities excluded from computation of diluted net loss per share			1,905,459	1,550,956
Warrants Member | Common Stock Member
Denominator:
Potentially dilutive securities excluded from computation of diluted net loss per share			3,592,905	2,052,128

Balance Sheet Components - Prop

Balance Sheet Components - Property and Equipment, net (Details) - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Property and Equipment, net
Total property and equipment	$ 2,942,000	$ 2,413,000
Less: Accumulated depreciation	(1,585,000)	(1,155,000)
Property and equipment, net	1,357,000	1,258,000
Depreciation expense	430,000	332,000
Lab equipment
Property and Equipment, net
Total property and equipment	2,390,000	2,200,000
Computer equipment and software
Property and Equipment, net
Total property and equipment	25,000	25,000
Construction in progress
Property and Equipment, net
Total property and equipment		$ 188,000
Leasehold improvements
Property and Equipment, net
Total property and equipment	$ 527,000

Balance Sheet Components - Inta

Balance Sheet Components - Intangible Assets, net (Details) - USD ($)	24 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Intangible Assets, net
Less: Accumulated amortization	$ (59,000)	$ (54,000)
Intangible assets, net	22,000	27,000
Amortization expense	5,000
License revenue
Intangible Assets, net
Licenses	$ 81,000	$ 81,000

Balance Sheet Components - In_2

Balance Sheet Components - Intangible Assets, Net- Amortization expense (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Acquired intangible amortization expense
2022	$ 5
2023	5
2024	5
2025	5
2026	2
Intangible assets, net	$ 22	$ 27

Balance Sheet Components - In_3

Balance Sheet Components - Intangible Assets, Net - Licenses (Details) - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
The University of Chicago Agreement
Intangible Assets, net
Maximum contingent milestone payments	$ 1,600,000
Milestone payments accrued		$ 100,000	$ 0
The Brigham and Women's Hospital, Inc
Intangible Assets, net
Maximum contingent milestone payments	860,000
Milestone payments accrued		0
The University of Iowa Research Foundation
Intangible Assets, net
Maximum contingent milestone payments	712,500
Milestone payments accrued	75,000	0
Brigham Young University
Intangible Assets, net
Maximum contingent milestone payments	$ 400,000
Milestone payments accrued		$ 0
Reimbursement of 3rd party costs (in percent)	33.00%
Kenta Biotech Ltd
Intangible Assets, net
Accrued royalty obligation	$ 0
Maximum royalty base for royalty payments	50,000,000
Emergent Product Development Gaithersburg Inc
Intangible Assets, net
Milestone payments under the agreement	$ 2,800,000

Balance Sheet Components - Lice

Balance Sheet Components - Licenses (Details) - The University of Alabama at Burmingham Research Foundation - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Minimum research funding agreed to provide	$ 50,000
Maximum contingent milestone payments	5,500,000
Milestone payments accrued	$ 0	$ 0
Reduction in payments for non-royalty income received for a combination product (as a percent)	50.00%
Minimum period of prior written notice for termination of agreement	90 days

Balance Sheet Components - Medi

Balance Sheet Components - Medimmune Limited License Agreement (Details) - USD ($) $ in Thousands	1 Months Ended	12 Months Ended
	Jul. 31, 2021	Dec. 31, 2021	Dec. 31, 2020
Research and development		$ 36,936	$ 16,956
Issuance of common stock		$ 29,011
Minimum | Customer risk | Revenue Benchmark | MedImmune Customer
Concentration risk percentage		12.50%
Maximum | Customer risk | Revenue Benchmark | MedImmune Customer
Concentration risk percentage		15.00%
Medimmune Limited | License Agreement
Issuance of common stock (in shares)	884,956	884,956
Contractual liability	$ 5,000
Medimmune Limited | License Agreement | Sales
Total aggregate milestone payments		$ 85,000
Medimmune Limited | License Agreement | Research and development
Issuance of common stock		6,500
Medimmune Limited | One license product | License Agreement
Total aggregate milestone payments		30,000
Medimmune Limited | Other Liabilities | License Agreement
Contractual obligation, cash payment		$ 5,000

Balance Sheet Components - Accr

Balance Sheet Components - Accrued Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Balance Sheet Components
Research and development services	$ 5,939	$ 872
Payroll related expenses	416	279
Professional services and other	109	179
Accrued liabilities	$ 6,464	$ 1,330

