Aridis Pharmaceuticals (ARDS) 10-K 8 Apr 20 2019 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Mar. 16, 2020	Jun. 30, 2019
Document and Entity Information [Abstract]
Entity Registrant Name	ARIDIS PHARMACEUTICALS, INC.
Entity Central Index Key	0001614067
Document Type	10-K
Document Period End Date	Dec. 31, 2019
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Small Business	true
Entity Emerging Growth Company	true
Entity Shell Company	false
Entity Ex Transition Period	false
Entity Filer Category	Non-accelerated Filer
Entity Interactive Data Current	Yes
Entity Public Float			$ 58.8
Entity Common Stock, Shares Outstanding		8,920,257
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	FY

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($)	Dec. 31, 2019	Dec. 31, 2018
Current assets:
Cash and cash equivalents	$ 20,897,000	$ 24,237,000
Accounts receivable	0	1,660,000
Other receivables	413,000	438,000
Contract costs	1,537,000
Prepaid expenses and other current assets	2,990,000	2,012,000
Total current assets	25,837,000	28,347,000
Property and equipment, net	1,006,000	1,271,000
Intangible assets, net	32,000	38,000
Equity method investment	9,000	960,000
Contract costs	526,000
Other assets	557,000	995,000
Total assets	27,967,000	31,611,000
Current liabilities:
Accounts payable	1,755,000	2,331,000
Accrued liabilities	2,974,000	2,944,000
Deferred revenue, current	14,602,000	22,000
Total current liabilities	19,331,000	5,297,000
Deferred revenue	5,000,000
Total liabilities	24,331,000	5,297,000
Commitments and contingencies (Note 13)
Stockholders' equity:
Common stock (par value $0.0001; 100,000,000 shares authorized; shares issued and outstanding: 8,918,461 and 8,104,757, as of December 31, 2019 and December 31, 2018, respectively )	1,000	1,000
Additional paid-in capital	104,404,000	97,401,000
Accumulated deficit	(100,769,000)	(71,088,000)
Total stockholders' equity	3,636,000	26,314,000
Total liabilities and stockholders' equity	$ 27,967,000	$ 31,611,000

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - $ / shares	Dec. 31, 2019	Dec. 31, 2018
Consolidated Balance Sheets
Convertible preferred stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Convertible preferred stock, shares authorized (in shares)	60,000,000	60,000,000
Convertible preferred stock, shares issued (in shares)	0	0
Convertible 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)	8,918,461	8,104,757
Common stock, shares outstanding (in shares)	8,918,461	8,104,757

Consolidated Statements of Oper

Consolidated Statements of Operations - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Revenue:
Total revenue	$ 1,022	$ 2,757
Operating expenses:
Research and development	24,083	23,000
General and administrative	6,026	3,874
Total operating expenses	30,109	26,874
Loss from operations	(29,087)	(24,117)
Other income (expense):
Interest and other income, net	357	420
Change in fair value of warrant liability		1,632
Share of loss from equity method investment	951	40
Net loss	(29,681)	(22,105)
Preferred dividends		(1,357)
Net loss available to common stockholders	$ (29,681)	$ (23,462)
Weighted-average common shares outstanding used in computing net loss per share available to common stockholders
Weighted-average common shares outstanding used in computing net loss per share available to common stockholders, basic and diluted:	8,458,277	3,146,632
Net loss per share available to common stockholders:
Net loss per share available to common stockholders, basic and diluted:	$ (3.51)	$ (7.45)
Collaboration revenue
Revenue:
Total revenue		$ 1,168
Grant revenue
Revenue:
Total revenue	$ 1,022	$ 1,589

Consolidated Statements of Chan

Consolidated Statements of Changes in Convertible Preferred Stock and Stockholders' Equity (Deficit) - USD ($) $ in Thousands	Series A Convertible Preferred Stock	Common StockPrivate placement	Common StockIPO	Common Stock	Additional Paid-In CapitalPrivate placement	Additional Paid-In CapitalIPO	Additional Paid-In Capital	Accumulated Deficit	Private placement	IPO	Total
Balances at the beginning of the period at Dec. 31, 2017	$ 74,202						$ (15,140)	$ (47,626)			$ (62,766)
Balances at the beginning of the period (in shares) at Dec. 31, 2017	36,196,193			166,373
Changes in equity
Series A convertible preferred stock dividends ($0.04 per share)	$ 1,358						(1)	(1,357)			(1,358)
Series A convertible preferred stock dividends (in shares)	669,647
Conversion of Series A convertible preferred stock into common stock upon initial public offering	$ (75,560)			$ 1			75,559				75,560
Conversion of Series A convertible preferred stock into common stock upon initial public offering (in shares)	(36,865,840)			5,744,586
Reclassification of warrant liability to equity upon initial public offering							10,236				10,236
Issuance of common stock						$ 25,079				$ 25,079
Issuance of common stock (in shares)			2,192,824
Exercise of stock options							10				10
Exercise of stock options (in shares)				974,000
Stock-based compensation							1,658				1,658
Net loss								(22,105)			(22,105)
Balances at the end of the period at Dec. 31, 2018				$ 1			97,401	(71,088)			26,314
Balances at the end of the period (shares) at Dec. 31, 2018				8,104,757
Changes in equity
Issuance of common stock					$ 4,958				$ 4,958
Issuance of common stock (in shares)		801,820
Exercise of stock options							35				35
Exercise of stock options (in shares)				11,884
Stock-based compensation							2,010				2,010
Net loss								(29,681)			(29,681)
Balances at the end of the period at Dec. 31, 2019				$ 1			$ 104,404	$ (100,769)			$ 3,636
Balances at the end of the period (shares) at Dec. 31, 2019				8,918,461

Consolidated Statements of Ch_2

Consolidated Statements of Changes in Convertible Preferred Stock and Stockholders' Equity (Deficit) (Parenthetical)	12 Months Ended
	Dec. 31, 2018$ / shares
Series A Convertible Preferred Stock
Preferred dividends:
Dividends per share (in dollars per share)	$ 0.04

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Cash flows from operating activities:
Net loss	$ (29,681)	$ (22,105)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	338	283
Stock-based compensation expense	2,010	1,658
Share of loss from equity method investment	951	40
Change in fair value of preferred stock warrants		(1,632)
Changes in operating assets and liabilities:
Accounts receivable	1,660	(1,660)
Other receivables	25
Prepaid expenses and other current assets	(1,433)	(2,207)
Contract costs	(1,576)
Other assets	438	(648)
Accounts payable	(469)	1,297
Accrued liabilities	(2)	800
Deferred revenue	19,580	(97)
Net cash used in operating activities	(8,159)	(24,271)
Cash flows from investing activities:
Purchase of equity method investment	(174)	(677)
Purchase of property and equipment		(1,000)
Net cash used in investing activities	(174)	(1,677)
Cash flows from financing activities:
Proceeds from issuance of common stock, net	4,958	25,079
Proceeds from stock option exercises	35	10
Net cash provided by financing activities	4,993	25,089
Net decrease in cash and cash equivalents	(3,340)	(859)
Cash and cash equivalents at:
Beginning of period	24,237	25,096
End of period	20,897	24,237
Supplemental cash flow disclosures:
Cash paid for taxes	2	2
Supplemental noncash investing and financing activities:
Preferred stock dividends accrued		1,357
Reclassification of warrant liability into equity		10,236
Property and equipment additions	$ 13	$ 120

Description of Business and Bas

Description of Business and Basis of Presentation	12 Months Ended
	Dec. 31, 2019
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”) 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 San Jose, California. We are a late-stage biopharmaceutical company focused on developing new breakthrough therapies for infectious diseases and addressing the growing problem of antibiotic resistance. The Company has a deep, diversified portfolio of clinical and pre-clinical stage non-antibiotic anti-infective product candidates that are complimented by a fully human monoclonal antibody discovery platform technology. The Company’s suite of anti-infective monoclonal antibodies offers opportunities to profoundly alter the current trajectory of increasing antibiotic resistance and improve the health outcome of many of the most serious life-threatening infections particularly in hospital settings. Basis of Presentation and Consolidation The accompanying consolidated financial statements have been prepared in accordance with the United States generally accepted accounting principles, or GAAP. The consolidated financial statements include the accounts of the Company and its two wholly-owned subsidiaries, Aridis Biopharmaceuticals, Inc. 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. Reclassifications Certain prior period amounts have been reclassified to conform to the current period presentation. These reclassifications had no effect on previously reported net loss, stockholders' equity (deficit) or cash flow activities. Reverse Stock Split On August 3, 2018, the Company effected a 1 for 6.417896 reverse stock split of the Company’s common stock. The par value and the number of authorized shares of the common and convertible preferred stock were not adjusted as a result of the reverse stock split. All common stock share and per-share amounts for all periods presented in this Annual Report on Form 10-K have been adjusted retroactively to reflect the reverse stock split. Initial Public Offering On August 13, 2018, the Company's registration statement on Form S-1 relating to its initial public offering of its common shares (the "IPO") was declared effective by the SEC. The IPO closed on August 16, 2018 and the Company issued and sold 2,000,000 common shares at a public offering price of $13.00 per share. Gross proceeds totaled $26.0 million and net proceeds totaled $22.8 million after deducting underwriting discounts and commissions of $1.8 million and other offering expenses of approximately $1.4 million. The underwriters of the IPO partially exercised their over-allotment option, and on August 30, 2018, the Company issued and sold 192,824 common shares at a public offering price of $13.00 per share for gross proceeds totaling approximately $2.5 million and net proceeds of approximately $2.3 million after deducting underwriting discounts and commissions of approximately $175,000 million. In connection with the IPO, the holders of a majority of the Series A Preferred Stock approved the mandatory conversion of the Series A Preferred Stock into one share of common stock for every 6.417896 shares of Series A Preferred Stock which converted immediately prior to the consummation of the IPO. Upon conversion, a total of 5,744,586 shares of common stock were issued for the converted Series A Preferred Stock which includes the accrued dividends upon conversion. All warrants to purchase Series A Preferred Stock became warrants to purchase common stock, adjusted for the 1 for 6.417896 shares reverse stock split. Going Concern The Company had recurring losses from operations since inception and negative cash flows from operating activities during the years ended December 31, 2019 and 2018. Management expects to incur additional operating losses in the foreseeable future as the Company continues its product development programs. At December 31, 2019, the Company had cash and cash equivalents of $20.9 million. Our research and development expenses and resulting cash burn during the year ended December 31, 2019, were largely due to costs associated with launching the Phase 3 study of AR-301 for the treatment of VAP caused by the Staphylococus aureus bacteria, the Phase 2 study of AR-105 for the treatment of VAP caused by the Pseudomonas aeruginosa bacteria, and the Phase 1/2 study of AR-501 for the treatment of chronic lung infections associated with cystic fibrosis. Current clinical development activities are focused on AR-301 and AR-501. While no further development resources will be allocated towards AR-105, we will continue to analyze the full data set to better understand these top-line results. We expect our expenses to increase in connection with our ongoing development activities, particularly as we continue the research, development and clinical trials of, and seek regulatory approval for, our therapeutic candidates. On March 11, 2020, the World Health Organization declared the COVID-19 outbreak a pandemic. The COVID-19 pandemic is affecting the United States and global economies and may affect the Company’s operations and those of third parties on which the Company relies, including 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. The Company may be unable to secure additional financing or other sources of funding on acceptable terms, or at all. 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 financial statement issuance date. The accompanying consolidated financial statements have been prepared on a going concern basis that contemplates the realization of assets and discharge of liabilities in their normal course of business. There is substantial doubt about the Company’s ability to continue as a going concern for one year after the date that these consolidated financial statements are issued. These consolidated financial statements do not include any adjustments that might be necessary from the outcome of this uncertainty.

