Aridis Pharmaceuticals (ARDS) 10-Q 12 Aug 21 2021 Q2 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	6 Months Ended
	Jun. 30, 2021	Jul. 31, 2021
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Jun. 30, 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
Trading Symbol	ARDS
Security Exchange Name	NASDAQ
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 Common Stock, Shares Outstanding		12,119,436
Entity Central Index Key	0001614067
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q2
Amendment Flag	false

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 3,592	$ 8,232
Other receivables	137	368
Contract costs	1,979	1,973
Prepaid expenses	3,229	2,182
Total current assets	8,937	12,755
Property and equipment, net	1,367	1,258
Intangible assets, net	24	27
Restricted cash	500	500
Contract costs, non-current	84	90
Other assets	475	487
Total assets	11,387	15,117
Current liabilities:
Accounts payable	2,464	1,886
Accrued liabilities	1,851	1,330
Deferred revenue	19,273	18,748
Note payable	0	439
Other liabilities	92	37
Total current liabilities	23,680	22,440
Deferred revenue, non-current	796	854
Note payable, non-current	0	276
Other liabilities	398	228
Total liabilities	24,874	23,798
Commitments and contingencies (Note 11)
Stockholders' deficit:
Preferred stock (par value $0.0001; 60,000,000 shares authorized; zero shares issued and outstanding as of June 30, 2021 and December 31, 2020)
Common stock (par value $0.0001; 100,000,000 shares authorized; 11,234,480 and 10,065,727 shares issued and outstanding as of June 30, 2021 and December 31, 2020, respectively)	1	1
Additional paid-in capital	121,995	114,420
Accumulated deficit	(135,483)	(123,102)
Total stockholders' deficit	(13,487)	(8,681)
Total liabilities and stockholders' deficit	$ 11,387	$ 15,117

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Parenthetical) - $ / shares	Jun. 30, 2021	Dec. 31, 2020
Condensed Consolidated Balance Sheets
Preferred stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Preferred stock, shares authorized (in shares)	60,000,000	60,000,000
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Common stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Common stock, shares authorized (in shares)	100,000,000	100,000,000
Common stock, shares issued (in shares)	11,234,480	10,065,727
Common stock, shares outstanding (in shares)	11,234,480	10,065,727

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Revenue:
Revenue	$ 33	$ 1,000	$ 33	$ 1,000
Operating expenses:
Research and development	4,573	3,647	9,528	8,564
General and administrative	1,694	1,583	3,638	3,222
Total operating expenses	6,267	5,230	13,166	11,786
Loss from operations	(6,234)	(4,230)	(13,133)	(10,786)
Other income (expense):
Interest income, net		10	1	71
Other income	22		29
Gain on extinguishment of Paycheck Protection Program loan	722		722
Share of loss from equity method investment				(9)
Net loss	(5,490)	(4,220)	(12,381)	(10,724)
Deemed dividends			(986)
Net loss available to common stockholders	$ (5,490)	$ (4,220)	$ (13,367)	$ (10,724)
Weighted-average common shares outstanding used in computing net loss per share available to common stockholders, basic and diluted	11,233,572	8,923,374	10,734,580	8,921,383
Net loss per share to common stockholders, basic and diluted	$ (0.49)	$ (0.47)	$ (1.25)	$ (1.20)
Grant revenue
Revenue:
Revenue		$ 1,000		$ 1,000
License revenue
Revenue:
Revenue	$ 33		$ 33

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Changes in Stockholders' Deficit - USD ($)	Preferred Stock	Common Stock	Additional Paid-In Capital	Accumulated Deficit	Total
Balances at the beginning of the period at Dec. 31, 2019		$ 1,000	$ 104,404,000	$ (100,769,000)	$ 3,636,000
Balances at the beginning of the period (in shares) at Dec. 31, 2019		8,918,461
Changes in equity
Exercise of stock options			14,000		14,000
Exercise of stock options (in shares)		4,913
Stock-based compensation	$ 0	$ 0	1,000,000	0	1,000,000
Net loss				(10,724,000)	(10,724,000)
Balances at the end of the period at Jun. 30, 2020	$ 0	$ 1,000	105,418,000	(111,493,000)	(6,074,000)
Balances at the end of the period (shares) at Jun. 30, 2020	0	8,923,374
Balances at the beginning of the period at Mar. 31, 2020	$ 0	$ 1,000	104,895,000	(107,273,000)	(2,377,000)
Balances at the beginning of the period (in shares) at Mar. 31, 2020	0	8,923,374
Changes in equity
Stock-based compensation	$ 0	$ 0	523,000	0	523,000
Net loss				(4,220,000)	(4,220,000)
Balances at the end of the period at Jun. 30, 2020	$ 0	$ 1,000	105,418,000	(111,493,000)	(6,074,000)
Balances at the end of the period (shares) at Jun. 30, 2020	0	8,923,374
Balances at the beginning of the period at Dec. 31, 2020		$ 1,000	114,420,000	(123,102,000)	(8,681,000)
Balances at the beginning of the period (in shares) at Dec. 31, 2020		10,065,727
Balances at the end of the period at Mar. 31, 2021	$ 0	$ 1,000	121,437,000	(129,993,000)	(8,555,000)
Balances at the end of the period (shares) at Mar. 31, 2021	0	11,232,921
Balances at the beginning of the period at Dec. 31, 2020		$ 1,000	114,420,000	(123,102,000)	(8,681,000)
Balances at the beginning of the period (in shares) at Dec. 31, 2020		10,065,727
Changes in equity
Issuance of common stock in registered direct offering, net of issuance costs			6,417,000		6,417,000
Issuance of common stock in registered direct offering, net of issuance costs (in shares)		1,037,405
Deemed dividends		124,789
Issuance of common stock for consulting services			33,000		33,000
Issuance of common stock for consulting services (in shares)		5,000
Exercise of stock options			5,000		$ 5,000
Exercise of stock options (in shares)		1,559			1,559
Stock-based compensation	$ 0	$ 0	1,120,000	0	$ 1,120,000
Net loss				(12,381,000)	(12,381,000)
Balances at the end of the period at Jun. 30, 2021	$ 0	$ 1,000	121,995,000	(135,483,000)	(13,487,000)
Balances at the end of the period (shares) at Jun. 30, 2021	0	11,234,480
Balances at the beginning of the period at Mar. 31, 2021	$ 0	$ 1,000	121,437,000	(129,993,000)	(8,555,000)
Balances at the beginning of the period (in shares) at Mar. 31, 2021	0	11,232,921
Changes in equity
Exercise of stock options			5,000		5,000
Exercise of stock options (in shares)		1,559
Stock-based compensation	$ 0	$ 0	553,000	0	553,000
Net loss				(5,490,000)	(5,490,000)
Balances at the end of the period at Jun. 30, 2021	$ 0	$ 1,000	$ 121,995,000	$ (135,483,000)	$ (13,487,000)
Balances at the end of the period (shares) at Jun. 30, 2021	0	11,234,480