Balance Sheet Components - Broa

Balance Sheet Components - Broad Institute of MIT and Harvard (Details) - Broad Institute of MIT and Harvard $ in Thousands	12 Months Ended
	Dec. 31, 2021USD ($)
Issue fee	$ 25,000
Annual License Maintenance Fee To Be Incurred In Year One	50,000
Annual License Maintenance Fee To Be Incurred In Year Two And Each Year Thereafter	$ 100,000
Royalty Expense As A Percentage Of Service Income	7.00%
Royalty Expense As A Percentage Of End Product Net Sales	0.50%

Equity Method Investment (Detai

Equity Method Investment (Details) - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Aug. 06, 2018	Feb. 11, 2018
Equity Method Investment
Contributions owed to the joint venture	$ 1,000,000
Loss from equity method investment		$ 9,000
Equity method investment	0
SABC
Equity Method Investment
Percentage of ownership interest				49.00%
Carryover basis of license contributed	0
JV Entity
Equity Method Investment
Loss from equity method investment	$ 0	$ 9,000
Hepalink | SABC
Equity Method Investment
Percentage of ownership interest			51.00%
Minimum amount obligated to make an additional equity investment at first future financing			$ 10,800,000
Hepalink | JV Entity
Equity Method Investment
Contractual obligation, cash payment			$ 7,200,000	$ 1,000,000

Collaboration, Development an_2

Collaboration, Development and License Agreements - Cystic Fibrosis Foundation Development Agreement (Details) - USD ($)	1 Months Ended		3 Months Ended	12 Months Ended
	Dec. 31, 2016	Nov. 30, 2016	Jun. 30, 2020	Dec. 31, 2021	Dec. 31, 2020	Sep. 30, 2021	Mar. 31, 2019
Collaborative Arrangements and Non-collaborative Arrangement Transactions
Deferred revenue				$ 20,838,000	$ 18,748,000
Revenue				1,535,000	1,000,000
Phase 1 MAD
Collaborative Arrangements and Non-collaborative Arrangement Transactions
Amount of achieved consideration			$ 1,000,000
CFF
Collaborative Arrangements and Non-collaborative Arrangement Transactions
Amount of award	$ 2,900,000	$ 7,500,000
Upfront payment received from CFF	$ 200,000
Deferred revenue				476,000
Revenue					$ 1,000,000
CFF | Phase 1 SAD
Collaborative Arrangements and Non-collaborative Arrangement Transactions
Amount of probable transaction price							$ 1,700,000
Amount of probable variable consideration							$ 1,000,000
CFF | Phase 2a Clinical Trial
Collaborative Arrangements and Non-collaborative Arrangement Transactions
Gross transaction price						$ 1,000,000
Amount of variable consideration				3,800,000
Revenue				$ 524,000

Collaboration, Development an_3

Collaboration, Development and License Agreements - Gates Foundation Grant (Details) - USD ($)	Oct. 15, 2021	Dec. 31, 2021	Dec. 31, 2020
Collaborative Arrangements and Non-collaborative Arrangement Transactions
Deferred revenue		$ 20,838,000	$ 18,748,000
Grant Agreement
Collaborative Arrangements and Non-collaborative Arrangement Transactions
Upfront payment received		1,930,000
Recognized deferred revenue		546,000
Deferred revenue		$ 1,387,000
Grant Agreement | Gates Foundation
Collaborative Arrangements and Non-collaborative Arrangement Transactions
Amount of compensation	$ 1,930,000