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2019
Summary of Significant Accounting Policies
Summary of Significant Accounting Policies	2. Summary of Significant Accounting Policies Use of Estimates The preparation of the consolidated financial statements requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities as of the date of the consolidated financial statements and the reported amounts of expenses during the reporting period. Such estimates include those related to the evaluation of our ability to continue as a going concern, best estimate of standalone selling price of revenue deliverables, allowance for doubtful accounts, long-lived assets, income taxes, assumptions used in the Black-Scholes-Merton (“BSM”) model to calculate the fair value of stock-based compensation, assumptions used in the Monte Carlo Simulation (“MSM”) model to calculate the fair value of warrants, deferred tax asset valuation allowances, valuation of the Company’s common and convertible preferred stock, preclinical study and clinical trial accruals. Actual results could differ from those estimates. Concentrations Credit Risk The Company’s cash and cash equivalents are maintained at financial institutions in the United States of America. Deposits held by these institutions may exceed the amount of insurance provided on such deposits. Customer Risk For the year ended December 31, 2019, one customer accounted for 100% of total revenue. For the year ended December 31, 2018, two customers accounted for 58% and 42% of total revenue. Both of the Company’s customers are located in the United States. As of December 31, 2019, there was no accounts receivable. As of December 31, 2018, two customers accounted for 60% and 40% of total accounts receivable. Cash and Cash Equivalents The Company considers all highly liquid investments purchased with an original maturity of three months or less to be cash equivalents. Cash equivalents consist primarily of checking account and money market account balances. Accounts Receivable and Allowance for Doubtful Accounts Accounts receivable are recorded at the invoiced amount and do not bear interest. The Company considers the credit worthiness of its customers but does not require collateral in advance of a sale. The Company evaluates collectability and maintains an allowance for doubtful accounts for estimated losses inherent in its accounts receivable portfolio when necessary. The allowance is based on the Company’s best estimate of the amount of losses in the Company’s existing accounts receivable, which is based on customer creditworthiness, facts and circumstances specific to outstanding balances, and payment terms. Account balances are charged off against the allowance after all means of collection have been exhausted and the potential for recovery is considered remote. As of December 31, 2019, and 2018, there were no allowances for doubtful accounts. Property and Equipment Property and equipment are stated at cost less accumulated depreciation. Depreciation is computed using the straight-line method over the estimated useful lives of the assets, generally between three and five years. Maintenance and repairs are charged to expense as incurred. When assets are retired or otherwise disposed of, the cost and accumulated depreciation are removed from the balance sheet and any resulting gain or loss is reflected in the consolidated statement of operations in the period realized. Intangible Assets Intangible assets are recorded at cost and amortized over the estimated useful life of the asset. Intangible assets consist of licenses with various institutions whereby the Company has rights to use intangible property obtained from such institutions. Impairment of Long-Lived Assets The Company reviews long-lived assets for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable. Recoverability is measured by comparison of the carrying amount to the future undiscounted net cash flows which the assets are expected to generate. If such assets are considered to be impaired, the impairment is measured by the excess of the carrying amount of the assets over fair value less the costs to sell the assets, generally determined using the projected discounted future net cash flows arising from the asset. There have been no such impairments of long-lived assets as of December 31, 2019 and 2018. Revenue Recognition Effective January 1, 2019, the Company adopted Accounting Standards Codification (“ASC”) 606, Revenue from Contracts with Customers (“ASC 606”), using the modified retrospective method. Under this method, results for reporting periods beginning after January 1, 2019 are presented under ASC 606, while prior period amounts are not adjusted and continue to be reported in accordance with ASC 605, Revenue Recognition (“ASC 605”). The Company only had one contract, the CFF Agreement, within the scope of ASC 606 as of the adoption date. The cumulative-effect of adopting ASC 606 on January 1, 2019, using the modified retrospective method, was immaterial. ASC 606 applies to all contracts with customers, except for contracts that are within the scope of other standards, such as leases, insurance, collaboration arrangements and financial instruments. See Note 6 for details of the collaboration, development and license agreements. To determine revenue recognition for arrangements that the Company determines are within the scope of ASC 606, the Company performs the following five steps: (i) identify the contract(s) with a customer; (ii) identify the performance obligations in the contract; (iii) determine the transaction price; (iv) allocate the transaction price to the performance obligations in the contract; and (v) recognize revenue at a point in time, or over time, as the entity satisfies performance obligations. The Company only applies the five-step model to contracts when it is probable that it will collect the consideration it is entitled to in exchange for the goods or services it transfers to the customer. At contract inception, once the contract is determined to be within the scope of ASC 606, the Company assesses the goods or services promised within each contract, determines those that are performance obligations, and assesses whether each promised good or service is distinct. The Company then recognizes as revenue the amount of the transaction price that is allocated to the respective performance obligation when (or as) the performance obligation is satisfied. As part of the accounting for customer arrangements, the Company must use judgment to determine: a) the number of performance obligations based on the determination under step (ii) above; b) the transaction price under step (iii) above; and c) the standalone selling price for each performance obligation identified in the contract for the allocation of the transaction price in step (iv) above. The Company uses judgment to determine whether milestones or other variable consideration should be included in the transaction price. The transaction price is allocated to each performance obligation on a relative standalone selling price basis. In developing the standalone price for a performance obligation, the Company considers applicable market conditions and relevant entity-specific factors, including factors that were contemplated in negotiating the agreement with the customer and estimated costs. The Company recognizes revenue as or when the performance obligations under the contract are satisfied. The Company receives payments from its customers based on payment schedules established in each contract. The Company records any amounts received prior to satisfying the revenue recognition criteria as deferred revenue on its consolidated balance sheet. Amounts recognized as revenue, but not yet received or invoiced are recorded within other receivables on the consolidated balance sheet. Amounts are recorded as other receivables on the consolidate 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. The Company only had one contract within the scope of ASC 606 upon adoption that had not been completed, the CFF Agreement. The most significant changes under ASC 606 relate to the Company’s determination of the transaction price at inception, determination of the standalone selling price for the performance obligation and at each reporting period the treatment of variable consideration in the form of milestone payments under the CFF Agreement. Under ASC 606, the Company is recognizing the revenue allocated to the one performance obligation measuring progress using the input (cost-to-cost) method, limited by the variable consideration attributed to the probable completion of certain milestones as defined in the CFF Agreement. The cumulative-effect of adopting ASC 606 on January 1, 2019 was immaterial. Under ASC 605, the Company recognized revenue under the milestone method up to the limit of the prior approval funding amounts, and when the Company determined that it had earned the right to receive the recognized portion according to the terms of the grant awarded. The upfront payment of $200,000 was recognized straight-line over the term of the contract as the Company believed the upfront fee related to services performed throughout the contract period and the upfront fee did not represent a substantive milestone within the agreement. Revenue for the year ended December 31, 2018, was recognized in accordance with ASC 605 which required that four basic criteria must be met before revenue can be recognized: (1) persuasive evidence of an arrangement exists; (2) delivery has occurred and title and the risks and rewards of ownership have been transferred to the client or services have been rendered; (3) the price is fixed or determinable; and (4) collectability is reasonably assured. During 2018, revenue includes grant awards and collaboration services entered into for specific research and development efforts. The Company recognized revenue under such awards and contracts as the related qualified research and development expenses were incurred or under the milestone method, up to the limit of the prior approval funding amounts, and when we had determined that we earned the right to receive the recognized portion according to the terms of the original grant awarded. Contract Assets The incremental costs of obtaining a contract under ASC 606 (i.e. costs that would not have been incurred if the contract had not been obtained) are recognized as an asset in the Company’s consolidated balance sheet if the Company expects to recover them. Management expects that the incremental fees paid to third-parties as a result of obtaining the License Agreement are recoverable and therefore the Company capitalized them as contract costs, current and noncurrent, in its consolidated balance sheet (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 year ended December 31, 2019, there was no amortization of the contract assets and there have been no impairments as of December 31, 2019. Deferred Revenue Amounts received prior to satisfying the above revenue recognition criteria, or in which the Company has an unconditional right to payment, are recorded as deferred revenue in the Company’s consolidated balance sheets. The Company has estimated the classification between current and noncurrent deferred revenue related to the respective license agreement within its consolidated balance sheet at December 31, 2019 (see Note 6). Costs for Collaborative Arrangements Costs incurred under collaborative arrangements include personnel costs, laboratory supplies and fees paid to third parties. These amounts are included in research and development in the accompanying consolidated statement of operations. For the year ended December 31, 2018, the Company had incurred expenses of approximately $604,000, related to its collaborative arrangement. The Company’s collaborative arrangement was terminated in 2018 therefore no related expenses in 2019. 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 Effective January 1, 2019, the Company early adopted Accounting Standards Update (“ASU”) No. 2018-07, Compensation—Stock Compensation (Topic 718), Improvements to Nonemployee Share-Based Payment Accounting . 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. Prior to the adoption of ASU No. 2018-07, the Company accounted for stock-based compensation arrangements with nonemployees by recording the expense of such services based on the estimated fair value of the common stock at the measurement date. The value of the equity instrument, including adjustment to fair value at each balance sheet date for the vested awards, is charged to operations over the term of the service agreement as earned. 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. Prior to the completion of the Company’s initial public offering of common stock on August 16, 2018, due to the absence of a public market trading for the Company’s common stock, it was necessary to estimate the fair value of the common stock underlying the Company’s stock-based awards when performing fair value calculations. 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 positions 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. Comprehensive Loss The Company has no items of comprehensive income or loss other than net loss. Loss Per Share Basic loss per common share is calculated by dividing net loss available to common stockholders 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, adjusted for any preferred dividends, available to common stockholders by the weighted-average number of common shares and potentially dilutive securities outstanding for the period. For the years ended December 31, 2019 and 2018, there is no difference in the number of shares used to compute basic and diluted net loss per share due to the Company’s net loss position. The following tables presents the computation of the basic and diluted net loss per share available to common stockholders (in thousands, except share and per share data): Year Ended December 31, 2019 2018 Numerator: Net loss available to common stockholders (basic and diluted) $ (29,681) $ (23,462) Denominator: Weighted-average shares of common stock (basic and diluted) 8,458,277 3,146,632 Basic and diluted net loss per share $ (3.51) $ (7.45) The following potentially dilutive securities were excluded from the computation of diluted net loss per share available to common stockholders for the periods presented because including them would have been antidilutive: Year Ended December 31, 2019 2018 Stock options to purchase common stock 1,380,312 825,205 Common stock warrants 1,733,322 1,966,930 3,113,634 2,792,135 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 adopted during the year ended December 31, 2019 Accounting Standards Update 2014-09 In May 2014, the Financial Accounting Standards Board (“FASB”) issued ASU No. 2014-09, which amends the guidance for accounting for revenue from contracts with customers. This ASU supersedes the revenue recognition requirements in ASC 605, Revenue Recognition (“ASC 605”) , and creates ASC 606. In 2015 and 2016, the FASB issued additional ASUs related to ASC 606 that delayed the effective date of the guidance and clarified various aspects of the new revenue guidance, including principal versus agent considerations, identifying performance obligations, and licensing, and they include other improvements and practical expedients. Companies have the option of applying this new guidance retrospectively to each prior reporting period presented (the full retrospective method) or retrospectively with the cumulative effect of initially applying this update recognized at the date of initial application (the modified retrospective method). For public entities, ASC 606 is effective for fiscal years beginning after December 15, 2017, and interim periods within those fiscal year. As a result of the Company having elected the extended transition period for complying with new or revised accounting standards pursuant to Section 107(b) of the JOBS Act, ASC 606 is effective for the Company on January 1, 2019, and all interim periods thereafter. The Company adopted this standard on January 1, 2019. The Company only had one contract, the CFF Agreement, within the scope of ASC 606 as of the adoption date. The cumulative-effect of adopting ASC 606 on January 1, 2019, using the modified retrospective method, was immaterial. Accounting Standards Update 2018-07 and 2019-08 In June 2018, the FASB issued ASU 2018-07, Compensation—Stock Compensation (ASC 718), Improvements to Nonemployee Share-Based Payment Accounting, which is intended to simplify the accounting for nonemployee share-based payment transactions by expanding the scope of Topic 718 to include share-based payment transactions for acquiring goods and services from nonemployees. In November 2019, the FASB issued ASU 2019-08, Compensation—Stock Compensation (ASC 718) and Revenue from Contracts with Customers (ASC 606), Improvements to Share-Based Consideration Payable to a Customer, which requires that an entity measure and classify share-based payment awards granted to a customer by applying the guidance in ASC 718. For public entities, ASU 2018-07 is effective for fiscal years beginning after December 15, 2018. As a result of the Company having elected the extended transition period for complying with new or revised accounting standards pursuant to Section 107(b) of the JOBS Act, ASU 2018-07 is effective for the Company for the year ending on December 31, 2020, and all interim periods within. Early adoption is permitted. For entities that have adopted the amendments in ASU 2018-07, the amendments in ASU 2019-08 are effective in fiscal years beginning after December 15, 2019, and all interim periods within. An entity may early adopt the amendments in ASU 2019-08, but not before it adopts the amendments in ASU 2018-07. The Company early adopted ASU 2018-07 on January 1, 2019 and ASU 2019-08 on July 1, 2019. The adoption of these standards did not have a material effect on our consolidated financial statements. Recently Issued Accounting Pronouncements not yet adopted as of December 31, 2019 Accounting Standards Update 2016-02 and 2018-11 In February 2016, the FASB issued ASU 2016-02, Leases (ASC 842) . In July 2018, the FASB issued ASU 2018-10, Codification Improvements to ASC 842, Leases , which provides clarification to ASU 2016-02. These ASUs (collectively, the new lease standard) require an entity to recognize a lease liability and a right-of-use asset on the balance sheet for leases with lease terms of more than twelve months. Lessor accounting is largely unchanged, while lessees will no longer be provided with a source of off-balance sheet financing. Initial guidance required the adoption of the new lease standard using the modified retrospective transition method. In July 2018, the FASB issued ASU 2018-11, Leases (ASC 842)—Targeted Improvements , which allows entities to elect an optional transition method where entities may continue to apply the existing lease guidance during the comparative periods and apply the new lease requirements through a cumulative effect adjustment in the period of adoptions rather than in the earliest period presented. In March 2019, FASB issued ASU 2019-01, Codification improvements , which provides clarification on implementation issued associated with adopting ASU 2016-02. ASU 2019-01 enhances the guidance in ASC 842 surrounding the fair value of underlying assets for lessors, presentation of sales-type and direct financing leases on the statement of cash flows, and transition guidance surrounding accounting changes and error corrections. This guidance is 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. As a result of the Company having elected the extended transition period for complying with new or revised accounting standards pursuant to Section 107(b) of the JOBS Act, the new leasing standard updates would be effective for the Company for the year ended December 31, 2021, and all interim periods within the year ended December 31, 2022, due to its option to defer the adoption of new accounting standards under the JOBS Act. Early adoption is permitted. While the Company continues to review its current accounting policies and practices to identify potential differences that would result from applying the new guidance, the Company expects that its non-cancellable operating lease commitments with a term of more than twelve months will be subject to the new guidance and recognized as right-of-use assets and operating lease liabilities on the Company’s consolidated balance sheets upon adoption. The Company expects to elect transitional practical expedients such that the Company will not need to reassess whether contracts are leases and will retain lease classification and initial direct costs for leases existing prior to the adoption of the new lease standard. Accounting Standards Update 2016-13 In June 2016, the FASB issued ASU 2016-13, “ Financial Instruments—Credit Losses (ASC 326) ”, which is intended to provide financial statement users with more useful information about expected credit losses on financial assets held by a reporting entity at each reporting date. The new standard replaces the existing incurred loss impairment methodology with a methodology that requires consideration of a broader range of reasonable and supportable forward-looking information to estimate all expected credit losses. For public business entities, ASU 2016-13 is effective for fiscal years and interim periods within those years beginning after December 15, 2020. As a result of the Company having elected the extended transition period for complying with new or revised accounting standards pursuant to Section 107(b) of the JOBS Act, ASU 2016-13 is effective for the Company for the fiscal year ending on December 31, 2022, and all interim periods within. Early adoption is permitted. The Company does not expect the adoption of ASU 2016-13 to have a material impact on the Company's consolidated financial statements and disclosures. Accounting Standards Update 2019-12 In December 2019, the FASB issued ASU 2019-12, “ Simplifying the Accounting for Income Taxes (ASC 740) ”, which removes certain exceptions to the general principles in Topic 740 and improves consistent application of and simplifies U.S. GAAP for other areas of Topic 740 by clarifying and amending existing guidance. For public entities, the ASU 2019-12 is effective for fiscal years and interim periods within those years beginning after December 15, 2020. As a result of the Company having elected the extended transition period for complying with new or revised accounting standards pursuant to Section 107(b) of the JOBS Act, ASU 2019-12 is effective for the Company for the fiscal year ending on December 31, 2022, and all interim periods within. Early adoption is permitted. The Company is currently evaluating the impact of this guidance on its consolidated financial statements.