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020
Cash flows from operating activities:
Net loss	$ (12,381)	$ (10,724)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	184	167
Stock-based compensation expense	1,120	1,000
Issuance of common stock in exchange for consulting services	33
Gain on extinguishment of Paycheck Protection Program loan	(722)
Share of loss from equity method investment		9
Changes in operating assets and liabilities:
Accounts receivable		(1,000)
Other receivables	421	61
Prepaid expenses	(1,047)	1,548
Contract costs		(488)
Other assets		(15)
Accounts payable	698	(44)
Accrued liabilities and other	613	(311)
Deferred revenue	467
Net cash used in operating activities	(10,614)	(9,797)
Cash flows from investing activities:
Purchase of property and equipment	(459)	(17)
Net cash used in investing activities	(459)	(17)
Cash flows from financing activities:
Proceeds from issuance of common stock, net	6,428
Proceeds from Paycheck Protection Program loan		715
Proceeds from stock option exercises	5	14
Net cash provided by financing activities	6,433	729
Net decrease in cash, cash equivalents and restricted cash	(4,640)	(9,085)
Cash, cash equivalents and restricted cash at:
Beginning of period	8,732	20,897
End of period	4,092	11,812
Supplemental cash flow disclosures:
Cash paid for taxes	2	$ 2
Supplemental noncash investing and financing activities:
Property and equipment additions	$ 61

Description of Business and Bas

Description of Business and Basis of Presentation	6 Months Ended
	Jun. 30, 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 condensed consolidated financial statements (unaudited) include the accounts of the Company and our wholly-owned subsidiaries and have been prepared in accordance with U.S. generally accepted accounting principles (“GAAP”) for interim financial information and in accordance with the instructions to Form 10-Q and Rule 10-01 of Regulation S-X. Accordingly, they do not include all of the information and footnotes required by GAAP for complete financial statements. The condensed consolidated financial statements (unaudited) have been prepared on the same basis as the annual consolidated financial statements. In the opinion of management, the accompanying condensed consolidated financial statements (unaudited) reflect all adjustments (consisting only of normal recurring adjustments) considered necessary for a fair presentation. These condensed consolidated financial statements (unaudited) should be read in conjunction with the audited consolidated financial statements and notes thereto for the preceding fiscal year included in the Company’s Annual Report on Form 10-K filed with the United States Securities and Exchange Commission (“SEC”) on March 30, 2021. The condensed consolidated financial statements (unaudited) 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. The on-going COVID-19 pandemic has caused an impact on patient enrollment globally and the rate of clinical site activations, and depending on the rate of resolution of the on-going COVID-19 pandemic, it could further delay the progress of the Company’s clinical trials. At this point, however, the extent to which COVID-19 may impact the Company’s financial condition or results of operations is uncertain. Going Concern The Company has had recurring losses from operations since inception and negative cash flows from operating activities during the three and six months ended June 30, 2021 and the year ended December 31, 2020. Management expects to incur additional operating losses and negative cash flows from operations in the foreseeable future as the Company continues its product development programs. The Company’s research and development expenses and resulting cash burn during the six months ended June 30, 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 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 on, by causing disruptions in the supply of 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. 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 losses from operations 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 will not be sufficient to fund its planned expenditures and meet the Company’s obligations for at least the one-year period following its condensed consolidated financial statement issuance date. The accompanying condensed 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 condensed consolidated financial statements are issued. These condensed 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	6 Months Ended
	Jun. 30, 2021
Summary of Significant Accounting Policies
Summary of Significant Accounting Policies	2. Summary of Significant Accounting Policies Use of Estimates The preparation of the condensed 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 condensed 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 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 three and six months ended June 30, 2021, one customer accounted for 100% of total revenue, and for the three and six months ended June 30, 2020, another customer accounted for 100% of total revenue. Both customers are located in the United States. As of June 30, 2021 and December 31, 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 and cash equivalents consist primarily of checking account and money market fund account balances. Restricted cash consists of deposits for a letter of credit that the Company has provided to secure its obligations under its facility lease. The following table provides a reconciliation of cash, cash equivalents and restricted cash within the condensed consolidated balance sheets which, in aggregate, represent the amount reported in the condensed consolidated statements of cash flows (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ June 30, December 31, ​ ​ 2021 ​ 2020 Cash and cash equivalents ​ $ 3,592 ​ $ 8,232 Restricted cash ​ 500 ​ 500 Total cash, cash equivalents and restricted cash ​ $ 4,092 ​ $ 8,732 ​ 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 June 30, 2021 and December 31, 2020, there were no accounts receivable and allowances for doubtful accounts. 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 June 30, 2021 and December 31, 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 condensed consolidated balance sheets. Amounts recognized as revenue, but not yet received or invoiced are recorded within other receivables on the condensed consolidated balance sheet. Amounts are recorded as other receivables on the condensed 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 condensed 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 three and six months ended June 30, 2021 and 2020, there was no amortization of the contract assets and there have been no impairments as of June 30, 2021. 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 condensed consolidated balance sheets. The Company has estimated the classification between current and noncurrent deferred revenue related to the respective license agreement within its condensed consolidated balance sheets at June 30, 2021 and December 31, 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, the Company issued 124,789 dividend shares to certain common stockholders with a fair value of approximately $986,000 (see Note 8) which is included in the net loss available to common stockholders’ for the six months ended June 30, 2021 in the below table. For the three and six months ended June 30, 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 table presents the computation of the basic and diluted net loss per share to common stockholders (in thousands, except share and per share data): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended Six Months Ended ​ ​ June 30, June 30, ​ 2021 2020 2021 2020 Numerator: (unaudited) (unaudited) ​ (unaudited) (unaudited) Net loss available to common stockholders (basic and diluted) ​ $ (5,490) ​ $ (4,220) ​ $ (13,367) ​ $ (10,724) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Denominator: ​ ​ ​ ​ Weighted-average common shares outstanding used in computing net loss per share available to common stockholders, basic and diluted ​ 11,233,572 ​ 8,923,374 ​ 10,734,580 ​ 8,921,383 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net loss per share to common stockholders, basic and diluted ​ $ (0.49) ​ $ (0.47) ​ $ (1.25) ​ $ (1.20) ​ 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: ​ ​ ​ ​ ​ ​ ​ ​ Six Months Ended ​ ​ June 30, ​ 2021 2020 ​ ​ (unaudited) ​ (unaudited) Stock options to purchase common stock 1,746,090 1,517,301 Common stock warrants 2,052,128 1,733,322 ​ 3,798,218 3,250,623 ​ 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 Accounting Standards Update 2016-02 and 2018-11 In February 2016, the FASB issued ASU 2016-02, Leases (ASC 842) Leases Leases (ASC 842)—Targeted Improvements Codification improvements This guidance was effective for public business entities for fiscal years beginning after December 15, 2018, including interim periods within those fiscal years. In November 2019, the FASB deferred the effective date for adopting the leasing standard updates for private companies, not-for-profit organizations, and smaller reporting companies. In June 2020, the FASB issued additional deferral guidance that defers the effective date of the leasing standard updates for one year for entities in the “all other” category and public not-for-profit entities that have not yet issued financial statements adopting the standard. The deferrals of the standard are intended to provide relief to nonpublic companies and not-for-profit entities that have had their implementation efforts delayed by the COVID-19 pandemic. 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	6 Months Ended
	Jun. 30, 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, prepaid expenses and other current assets, other assets, accounts payable, accrued liabilities, and note payable approximate fair value due to the short-term nature of these items.