Collaboration, Development an_4

Collaboration, Development and License Agreements - Serum License Agreement (Details) - USD ($)	1 Months Ended			12 Months Ended
	Mar. 31, 2021	Sep. 30, 2019	Jul. 31, 2019	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Collaborative Arrangements and Non-collaborative Arrangement Transactions
Issuance of common stock				$ 29,011,000
Revenue from Contract with Customer, Excluding Assessed Tax				1,535,000	$ 1,000,000
Deferred revenue, noncurrent				913,000	854,000
Capitalized contract cost, Current				1,967,000	1,973,000
Capitalized contract cost, Noncurrent				96,000	90,000
Deferred revenue				20,838,000	18,748,000
License revenue
Collaborative Arrangements and Non-collaborative Arrangement Transactions
Contractual liability				18,600,000	18,700,000
Capitalized contract costs					2,100,000	$ 2,100,000
Revenue				0	0
Deferred revenue, noncurrent				913,000	854,000
Capitalized contract cost, Current				2,000,000	2,000,000
Capitalized contract cost, Noncurrent				96,000	90,000
Licenses and know-how
Collaborative Arrangements and Non-collaborative Arrangement Transactions
Contractual liability				14,500,000
Development support services
Collaborative Arrangements and Non-collaborative Arrangement Transactions
Contractual liability				79,000
Research and Development Option
Collaborative Arrangements and Non-collaborative Arrangement Transactions
Contractual liability				892,000
Manufacturing rights option
Collaborative Arrangements and Non-collaborative Arrangement Transactions
Contractual liability				4,100,000
License Agreement with SIBV
Collaborative Arrangements and Non-collaborative Arrangement Transactions
Upfront payment received			$ 5,000,000
CFF
Collaborative Arrangements and Non-collaborative Arrangement Transactions
Revenue from Contract with Customer, Excluding Assessed Tax					$ 1,000,000
Deferred revenue				476,000
License Agreement with SAMR
Collaborative Arrangements and Non-collaborative Arrangement Transactions
Buy back manufacturing rights		$ 5,000,000
Upfront payment received		15,000,000	$ 5,000,000
Maximum additional payments entitled		$ 42,500,000		42,500,000
License Agreement and Option Agreement
Collaborative Arrangements and Non-collaborative Arrangement Transactions
Fair value of net proceeds						5,000,000
Fair value of gross proceeds						5,400,000
Contractual liability				19,600,000		19,600,000
Deferred revenue based on upfront payments				15,000,000		15,000,000
Deferred revenue from equity allocation				4,600,000		4,600,000
Issuance costs from equity allocation						$ 441,000
Kermode Licensing and Product Discovery Agreement
Collaborative Arrangements and Non-collaborative Arrangement Transactions
Maximum additional payments entitled				250,000
Gross Transaction Price				750,000
Revenue recognized				465,000
Deferred revenue				285,000
Kermode Licensing and Product Discovery Agreement | Upfront payment
Collaborative Arrangements and Non-collaborative Arrangement Transactions
Maximum additional payments entitled				250,000
Kermode Licensing and Product Discovery Agreement | License revenue | Upfront payment
Collaborative Arrangements and Non-collaborative Arrangement Transactions
Upfront payment received	$ 500,000
Kermode Licensing and Product Discovery Agreement | Research and Development Option
Collaborative Arrangements and Non-collaborative Arrangement Transactions
Maximum additional payments entitled				250,000
Serum International B.V. ("SIBV")
Collaborative Arrangements and Non-collaborative Arrangement Transactions
Issuance of common stock (in shares)			801,820
Issuance of common stock			$ 10,000,000
Serum International B.V. ("SIBV") | License Agreement with SIBV
Collaborative Arrangements and Non-collaborative Arrangement Transactions
Deferred revenue from equity allocation				$ 4,600,000
Restricted common stock | Serum International B.V. ("SIBV")
Collaborative Arrangements and Non-collaborative Arrangement Transactions
Issuance of common stock (in shares)			801,820
Issuance of common stock			$ 10,000,000

Notes Payable - Note Purchase A

Notes Payable - Note Purchase Agreement and Insurance Financing (Details) - USD ($)	Nov. 23, 2021	Dec. 31, 2021	Dec. 31, 2020	May 01, 2020
Debt Instrument [Line Items]
Note payable, non-current		$ 5,282,000	$ 276,000
Total premiums, taxes and fees financed		$ 1,645,000
Annual interest rate		3.67%
Note payable current		$ 696,000	$ 439,000
If prepayment occurs on or before three-month anniversary of the Issuance Date
Debt Instrument [Line Items]
Percent of prepayment	105.00%
Note Purchase Agreement
Debt Instrument [Line Items]
Original issue discount	$ 250,000
Interest rate (as percent)	6.00%
Maximum Monthly Redemption Amount	$ 450,000
Interest expense related to fees		250,000
Note payable, non-current		5,282,000
Total initial fair value at issuance		5,250,000
Increase in remeasurement of fair value recognized expense		33,000
Note Purchase Agreement | First exercise
Debt Instrument [Line Items]
Increase in unpaid interest	0.50%
Note Purchase Agreement | Second exercise
Debt Instrument [Line Items]
Increase in unpaid interest	1.00%
Note Purchase Agreement | Third exercise
Debt Instrument [Line Items]
Increase in unpaid interest	1.50%
Note Purchase Agreement | If prepayment occurs after three-month anniversary of Issuance Date but on or before six-month anniversary of the Issuance Date
Debt Instrument [Line Items]
Percent of prepayment	107.50%
Note Purchase Agreement | If prepayment occurs after six-month anniversary of Issuance Date
Debt Instrument [Line Items]
Percent of prepayment	110.00%
Note Purchase Agreement | Lender | Secured Promissory Note [Member]
Debt Instrument [Line Items]
Aggregate loan amount granted	$ 5,250,000
Paycheck Protection Program (the "PPP")
Debt Instrument [Line Items]
Aggregate loan amount granted		$ 715,000		$ 715,000