Fair Value Disclosure

Fair Value Disclosure	12 Months Ended
	Dec. 31, 2019
Fair Value Disclosure
Fair Value Disclosure	3. Fair Value Disclosure The carrying value of the Company’s cash and cash equivalents, prepaid expenses and other current assets, other assets, accounts payable, and accrued liabilities approximate fair value due to the short-term nature of these items. 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 I 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. As of December 31, 2019, the Company did not have any assets or liabilities to be measured at fair value on its consolidated balance sheet. The following table presents the Company’s fair value hierarchy for its liabilities measured at fair value as of December 31, 2018 (in thousands): Fair Value at December 31, 2018 ($ in thousands) Total Level 1 Level 2 Level 3 Assets: Deferred charge related to stock options $ 455 $ — $ 455 $ — Totals $ 455 $ — $ 455 $ — Liabilities: Stock option liability $ 455 $ — $ 455 $ — Totals $ 455 $ — $ 455 $ —

Balance Sheet Components

Balance Sheet Components	12 Months Ended
	Dec. 31, 2019
Balance Sheet Components
Balance Sheet Components	4. Balance Sheet Components Property and Equipment, net Property and equipment, net consist of the following (in thousands): December 31, 2019 2018 Lab equipment $ 1,804 $ 1,737 Computer equipment and software 25 25 Total property and equipment 1,829 1,762 Less: Accumulated depreciation (823) (491) Property and equipment, net $ 1,006 $ 1,271 Depreciation expense was approximately $332,000 and $278,000 for the year ended December 31, 2019 and 2018, respectively. Intangible Assets, net Intangible assets, net consist of the following (in thousands): December 31, 2019 2018 Licenses $ 81 $ 81 Less: Accumulated amortization (49) (43) Intangible assets, net $ 32 $ 38 Amortization expense was approximately $6,000 and $5,000 for the years ended December 31, 2019 and 2018, respectively. The estimated acquired intangible amortization expense for the next five fiscal years is as follows (in thousands): Year Ended December 31, 2020 $ 5 2021 5 2022 5 2023 5 2024 and thereafter 12 Total $ 32 Licenses University Licensing Agreements The University of Chicago—Exclusive Patent License Agreement We are party to an exclusive licensing agreement with The University of Chicago (UOC), a non-profit university. This agreement granted to us an exclusive, royalty-bearing license for staph alpha toxin technology. The UOC agreement also granted to us the right to sublicense. UOC retained the non-transferrable right to use such patent rights for academic and research purposes, and also to certain pre-existing rights of the U.S. government. We paid upfront fees upon the execution of the agreement and are obligated to pay an annual maintenance fee. We also are obligated to pay UOC low single digit percentage royalties on net sales from our and our sublicensee’s sale of any commercialized licensed product or process, and certain other payments, subject to a minimum amount. The aggregate milestone payments under the UOC agreement potentially total up to $1.6 million. No milestones were met or accrued for during 2019 or 2018. We are responsible for our pro rata share of patent expenses. The agreement provides that we have certain obligations to conduct further research and development, and are obligated to utilize reasonable efforts to commercialize, either directly or through a sublicensee, the licensed UOC patent rights as licensed products or processes. The term of the agreement continues until all patents and filed patent applications, included within the licensed UOC patents, have expired or been abandoned, or until the agreement is earlier terminated. We may terminate the agreement on prior written notice to UOC. Each party has the right to terminate the agreement for the other party’s uncured material breach of obligations under the agreement. The Brigham and Women’s Hospital, Inc.—Exclusive Patent License Agreement We are party to an exclusive licensing agreement with The Brigham and Women’s Hospital, Inc. (BWH), a non-profit corporation. This agreement granted to us an exclusive, royalty-bearing license under its and Beth Israel Deaconess Medical Center’s (BIDMC) rights in methods and composition relating to specific binding peptides to P. aeruginosa mucoid exopolysaccharide to make, use and sell products and processes for the treatment of pseudomonas infections in humans that are covered by such patent rights. The BWH agreement also granted to us the right to sublicense. BWH and BIDMC retained the non-transferrable right to use such patent rights for academic and research purposes, and also to certain pre-existing rights of the U.S. government. We also are obligated to pay BWH low single digit percentage royalties on net sales from our and our sublicensee’s sale of any commercialized licensed product or process, and certain other payments. The aggregate milestone payments under the BHW agreement potentially total up to $860,000. No milestones were met or accrued for during 2019 or 2018. We are responsible for diligently prosecuting and maintaining the licensed patent rights, at our sole cost and expense. The agreement provides that we have certain obligations to conduct further research and development, and are obligated to utilize reasonable efforts to commercialize, either directly or through a sublicensee, the licensed BWH patent rights as licensed products or processes. The term of the agreement continues until all patents and filed patent applications, included within the licensed BWH patents, have expired or been abandoned, or until the agreement is earlier terminated. We may terminate the agreement on prior written notice to BWH. Each party has the right to terminate the agreement for the other party’s uncured material breach of obligations under the agreement. The University of Iowa Research Foundation—Exclusive Patent License Agreement We are party to an exclusive licensing agreement with The University of Iowa Research Foundation (UIRF). The UIRF agreement granted to us an exclusive, royalty-bearing license under its rights in methods relating to gallium containing compounds for the treatment of infections to make, use and sell products that are covered by such patent rights. The UIRF agreement also granted to us the right to sublicense. UIRF retained the right and ability to grant right to use such patent rights for academic and research purposes, and also to certain pre-existing rights of the U.S. government including the United States Department of Veterans Affairs. We also are obligated to pay UIRF low single digit percentage royalties on net sales from our and our sublicensee’s sale of any commercialized licensed product or process, and certain other payments. The aggregate milestone payments under the UIRF agreement potentially total up to $712,500. No milestones were met or accrued for during 2019 or 2018. We are responsible for diligently prosecuting and maintaining the licensed UIRF patent rights, at our sole cost and expense. The agreement provides that we have certain obligations to conduct further research and development, and are obligated to utilize reasonable efforts to commercialize, either directly or through a sublicensee, the licensed UIRF patent rights as licensed products or processes. The term of the agreement continues until the expiration of the last to expire patents, included within the licensed UIRF patents, or until the agreement is earlier terminated. We may terminate the agreement on prior written notice to UIRF. Each party has the right to terminate the agreement for the other party’s uncured material breach of obligations under the agreement. Brigham Young University—Exclusive Patent License Agreement We are party to an exclusive licensing agreement with Brigham Young University (BYU). This agreement granted to us an exclusive, royalty-bearing license under its rights in stabilization of biological agents methods relating to human vaccines to make, use and sell products that are covered by such patent rights. The agreement also granted to us the right to sublicense. BYU and the Church of Jesus Christ of Latter-day Saints and the Church Education System retained the right and ability to use such patent rights for academic and ecclesiastical purposes and also to purchase products using such patents rights at a discounted price. We also are obligated to pay BYU low single digit percentage royalties on net sales from our and our sublicensee’s sale of any commercialized licensed product, and certain other payments. The aggregate milestone payments under the BYU agreement potentially total up to $400,000. No milestones were met or accrued for during 2019 or 2018. BYU is responsible for diligently prosecuting and maintaining the licensed BYU patent rights and we reimburse them for one-third of their costs. The agreement provides that we have certain obligations to conduct further research and development, and are obligated to utilize reasonable efforts to commercialize, either directly or through a sublicensee, the licensed BYU patent rights as licensed products or processes. The term of this agreement continues until the expiration of the last to expire patents, included within the licensed BYU patents, or until the agreement is earlier terminated. We may terminate the agreement on prior written notice to BYU. Each party has the right to terminate the agreement for the other party’s uncured material breach of obligations under the agreement. Public Health Service Licensing Agreement NIH ("National Institutes of Health")—Exclusive and Non-Exclusive Patent License Agreement We are party to an exclusive and non-exclusive licensing agreement with the NIH. This agreement granted to us an exclusive, royalty-bearing license in our exclusive territory and non-exclusive rights in the non-exclusive territory under its rights in a human rotavirus vaccine based on their human-bovine rotavirus reassortants to make, use and sell products and processes that are covered by such patent rights. The agreement also granted to us the right to sublicense. Our license under this agreement is subject to the U.S. government’s retained rights under a non-exclusive, worldwide, royalty-free license for the practice of all inventions licensed under the Public Health Service, or PHS, patent rights, by or on behalf of the U.S. government and on behalf of any foreign government or international organization pursuant to any existing or future treaty or agreement to which the U.S. government is a signatory. For purposes of encouraging basic research, the U.S. government also reserves the right to grant or require us to grant to a third party on reasonable terms a non-exclusive, non-transferable license to make and use the licensed products or licensed processes for research purpose only, but subject to PHS consulting with us in the event such third party is a commercial entity. Under certain exceptional and enumerated circumstances, the U.S. government may require us to grant a sublicense to a responsible third party applicant, on terms that are reasonable under the circumstances. The PHS takes responsibility for all aspects of the preparation, filing, prosecution and maintenance of any and all patent applications or patents included in the licensed PHS patent rights, subject to our payment of certain patent-related expenses. We also are obligated to pay PHS low single digit percentage royalties on net sales from our and our sublicensee’s sale of any commercialized licensed product or process, and certain other payments. The aggregate milestone payments under the NIH agreement potentially total up to $850,000. No milestones were met or accrued for during 2019 or 2018. PHS is responsible for diligently prosecuting and maintaining the licensed PHS patent rights, and we reimburse them for a portion of their costs. The agreement provides that we have certain obligations to conduct further research and development, and are obligated to utilize reasonable efforts to commercialize, either directly or through a sublicensee, the licensed PHS patent rights as licensed products or processes. The term of the PHS agreement continues until the expiration of all royalty obligations, included within the licensed PHS patents, or until the agreement is earlier terminated. We may terminate the agreement on prior written notice to PHS. Each party has the right to terminate the agreement for the other party’s uncured material breach of obligations under the agreement. Non-Profit Licensing Agreements Program for Appropriate Technology in Health and PATH Vaccine Solutions We granted the Program for Appropriate Technology in Health (PATH), a global non-profit organization, and the PATH Vaccine Solutions a non-exclusive license, with right to sublicense formulations, for use with the measles, rotavirus, live-attenuated influenza, pneumococcal and enteric vaccines only for sale in developing countries. We have also agreed to provide rotavirus vaccines to public sector purchasers in developing countries at a preferential price relative to private sector purchasers in developing countries where the rotavirus vaccine utilizing the enabling formulation technology is offered for sale. Corporate Licensing Agreements Kenta Biotech Ltd. We are party to an asset purchase agreement with Kenta Biotech Ltd. (Kenta), a for profit corporation (Aktiengesellschaft) duly incorporated in Schlieren (Canton of Zurich, Switzerland), registered under the identification number CH‑035.3.035.876‑2. The agreement assigned and transferred certain of Kenta’s physical assets, contracts and technology to us. The physical assets included all physical assets owned or controlled by Kenta, including but not limited to cell lines, genes, antibodies, diagnostic assays and related documentation, which were related to Kenta’s MabIgX technology platform for hybridoma generation and its mAb targeting S. aureus , P. aeruginosa , A. baumannii and RSV. The technology included all intellectual property, including but not limited to patents, patent applications, trademarks, knowhow, trade secrets, regulatory filings, clinical trials, clinical trial information, all supporting documentation and all other related intellectual property which are related to Kenta’s MabIgX technology platform for hybridoma generation and its mAb targeting S. aureus , P. aeruginosa , A . baumannii and RSV. The contracts included the contracts and agreements (including all rights and obligations thereunder), whether oral or written, which Kenta has concluded and which pertain to the assets. The contracts were primarily related to the ongoing clinical trial of AR 301. We were obligated to pay Kenta a fixed purchase price, which was fully paid during 2013 and 2014, and a declining scale of low double digit to low single digit percentage royalties on gross licensing revenues from either our licensing of the assets or net sales revenues actually received by us up to a maximum of $50 million. As of December 31, 2019, the Company accrued approximately $488,000 due to Kenta for a royalty obligation resulting from the license agreement entered into in September 2019 (see Note 6). As of December 31, 2018, no royalty obligation due to Kenta had been met. Emergent Product Development Gaithersburg Inc. We are party to a license agreement with Emergent Product Development Gaithersburg Inc. (Emergent). We granted Emergent an exclusive, perpetual, royalty-bearing license to use certain of our patents and related know how for the prevention or treatment of infection or illness caused by biodefense pathogens. We also granted a non-exclusive, royalty-bearing license to use certain of our patents and related know how for the prevention or treatment of tularemia and viral hemorrhagic fever indications. Emergent is obligated to pay us low single digit percentage royalties on net sales from their and their sublicensee’s sale of any commercialized licensed product, and certain other payments. The aggregate milestone payments that the Company could receive under the Emergent agreement amount to $2.8 million.The Company is not aware of Emergent achieving any milestones under the agreement and has not received any milestone payments. The Company has certain diligence obligations to conduct further research and development, and to exploit licensed products. Accrued Liabilities Accrued liabilities consist of the following (in thousands): December 31, 2019 2018 Research and development services $ 2,709 $ 2,179 Stock option liability — 455 Payroll related expenses 150 254 Professional services 115 56 Accrued liabilities $ 2,974 $ 2,944