Balance Sheet Components

Balance Sheet Components	6 Months Ended
	Jun. 30, 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): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ June 30, ​ December 31, ​ 2021 2020 ​ ​ (unaudited) ​ ​ ​ Lab equipment ​ $ 2,216 ​ $ 2,200 Computer equipment and software ​ 25 ​ 25 Construction in progress ​ ​ 462 ​ ​ 188 Total property and equipment ​ 2,703 ​ 2,413 Less: Accumulated depreciation ​ (1,336) ​ (1,155) Property and equipment, net ​ $ 1,367 ​ $ 1,258 ​ Depreciation expense was approximately $91,000 and $83,000 for the three months ended June 30, 2021 and 2020, respectively, and approximately $181,000 and $165,000 for the six months ended June 30, 2021 and 2020, respectively. In October 2020, the Company entered into a new lease agreement for its new headquarters facility in Los Gatos, California (see Note 11). The Company moved into the new facility in December 2020 and recorded approximately $462,000 and $188,000 as of June 30, 2021 and December 31, 2020, respectively, in construction in progress related to leasehold improvements made by the Company related to the new facility. Intangible Assets, net Intangible assets, net consist of the following (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ June 30, ​ December 31, ​ 2021 2020 ​ ​ (unaudited) ​ ​ ​ Licenses ​ $ 81 ​ $ 81 Less: Accumulated amortization ​ (57) ​ (54) Intangible assets, net ​ $ 24 ​ $ 27 ​ Amortization expense was approximately $2,000 and $1,000 for the three months ended June 30, 2021 and 2020, respectively, and approximately $3,000 and $2,000 for the six months ended June 30, 2021 and 2020, respectively Licenses The Broad Institute of MIT and Harvard — Non-Exclusive Manufacturing Licensing Agreement The Company entered into a non-exclusive manufacturing licensing agreement with the Broad Institute of MIT and Harvard University (the “Broad Institute”) in January 2021 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 ʎPEX TM Pursuant to this agreement, the Company is 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 and each year thereafter. Additionally, the Company is obligated to pay a royalty of a single digit percentage of all service income received from a customer for the manufacture, sale or transfer of CRISPR modified cell line, CRISPR Modified Animals and CRISPR Modified Plants or end products, as well as a small royalty (a fraction of a percent) on end product net sales from use of any commercialized product that contains any small or large molecule made through the use of a CRISPR modified cell line, CRISPR Modified Animals and CRISPR Modified Plants. The term of the license agreement continues until all patents and filed patent applications, included within the licensed Broad Institute patents, have expired or been abandoned. Accrued Liabilities Accrued liabilities consist of the following (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ June 30, December 31, ​ ​ 2021 ​ 2020 ​ ​ (unaudited) ​ ​ ​ Research and development services ​ $ 1,178 ​ $ 872 Payroll related expenses ​ 365 ​ 279 Professional services and other ​ 308 ​ 179 Accrued liabilities ​ $ 1,851 ​ $ 1,330 ​

Equity Method Investment

Equity Method Investment	6 Months Ended
	Jun. 30, 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 People’s 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 10). 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 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 zero. The Company recognized losses from the operations of the JV Entity of zero and $9,000 for the six months ended June 30, 2021 and 2020, respectively. The Company did not recognize any losses from the operations of the JV Entity for the three months ended June 30, 2021 and 2020, as the net book value of the equity method investment has been zero since March 31, 2020.

Development and License Agreeme

Development and License Agreements	6 Months Ended
	Jun. 30, 2021
Development and License Agreements
Development and License Agreements	6. 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 as of June 30, 2021, the transaction price for the Phase 2a clinical trial contract was zero as none of the four development-based milestones, which consideration totals approximately $3.8 million, could be included in the transaction price, as it was not probable that a significant reversal of cumulative revenue recognized would not occur if these milestones were included. 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 three and six months ended June 30, 2021, the Company did not recognize any revenue from the CFF Agreement. For the three and six months ended June 30, 2020, the Company recognized $1.0 million in revenue from the CFF Agreement, mainly due to the achievement of one development-based milestone related to the Phase 1 MAD clinical trial in the second quarter of 2020. 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 $5.0 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 $10.0 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”). Under the License Agreement, the Company received upfront payments totaling $15.0 million, of which $5.0 million was received in July 2019 through the option agreement referred to above. 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 and AR-201 in certain territories as defined in the License Agreement (the “licenses and know-how”), and granted 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 of these products in certain territories (the “research and development option”). Further, under the License Agreement the Company will provide development support related to the licensed products in order to assist SAMR in its efforts around 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 does not allow for manufacturing of certain products. 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 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 certain territories by paying to SAMR $5.0 million. 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 June 30, 2021 and December 31, 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 during the second half of 2021. The Company determined that no performance obligations or material promises were satisfied as of June 30, 2021, and therefore, no revenue related to the License Agreement was recognized for the three and six months ended June 30, 2021 and 2020. The Company has recorded contract liabilities resulting from the License Agreement of approximately $18.8 million and $18.7 million to deferred revenue, current, and approximately $796,000 and $854,000 to deferred revenue, noncurrent, on its condensed consolidated balance sheets as of June 30, 2021 and December 31, 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 condensed consolidated balance sheets, of which approximately $2.0 million and $2.0 million is classified as current, and approximately $84,000 and $90,000 is classified as noncurrent, as of June 30, 2021 and December 31, 2020, respectively. K ermode 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 will receive two milestone payments of $250,000 each 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 June 30, 2021, the transaction price of the Kermode Agreement was $500,000, consisting of the nonrefundable upfront payment. The two milestone payments, totaling $500,000, 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 payments 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 the three and six months ended June 30, 2021, the Company recognized approximately $33,000 in revenue related to the Kermode Agreement. The Company has recorded the remaining portion of the nonrefundable upfront payment of $467,000 to deferred revenue, current, on its condensed consolidated balance sheets as of June 30, 2021.

Paycheck Protection Program Loa

Paycheck Protection Program Loan	6 Months Ended
	Jun. 30, 2021
Paycheck Protection Program Loan
Paycheck Protection Program Loan	7. 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. The loans and accrued interest may be forgiven as long as the borrower uses the loan proceeds for eligible purposes, including payroll, benefits, rent and utilities, and maintains its payroll levels. The amount of loan forgiveness will be reduced if the borrower terminates employees or reduces salaries during the covered period. The Loan was payable over two years at an interest rate of 1% per annum, with an estimated deferral of payments until mid-2021. The Company is required to pay principal and interest on the Loan in equal monthly installments estimated to begin in mid-2021 and the outstanding interest balance accrued during the deferral period is to be paid on the maturity date, which is May 1, 2022. The Loan may be prepaid by the Company at any time prior to maturity with no prepayment penalties. The Loan contains events of default (as defined in the PPP Loan agreement), in which the occurrence could result in the acceleration of all amounts due under the Loan. The Company’s Loan forgiveness application was submitted to the Small Business Administration (“SBA”) in October 2020. Since the forgiveness of the Loan was outside the Company’s control, the Company accounted for its PPP Loan as debt. At December 31, 2020, the Company recognized the entire amount of the PPP Loan proceeds of approximately $715,000 as a note payable, and classified approximately $439,000 as current and $276,000 as noncurrent, in its condensed consolidated balance sheet. The Company recognized approximately $1,000 and $1,000, for the three months ended June 30, 2021 and 2020, respectively, and for the six months ended June 30, 2021 and 2020, recognized approximately $3,000 and $1,000, respectively, in interest expense in its condensed consolidated statements of operations. 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 three and six months ended June 30, 2021, the Company recognized in its condensed 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 June 30, 2021, the Company had no liabilities related to the PPP Loan recorded in its condensed consolidated balance sheet. ​

Common Stock

Common Stock	6 Months Ended
	Jun. 30, 2021
Common Stock
Common Stock	8. Common Stock As of June 30, 2021 (unaudited), the Company had reserved the following common stock for future issuance: ​ ​ ​ ​ Shares reserved for exercise of outstanding warrants to purchase common stock 2,052,128 Shares reserved for exercise of outstanding options to purchase common stock 1,746,090 Shares reserved for issuance of future options 387,468 Total 4,185,686 ​ 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 condensed consolidated statement of changes in stockholders’ deficit for the six months ended June 30, 2021.