Notes Payable - Paycheck Protec

Notes Payable - Paycheck Protection Program Loan (Details) - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	May 01, 2020
Debt Instrument [Line Items]
Gain on extinguishment of debt	$ 722,000
Liabilities	39,906,000	$ 23,798,000
Paycheck Protection Program (the "PPP")
Debt Instrument [Line Items]
Aggregate loan amount granted	715,000		$ 715,000
Gain on extinguishment of debt	722,000
Accrued interest	7,000
Liabilities	$ 0

Warrants - Common Stock Warrant

Warrants - Common Stock Warrant Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Warrants
Share-based Compensation	$ 2,251	$ 2,128

Warrants - Warrants Issued in R

Warrants - Warrants Issued in Registered Direct Offering (Details)	1 Months Ended				12 Months Ended
	Dec. 31, 2021USD ($)shares	Aug. 31, 2021USD ($)$ / sharesshares	Mar. 31, 2021USD ($)shares	Oct. 31, 2020USD ($)D$ / sharesshares	Dec. 31, 2021shares	Dec. 31, 2020USD ($)shares
Class of Warrant or Right [Line Items]
Common Stock, Shares, Issued | shares	17,701,592				17,701,592	10,065,727
Gross proceeds from issuance of common stock			$ 5,000,000
Dividend yield (in percent)					0.00%
Relative fair value of the Warrant Shares						$ 2,005,000
Pre-Funded Warrants
Class of Warrant or Right [Line Items]
Issuance of common stock upon exercise of warrants (in shares) | shares	3,647,556
Proceeds from warant exercises	$ 4,000
Options
Class of Warrant or Right [Line Items]
Vesting period (in years)					4 years
Securities Purchase Agreement Member
Class of Warrant or Right [Line Items]
Issuance of common stock (in shares) | shares		1,300,000	1,037,405
Common Stock, Shares, Issued | shares				1,134,470
Warrant to purchase number of Common Stock (in shares) | shares				567,234
Combined purchase price for each Common Stock and accompanying Warrant | $ / shares		$ 5.053		$ 7.4925
Combined purchase price for each Pre-Funded Warrant and accompanying Warrant | $ / shares		5.052
Difference between Combined purchase price for each share of Common Stock and accompanying Warrant to Pre-Funded Warrant and accompanying Warrant | $ / shares		$ 0.001
Gross proceeds from issuance of common stock		$ 25,000,000	$ 7,000,000	$ 8,500,000
Proceeds from issuance of common stock, net		$ 22,600,000	$ 6,400,000	7,800,000
Relative fair value of the Common Stock Shares				5,800,000
Relative fair value of the Warrant Shares				$ 2,000,000
Securities Purchase Agreement Member | Series A Warrant
Class of Warrant or Right [Line Items]
Exercise price of warrants (in dollars per share) | $ / shares				$ 7.43
Exercisable term of warrants				6 months
Expiration term of warrants				3 years 6 months
Securities Purchase Agreement Member | Series B Warrant
Class of Warrant or Right [Line Items]
Exercise price of warrants (in dollars per share) | $ / shares				$ 9
Exercisable term of warrants				6 months
Expiration term of warrants				3 years 6 months
Redemption price of warrants (in dollars per share) | $ / shares				$ 0.01
Redeemable of warrant, minimum price of the Company's common stock for five consecutive trading days (in dollars per share) | $ / shares				$ 9
Redeemable of warrant, number of consecutive trading days upon the price of the Company's common stock closing at $9.00 or more | D				5
Securities Purchase Agreement Member | Pre-Funded Warrants
Class of Warrant or Right [Line Items]
Warrant to purchase number of Common Stock (in shares) | shares		3,647,556
Combined purchase price for each Pre-Funded Warrant and accompanying Warrant | $ / shares		$ 5.052
Exercise price of warrants (in dollars per share) | $ / shares		$ 0.001
Number of shares issuable per warrant | shares		1
Percentage of ownership on issue of outstanding common stock for warrants		4.99%
Percentage on issue of outstanding common stock for warrants		9.99
Securities Purchase Agreement Member | Warrants Member
Class of Warrant or Right [Line Items]
Warrant to purchase number of Common Stock (in shares) | shares		2,473,778
Exercise price of warrants (in dollars per share) | $ / shares		$ 5
Number of shares issuable per warrant | shares		1
Percentage of ownership on issue of outstanding common stock for warrants		4.99%
Percentage on issue of outstanding common stock for warrants		9.99
Expected term (in years)		7 years		4 years
Expected volatility		97.00%
Risk-free interest-rate		0.96%
Dividend yield (in percent)		0.00%
Securities Purchase Agreement Member | Common Stock Shares and the Warrants Shares
Class of Warrant or Right [Line Items]
Proceeds from issuance of common stock, net		$ 22,600,000
Relative fair value of the Common Stock Shares		4,400,000
Relative fair value of the prefunded warrants		12,200,000
Relative fair value of the Warrant Shares		$ 6,000,000
Warrants Member | Securities Purchase Agreement Member
Class of Warrant or Right [Line Items]
Expected volatility				104.00%
Risk-free interest-rate				0.25%
Dividend yield (in percent)				0.00%