Equity Method Investment

Equity Method Investment	12 Months Ended
	Dec. 31, 2019
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”), for developing and commercializing products for infectious diseases. Under the terms of the JV Agreement, the Company contributed $1.0 million and the license of its technology relating to the Company’s AR-101 and AR-301 product candidates for use in the joint venture company named Shenzhen Arimab BioPharmaceuticals Co., Ltd. (the “JV Entity”) in the territories of the Republic of China, Hong Kong, Macau and Taiwan (the “Territory”) and initially owns 49% of the JV Entity. On July 2, 2018, the JV Entity received final approval from the government of the Peoples Republic of China. It was agreed by the parties that the Company shall be reimbursed for certain legal and contract manufacturing expenses related to the clinical drug supply for a Phase 3 clinical study of AR-301 and the clinical drug supply for a clinical study of AR-105 (see Note 12). On August 6, 2018, the Company entered into an amendment to the JV Agreement with Hepalink whereby the Company agreed to additionally contribute an exclusive, revocable, and royalty-free right and license to its AR-105 product candidate in the Territory. Pursuant to the JV Agreement and the amendment, Hepalink initially owns 51% of the JV Entity and is obligated to contribute the equivalent of $7.2 million to the JV Entity. Additionally, Hepalink is obligated to make an additional equity investment of $10.8 million or more at the time of the JV Entity’s first future financing The Company evaluated the accounting for the JV Agreement entered into noting that it did not meet the accounting definition of a joint venture and instead meets the definition of a variable interest entity. The Company concluded that it is not the primary beneficiary of the JV Entity and therefore is not required to consolidate the entity. This conclusion was based on the fact that the equity-at-risk is insufficient to support operations without additional investment and that the Company does not hold decision-making power over activities that significantly impact the JV Entity’s operations. The Company accounted for its investment in the JV Entity as an equity method investment. The Company recorded the equity method investment at $1.0 million which represents the Company’s contribution into the JV Entity. The Company’s license contributed to the JV Entity was recorded at its carryover basis of $0. For the years ended December 31, 2019 and 2018, the Company recognized approximately $951,000 and $40,000 losses from the operations of the JV Entity, respectively. As of December 31, 2019 and 2018, the Company’s equity method investment in the JV Entity was approximately $9,000 and $960,000, respectively.

Collaboration, Development and

Collaboration, Development and License Agreements	12 Months Ended
	Dec. 31, 2019
Collaboration, Development and License Agreements
Collaboration, Development and License Agreements	6. Collaboration, Development and License Agreements GlaxoSmithKline plc Collaboration and Option Agreement In 2017, the Company entered into a collaborative research and development agreement with GlaxoSmithKline plc (“GSK”). In accordance with the agreement, the Company received an upfront fee and is due annual fees and amounts for development work to be performed as specifically outlined under the agreement. The work to be performed was delineated into three specific research projects. In assessing the appropriate revenue recognition related to a collaboration agreement, the Company determined that the arrangement was under ASC 605. As such, the Company determined whether the arrangement included multiple elements, such as the delivery of intellectual property rights and research and development services. Under ASC 605, the recognition of revenue was based on the terms of the contract and recognized under the proportional performance method derived from the completion of certain stages as defined within the contract. For the year ended December 31, 2018, approximately $1.2 million was recorded as collaboration revenue related to the Company’s agreement with GSK. In December 2018, at a meeting of the joint steering committee it was agreed by both parties to terminate the collaboration agreement and the Company had no further commitments under the arrangement. As a result of the termination of the collaboration agreement, the Company recognized all previously deferred revenue and an additional $440,000 for additional work performed during the term of the agreement. No revenue related to this agreement was recognized in 2019. Cystic Fibrosis Foundation Development Agreement In December 2016, the Company received an award from the Cystic Fibrosis Foundation (“CFF”), or 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 as it receives from the non-profit organization. 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 non-profit organization. In November 2018, the CF Foundation increased the award to approximately $7.5 million. The Company determined that the CFF Agreement is within the scope of ASC 606 and that the clinical research activities are considered one performance obligation. Hence, the entire estimated transaction price is allocated to this combined performance obligation and is recognized as revenue by measuring progress using the input (cost-to-cost) method, limited by the variable consideration attributed to the probable completion of certain milestones as defined in the CFF Agreement. The remaining milestones at December 31, 2019 of approximately $ 4.8 million related to clinical research activities are constrained and evaluated at every reporting period. For the years ended December 31, 2019 and 2018, all grant revenue totaling approximately $1.0 million and $1.6 million, respectively, was derived from the CFF Agreement. Serum License Agreement In July 2019, the Company and Serum International B.V. (“SIBV”), an affiliate of Serum Institute of India Private Limited, entered into an option agreement which granted SIBV the option to license multiple programs from the Company and access the Company’s MabIgX® platform technology for asset identification and selection. The Company received an upfront cash payment of $5 million upon execution of this option agreement. In connection with the option agreement, SIBV made an equity investment whereby the Company issued 801,820 shares of its restricted common stock in a private placement to SIBV for total gross proceeds of $10 million. As a result of this transaction, SIBV and its affiliates, are considered related parties to the Company. In September 2019, the Company and Serum AMR Products (“SAMR”), a party under common ownership of SIBV, entered into a License, Development and Commercialization Agreement (the “License Agreement”). Pursuant to the License Agreement, the Company granted to SAMR exclusive licenses, and rights to sublicense, certain patent rights and technology related know-how to the Company’s products AR-301, AR-105, AR-101 (i.e. exclusive rights to, among other things, develop, distribute, market, promote, sell, import and otherwise commercialize) in (a) the country of India, and (b) all other countries of the world except the USA, Canada, EU Territory, UK, China, Australia, South Korea, Brazil, New Zealand, and Japan (products AR-105 and AR-101 countries do not exclude South Korea and Brazil) (the “Limited Territory”); and AR-201 (i.e. exclusive rights to, among other things, develop, manufacture, make, distribute, market, promote, sell, import and otherwise commercialize) in all countries of the world except China, Hong Kong, Macau and Taiwan (the “Worldwide Territory”) (the “licenses and know-how”). Further, the License Agreement grants SAMR an option for the Company to provide research services using its MabIgX® platform technology for the identification of up to five (5) candidates including product development of these identified candidates and an exclusive license to develop, manufacture, make, distribute, market, promote, sell, import and otherwise commercialize these development products in the Worldwide Territory (the “research and development option”). Pursuant to the License Agreement, the Company will provide development support related to the licensed products above in order to assist SAMR in its efforts to develop, receive regulatory approval, and manufacture and sell the licensed products in SAMR’s authorized territories which will be performed under the direction of a Joint Steering Committee (“JSC”) which the Company will participate in (collectively “development support services”). In addition, under the License Agreement, SAMR was granted an exclusive manufacturing license option as the initial license granted above for AR-301, AR-105 and AR-101 does not allow for manufacturing. This manufacturing option provides incremental rights related to these products beyond what is granted as part of the licensing discussed above (the “manufacturing rights option”). If this option is exercised, after SAMR has met certain requirements to exercise the option as defined in the License Agreement, it would provide for an exclusive license for use by SAMR to manufacture and supply the products for SAMR’s own use in the Limited Territory and to manufacture and supply these products to the Company, or their affiliates, for the Company’s use outside the Limited Territory. Should SAMR exercise the development and research option or the manufacturing rights option discussed above, SAMR and the Company shall negotiate in good faith the economic terms around these arrangements. If a third party sublicensee of AR-301, AR-105 and AR-101 wishes to manufacture these products by itself for the territory for which it has a license from the Company, then the Company shall have the right to buy back the manufacturing rights for all territories outside of the Limited Territory by paying to SAMR $5 million. Under the License Agreement, the Company received upfront payments totaling $15 million, of which $5 million was received in July 2019 through the option agreement referred to above. The Company is also entitled to additional payments from SAMR of up to $42.5 million, conditioned upon the achievement of specified milestones related to completion of certain trials and regulatory approvals as defined in the License Agreement. Further, the Company may receive additional royalty-based payments from SAMR if certain sales levels on licensed products are achieved as defined in the License Agreement. Given the equity investment by SIBV was negotiated in conjunction with the option agreement, which resulted in the execution of the License Agreement, all arrangements were evaluated as a single agreement and amounts were allocated to the elements of the arrangement based on their fair value. See Note 9. The Company allocated the proceeds received from the sale of the restricted common stock and upfront payment from the License Agreement, net of issuance and contract costs, of approximately $22.5 million accordingly: · 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 recorded approximately $19.6 million to deferred revenue based on the $15 million from upfront payments under the License Agreement and approximately $4.6 million from the equity allocation; and · the Company capitalized approximately $2.1 million to contract costs, which consists of approximately $376,000 issuance costs from the equity allocation and approximately $1.7 million in other direct costs to obtain the License Agreement. 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 ongoing development support services promised will not significantly change the intellectual property underlying the licenses. Further, the Company believes that SAMR can benefit from the license and know-how either on its own or together with other resources that are readily available, has the ability to sublicense these licensed products and these licenses are separately identifiable from the other promises in the License Agreement. The development support services, the research and development option, and the manufacturing rights option are not integrated or dependent upon each other and are provided by the Company separately from each other. 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 as opposed to over time. The on-going development support services are to be transferred ratably over the period that the Company expects to assist SAMR in its efforts around the licensed products in SAMR’s authorized territories. These development support services will begin with the formation and first formal meeting of the JSC. To allocate the transaction price among the performance obligations and the material promises, the Company estimated the standalone selling prices (“SSP”) for each. For the licenses and knowhow related to AR-301, AR-105, AR-101 and the manufacturing rights option, the SSP was estimated using the income approach based on assumptions regarding SAMR’s future revenues from the licensed intellectual property, projected costs of research and development, manufacturing and commercialization expenses, as well as the discount rate, the development timeline, and probabilities of technical and regulatory success. To estimate the SSP of AR-201, due to this product is in a pre-clinical stage, development support services, and the research and development option, the Company used a cost-plus margin approach which included the actual costs the Company has incurred for the product technology through the date of the License Agreement and estimating the costs the Company expects to incur and applying a margin, if necessary. The Company believes that a change in the assumptions used to determine its best estimate of SSP for the performance obligations and material promises would not have a significant effect on the allocation of consideration received to the performance obligations and material promises. Under ASC 606 an option to acquire additional goods or services gives rise to a material promise if the option provides a material right to the customer. The research and development option allows SAMR to receive additional services from the Company, for cost reimbursement. In addition to the cost reimbursement, the Company could potentially receive milestone and royalty payments depending on the ultimate success of the research and development activities. Furthermore, a portion of the upfront fee incentivizes SAMR to exercise the options. The manufacturing rights option grants an additional license to SAMR for no additional consideration after it has met the requirements to exercise the option. The Company considers this license valuable and would expect to be compensated accordingly in a standalone transaction. Furthermore, the Company’s valuation of these options indicate they had significant value on the agreement date. The Company determined that the above described research and development option and manufacturing rights options do constitute material rights to the customer. 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 the completion of certain trials and regulatory approvals as defined in the License Agreement. Further, SAMR will pay the Company royalty payments ranging between 4% to 6% on net sales of licensed products, except for AR-301, AR-105 and AR-101 products in the EU, should such be authorized at a later date, which would require payment of 20% royalties on the net sales of those products, as defined in the License Agreement. The Company concluded that these milestones and royalty payments each contain a significant uncertainty associated with a future event. As such, these milestone and royalty payments are constrained at contract inception and are not included in the transaction price as the Company could not conclude that it is probable a significant reversal in the amount of cumulative revenue recognized will not occur surrounding these payments. At the end of each reporting period, the Company will update its assessment of whether the milestone and royalty payments are constrained by considering both the likelihood and magnitude of the potential revenue reversal. At December 31, 2019, 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 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 SSP. 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 no performance obligations or material promises were satisfied as of December 31, 2019, and therefore, no revenue related to the License Agreement was recognized for the year ended December 31, 2019. The Company has recorded contract liabilities resulting from the License Agreement of approximately $14.6 million to deferred revenue, current, and approximately $5.0 million to deferred revenue, noncurrent, on its consolidated balance sheet at December 31, 2019. The Company capitalized a contract asset resulting from the License Agreement of approximately $2.1 million related to the incremental costs of obtaining the License Agreement on its consolidated balance sheet, of which approximately $1.5 million is classified as current, and approximately $526,000 is classified as noncurrent, as of December 31, 2019.