Stock-Based Compensation

Stock-Based Compensation	6 Months Ended
	Jun. 30, 2021
Stock-Based Compensation
Stock-Based Compensation	9. 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. 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 six months ended June 30, 2021 is represented in the following table: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Options Outstanding ​ ​ ​ Weighted- ​ ​ Shares Available ​ Number of ​ Average ​ ​ for Grant ​ Shares ​ Exercise Price Balances at December 31, 2020 584,161 1,550,956 ​ $ 9.43 Additional shares reserved — — ​ ​ — Options granted ​ (224,140) ​ 224,140 ​ ​ 7.20 Options exercised ​ — ​ (1,559) ​ ​ 2.89 Options cancelled 27,447 (27,447) ​ ​ 11.33 Balances at June 30, 2021 387,468 1,746,090 ​ $ 9.12 ​ 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 three and six months ended June 30, 2021 and 2020 were estimated using the following assumptions: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ Six Months Ended ​ ​ ​ June 30, ​ June 30, ​ ​ 2021 2020 2021 2020 ​ Expected term (in years) 6.00 6.00 6.00 ​ 6.00 ​ Expected volatility ​ 99%-100% ​ 94%- 96% ​ 99%- 100% ​ 84%-96% ​ Risk-free interest-rate ​ 1.07% - 1.14% ​ 0.43% - 0.46% ​ 0.75% - 1.14% ​ 0.43% - 1.73% ​ Dividend yield ​ 0% ​ 0% ​ 0% ​ 0% ​ ​ During the three and six months ended June 30, 2021, the Company granted options to purchase 83,340 shares and 224,140 shares with a weighted-average grant date fair value of $4.89 and $5.04 per share, respectively. During the three and six months ended June 30, 2020, the Company granted options to purchase 145,000 shares and 173,500 shares with a weighted-average grant date fair value of $4.83 and $4.63 per share, respectively. There were 1,559 options exercised during the three and six months ended June 30, 2021, and the aggregate intrinsic value of these options exercised was approximately $5,000. There were no options exercised during the three months ended June 30, 2020. There were 4,913 options exercised during the six months ended June 30, 2020, and the aggregate intrinsic value of these options exercised was approximately $17,000. Stock-Based Compensation The following table presents stock-based compensation expense related to stock options (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ Six Months Ended ​ ​ June 30, ​ June 30, ​ 2021 2020 2021 2020 ​ ​ (unaudited) ​ (unaudited) ​ (unaudited) ​ (unaudited) Research and development ​ $ 172 ​ $ 130 ​ $ 332 ​ $ 275 General and administrative ​ ​ 381 ​ ​ 393 ​ ​ 788 ​ ​ 725 Total ​ $ 553 ​ $ 523 ​ $ 1,120 ​ $ 1,000 ​ As of June 30, 2021, total unrecognized stock-based compensation expenses related to unvested stock options was approximately $3.4 million, which is expected to be recognized on a straight-line basis over a weighted-average period of approximately 2.1 years.

Related Parties

Related Parties	6 Months Ended
	Jun. 30, 2021
Related Parties
Related Parties	10. 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 three months ended June 30, 2021 and 2020, the Company recorded approximately $14,000 and $112,000, respectively, and for the six months ended June 30, 2021 and 2020, the Company recorded approximately $47,000 and $184,000, respectively, as a reduction to operating expenses in the condensed consolidated statements of operations for amounts reimbursed to the Company by the JV Entity under this arrangement. As of June 30, 2021 and December 31, 2020, the Company recorded approximately $14,000 and $3,000, respectively, in other receivables on the condensed 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 $10.0 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”) (see Note 6). The Company determined that no performance obligations or material promises were satisfied as of June 30, 2021, and therefore, no revenue related to the License Agreement was recognized for the three and six months ended June 30, 2021 and, 2020. The Company has recorded contract liabilities resulting from the License Agreement of approximately $18.8 million and $18.7 million to deferred revenue, current, and approximately $796,000 and $854,000 to deferred revenue, noncurrent, on its condensed consolidated balance sheets as of June 30, 2021 and December 31, 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 condensed consolidated balance sheets, of which approximately $2.0 million and $2.0 million is classified as current, and approximately $84,000 and $90,000 is classified as noncurrent, as of June 30, 2021 and December 31, 2020, respectively.

Commitments and Contingencies

Commitments and Contingencies	6 Months Ended
	Jun. 30, 2021
Commitments and Contingencies
Commitments and Contingencies	11. Commitments and Contingencies Facility Lease 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 condensed consolidated balance sheet. The future minimum lease payments for the new facility as of June 30, 2021 are as follows (in thousands): ​ ​ ​ ​ ​ Period ending : ​ ​ Six months ending December 31, 2021 ​ $ 296 Year ending December 31, 2022 ​ 610 Year ending December 31, 2023 ​ 628 Year ending December 31, 2024 ​ 646 Year ending December 31, 2025 ​ 666 Thereafter ​ 57 Total ​ $ 2,903 ​ Rent expense was approximately $156,000 and $113,000 for the three months ended June 30, 2021 and 2020, respectively, and $318,000 and $215,000 for the six months ended June 30, 2021 and 2020, respectively. The Company has recorded approximately $77,000 and $37,000 to deferred rent and lease incentive obligation, classified as current other liabilities, and approximately $398,000 and $223,000 to deferred rent and lease incentive obligation, classified as noncurrent other liabilities, on its condensed consolidated balance sheets as of June 30, 2021 and December 31, 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. 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 future expenditures will be made and such expenditures can be reasonably estimated. As of June 30, 2021 and December 31, 2020, no accruals have been made related to commitments and 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 year ended December 31, 2020, and as of June 30, 2021, there were no other pending legal proceedings. 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. 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 June 30, 2021 and December 31, 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 June 30, 2021. Kermode Agreement In February 2021, the Company entered into the Kermode Agreement, in which the Company received an upfront payment of $500,000 and 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 single digit percentage royalty of net sales from those products. None of these events occurred as of June 30, 2021.

Subsequent Events

Subsequent Events	6 Months Ended
	Jun. 30, 2021
Subsequent Events
Subsequent Events	12. Subsequent Events ​ 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 “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 staphylococcus aureus alpha toxin (the “Licensed Product”). As consideration for the License Agreement, Medimmune will receive 884,956 shares of the Company’s common stock and a $5.0 million cash payment upon the earlier of (i) a registered direct offering in which the Company receives third-party funding or (ii) 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 in the low to mid-teens. 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. ​ Securities Purchase Agreement ​ On August 2, 2021, the Company entered into a 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 the Company’s estimated offering expenses, net proceeds were approximately $23.2 million. ​ 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 is 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 (see Note 8). ​