Common Stock (Details)

Common Stock (Details)	Dec. 31, 2021shares
Common Stock for future issuance
Total common stock for future issuance	5,726,463
Options
Common Stock for future issuance
Total common stock for future issuance	1,905,459
Future Options
Common Stock for future issuance
Total common stock for future issuance	228,099
Warrants Member
Common Stock for future issuance
Total common stock for future issuance	3,592,905

Common Stock - March 2021 Secur

Common Stock - March 2021 Securities Purchase Agreement (Details) - USD ($)	Jan. 19, 2022	Aug. 31, 2021	Mar. 31, 2021	Oct. 31, 2020	Sep. 30, 2019	Jul. 31, 2019	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Jan. 10, 2022	May 14, 2020
Common Stock for future issuance
Common stock, par value per share (in dollars per share)							$ 0.0001
Aggregate gross proceeds from issuance of common stock			$ 5,000,000
License Agreement and Option Agreement
Common Stock for future issuance
Fair value of gross proceeds									$ 5,400,000
Options
Common Stock for future issuance
Expected term (in years)							6 years	6 years
Serum International B.V. ("SIBV")
Common Stock for future issuance
Issuance of common stock (in shares)						801,820
Serum International B.V. ("SIBV") | Restricted common stock
Common Stock for future issuance
Issuance of common stock (in shares)						801,820
ATM offering Agreement
Common Stock for future issuance
Issuance of common stock (in shares)							7,883
Aggregate gross proceeds from issuance of common stock							$ 64,000
Proceeds from issuance of common stock, net							$ 62,000
Maximum aggregate offering price					$ 25,000,000						$ 22,000,000
Maximum commission (as a percent)					3.00%
Maximum value of shares under prospectus supplement covering					$ 100,000,000
ATM offering Agreement | Cantor Fitzgerald & Co | Subsequent event
Common Stock for future issuance
Maximum aggregate offering price										$ 25,000,000
ATM offering Agreement | Virtu Americas LLC. | Subsequent event
Common Stock for future issuance
Common stock, par value per share (in dollars per share)	$ 0.0001
Maximum aggregate offering price	$ 25,000,000
Maximum commission (as a percent)	3.00%
Securities Purchase Agreement Member
Common Stock for future issuance
Issuance of common stock (in shares)		1,300,000	1,037,405
Common stock, par value per share (in dollars per share)			$ 0.0001	$ 0.0001
Aggregate gross proceeds from issuance of common stock		$ 25,000,000	$ 7,000,000	$ 8,500,000
Proceeds from issuance of common stock, net		$ 22,600,000	$ 6,400,000	$ 7,800,000
Dividend shares to its common stock stockholders		634,600	124,789
Fair value of dividend shares issued to common stockholders		$ 3,100,000	$ 986,000
Securities Purchase Agreement Member | Arcadia Securities, LLC
Common Stock for future issuance
Fee, percentage of aggregate purchase price				3.50%
Securities Purchase Agreement Member | Cantor Fitzgerald & Co
Common Stock for future issuance
Fee, percentage of aggregate purchase price				3.50%

Common Stock - MedImmune Limite

Common Stock - MedImmune Limited License Agreement (Details) - USD ($) $ in Thousands	Jul. 12, 2021	Dec. 31, 2021	Dec. 31, 2020
Common Stock for future issuance
Research and development		$ 36,936	$ 16,956
MedImmune Limited License Agreement
Common Stock for future issuance
Research and development		$ 6,500
MedImmune Limited License Agreement | Common Stock Member
Common Stock for future issuance
Stock issued shares	884,956
Stock issued value	$ 6,500