Warrants

Warrants	12 Months Ended
	Dec. 31, 2019
Warrants
Warrants	7 . Warrants Common Stock Warrant Expense In November 2015, an engagement letter was effectuated with the Company’s former Vice Chairman of the Board of Directors. Under the terms of the engagement, upon being appointed the Company’s Vice Chairman and the closing of a minimum of $25 million in gross proceeds from sales of its Series A convertible preferred stock under a private placement memorandum, the Vice Chairman would receive 234,860 common stock warrants. On December 12, 2016, both of the aforementioned conditions had been met and the Company issued 234,860 common stock warrants at an exercise price of $14.50 per share. The fair value of the warrants was determined using a Monte Carlo simulation method which calculates the estimated value based on running numerous simulations and analyzing the various outcomes. The total fair value of the award was approximately $661,000 and was being amortized over a five-year vesting period. On August 13, 2019, this board member was not up for re-election at the annual shareholder’s meeting, therefore the vesting of the common stock warrants ceased on August 13, 2019 resulting in the cancellation of 109,601 unvested warrants. For the years ended December 31, 2019 and 2018, the Company recorded stock-based compensation expense of approximately $82,000 and $132,000, respectively, related to these warrants. Warrant Liability The Company evaluated the accounting treatment for the Series A convertible preferred stock warrants issued in 2017 and in prior years and concluded pursuant to its evaluation of Accounting Standard Codification 480, Distinguishing Liabilities From Equity , that due to the contingent liquidation redemption feature in the underlying Series A convertible preferred stock not being solely within the control of the Company, the Series A convertible preferred stock warrants issued were considered a liability in the consolidated balance sheet. As a result, the Company recorded a warrant liability and the subsequent changes in fair value were recorded as a component in other income (expense) in the consolidated statement of operations. The warrant liability required the Company to remeasure the value of the underlying warrants and report the effect of the changes on our operations until the warrants are exercised or expired. The change in fair value of the warrant liability recorded in the consolidated statement of operations in 2018 was a gain of $1.6 million. The primary underlying risk exposure pertaining to the warrants is the change in fair value of the underlying preferred stock for each reporting period. The warrant liability was measured using the Monte Carlo valuation model. Upon the Company’s IPO, the Series A convertible preferred stock warrants were converted into common stock warrants which resulted in the warrant liability being remeasured at the IPO date and classified into additional paid-in-capital. The following table (in thousands) summarizes the Company’s warrant activity and fair value calculations of its derivative warrants for the year ended December 31, 2018: Warrant Liability Balance at December 31, 2017 $ 11,868 Change in fair value of warrants (1,632) Reclassification into equity upon initial public offering (10,236) Balance at December 31, 2018 $ —

Convertible Preferred Stock

Convertible Preferred Stock	12 Months Ended
	Dec. 31, 2019
Convertible Preferred Stock
Convertible Preferred Stock	8 . Convertible Preferred Stock In connection with the IPO, the holders of a majority of the Series A Preferred Stock approved the mandatory conversion of the Series A Preferred Stock into one share of common stock for every 6.417896 shares of Series A Preferred Stock which converted immediately prior to the consummation of the IPO. Upon conversion, a total of 5,744,586 shares of common stock were issued for the converted Series A Preferred Stock which includes accrued dividends upon conversion. All warrants to purchase Series A Preferred Stock became warrants to purchase common stock, adjusted for the 1 for 6.417896 shares reverse stock split. All holders of Series A convertible preferred stock as of June 30, 2016 began accruing a 3% stock dividend beginning on July 1, 2016. Subsequent acquirers began accruing on the date they acquired their respective shares. Accrued dividends were payable annually on December 31. Dividends stopped accruing on August 13, 2018, upon the Company’s IPO, when all outstanding preferred stock converted into common stock. On August 13, 2018, the Company issued 669,489 dividend shares to its preferred stockholders with a fair value of approximately $1.4 million.

Common Stock

Common Stock	12 Months Ended
	Dec. 31, 2019
Common Stock
Common Stock	9. Common Stock As of December 31, 2019, the Company had reserved the following common stock for future issuance: Shares reserved for exercise of outstanding warrants to purchase common stock 1,733,322 Shares reserved for exercise of outstanding options to purchase common stock 1,380,312 Shares reserved for issuance of future options 196,982 Total 3,310,616 Private Placement In July 2019, the Company and SIBV, 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. In connection with the option agreement, SIBV made an equity investment whereby the Company issued 801,820 shares of its restricted common stock to SIBV in a private placement for total gross proceeds of $10 million, and after deducting commissions and offering costs of approximately $816,000, the net proceeds were approximately $9.2 million. Under the arrangement, the Company did not register the common stock purchased by SIBV with the Securities and Exchange Commission and has no contractual obligation to register the shares. Therefore, the common stock is subject to restrictions on transfer, including but not limited to a minimum holding period of at least six months. In September 2019, the Company entered into a License Agreement with SAMR, a wholly owned subsidiary of SIBV. See Note 6 for details of the License Agreement. Given the equity investment by SIBV was negotiated with the option agreement, which then 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 measured the fair value of the restricted common stock issued to SIBV based upon a Black-Scholes valuation to measure the lack of marketability discount. The Black-Scholes valuation used the following assumptions: expected term of one year, expected volatility of 84%, risk-free interest rate of 1.94%, and dividend yield of 0%. The Company allocated the net proceeds received from the sale of the restricted common stock and upfront payment from the License Agreement of approximately $22.5 million (see Note 6 for details of allocation). 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. ATM Agreement In September 2019, the Company entered into a Common Stock Sales Agreement (the “ATM Agreement”) with Cantor Fitzgerald & Co. (“Cantor”) under which the Company may offer and sell, from time to time, in its sole discretion, shares of common stock having an aggregate offering price of up to $25 million through Cantor as its sales agent. The Company’s registration statement on Form S-3 contemplated under the ATM Agreement was declared effective by the SEC on September 5, 2019. The registration statement on Form S-3 includes a base prospectus covering the offering of up to $100 million in aggregate shares of securities as defined within the prospectus and a prospectus supplement of up to a maximum aggregate offering of $25 million in common stock in accordance with the ATM Agreement. As of December 31, 2019, the company had not sold any shares of common stock under the ATM Agreement. Cantor may sell common stock under the ATM Agreement by any method permitted by law deemed to be an “at the market offering” as defined in Rule 415 of the Securities Act of 1933, as amended (the "Securities Act"), including without limitation sales made by means of ordinary brokers’ transactions on the Nasdaq Global Market or otherwise at market prices prevailing at the time of sale, in block transactions, or as otherwise directed by the Company. Cantor will use commercially reasonable efforts to sell the common stock from time to time, based upon instructions from the Company (including any price, time or size limits or other customary parameters or conditions the Company may impose). The Company will pay Cantor a commission of up to three percent (3.0%) of the gross sales proceeds of any common stock sold through Cantor under the ATM Agreement, and also has provided Cantor with customary indemnification rights. The Company is not obligated to make any sales of common stock under the ATM Agreement. The offering of shares of common stock pursuant to the ATM Agreement will terminate upon the earlier of (i) the sale of all common stock subject to the ATM Agreement, or (ii) termination of the ATM Agreement in accordance with its terms.