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	6 Months Ended
	Jun. 30, 2021
Summary of Significant Accounting Policies
Use of Estimates	Use of Estimates The preparation of the condensed 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 condensed 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	Concentration of Risk 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 three and six months ended June 30, 2021, one customer accounted for 100% of total revenue, and for the three and six months ended June 30, 2020, another customer accounted for 100% of total revenue. Both customers are located in the United States. As of June 30, 2021 and December 31, 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 and cash equivalents consist primarily of checking account and money market fund account balances. Restricted cash consists of deposits for a letter of credit that the Company has provided to secure its obligations under its facility lease. The following table provides a reconciliation of cash, cash equivalents and restricted cash within the condensed consolidated balance sheets which, in aggregate, represent the amount reported in the condensed consolidated statements of cash flows (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ June 30, December 31, ​ ​ 2021 ​ 2020 Cash and cash equivalents ​ $ 3,592 ​ $ 8,232 Restricted cash ​ 500 ​ 500 Total cash, cash equivalents and restricted cash ​ $ 4,092 ​ $ 8,732 ​
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 June 30, 2021 and December 31, 2020, there were no accounts receivable and allowances for doubtful accounts.
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 June 30, 2021 and December 31, 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 condensed consolidated balance sheets. Amounts recognized as revenue, but not yet received or invoiced are recorded within other receivables on the condensed consolidated balance sheet. Amounts are recorded as other receivables on the condensed 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 condensed 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 three and six months ended June 30, 2021 and 2020, there was no amortization of the contract assets and there have been no impairments as of June 30, 2021. 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 condensed consolidated balance sheets. The Company has estimated the classification between current and noncurrent deferred revenue related to the respective license agreement within its condensed consolidated balance sheets at June 30, 2021 and December 31, 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, the Company issued 124,789 dividend shares to certain common stockholders with a fair value of approximately $986,000 (see Note 8) which is included in the net loss available to common stockholders’ for the six months ended June 30, 2021 in the below table. For the three and six months ended June 30, 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 table presents the computation of the basic and diluted net loss per share to common stockholders (in thousands, except share and per share data): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended Six Months Ended ​ ​ June 30, June 30, ​ 2021 2020 2021 2020 Numerator: (unaudited) (unaudited) ​ (unaudited) (unaudited) Net loss available to common stockholders (basic and diluted) ​ $ (5,490) ​ $ (4,220) ​ $ (13,367) ​ $ (10,724) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Denominator: ​ ​ ​ ​ Weighted-average common shares outstanding used in computing net loss per share available to common stockholders, basic and diluted ​ 11,233,572 ​ 8,923,374 ​ 10,734,580 ​ 8,921,383 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net loss per share to common stockholders, basic and diluted ​ $ (0.49) ​ $ (0.47) ​ $ (1.25) ​ $ (1.20) ​ 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: ​ ​ ​ ​ ​ ​ ​ ​ Six Months Ended ​ ​ June 30, ​ 2021 2020 ​ ​ (unaudited) ​ (unaudited) Stock options to purchase common stock 1,746,090 1,517,301 Common stock warrants 2,052,128 1,733,322 ​ 3,798,218 3,250,623 ​
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 June 30, 2021 Accounting Standards Update 2016-02 and 2018-11 In February 2016, the FASB issued ASU 2016-02, Leases (ASC 842) Leases Leases (ASC 842)—Targeted Improvements Codification improvements This guidance was effective for public business entities for fiscal years beginning after December 15, 2018, including interim periods within those fiscal years. In November 2019, the FASB deferred the effective date for adopting the leasing standard updates for private companies, not-for-profit organizations, and smaller reporting companies. In June 2020, the FASB issued additional deferral guidance that defers the effective date of the leasing standard updates for one year for entities in the “all other” category and public not-for-profit entities that have not yet issued financial statements adopting the standard. The deferrals of the standard are intended to provide relief to nonpublic companies and not-for-profit entities that have had their implementation efforts delayed by the COVID-19 pandemic. 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)	6 Months Ended
	Jun. 30, 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 condensed consolidated balance sheets which, in aggregate, represent the amount reported in the condensed consolidated statements of cash flows (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ June 30, December 31, ​ ​ 2021 ​ 2020 Cash and cash equivalents ​ $ 3,592 ​ $ 8,232 Restricted cash ​ 500 ​ 500 Total cash, cash equivalents and restricted cash ​ $ 4,092 ​ $ 8,732
Schedule of computation of the basic and diluted net loss per share	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended Six Months Ended ​ ​ June 30, June 30, ​ 2021 2020 2021 2020 Numerator: (unaudited) (unaudited) ​ (unaudited) (unaudited) Net loss available to common stockholders (basic and diluted) ​ $ (5,490) ​ $ (4,220) ​ $ (13,367) ​ $ (10,724) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Denominator: ​ ​ ​ ​ Weighted-average common shares outstanding used in computing net loss per share available to common stockholders, basic and diluted ​ 11,233,572 ​ 8,923,374 ​ 10,734,580 ​ 8,921,383 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net loss per share to common stockholders, basic and diluted ​ $ (0.49) ​ $ (0.47) ​ $ (1.25) ​ $ (1.20)
Schedule of potentially dilutive securities were excluded from the computation of diluted net loss per share	​ ​ ​ ​ ​ ​ ​ ​ Six Months Ended ​ ​ June 30, ​ 2021 2020 ​ ​ (unaudited) ​ (unaudited) Stock options to purchase common stock 1,746,090 1,517,301 Common stock warrants 2,052,128 1,733,322 ​ 3,798,218 3,250,623

Balance Sheet Components (Table

Balance Sheet Components (Tables)	6 Months Ended
	Jun. 30, 2021
Balance Sheet Components
Schedule of property and equipment, net	Property and equipment, net consist of the following (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ June 30, ​ December 31, ​ 2021 2020 ​ ​ (unaudited) ​ ​ ​ Lab equipment ​ $ 2,216 ​ $ 2,200 Computer equipment and software ​ 25 ​ 25 Construction in progress ​ ​ 462 ​ ​ 188 Total property and equipment ​ 2,703 ​ 2,413 Less: Accumulated depreciation ​ (1,336) ​ (1,155) Property and equipment, net ​ $ 1,367 ​ $ 1,258 ​
Schedule of intangible assets, net	Intangible assets, net consist of the following (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ June 30, ​ December 31, ​ 2021 2020 ​ ​ (unaudited) ​ ​ ​ Licenses ​ $ 81 ​ $ 81 Less: Accumulated amortization ​ (57) ​ (54) Intangible assets, net ​ $ 24 ​ $ 27
Schedule of accrued liabilities	Accrued liabilities consist of the following (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ June 30, December 31, ​ ​ 2021 ​ 2020 ​ ​ (unaudited) ​ ​ ​ Research and development services ​ $ 1,178 ​ $ 872 Payroll related expenses ​ 365 ​ 279 Professional services and other ​ 308 ​ 179 Accrued liabilities ​ $ 1,851 ​ $ 1,330

Common Stock (Tables)

Common Stock (Tables)	6 Months Ended
	Jun. 30, 2021
Common Stock
Schedule of company reserved common stock for future issuance	As of June 30, 2021 (unaudited), the Company had reserved the following common stock for future issuance: ​ ​ ​ ​ Shares reserved for exercise of outstanding warrants to purchase common stock 2,052,128 Shares reserved for exercise of outstanding options to purchase common stock 1,746,090 Shares reserved for issuance of future options 387,468 Total 4,185,686