Common Stock - August 2021 Secu

Common Stock - August 2021 Securities Purchase Agreement (Details) - USD ($)	1 Months Ended
	Aug. 31, 2021	Mar. 31, 2021	Oct. 31, 2020	Dec. 31, 2021	Dec. 31, 2020
Common Stock for future issuance
Common stock, par value per share (in dollars per share)				$ 0.0001
Common Stock, Shares, Issued				17,701,592	10,065,727
Gross proceeds from issuance of common stock		$ 5,000,000
Securities Purchase Agreement Member
Common Stock for future issuance
Issuance of common stock (in shares)	1,300,000	1,037,405
Common stock, par value per share (in dollars per share)		$ 0.0001	$ 0.0001
Common Stock, Shares, Issued			1,134,470
Warrant to purchase number of Common Stock (in shares)			567,234
Combined purchase price for each Common Stock and accompanying Warrant	$ 5.053		$ 7.4925
Combined purchase price for each Pre-Funded Warrant and accompanying Warrant	5.052
Difference between Combined purchase price for each share of Common Stock and accompanying Warrant to Pre-Funded Warrant and accompanying Warrant	$ 0.001
Gross proceeds from issuance of common stock	$ 25,000,000	$ 7,000,000	$ 8,500,000
Proceeds from issuance of common stock, net	$ 22,600,000	$ 6,400,000	$ 7,800,000
Dividend shares to its common stock stockholders	634,600	124,789
Fair value of dividend shares issued to common stockholders	$ 3,100,000	$ 986,000
Securities Purchase Agreement Member | Pre-Funded Warrants
Common Stock for future issuance
Warrant to purchase number of Common Stock (in shares)	3,647,556
Combined purchase price for each Pre-Funded Warrant and accompanying Warrant	$ 5.052
Securities Purchase Agreement Member | Warrants Member
Common Stock for future issuance
Warrant to purchase number of Common Stock (in shares)	2,473,778
Securities Purchase Agreement Member | Maximum
Common Stock for future issuance
Warrant to purchase number of Common Stock (in shares)			567,234
Securities Purchase Agreement
Common Stock for future issuance
Combined purchase price for each Common Stock and accompanying Warrant	$ 5.053

Stock-Based Compensation - Stat

Stock-Based Compensation - Status of options (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Number of options
Options outstanding	1,905,459	1,550,956
Options vested and exercisable	1,287,094
Weighted average exercise price
Options outstanding (in dollars per share)	$ 8.47	$ 9.43
Options vested and exercisable (in dollars per share)	$ 9.70
Weighted average contractual term and aggregate intrinsic value
Options outstanding (in years)	6 years 11 months 19 days
Options vested and exercisable (in years)	6 years 1 month 9 days
Options outstanding (in dollars)	$ 13

Stock-Based Compensation - Stoc

Stock-Based Compensation - Stock option activity (Details) - $ / shares	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Shares Available for Grant
Beginning of the period (in shares)	584,161
Options granted (in shares)	(493,440)	(207,155)
Options exercised (in shares)	1,559	4,913
Options cancelled (in shares)	137,378
End of the period (in shares)	228,099	584,161
Number of options
Number of Shares, beginning of the period (in shares)	1,550,956
Number of Shares, Stock option granted	493,440	207,155
Number of Shares, Options exercised (in shares)	(1,559)
Number of Shares, Options cancelled (in shares)	(137,378)
Number of Shares, end of the period (in shares)	1,905,459	1,550,956
Weighted average exercise price
Weighted-Average Exercise Price, beginning of the period (in dollars per share)	$ 9.43
Weighted-Average Exercise Price, Options granted (in dollars per share)	5.04
Weighted-Average Exercise Price, Options exercised (in dollars per share)	2.89
Weighted-Average Exercise Price, Options cancelled (in dollars per share)	7.05
Weighted-Average Exercise Price, end of the period (in dollars per share)	$ 8.47	$ 9.43

Stock-Based Compensation - Assu

Stock-Based Compensation - Assumptions (Details) - shares	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Fair value of the options granted, estimated using assumptions
Dividend yield (in percent)	0.00%
Granted (in shares)	493,440	207,155
Options
Fair value of the options granted, estimated using assumptions
Expected term (in years)	6 years	6 years
Expected volatility, minimum	99.00%	84.00%
Expected volatility, maximum	100.00%	100.00%
Risk-free interest-rate, minimum	0.80%	0.38%
Risk-free interest-rate, maximum	1.17%	1.73%
Dividend yield (in percent)	0.00%	0.00%

Stock-Based Compensation - Expe

Stock-Based Compensation - Expenses (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Stock-Based Compensation
Total stock-based compensation expense	$ 2,251	$ 2,128
Research and development
Stock-Based Compensation
Total stock-based compensation expense	687	590
General and administrative
Stock-Based Compensation
Total stock-based compensation expense	$ 1,564	$ 1,538