Stock-Based Compensation

Stock-Based Compensation	12 Months Ended
	Dec. 31, 2019
Stock-Based Compensation
Stock-Based Compensation	10. Stock-Based Compensation Equity Incentive Plan In May 2014, the Company adopted and the shareholders approved the 2014 Equity Incentive Plan (the 2014 Plan). Under the 2014 Plan, 233,722 shares of the Company’s common stock were initially reserved for the issuance of stock options to employees, directors, and consultants, under terms and provisions established by the Board of Directors. Under the terms of the 2014 Plan, options may be granted at an exercise price not less than fair market value. For employees holding more than 10% of the voting rights of all classes of stock, the exercise prices for incentive stock options may not be less than 110% of fair market value, as determined by the Board of Directors. The terms of options granted under the 2014 Plan may not exceed ten years. In addition, the 2014 Plan contains an “evergreen” provision allowing for an annual increase in the number of shares of our common stock available for issuance under the 2014 Plan on the first day of each fiscal year beginning in fiscal year 2015. The annual increase in the number of shares shall be equal to the greater of: · 77,908 shares of our common stock; or · such number of shares as is equal to the number of shares sufficient to cause the option pool to equal 20% of the issued and outstanding common stock of the Company, provided, however, that if on any calculation date the number of shares equal to 20% of the total issued and outstanding shares of common stock is less than the number of shares of common stock available for issuance under the 2014 Plan, no change will be made to the aggregate number of shares of common stock issuable under the 2014 Plan for that year (such that the aggregate number of shares of common stock available for issuance under the 2014 Plan will never decrease). Stock Options The number of shares, terms, and vesting periods are determined by the Company’s Board of Directors or a committee thereof on an option by option basis. Options generally vest ratably over service periods of up to four years and expire ten years from the date of grant. Stock option activity for the year ended December 31, 2019 is represented in the following table: Options Outstanding Shares Weighted- Available Number of Average for Grant Shares Exercise Price Balances at December 31, 2018 — 825,205 $ 12.15 Additional shares reserved 763,973 — — Options granted (696,874) 696,874 8.52 Options exercised — (11,884) 2.89 Options cancelled 129,883 (129,883) 11.67 Balances at December 31, 2019 196,982 1,380,312 $ 10.06 Additional information related to the status of options as of December 31, 2019 is summarized as follows: Weighted- Weighted- Average Average Number of Exercise Contractual Aggregate Options Price Term (Years) Intrinsic Value (in thousands) Options outstanding 1,380,312 $ 10.06 7.89 $ 258 Options vested and expected to vest 1,380,312 $ 10.06 7.89 $ 258 Options vested and exercisable 699,519 $ 10.48 6.72 $ 258 The Company estimated the fair value of options using the BSM option valuation model. The fair value of options is being amortized on a straight-line basis over the requisite service period of the awards. The fair value of the options granted during the years ended December 31, 2019 and 2018 were estimated using the following assumptions: Year Ended December 31, 2019 2018 Expected term (in years) 6.25 6.25 - 9.7 Expected volatility 79% - 95% 77% - 84% Risk-free interest-rate 1.59% - 2.67% 2.22% - 3.01% Dividend yield 0% 0% During the years ended December 31, 2019 and 2018, the Company granted options to employees to purchase 550,582 and 351,516 shares with a weighted-average grant date fair value of $5.97 and $9.89 per share, respectively, and the aggregate intrinsic value of options exercised was approximately $51,000 and $3,000, respectively. The Company recognized stock-based compensation expenses related to employee stock options of approximately $1.9 million and $1.5 million for the years ended December 31, 2019 and 2018, respectively. As of December 31, 2019, total unrecognized stock-based compensation expenses related to unvested employee stock options was approximately $4.3 million, which is expected to be recognized on a straight-line basis over a weighted-average period of approximately 2.64 years. Nonemployee Stock-Based Compensation The Company grants options to purchase common stock to nonemployees in exchange for services during the normal course of business. Stock-based compensation expense related to stock options granted to nonemployees is recognized on a straight-line basis, as the stock options are earned. The Company issued options to nonemployees, which generally vest ratably over the time period the Company expects to receive services from the nonemployee. The Company granted 69,875 stock options, with a weighted-average grant date fair value of $5.47, and 16,000 stock options, with a weighted-average exercise price of $12.37, to purchase shares of common stock to nonemployees during the years ended December 31, 2019 and 2018, respectively. For the years ended December 31, 2019 and 2018, the Company recorded stock-based compensation expense related to options granted to nonemployees of approximately $77,000 and $38,000, respectively. As of December 31, 2019, total unrecognized stock-based compensation expenses related to unvested nonemployee stock options was approximately $289,000, which is expected to be recognized on a straight-line basis over a weighted-average period of approximately 3.21 years. On January 1, 2019, the Company adopted the ASU No. 2018-07, Improvements to Nonemployee Share-Based Payment Accounting , which simplifies the accounting for share-based payments to nonemployees by aligning it with the accounting for share-based payment to employees, with certain exceptions. Prior to the adoption of ASU No. 2018-07, the Company measured the fair value of the vested options at each period using the Black-Scholes option-pricing model. Stock-Based Compensation The following table presents stock-based compensation expense related to stock options (in thousands): Twelve Months Ended December 31, 2019 2018 Research and development $ 662 $ 461 General and administrative 1,266 1,065 Total $ 1,928 $ 1,526 Deferred Charge and Stock Option Liability In December 2018, the Company granted 76,417 stock options that were in excess of the number of shares available under the 2014 Plan (the 76,417 stock options are included in the options granted amounts within the 2019 stock option activity rollforward table above). The Company estimated the fair value of these options using the BSM option valuation model which resulted in a deferred charge of approximately $455,000 that was included in prepaid expenses and other current assets on the consolidated balance sheet and a stock option liability in the amount of approximately $455,000 that was included was accrued liabilities in the consolidated balance sheet as of December 31, 2018. On January 1, 2019, the Company increased the number of shares available under the 2014 Plan through the annual evergreen provision pursuant to the plan, and accordingly, the Company reversed the deferred charge in prepaid expenses and other current assets and the stock option liability in accrued liabilities in the consolidated balance sheet. The fair value of the deferred charge and stock option liability during the year ended December 31, 2018 were estimated using the following assumptions: Year Ended December 31, 2018 Expected term (in years) 6.25 Expected volatility 77% - 79% Risk-free interest-rate 2.22% - 2.99% Dividend yield 0%

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2019
Income Taxes
Income Taxes	11. Income Taxes The Company has accumulated net losses since inception and has not recorded an income tax provision or benefit during the years ended December 31, 2019 and December 31, 2018. A reconciliation between the statutory rate U.S. federal rate and the Company’s effective tax rate is as follows (in thousands): Year Ended December 31, 2019 2018 Federal income taxat statutory rate $ (6,233) $ (4,642) State income tax, net of federal benefit (1,293) (1,300) Foreign taxdifferential 2,346 733 Permanent differences 394 178 Taxcredits generated in current year (732) (783) Other 840 1 Valuation allowance change 4,678 5,813 $ — $ — Deferred income taxes reflect the net tax effects of temporary differences between the carrying amounts of assets and liabilities for financial reporting purposes and the amounts used for income tax purposes. Significant components of our deferred tax assets (in thousands) are as follows: Year Ended December 31, 2019 2018 Net operating loss carryforwards $ 14,519 $ 10,228 Accruals and reserves 1,292 1,053 Research and development credits 1,534 1,368 Deferred revenue — 6 Depreciation and amortization (34) (23) Total 17,311 12,632 Valuation allowance (17,311) (12,632) Net deferred taxassets $ — $ — A reconciliation of the beginning and ending amount of the Company’s liability for uncertain tax positions (in thousands) is as follows: Years Ended December 31, 2019 2018 Balance at the beginning of the year $ 486 $ 213 Increase based on current year tax positions 254 271 Increase (decrease) for prior year tax positions (206) 2 Balance at the end of the year $ 534 $ 486 Due to the existence of the valuation allowance, future changes in the Company’s liability for uncertain tax positions will not impact the Company’s effective tax rate. The Company does not anticipate that there will be a substantial change in its liability for uncertain tax positions in the next twelve months. Tax Legislation subjects a U.S. shareholder to tax on Global Intangible Low-Taxed Income (“GILTI”) earned by certain foreign subsidiaries. The FASB Staff Q&A, Topic 740, No. 5, Accounting for Global Intangible Low-Taxed Income , states that an entity can make an accounting policy election to either recognize deferred taxes for temporary basis differences expected to reverse as GILTI in future years or to provide for the tax expense related to GILTI in the year the tax is incurred as a period expense only. The Company has elected to account for GILTI in the year the tax is incurred. The Company does not have a GILTI inclusion in 2019 or 2018; therefore, no GILTI tax has been recorded for the year ended December 31, 2019 and December 31, 2018. Based on the available objective evidence, management believes it is more-likely-than-not that the deferred tax assets were not fully realizable as of December 31, 2019 and 2018. Accordingly, the Company has established a full valuation allowance against its deferred tax assets. The net change in the valuation allowance for the years ended December 31, 2019 and 2018 was approximately $4.7 million and $5.8 million, respectively. At December 31, 2019, the Company had federal net operating loss carryforwards of approximately $19.5 million that begin to expire in 2034. The Company also has federal net operating losses of approximately $31.8 million that arose after the 2017 tax year and will carryforward indefinitely. The Company has state net operating loss carryforwards of approximately $53.6 million that will begin to expire in 2034. At December 31, 2019, the Company has research credit carryforwards of approximately $1.7 million and approximately $437,000 for federal and California state income tax purposes, respectively. The federal credits begin to expire in 2034 and the state credits can be carried forward indefinitely. Under the Internal Revenue Code (“IRC”) Sections 382 and 383, annual use of the Company’s net operating loss and research tax credit carryforwards to offset taxable income may be limited based on cumulative changes in ownership. The Company has not completed an analysis to determine whether any such limitations have been triggered as of December 31, 2019. The Company has no income tax affect due to the recognition of a full valuation allowance on the expected tax benefits of future loss carry forwards based on uncertainty surrounding realization of such assets. Any annual limitation may result in the expiration of net operating losses and credits before utilization. The Company may continue to experience ownership changes in the future as a result of, future expected equity financings and subsequent shifts in its stock ownership, some of which may be outside of its control. The Company is subject to taxation in the United States, California, the Netherlands and China. The Company remains subject to possible examination by tax authorities in these jurisdictions for tax years dating back to 2014. The Company does not have any pending tax examinations.

Related Parties

Related Parties	12 Months Ended
	Dec. 31, 2019
Related Parties
Related Parties	12. Related Parties Joint Venture On February 11, 2018, the Company entered into a Joint Venture (“JV”) Agreement with Hepalink which is a related party and principal shareholder in the Company, pursuant to which the Company formed a JV Entity for developing and commercializing products for infectious diseases in the greater China territories. It was agreed by the parties that the Company shall be reimbursed for certain legal and contract manufacturing expenses related to the clinical drug supply for a Phase 3 clinical study of AR-301 and the clinical drug supply for a clinical study of AR-105. For the years ended December 31, 2019 and 2018, the Company recorded approximately $1.5 million and $360,000, respectively, as a reduction to operating expenses in the consolidated statement of operations for amounts reimbursed to the Company by the JV Entity under this arrangement. As of December 31, 2019 and December 31, 2018, the Company recorded approximately $152,000 and $360,000, respectively, in other receivables on the consolidated balance sheets for amounts owed to the Company by the JV Entity under this arrangement and the Company expects the amounts to be collectable and as a result, no reserve for uncollectability was established. Serum International B.V. In July 2019, the Company issued 801,820 shares of its restricted common stock in a private placement to Serum International B.V. (“SIBV”), an affiliate of Serum Institute of India Private Limited, for total gross proceeds of $10 million (see Note 9). As a result of this transaction, SIBV and its affiliates, are considered related parties to the Company. In September 2019, the Company and Serum AMR Products (“SAMR”), a party under common ownership of SIBV, entered into a License, Development and Commercialization Agreement (the “ License Agreement”)(see Note 6). The Company determined that no performance obligations were satisfied as of December 31, 2019, and therefore, no revenue related to the License Agreement was recognized for the year ended December 31, 2019. The Company has recorded contract liabilities resulting from the License Agreement of approximately $14.6 million to deferred revenue, current, and approximately $5.0 million to deferred revenue, noncurrent, on its consolidated balance sheet at December 31, 2019. The Company capitalized a contract asset resulting from the License Agreement of approximately $2.1 million related to the incremental costs of obtaining the License Agreement on its consolidated balance sheet, of which approximately $1.5 million is classified as current, and approximately $526,000 million is classified as noncurrent, as of December 31, 2019.

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2019
Commitments and Contingencies
Commitments and Contingencies	13. Commitments and Contingencies Leases The Company leases office and lab space in San Jose, California under an operating lease arrangement which can be terminated at any time with 90 days’ notice (see Note 14). The Company recognizes rent expense as incurred. Rent expense was approximately $341,000 and $314,000, for the years ended December 31, 2019 and 2018, 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. 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 December 31, 2019 and 2018, 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. As of December 31, 2019 and 2018, there were no pending legal proceedings. See Note 14 for a legal complaint filed subsequent to December 31, 2019. Grant Income The Company receives various grants that are subject to audit by the grantors or their representatives. Such audits could result in requests for reimbursement for expenditures disallowed under the terms of the grant; however, management believes that these disallowances, if any, would be immaterial. Cystic Fibrosis Foundation Agreement In December 2016, the Company received an award for up to $2.9 million from the CFF to advance research on potential drugs utilizing inhaled gallium citrate anti-infective. In November 2018, the CFF increased the award to $7.5 million. Under the award agreement, the CFF will make payments to the Company as certain milestones are met. The award agreement also contains a provision whereby if the Company spends less on developing a potential drug utilizing inhaled gallium citrate anti-infective than the Company actually receives under this award agreement, the Company will be required to return the excess portion of the award to the CFF. At the end of any reporting period, if the Company determines that the cumulative amount spent on this program is less than the cumulative cash received from the CFF, the Company will record the excess amount received as a liability. No liability related to this excess amount was recorded by the Company as of December 31, 2019 and 2018. In the event that development efforts are successful and the Company commercialized 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 Aridis 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 Aridis 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. The Company then has thirty (30) days to respond to such notice. If the Company does not respond within thirty (30) days, an interruption license shall be effective. The interruption license to the CFF is an exclusive, worldwide license under the development program technology to manufacture, have manufactured, license, use, sell, offer to sell, and support the product in the field and includes financial conditions for both parties. None of these events have occurred as of December 31, 2019.