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	6 Months Ended
	Jun. 30, 2021
Stock-Based Compensation
Schedule of stock option activity	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Options Outstanding ​ ​ ​ Weighted- ​ ​ Shares Available ​ Number of ​ Average ​ ​ for Grant ​ Shares ​ Exercise Price Balances at December 31, 2020 584,161 1,550,956 ​ $ 9.43 Additional shares reserved — — ​ ​ — Options granted ​ (224,140) ​ 224,140 ​ ​ 7.20 Options exercised ​ — ​ (1,559) ​ ​ 2.89 Options cancelled 27,447 (27,447) ​ ​ 11.33 Balances at June 30, 2021 387,468 1,746,090 ​ $ 9.12
Schedule of fair value of the options granted estimated using assumptions	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ Six Months Ended ​ ​ ​ June 30, ​ June 30, ​ ​ 2021 2020 2021 2020 ​ Expected term (in years) 6.00 6.00 6.00 ​ 6.00 ​ Expected volatility ​ 99%-100% ​ 94%- 96% ​ 99%- 100% ​ 84%-96% ​ Risk-free interest-rate ​ 1.07% - 1.14% ​ 0.43% - 0.46% ​ 0.75% - 1.14% ​ 0.43% - 1.73% ​ Dividend yield ​ 0% ​ 0% ​ 0% ​ 0% ​
Schedule of stock-based compensation expense related to stock options	The following table presents stock-based compensation expense related to stock options (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ Six Months Ended ​ ​ June 30, ​ June 30, ​ 2021 2020 2021 2020 ​ ​ (unaudited) ​ (unaudited) ​ (unaudited) ​ (unaudited) Research and development ​ $ 172 ​ $ 130 ​ $ 332 ​ $ 275 General and administrative ​ ​ 381 ​ ​ 393 ​ ​ 788 ​ ​ 725 Total ​ $ 553 ​ $ 523 ​ $ 1,120 ​ $ 1,000

Commitments and Contingencies (

Commitments and Contingencies (Tables)	6 Months Ended
	Jun. 30, 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 June 30, 2021 are as follows (in thousands): ​ ​ ​ ​ ​ Period ending : ​ ​ Six months ending December 31, 2021 ​ $ 296 Year ending December 31, 2022 ​ 610 Year ending December 31, 2023 ​ 628 Year ending December 31, 2024 ​ 646 Year ending December 31, 2025 ​ 666 Thereafter ​ 57 Total ​ $ 2,903

Description of Business and B_2

Description of Business and Basis of Presentation (Details)	6 Months Ended
	Jun. 30, 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)	3 Months Ended	6 Months Ended
	Jun. 30, 2021USD ($)	Jun. 30, 2021USD ($)	Dec. 31, 2020USD ($)
Summary of Significant Accounting Policies
Accounts receivable	$ 0	$ 0	$ 0
Customer 1 | Customer risk
Summary of Significant Accounting Policies
Number of customers	1	1
Contract revenue | Customer 1 | Customer risk
Summary of Significant Accounting Policies
Concentration risk percentage	100.00%	100.00%
Contract revenue | Customer 2 | Customer risk
Summary of Significant Accounting Policies
Concentration risk percentage	100.00%	100.00%

Summary of Significant Accoun_5

Summary of Significant Accounting Policies - Cash, Cash Equivalents and Restricted Cash (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020	Jun. 30, 2020	Dec. 31, 2019
Summary of Significant Accounting Policies
Cash and cash equivalents	$ 3,592	$ 8,232
Restricted cash	500	500
Total cash, cash equivalents and restricted cash	$ 4,092	$ 8,732	$ 11,812	$ 20,897

Summary of Significant Accoun_6

Summary of Significant Accounting Policies - Accounts Receivable and Allowance for Doubtful Accounts (Details) - USD ($)	Jun. 30, 2021	Dec. 31, 2020
Summary of Significant Accounting Policies
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)	6 Months Ended
	Jun. 30, 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 ($)	6 Months Ended	12 Months Ended
	Jun. 30, 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 ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Summary of Significant Accounting Policies
Amortization of contract assets	$ 0	$ 0	$ 0	$ 0
Impairments of contract assets			$ 0

Summary of Significant Accou_10

Summary of Significant Accounting Policies - Stock-Based Compensation (Details)	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Summary of Significant Accounting Policies
Dividend yield (in percent)	0.00%	0.00%	0.00%	0.00%

Summary of Significant Accou_11

Summary of Significant Accounting Policies - Loss Per Share (Details) - USD ($)	3 Months Ended			6 Months Ended
	Jun. 30, 2021	Mar. 31, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Summary of Significant Accounting Policies
Fair value of dividend shares issued to common stockholders				$ (986,000)
Numerator:
Net loss available to common stockholders (basic and diluted)	$ (5,490,000)		$ (4,220,000)	$ (13,367,000)	$ (10,724,000)
Denominator:
Weighted-average common shares outstanding used in computing net loss per share available to common stockholders, basic and diluted	11,233,572		8,923,374	10,734,580	8,921,383
Net loss per share to common stockholders, basic and diluted	$ (0.49)		$ (0.47)	$ (1.25)	$ (1.20)
Potentially dilutive securities excluded from computation of diluted net loss per share				3,798,218	3,250,623
Common Stock
Summary of Significant Accounting Policies
Dividend shares to its common stock stockholders		124,789
Fair value of dividend shares issued to common stockholders		$ 986,000
Options | Common Stock
Denominator:
Potentially dilutive securities excluded from computation of diluted net loss per share				1,746,090	1,517,301
Warrants | Common Stock
Denominator:
Potentially dilutive securities excluded from computation of diluted net loss per share				2,052,128	1,733,322

Balance Sheet Components - Prop

Balance Sheet Components - Property and Equipment, net (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020
Property and Equipment, net
Total property and equipment	$ 2,703,000		$ 2,703,000		$ 2,413,000
Less: Accumulated depreciation	(1,336,000)		(1,336,000)		(1,155,000)
Property and equipment, net	1,367,000		1,367,000		1,258,000
Depreciation expense	91,000	$ 83,000	181,000	$ 165,000
Lab equipment
Property and Equipment, net
Total property and equipment	2,216,000		2,216,000		2,200,000
Computer equipment and software
Property and Equipment, net
Total property and equipment	25,000		25,000		25,000
Construction in progress
Property and Equipment, net
Total property and equipment	$ 462,000		$ 462,000		$ 188,000

Balance Sheet Components - Inta

Balance Sheet Components - Intangible Assets, net (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020
Intangible Assets, net
Less: Accumulated amortization	$ (57,000)		$ (57,000)		$ (54,000)
Intangible assets, net	24,000		24,000		27,000
Amortization expense	2,000	$ 1,000	3,000	$ 2,000
License revenue
Intangible Assets, net
Intangible assets, gross	$ 81,000		$ 81,000		$ 81,000

Balance Sheet Components - Lice

Balance Sheet Components - Licenses (Details)	6 Months Ended
	Jun. 30, 2021USD ($)
Issue fee	$ 25,000
The UAB Research Foundation
Minimum research funding agreed to provide	50,000
Maximum contingent milestone payments	$ 100,000

Balance Sheet Components - Accr

Balance Sheet Components - Accrued Liabilities (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Balance Sheet Components
Research and development services	$ 1,178	$ 872
Payroll related expenses	365	279
Professional services and other	308	179
Accrued liabilities	$ 1,851	$ 1,330

Equity Method Investment (Detai

Equity Method Investment (Details) - USD ($)	Feb. 11, 2018	Jun. 30, 2021	Jun. 30, 2020	Mar. 31, 2020	Aug. 06, 2018
Equity Method Investment
Loss from equity method investment			$ 9,000
JV Entity
Equity Method Investment
Contribution into the JV Entity	$ 1,000,000
Percentage of ownership interest	49.00%
Contributions owed to the joint venture		$ 1,000,000
Loss from equity method investment		0	$ 9,000
Carryover basis of license contributed		$ 0
Equity method investment				$ 0
Hepalink | JV Entity
Equity Method Investment
Contribution obligated					$ 7,200,000
Percentage of ownership interest					51.00%
Minimum amount obligated to make an additional equity investment at first future financing					$ 10,800,000

Development and License Agree_2

Development and License Agreements - Cystic Fibrosis Foundation Development Agreement (Details) - USD ($)	1 Months Ended	3 Months Ended		6 Months Ended		12 Months Ended
	Nov. 30, 2018	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2016	Mar. 31, 2019
Collaborative Arrangements and Non-collaborative Arrangement Transactions
Grant revenue		$ 33,000	$ 1,000,000	$ 33,000	$ 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	$ 7,500,000					$ 2,900,000
Upfront payment received from CFF						$ 200,000
Grant 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		$ 3,800,000		$ 3,800,000