Stock-Based Compensation - Addi

Stock-Based Compensation - Additional information (Details) - USD ($)	1 Months Ended		12 Months Ended
	Jun. 30, 2020	May 31, 2014	Dec. 31, 2021	Dec. 31, 2020
Stock-Based Compensation
Reserved for issuance (in shares)	2,183,692	233,722
Voting rights of all classes of stock (in percent)		10.00%
Exercise price for incentive stock options to the percentage of fair market value		110.00%
Number of Shares, Stock option granted			493,440	207,155
Weighted-average grant date fair value (in dollars per share)			$ 3.68	$ 4.72
Options outstanding (in dollars)			$ 13,000
Aggregate intrinsic value			$ 5,000	$ 17,000
Options exercised (in shares)			1,559	4,913
Amendment To The 2014 Plan
Stock-Based Compensation
Annual increase in the number of shares to the shares of common stock	400,000
Evergreen Provision
Stock-Based Compensation
Annual increase in the number of shares to the shares of common stock	162,736
Options
Stock-Based Compensation
Expiration period (in years)		10 years
Unrecognized stock-based compensation expenses related to stock options			$ 2,500,000
Unrecognized stock-based compensation expenses expected to be recognized			2 years 5 months 1 day

Income Taxes - Effective income

Income Taxes - Effective income tax rate reconciliation, Amount (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Income tax expense benefit reconciliation
Federal income tax at statutory rate	$ (8,860)	$ (4,690)
State income tax, net of federal benefit	(759)	(36)
Foreign tax differential	1,345	1,906
State Rate change	(346)	287
Permanent differences	66	1,088
Tax credits generated in current year	(894)	(649)
Uncertain tax position change	224	162
Other	28	(92)
Valuation allowance change	$ 9,196	$ 2,024

Income Taxes - Components of de

Income Taxes - Components of deferred tax assets (liabilities) (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Components of deferred tax assets
Net operating loss carryforwards	$ 22,603	$ 14,793
Accruals and reserves	175	39
Stock based compensations	1,607	1,153
Research and development credits	2,692	2,021
Deferred revenue	1,454	1,338
Depreciation and amortization		(9)
Total	28,531	19,335
Valuation allowance	$ (28,531)	$ (19,335)

Income Taxes - Uncertain tax po

Income Taxes - Uncertain tax positions (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Income Taxes
Balance at the beginning of the year	$ 705	$ 534
Increase/(decrease) based on current year tax positions	235	171
Balance at the end of the year	$ 940	$ 705

Income Taxes - Tax Cuts and Job

Income Taxes - Tax Cuts and Jobs Act of 2017 (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Income Taxes
Net change in the valuation allowance	$ 9.2	$ 2

Income Taxes - Net operating lo

Income Taxes - Net operating loss carryforwards and Tax credit carryforwards (Details)	Dec. 31, 2021USD ($)
Income Taxes
Net operating loss carryforwards	$ 69,200,000
Federal
Income Taxes
Net operating loss carryforwards	19,500,000
Research credit carryforwards | Federal
Income Taxes
Tax credit carryforwards	2,900,000
Research credit carryforwards | State
Income Taxes
Tax credit carryforwards	814,000
After tax year 2017 | Federal
Income Taxes
Net operating loss carryforwards	$ 66,500,000

Related Parties (Details)

Related Parties (Details) - USD ($)	1 Months Ended	12 Months Ended
	Jul. 31, 2019	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Related parties
Issuance of common stock		$ 29,011,000
Deferred revenue		20,838,000	$ 18,748,000
Deferred revenue, noncurrent		913,000	854,000
Capitalized contract cost, Current		1,967,000	1,973,000
Capitalized contract cost, Noncurrent		$ 96,000	90,000
Common Stock Member
Related parties
Issuance of common stock (in shares)		2,337,405
Issuance of common stock		$ 0
License revenue
Related parties
Revenue		0	0
Deferred revenue, noncurrent		913,000	854,000
Capitalized contract costs			2,100,000	$ 2,100,000
Capitalized contract cost, Current		2,000,000	2,000,000
Capitalized contract cost, Noncurrent		96,000	90,000
Shenzhen Hepalink Pharmaceutical Group Co., Ltd.("Hepalink")
Related parties
Reduction to operating expenses on reimbursed to JV entity		(75,000)	(188,000,000,000)
Serum International B.V. ("SIBV") | License revenue
Related parties
Revenue		0	0
Deferred revenue		18,700,000	18,700,000
Deferred revenue, noncurrent		913,000	854,000,000,000
Capitalized contract costs		2,100,000
Capitalized contract cost, Current		2,000,000	2,000,000
Capitalized contract cost, Noncurrent		96,000	90,000
Serum International B.V. ("SIBV")
Related parties
Issuance of common stock (in shares)	801,820
Issuance of common stock	$ 10,000,000
Other receivables | Shenzhen Hepalink Pharmaceutical Group Co., Ltd.("Hepalink")
Related parties
Outstanding receivable for reimbursable expenses		$ 43,000	$ 3,000