Subsequent Events

Subsequent Events	12 Months Ended
	Dec. 31, 2019
Subsequent Events
Subsequent Events	14. Subsequent Events Legal Proceeding 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 Company believes that the claims in this complaint are without merit and intends to defend vigorously against them. Leases The Company’s operating lease for its office and lab space is in San Jose, California. In February 2020, the Company was given the option by its landlord of moving its offices to the first floor of its office building or moving out. The Company is currently considering such a move or a move to another facility in the San Jose area. The Company plans to vacate these premises and move to new premises by mid-2020. COVID-19 The COVID-19 outbreak in the United States has caused business disruption. The extent of the impact of COVID-19 on the Company’s operational and financial performance will depend on certain developments, including the duration and spread of the outbreak and impact on the Company’s clinical trials, employees and vendors, all of which are uncertain and cannot be predicted. At this point, the extent to which COVID-19 may impact the Company’s financial condition or results of operations is uncertain.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2019
Summary of Significant Accounting Policies
Use of Estimates	Use of Estimates The preparation of the consolidated financial statements requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities as of the date of the consolidated financial statements and the reported amounts of expenses during the reporting period. Such estimates include those related to the evaluation of our ability to continue as a going concern, best estimate of standalone selling price of revenue deliverables, allowance for doubtful accounts, long-lived assets, income taxes, assumptions used in the Black-Scholes-Merton (“BSM”) model to calculate the fair value of stock-based compensation, assumptions used in the Monte Carlo Simulation (“MSM”) model to calculate the fair value of warrants, deferred tax asset valuation allowances, valuation of the Company’s common and convertible preferred stock, preclinical study and clinical trial accruals. Actual results could differ from those estimates.
Concentrations	Concentrations Credit Risk The Company’s cash and cash equivalents are maintained at financial institutions in the United States of America. Deposits held by these institutions may exceed the amount of insurance provided on such deposits. Customer Risk For the year ended December 31, 2019, one customer accounted for 100% of total revenue. For the year ended December 31, 2018, two customers accounted for 58% and 42% of total revenue. Both of the Company’s customers are located in the United States. As of December 31, 2019, there was no accounts receivable. As of December 31, 2018, two customers accounted for 60% and 40% of total accounts receivable.
Cash and Cash Equivalents	Cash and Cash Equivalents The Company considers all highly liquid investments purchased with an original maturity of three months or less to be cash equivalents. Cash equivalents consist primarily of checking account and money market account balances.
Accounts Receivable and Allowance for Doubtful Accounts	Accounts Receivable and Allowance for Doubtful Accounts Accounts receivable are recorded at the invoiced amount and do not bear interest. The Company considers the credit worthiness of its customers but does not require collateral in advance of a sale. The Company evaluates collectability and maintains an allowance for doubtful accounts for estimated losses inherent in its accounts receivable portfolio when necessary. The allowance is based on the Company’s best estimate of the amount of losses in the Company’s existing accounts receivable, which is based on customer creditworthiness, facts and circumstances specific to outstanding balances, and payment terms. Account balances are charged off against the allowance after all means of collection have been exhausted and the potential for recovery is considered remote. As of December 31, 2019, and 2018, there were no allowances for doubtful accounts.
Property and Equipment	Property and Equipment Property and equipment are stated at cost less accumulated depreciation. Depreciation is computed using the straight-line method over the estimated useful lives of the assets, generally between three and five years. Maintenance and repairs are charged to expense as incurred. When assets are retired or otherwise disposed of, the cost and accumulated depreciation are removed from the balance sheet and any resulting gain or loss is reflected in the consolidated statement of operations in the period realized.
Intangible Assets	Intangible Assets Intangible assets are recorded at cost and amortized over the estimated useful life of the asset. Intangible assets consist of licenses with various institutions whereby the Company has rights to use intangible property obtained from such institutions.
Impairment of Long-Lived Assets	Impairment of Long-Lived Assets The Company reviews long-lived assets for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable. Recoverability is measured by comparison of the carrying amount to the future undiscounted net cash flows which the assets are expected to generate. If such assets are considered to be impaired, the impairment is measured by the excess of the carrying amount of the assets over fair value less the costs to sell the assets, generally determined using the projected discounted future net cash flows arising from the asset. There have been no such impairments of long-lived assets as of December 31, 2019 and 2018.
Revenue Recognition, Contract Assets, and Deferred Revenue	Revenue Recognition Effective January 1, 2019, the Company adopted Accounting Standards Codification (“ASC”) 606, Revenue from Contracts with Customers (“ASC 606”), using the modified retrospective method. Under this method, results for reporting periods beginning after January 1, 2019 are presented under ASC 606, while prior period amounts are not adjusted and continue to be reported in accordance with ASC 605, Revenue Recognition (“ASC 605”). The Company only had one contract, the CFF Agreement, within the scope of ASC 606 as of the adoption date. The cumulative-effect of adopting ASC 606 on January 1, 2019, using the modified retrospective method, was immaterial. ASC 606 applies to all contracts with customers, except for contracts that are within the scope of other standards, such as leases, insurance, collaboration arrangements and financial instruments. See Note 6 for details of the collaboration, development and license agreements. To determine revenue recognition for arrangements that the Company determines are within the scope of ASC 606, the Company performs the following five steps: (i) identify the contract(s) with a customer; (ii) identify the performance obligations in the contract; (iii) determine the transaction price; (iv) allocate the transaction price to the performance obligations in the contract; and (v) recognize revenue at a point in time, or over time, as the entity satisfies performance obligations. The Company only applies the five-step model to contracts when it is probable that it will collect the consideration it is entitled to in exchange for the goods or services it transfers to the customer. At contract inception, once the contract is determined to be within the scope of ASC 606, the Company assesses the goods or services promised within each contract, determines those that are performance obligations, and assesses whether each promised good or service is distinct. The Company then recognizes as revenue the amount of the transaction price that is allocated to the respective performance obligation when (or as) the performance obligation is satisfied. As part of the accounting for customer arrangements, the Company must use judgment to determine: a) the number of performance obligations based on the determination under step (ii) above; b) the transaction price under step (iii) above; and c) the standalone selling price for each performance obligation identified in the contract for the allocation of the transaction price in step (iv) above. The Company uses judgment to determine whether milestones or other variable consideration should be included in the transaction price. The transaction price is allocated to each performance obligation on a relative standalone selling price basis. In developing the standalone price for a performance obligation, the Company considers applicable market conditions and relevant entity-specific factors, including factors that were contemplated in negotiating the agreement with the customer and estimated costs. The Company recognizes revenue as or when the performance obligations under the contract are satisfied. The Company receives payments from its customers based on payment schedules established in each contract. The Company records any amounts received prior to satisfying the revenue recognition criteria as deferred revenue on its consolidated balance sheet. Amounts recognized as revenue, but not yet received or invoiced are recorded within other receivables on the consolidated balance sheet. Amounts are recorded as other receivables on the consolidate 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. The Company only had one contract within the scope of ASC 606 upon adoption that had not been completed, the CFF Agreement. The most significant changes under ASC 606 relate to the Company’s determination of the transaction price at inception, determination of the standalone selling price for the performance obligation and at each reporting period the treatment of variable consideration in the form of milestone payments under the CFF Agreement. Under ASC 606, the Company is recognizing the revenue allocated to the one performance obligation measuring progress using the input (cost-to-cost) method, limited by the variable consideration attributed to the probable completion of certain milestones as defined in the CFF Agreement. The cumulative-effect of adopting ASC 606 on January 1, 2019 was immaterial. Under ASC 605, the Company recognized revenue under the milestone method up to the limit of the prior approval funding amounts, and when the Company determined that it had earned the right to receive the recognized portion according to the terms of the grant awarded. The upfront payment of $200,000 was recognized straight-line over the term of the contract as the Company believed the upfront fee related to services performed throughout the contract period and the upfront fee did not represent a substantive milestone within the agreement. Revenue for the year ended December 31, 2018, was recognized in accordance with ASC 605 which required that four basic criteria must be met before revenue can be recognized: (1) persuasive evidence of an arrangement exists; (2) delivery has occurred and title and the risks and rewards of ownership have been transferred to the client or services have been rendered; (3) the price is fixed or determinable; and (4) collectability is reasonably assured. During 2018, revenue includes grant awards and collaboration services entered into for specific research and development efforts. The Company recognized revenue under such awards and contracts as the related qualified research and development expenses were incurred or under the milestone method, up to the limit of the prior approval funding amounts, and when we had determined that we earned the right to receive the recognized portion according to the terms of the original grant awarded. Contract Assets The incremental costs of obtaining a contract under ASC 606 (i.e. costs that would not have been incurred if the contract had not been obtained) are recognized as an asset in the Company’s consolidated balance sheet if the Company expects to recover them. Management expects that the incremental fees paid to third-parties as a result of obtaining the License Agreement are recoverable and therefore the Company capitalized them as contract costs, current and noncurrent, in its consolidated balance sheet (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 year ended December 31, 2019, there was no amortization of the contract assets and there have been no impairments as of December 31, 2019. Deferred Revenue Amounts received prior to satisfying the above revenue recognition criteria, or in which the Company has an unconditional right to payment, are recorded as deferred revenue in the Company’s consolidated balance sheets. The Company has estimated the classification between current and noncurrent deferred revenue related to the respective license agreement within its consolidated balance sheet at December 31, 2019 (see Note 6).
Costs for Collaborative Arrangements	Costs for Collaborative Arrangements Costs incurred under collaborative arrangements include personnel costs, laboratory supplies and fees paid to third parties. These amounts are included in research and development in the accompanying consolidated statement of operations. For the year ended December 31, 2018, the Company had incurred expenses of approximately $604,000, related to its collaborative arrangement. The Company’s collaborative arrangement was terminated in 2018 therefore no related expenses in 2019.
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 Effective January 1, 2019, the Company early adopted Accounting Standards Update (“ASU”) No. 2018-07, Compensation—Stock Compensation (Topic 718), Improvements to Nonemployee Share-Based Payment Accounting . 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. Prior to the adoption of ASU No. 2018-07, the Company accounted for stock-based compensation arrangements with nonemployees by recording the expense of such services based on the estimated fair value of the common stock at the measurement date. The value of the equity instrument, including adjustment to fair value at each balance sheet date for the vested awards, is charged to operations over the term of the service agreement as earned. 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. Prior to the completion of the Company’s initial public offering of common stock on August 16, 2018, due to the absence of a public market trading for the Company’s common stock, it was necessary to estimate the fair value of the common stock underlying the Company’s stock-based awards when performing fair value calculations.
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 positions 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.
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 common share is calculated by dividing net loss available to common stockholders 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, adjusted for any preferred dividends, available to common stockholders by the weighted-average number of common shares and potentially dilutive securities outstanding for the period. For the years ended December 31, 2019 and 2018, there is no difference in the number of shares used to compute basic and diluted net loss per share due to the Company’s net loss position. The following tables presents the computation of the basic and diluted net loss per share available to common stockholders (in thousands, except share and per share data): Year Ended December 31, 2019 2018 Numerator: Net loss available to common stockholders (basic and diluted) $ (29,681) $ (23,462) Denominator: Weighted-average shares of common stock (basic and diluted) 8,458,277 3,146,632 Basic and diluted net loss per share $ (3.51) $ (7.45) The following potentially dilutive securities were excluded from the computation of diluted net loss per share available to common stockholders for the periods presented because including them would have been antidilutive: Year Ended December 31, 2019 2018 Stock options to purchase common stock 1,380,312 825,205 Common stock warrants 1,733,322 1,966,930 3,113,634 2,792,135
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	Recently Issued Accounting Pronouncements adopted during the year ended December 31, 2019 Accounting Standards Update 2014-09 In May 2014, the Financial Accounting Standards Board (“FASB”) issued ASU No. 2014-09, which amends the guidance for accounting for revenue from contracts with customers. This ASU supersedes the revenue recognition requirements in ASC 605, Revenue Recognition (“ASC 605”) , and creates ASC 606. In 2015 and 2016, the FASB issued additional ASUs related to ASC 606 that delayed the effective date of the guidance and clarified various aspects of the new revenue guidance, including principal versus agent considerations, identifying performance obligations, and licensing, and they include other improvements and practical expedients. Companies have the option of applying this new guidance retrospectively to each prior reporting period presented (the full retrospective method) or retrospectively with the cumulative effect of initially applying this update recognized at the date of initial application (the modified retrospective method). For public entities, ASC 606 is effective for fiscal years beginning after December 15, 2017, and interim periods within those fiscal year. As a result of the Company having elected the extended transition period for complying with new or revised accounting standards pursuant to Section 107(b) of the JOBS Act, ASC 606 is effective for the Company on January 1, 2019, and all interim periods thereafter. The Company adopted this standard on January 1, 2019. The Company only had one contract, the CFF Agreement, within the scope of ASC 606 as of the adoption date. The cumulative-effect of adopting ASC 606 on January 1, 2019, using the modified retrospective method, was immaterial. Accounting Standards Update 2018-07 and 2019-08 In June 2018, the FASB issued ASU 2018-07, Compensation—Stock Compensation (ASC 718), Improvements to Nonemployee Share-Based Payment Accounting, which is intended to simplify the accounting for nonemployee share-based payment transactions by expanding the scope of Topic 718 to include share-based payment transactions for acquiring goods and services from nonemployees. In November 2019, the FASB issued ASU 2019-08, Compensation—Stock Compensation (ASC 718) and Revenue from Contracts with Customers (ASC 606), Improvements to Share-Based Consideration Payable to a Customer, which requires that an entity measure and classify share-based payment awards granted to a customer by applying the guidance in ASC 718. For public entities, ASU 2018-07 is effective for fiscal years beginning after December 15, 2018. As a result of the Company having elected the extended transition period for complying with new or revised accounting standards pursuant to Section 107(b) of the JOBS Act, ASU 2018-07 is effective for the Company for the year ending on December 31, 2020, and all interim periods within. Early adoption is permitted. For entities that have adopted the amendments in ASU 2018-07, the amendments in ASU 2019-08 are effective in fiscal years beginning after December 15, 2019, and all interim periods within. An entity may early adopt the amendments in ASU 2019-08, but not before it adopts the amendments in ASU 2018-07. The Company early adopted ASU 2018-07 on January 1, 2019 and ASU 2019-08 on July 1, 2019. The adoption of these standards did not have a material effect on our consolidated financial statements. Recently Issued Accounting Pronouncements not yet adopted as of December 31, 2019 Accounting Standards Update 2016-02 and 2018-11 In February 2016, the FASB issued ASU 2016-02, Leases (ASC 842) . In July 2018, the FASB issued ASU 2018-10, Codification Improvements to ASC 842, Leases , which provides clarification to ASU 2016-02. These ASUs (collectively, the new lease standard) require an entity to recognize a lease liability and a right-of-use asset on the balance sheet for leases with lease terms of more than twelve months. Lessor accounting is largely unchanged, while lessees will no longer be provided with a source of off-balance sheet financing. Initial guidance required the adoption of the new lease standard using the modified retrospective transition method. In July 2018, the FASB issued ASU 2018-11, Leases (ASC 842)—Targeted Improvements , which allows entities to elect an optional transition method where entities may continue to apply the existing lease guidance during the comparative periods and apply the new lease requirements through a cumulative effect adjustment in the period of adoptions rather than in the earliest period presented. In March 2019, FASB issued ASU 2019-01, Codification improvements , which provides clarification on implementation issued associated with adopting ASU 2016-02. ASU 2019-01 enhances the guidance in ASC 842 surrounding the fair value of underlying assets for lessors, presentation of sales-type and direct financing leases on the statement of cash flows, and transition guidance surrounding accounting changes and error corrections. This guidance is 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. As a result of the Company having elected the extended transition period for complying with new or revised accounting standards pursuant to Section 107(b) of the JOBS Act, the new leasing standard updates would be effective for the Company for the year ended December 31, 2021, and all interim periods within the year ended December 31, 2022, due to its option to defer the adoption of new accounting standards under the JOBS Act. Early adoption is permitted. While the Company continues to review its current accounting policies and practices to identify potential differences that would result from applying the new guidance, the Company expects that its non-cancellable operating lease commitments with a term of more than twelve months will be subject to the new guidance and recognized as right-of-use assets and operating lease liabilities on the Company’s consolidated balance sheets upon adoption. The Company expects to elect transitional practical expedients such that the Company will not need to reassess whether contracts are leases and will retain lease classification and initial direct costs for leases existing prior to the adoption of the new lease standard. Accounting Standards Update 2016-13 In June 2016, the FASB issued ASU 2016-13, “ Financial Instruments—Credit Losses (ASC 326) ”, which is intended to provide financial statement users with more useful information about expected credit losses on financial assets held by a reporting entity at each reporting date. The new standard replaces the existing incurred loss impairment methodology with a methodology that requires consideration of a broader range of reasonable and supportable forward-looking information to estimate all expected credit losses. For public business entities, ASU 2016-13 is effective for fiscal years and interim periods within those years beginning after December 15, 2020. As a result of the Company having elected the extended transition period for complying with new or revised accounting standards pursuant to Section 107(b) of the JOBS Act, ASU 2016-13 is effective for the Company for the fiscal year ending on December 31, 2022, and all interim periods within. Early adoption is permitted. The Company does not expect the adoption of ASU 2016-13 to have a material impact on the Company's consolidated financial statements and disclosures. Accounting Standards Update 2019-12 In December 2019, the FASB issued ASU 2019-12, “ Simplifying the Accounting for Income Taxes (ASC 740) ”, which removes certain exceptions to the general principles in Topic 740 and improves consistent application of and simplifies U.S. GAAP for other areas of Topic 740 by clarifying and amending existing guidance. For public entities, the ASU 2019-12 is effective for fiscal years and interim periods within those years beginning after December 15, 2020. As a result of the Company having elected the extended transition period for complying with new or revised accounting standards pursuant to Section 107(b) of the JOBS Act, ASU 2019-12 is effective for the Company for the fiscal year ending on December 31, 2022, and all interim periods within. Early adoption is permitted. The Company is currently evaluating the impact of this guidance on its consolidated financial statements.