Development and License Agree_3

Development and License Agreements - Serum License Agreement (Details) - USD ($)	1 Months Ended		3 Months Ended			6 Months Ended
	Sep. 30, 2019	Jul. 31, 2019	Jun. 30, 2021	Mar. 31, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020
Collaborative Arrangements and Non-collaborative Arrangement Transactions
Issuance of stock						$ 6,417,000
Deferred revenue, noncurrent			$ 796,000			796,000		$ 854,000
Capitalized contract cost, Current			1,979,000			1,979,000		1,973,000
Capitalized contract cost, Noncurrent			84,000			84,000		90,000
Deferred revenue			19,273,000			19,273,000		18,748,000
License revenue
Collaborative Arrangements and Non-collaborative Arrangement Transactions
Revenue			0		$ 0	0	$ 0
Licenses and know-how
Collaborative Arrangements and Non-collaborative Arrangement Transactions
Deferred revenue			14,500,000			14,500,000
Development support services
Collaborative Arrangements and Non-collaborative Arrangement Transactions
Deferred revenue			79,000			79,000
Research and Development Option
Collaborative Arrangements and Non-collaborative Arrangement Transactions
Deferred revenue			892,000			892,000
Manufacturing rights option
Collaborative Arrangements and Non-collaborative Arrangement Transactions
Deferred revenue			4,100,000			4,100,000
License Agreement with SIBV
Collaborative Arrangements and Non-collaborative Arrangement Transactions
Upfront payment received	$ 15,000,000	$ 5,000,000
License Agreement with SAMR
Collaborative Arrangements and Non-collaborative Arrangement Transactions
Buy back manufacturing rights	$ 5,000,000
Maximum additional payments entitled						42,500,000
License Agreement and Option Agreement
Collaborative Arrangements and Non-collaborative Arrangement Transactions
Deferred revenue			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
Kermode Licensing and Product Discovery Agreement
Collaborative Arrangements and Non-collaborative Arrangement Transactions
Upfront payment received						500,000
Revenue recognized						33,000
Deferred revenue			467,000			467,000
Kermode Licensing and Product Discovery Agreement | Upfront payment
Collaborative Arrangements and Non-collaborative Arrangement Transactions
Upfront payment received						500,000
Maximum additional payments entitled						250,000
Kermode Licensing and Product Discovery Agreement | License revenue | Upfront payment
Collaborative Arrangements and Non-collaborative Arrangement Transactions
Maximum additional payments entitled						500,000
Serum International B.V. ("SIBV")
Collaborative Arrangements and Non-collaborative Arrangement Transactions
Issuance of common stock (in shares)		801,820
Issuance of stock		$ 10,000,000
Deferred revenue			19,600,000			19,600,000
Serum International B.V. ("SIBV") | License revenue
Collaborative Arrangements and Non-collaborative Arrangement Transactions
Capitalized contract costs			2,100,000			2,100,000		2,100,000
Revenue				$ 0		0
Deferred revenue, noncurrent			796,000			796,000		854,000
Capitalized contract cost, Current			2,000,000			2,000,000		2,000,000
Capitalized contract cost, Noncurrent			84,000			84,000		90,000
Deferred revenue			18,800,000			18,800,000		18,700,000
Serum International B.V. ("SIBV") | License Agreement with SIBV
Collaborative Arrangements and Non-collaborative Arrangement Transactions
Deferred revenue			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			$ 4,600,000			4,600,000
Deferred revenue, noncurrent								854,000
Capitalized contract cost, Noncurrent								$ 90,000
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 stock		$ 10,000,000
Proceeds from sale of restricted common stock and upfront payment						5,400,000
Fair value of net proceeds						441,000
Payments of Stock Issuance Costs						$ 5,000,000

Paycheck Protection Program L_2

Paycheck Protection Program Loan (Details) - USD ($)	May 01, 2020	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020
Debt Instrument [Line Items]
Gain on extinguishment of Paycheck Protection Program loan		$ 722,000		$ 722,000
Note payable current		0		0		$ 439,000
Note payable, noncurrent		0		0		276,000
Liabilities		24,874,000		24,874,000		23,798,000
Paycheck Protection Program (the "PPP")
Debt Instrument [Line Items]
Gain on extinguishment of Paycheck Protection Program loan				722,000
Aggregate loan amount granted	$ 715,000	715,000		715,000
Debt instrument maturity period	2 years
Effective interest rate	1.00%
Accrued interest		7,000		7,000
Note payable		0		0		715,000
Note payable current						439,000
Note payable, noncurrent						$ 276,000
Interest expense		$ 1,000	$ 1,000	$ 3,000	$ 1,000

Common Stock (Details)

Common Stock (Details)	Jun. 30, 2021shares
Common Stock for future issuance
Total common stock for future issuance	4,185,686
Options
Common Stock for future issuance
Total common stock for future issuance	1,746,090
Future Options
Common Stock for future issuance
Total common stock for future issuance	387,468
Warrants
Common Stock for future issuance
Total common stock for future issuance	2,052,128

Common Stock - Securities Purch

Common Stock - Securities Purchase Agreement (Details) - USD ($)	1 Months Ended		3 Months Ended	6 Months Ended
	Mar. 31, 2021	Jul. 31, 2019	Mar. 31, 2021	Jun. 30, 2021	Dec. 31, 2020
Common Stock for future issuance
Common stock, par value per share (in dollars per share)				$ 0.0001	$ 0.0001
Proceeds from issuance of common stock, net				$ 6,428,000
Fair value of dividend shares issued to common stockholders				$ (986,000)
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
Securities Purchase Agreement
Common Stock for future issuance
Issuance of common stock (in shares)			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			$ 7,000,000
Proceeds from issuance of common stock, net			$ 6,400,000
Dividend shares to its common stock stockholders	124,789
Fair value of dividend shares issued to common stockholders	$ 986,000

Stock-Based Compensation - (Det

Stock-Based Compensation - (Details) - shares	1 Months Ended
	May 31, 2014	Jun. 30, 2020
Stock-Based Compensation
Reserved for issuance (in shares)	233,722	2,183,692
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%
Options
Stock-Based Compensation
Vesting period (in years)	4 years
Expiration period (in years)	10 years

Stock-Based Compensation - Stoc

Stock-Based Compensation - Stock option activity (Details) - $ / shares	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Shares Available for Grant
Beginning of the period (in shares)			584,161
Options granted (in shares)	(83,340)	(145,000)	(224,140)	(173,500)
Options exercised (in shares)	1,559	0	1,559	4,913
Options cancelled (in shares)			27,447
End of the period (in shares)	387,468		387,468
Number of options
Number of Shares, beginning of the period (in shares)			1,550,956
Number of Shares, Stock option granted	83,340	145,000	224,140	173,500
Number of Shares, Options exercised (in shares)			(1,559)
Number of Shares, Options cancelled (in shares)			(27,447)
Number of Shares, end of the period (in shares)	1,746,090		1,746,090
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)			7.20
Weighted-Average Exercise Price, Options exercised (in dollars per share)			2.89
Weighted-Average Exercise Price, Options cancelled (in dollars per share)			11.33
Weighted-Average Exercise Price, end of the period (in dollars per share)	$ 9.12		$ 9.12