Commitments and Contingencies -

Commitments and Contingencies - Facility lease - (Details)	Oct. 31, 2020USD ($)ft²
Commitments and Contingencies
Area of Land | ft²	15,129
Leasehold improvements may be reimbursed	$ 378,000
Initial Term	5 years
Renewal Term	3 years
Amount of letter of credit as security deposit to the Landlord	$ 500,000

Commitments and Contingencies_2

Commitments and Contingencies - Future minimum lease payments (Details) $ in Thousands	Dec. 31, 2021USD ($)
Commitments and Contingencies
2022	$ 610
2023	628
2024	646
2025	666
2026	57
Total	$ 2,607

Commitments and Contingencies_3

Commitments and Contingencies - Leases and Contingencies (Details) - USD ($)	1 Months Ended		12 Months Ended		24 Months Ended
	Sep. 30, 2021	Feb. 29, 2020	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2021
Loss Contingencies [Line Items]
Rent expense			$ 630,000	$ 529,000
Compensatory damages sought		$ 277,000
Liability Recognized					$ 0
Cantor Fitzgerald & Co
Loss Contingencies [Line Items]
Compensatory damages sought	$ 1,800,000

Commitments and Contingencies_4

Commitments and Contingencies - Cystic Fibrosis Foundation Agreement and Joint Venture Agreement (Details) - CF Foundation $ in Thousands	1 Months Ended	12 Months Ended
	Dec. 31, 2016USD ($)installmentitem	Dec. 31, 2016USD ($)	Dec. 31, 2021USD ($)	Dec. 31, 2020USD ($)	Nov. 30, 2018USD ($)
Cystic Fibrosis Foundation Agreement
Amount of award received for advance research on potential drugs	$ 2,900	$ 2,900			$ 7,500
Excess amount recorded as liability			$ 0	$ 0
Period for payment of annual installments		90 days
Maximum percentage of awarded amount of net sales	15.00%
Number of multiplication on awarded amount payable if change of control prior to completion of the first commercial sale | item	9
Payment of amount received in connection with Disposition Transaction (as a percent)	15.00%
Maximum
Cystic Fibrosis Foundation Agreement
Number of annual installments for repayment of award | installment	5

Commitments and Contingencies_5

Commitments and Contingencies - Kermode Agreement (Details)	1 Months Ended
	Feb. 28, 2021
Kermode Agreement
Long-term Purchase Commitment [Line Items]
Royalty, percent of net sales	5.00%

Commitments and Contingencies_6

Commitments and Contingencies - Medimmune Limited License Agreement (Details) - MedImmune Limited License Agreement	1 Months Ended
	Jul. 31, 2021USD ($)
Other Commitments [Line Items]
Total aggregate payments upon achievement of certain regulatory approvals	$ 30,000,000
Total aggregate payments upon achievement of sales related milestone	85,000,000
Total aggregate payments upon achievement of development related milestone	$ 0
Minimum
Other Commitments [Line Items]
Royalty, percent of net sales	12.50%
Maximum
Other Commitments [Line Items]
Royalty, percent of net sales	15.00%

Subsequent Events (Details)

Subsequent Events (Details) - USD ($)	Jan. 19, 2022	Sep. 30, 2019	Feb. 21, 2022	Jan. 10, 2022	Dec. 31, 2021	Nov. 23, 2021	May 14, 2020
Subsequent Events
Common stock, par value per share (in dollars per share)					$ 0.0001
ATM offering Agreement
Subsequent Events
Maximum Aggregate Offering Price		$ 25,000,000					$ 22,000,000
Maximum commission (as a percent)		3.00%
Subsequent event | Cantor Fitzgerald & Co | ATM offering Agreement
Subsequent Events
Maximum Aggregate Offering Price				$ 25,000,000
Subsequent event | Virtu Americas LLC. | ATM offering Agreement
Subsequent Events
Maximum Aggregate Offering Price	$ 25,000,000
Maximum commission (as a percent)	3.00%
Common stock, par value per share (in dollars per share)	$ 0.0001
Note Purchase Agreement | Secured Promissory Note [Member] | Streeterville Capital, LLC
Subsequent Events
Aggregate principal amount						$ 5,250,000
Note Purchase Agreement | Subsequent event | Secured Promissory Note [Member] | Streeterville Capital, LLC
Subsequent Events
Aggregate principal amount			$ 5,250,000