Stock-Based Compensation - Assu

Stock-Based Compensation - Assumptions (Details) - shares	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Fair value of the options granted, estimated using assumptions
Expected term (in years)	6 years	6 years	6 years	6 years
Expected volatility, minimum	99.00%	94.00%	99.00%	84.00%
Expected volatility, maximum	100.00%	96.00%	100.00%	96.00%
Risk-free interest-rate, minimum	1.07%	0.43%	0.75%	0.43%
Risk-free interest-rate, maximum	1.14%	0.46%	1.14%	1.73%
Dividend yield (in percent)	0.00%	0.00%	0.00%	0.00%
Granted (in shares)	83,340	145,000	224,140	173,500

Stock-Based Compensation - Expe

Stock-Based Compensation - Expenses (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2020	Jun. 30, 2019
Stock-Based Compensation
Total stock-based compensation expense	$ 553	$ 523	$ 1,120	$ 1,000
Research and development
Stock-Based Compensation
Total stock-based compensation expense	172	130	332	275
General and administrative
Stock-Based Compensation
Total stock-based compensation expense	$ 381	$ 393	$ 788	$ 725

Stock-Based Compensation - Addi

Stock-Based Compensation - Additional information (Details) - USD ($)	1 Months Ended	3 Months Ended		6 Months Ended
	May 31, 2014	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Stock-Based Compensation
Reserved for issuance (in shares)	233,722		2,183,692		2,183,692
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		83,340	145,000	224,140	173,500
Weighted-average grant date fair value (in dollars per share)		$ 4.89	$ 4.83	$ 5.04	$ 4.63
Aggregate intrinsic value				$ 5,000	$ 17,000
Options exercised (in shares)		1,559	0	1,559	4,913
Options
Stock-Based Compensation
Vesting period (in years)	4 years
Expiration period (in years)	10 years
Unrecognized stock-based compensation expenses related to stock options		$ 3,400,000		$ 3,400,000
Unrecognized stock-based compensation expenses expected to be recognized				2 years 1 month 6 days

Related Parties (Details)

Related Parties (Details) - USD ($)	1 Months Ended	3 Months Ended			6 Months Ended
	Jul. 31, 2019	Jun. 30, 2021	Mar. 31, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020
Related parties
Issuance of stock					$ 6,417,000
Deferred revenue		$ 19,273,000			19,273,000		$ 18,748,000
Deferred revenue, noncurrent		796,000			796,000		854,000
Capitalized contract cost, Current		1,979,000			1,979,000		1,973,000
Capitalized contract cost, Noncurrent		84,000			84,000		90,000
License revenue
Related parties
Revenue		0		$ 0	0	$ 0
Shenzhen Hepalink Pharmaceutical Group Co., Ltd.("Hepalink")
Related parties
Reduction to operating expenses on reimbursed to JV entity		14,000		$ 112,000	47,000	$ 184,000
Serum International B.V. ("SIBV")
Related parties
Issuance of common stock (in shares)	801,820
Issuance of stock	$ 10,000,000
Serum International B.V. ("SIBV") | License revenue
Related parties
Revenue			$ 0		0
Deferred revenue		18,800,000			18,800,000		18,700,000
Deferred revenue, noncurrent		796,000			796,000		854,000
Capitalized contract costs		2,100,000			2,100,000		2,100,000
Capitalized contract cost, Current		2,000,000			2,000,000		2,000,000
Capitalized contract cost, Noncurrent		84,000			84,000		90,000
Other receivables | Shenzhen Hepalink Pharmaceutical Group Co., Ltd.("Hepalink")
Related parties
Outstanding receivable for reimbursable expenses		$ 14,000			$ 14,000		$ 3,000

Commitments and Contingencies -

Commitments and Contingencies - Facility lease - (Details)	Oct. 31, 2020USD ($)ft²
Commitments and Contingencies
Initial Term	5 years
Area of Land | ft²	15,129
Leasehold improvements may be reimbursed	$ 378,000
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	Jun. 30, 2021USD ($)
Commitments and Contingencies
Six months ending December 31, 2021	$ 296
Year ending December 31, 2022	610
Year ending December 31, 2023	628
Year ending December 31, 2024	646
Year ending December 31, 2025	666
Thereafter	57
Total	$ 2,903

Commitments and Contingencies_3

Commitments and Contingencies - Leases and Contingencies (Details) - USD ($)	1 Months Ended	3 Months Ended		6 Months Ended
	Feb. 29, 2020	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020
Commitments and Contingencies
Rent expense		$ 156,000	$ 113,000	$ 318,000	$ 215,000
Compensatory damages sought	$ 277,000
Deferred rent		77,000		77,000		$ 398,000
Lease incentive obligation		$ 37,000		$ 37,000		$ 223,000

Commitments and Contingencies_4

Commitments and Contingencies - Cystic Fibrosis Foundation Agreement and Joint Venture Agreement (Details) - CF Foundation	1 Months Ended
	Dec. 31, 2016USD ($)installmentitem	Jun. 30, 2021USD ($)	Dec. 31, 2020USD ($)	Nov. 30, 2018USD ($)
Cystic Fibrosis Foundation Agreement
Amount of award received for advance research on potential drugs	$ 2,900,000			$ 7,500,000
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%
Payment of amount received in connection with Disposition Transaction (as a percent)	15.00%
Number of multiplication on awarded amount payable if change of control prior to completion of the first commercial sale | item	9
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, 2021USD ($)
Kermode Agreement
Long-term Purchase Commitment [Line Items]
Upfront payment received	$ 500,000

Subsequent Events (Details)

Subsequent Events (Details) - License Agreement with Medimmune - Subsequent event $ in Millions	1 Months Ended
	Jul. 31, 2021USD ($)shares
Subsequent Events
Shares of common stock agreed to be issued | shares	884,956
Cash payment	$ 5
Total aggregate payments upon achievement of certain regulatory approvals	30
Total aggregate payments upon achievement of sales related milestone	85
Total aggregate payments upon achievement of development related milestone	$ 0

Subsequent Events - Securities

Subsequent Events - Securities Purchase Agreement (Details) - USD ($) $ / shares in Units, $ in Thousands	Aug. 02, 2021	Mar. 31, 2021	Mar. 31, 2021	Jun. 30, 2021	Dec. 31, 2020
Class of Warrant or Right [Line Items]
Common stock, par value per share (in dollars per share)				$ 0.0001	$ 0.0001
Proceeds from issuance of common stock, net				$ 6,428
Securities Purchase Agreement
Class of Warrant or Right [Line Items]
Issuance of common stock (in shares)			1,037,405
Common stock, par value per share (in dollars per share)		$ 0.0001	$ 0.0001
Gross proceeds from issuance of common stock			$ 7,000
Proceeds from issuance of common stock, net			$ 6,400
Dividend shares to its common stock stockholders		124,789
Subsequent event | Securities Purchase Agreement
Class of Warrant or Right [Line Items]
Gross proceeds from issuance of common stock	$ 25,000
Proceeds from issuance of common stock, net	$ 23,200
Subsequent event | Forecast | Securities Purchase Agreement
Class of Warrant or Right [Line Items]
Issuance of common stock (in shares)	1,300,000
Combined purchase price for each Common Stock and accompanying Warrant	$ 5.053
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
Dividend shares to its common stock stockholders	634,600
Subsequent event | Forecast | Securities Purchase Agreement | Pre-Funded Warrants
Class of Warrant or Right [Line Items]
Warrant to purchase number of Common Stock (in shares)	3,647,556
Subsequent event | Forecast | Securities Purchase Agreement | Warrants
Class of Warrant or Right [Line Items]
Warrant to purchase number of Common Stock (in shares)	2,473,778