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2019
Summary of Significant Accounting Policies
Schedule of potentially dilutive securities excluded from computation of diluted net loss per share	Year Ended December 31, 2019 2018 Numerator: Net loss available to common stockholders (basic and diluted) $ (29,681) $ (23,462) Denominator: Weighted-average shares of common stock (basic and diluted) 8,458,277 3,146,632 Basic and diluted net loss per share $ (3.51) $ (7.45) The following potentially dilutive securities were excluded from the computation of diluted net loss per share available to common stockholders for the periods presented because including them would have been antidilutive: Year Ended December 31, 2019 2018 Stock options to purchase common stock 1,380,312 825,205 Common stock warrants 1,733,322 1,966,930 3,113,634 2,792,135

Fair Value Disclosure (Tables)

Fair Value Disclosure (Tables)	12 Months Ended
	Dec. 31, 2019
Fair Value Disclosure
Schedule of categorization of financial instruments within the valuation hierarchy	As of December 31, 2019, the Company did not have any assets or liabilities to be measured at fair value on its consolidated balance sheet. The following table presents the Company’s fair value hierarchy for its liabilities measured at fair value as of December 31, 2018 (in thousands): Fair Value at December 31, 2018 ($ in thousands) Total Level 1 Level 2 Level 3 Assets: Deferred charge related to stock options $ 455 $ — $ 455 $ — Totals $ 455 $ — $ 455 $ — Liabilities: Stock option liability $ 455 $ — $ 455 $ — Totals $ 455 $ — $ 455 $ —

Balance Sheet Components (Table

Balance Sheet Components (Tables)	12 Months Ended
	Dec. 31, 2019
Balance Sheet Components
Schedule of property and equipment, net	Property and equipment, net consist of the following (in thousands): December 31, 2019 2018 Lab equipment $ 1,804 $ 1,737 Computer equipment and software 25 25 Total property and equipment 1,829 1,762 Less: Accumulated depreciation (823) (491) Property and equipment, net $ 1,006 $ 1,271
Schedule of intangible assets, net	Intangible assets, net consist of the following (in thousands): December 31, 2019 2018 Licenses $ 81 $ 81 Less: Accumulated amortization (49) (43) Intangible assets, net $ 32 $ 38
Schedule of estimated acquired intangible amortization expense	The estimated acquired intangible amortization expense for the next five fiscal years is as follows (in thousands): Year Ended December 31, 2020 $ 5 2021 5 2022 5 2023 5 2024 and thereafter 12 Total $ 32
Schedule of accrued liabilities	Accrued liabilities consist of the following (in thousands): December 31, 2019 2018 Research and development services $ 2,709 $ 2,179 Stock option liability — 455 Payroll related expenses 150 254 Professional services 115 56 Accrued liabilities $ 2,974 $ 2,944

Warrants (Tables)

Warrants (Tables)	12 Months Ended
	Dec. 31, 2019
Warrants
Schedule of fair value of derivative warrants	The following table (in thousands) summarizes the Company’s warrant activity and fair value calculations of its derivative warrants for the year ended December 31, 2018: Warrant Liability Balance at December 31, 2017 $ 11,868 Change in fair value of warrants (1,632) Reclassification into equity upon initial public offering (10,236) Balance at December 31, 2018 $ —

Common Stock (Tables)

Common Stock (Tables)	12 Months Ended
	Dec. 31, 2019
Common Stock
Schedule of company reserved common stock for future issuance	Shares reserved for exercise of outstanding warrants to purchase common stock 1,733,322 Shares reserved for exercise of outstanding options to purchase common stock 1,380,312 Shares reserved for issuance of future options 196,982 Total 3,310,616

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	12 Months Ended
	Dec. 31, 2019
Stock-Based Compensation
Schedule of stock option activity	Options Outstanding Shares Weighted- Available Number of Average for Grant Shares Exercise Price Balances at December 31, 2018 — 825,205 $ 12.15 Additional shares reserved 763,973 — — Options granted (696,874) 696,874 8.52 Options exercised — (11,884) 2.89 Options cancelled 129,883 (129,883) 11.67 Balances at December 31, 2019 196,982 1,380,312 $ 10.06
Schedule of the status of options	Weighted- Weighted- Average Average Number of Exercise Contractual Aggregate Options Price Term (Years) Intrinsic Value (in thousands) Options outstanding 1,380,312 $ 10.06 7.89 $ 258 Options vested and expected to vest 1,380,312 $ 10.06 7.89 $ 258 Options vested and exercisable 699,519 $ 10.48 6.72 $ 258
Schedule of stock-based compensation expense related to stock options	Twelve Months Ended December 31, 2019 2018 Research and development $ 662 $ 461 General and administrative 1,266 1,065 Total $ 1,928 $ 1,526
Options
Stock-Based Compensation
Schedule of fair value of the options granted estimated using assumptions	Year Ended December 31, 2019 2018 Expected term (in years) 6.25 6.25 - 9.7 Expected volatility 79% - 95% 77% - 84% Risk-free interest-rate 1.59% - 2.67% 2.22% - 3.01% Dividend yield 0% 0%
Number of shares excess granted under the 2014 Plan | Options
Stock-Based Compensation
Schedule of fair value of the options granted estimated using assumptions	Year Ended December 31, 2018 Expected term (in years) 6.25 Expected volatility 77% - 79% Risk-free interest-rate 2.22% - 2.99% Dividend yield 0%

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2019
Income Taxes
Schedule of the difference between income tax expense and the amount computed by applying the statutory federal income tax rate to income before income tax	A reconciliation between the statutory rate U.S. federal rate and the Company’s effective tax rate is as follows (in thousands): Year Ended December 31, 2019 2018 Federal income taxat statutory rate $ (6,233) $ (4,642) State income tax, net of federal benefit (1,293) (1,300) Foreign taxdifferential 2,346 733 Permanent differences 394 178 Taxcredits generated in current year (732) (783) Other 840 1 Valuation allowance change 4,678 5,813 $ — $ —
Significant components of deferred tax assets	Significant components of our deferred tax assets (in thousands) are as follows: Year Ended December 31, 2019 2018 Net operating loss carryforwards $ 14,519 $ 10,228 Accruals and reserves 1,292 1,053 Research and development credits 1,534 1,368 Deferred revenue — 6 Depreciation and amortization (34) (23) Total 17,311 12,632 Valuation allowance (17,311) (12,632) Net deferred taxassets $ — $ —
Schedule of reconciliation of the beginning and ending amount of the Company's liability for uncertain tax positions	A reconciliation of the beginning and ending amount of the Company’s liability for uncertain tax positions (in thousands) is as follows: Years Ended December 31, 2019 2018 Balance at the beginning of the year $ 486 $ 213 Increase based on current year tax positions 254 271 Increase (decrease) for prior year tax positions (206) 2 Balance at the end of the year $ 534 $ 486

Description of Business and B_2

Description of Business and Basis of Presentation - Basis of Presentation and Consolidation (Details)	12 Months Ended
	Dec. 31, 2019segmentsubsidiary
Description of Business and Basis of Presentation
Subsidiaries (in subsidiaries) | subsidiary	2
Operating segments (in segments)	1
Reporting segments (in segments)	1

Description of Business and B_3

Description of Business and Basis of Presentation - Reverse Stock Split and Going Concern (Details)	Aug. 30, 2018USD ($)$ / sharesshares	Aug. 16, 2018USD ($)$ / sharesshares	Aug. 03, 2018shares	Sep. 30, 2019USD ($)	Jul. 31, 2019USD ($)	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)
Description of Business and Basis of Presentation
Cash and cash equivalents						$ 20,897,000	$ 24,237,000
Accumulated deficit						100,769,000	71,088,000
Proceeds from issuance of common stock, net						4,958,000	$ 25,079,000
License Agreement with SIBV
Description of Business and Basis of Presentation
Upfront payment received					$ 5,000,000
License Agreement with SAMR
Description of Business and Basis of Presentation
Upfront payment received				$ 15,000,000	$ 5,000,000	$ 42,500,000
Common Stock
Description of Business and Basis of Presentation
Ratio of reverse stock split			0.155814
Conversion of Series A convertible preferred stock into common stock upon initial public offering (in shares) | shares			5,744,586
IPO
Description of Business and Basis of Presentation
other offering expenses		$ 1,400,000
Proceeds from issuance of common stock, gross	$ 2,500,000	26,000,000
Proceeds from issuance of common stock, net	$ 2,300,000	$ 22,800,000
IPO | Common Stock
Description of Business and Basis of Presentation
Issuance of common stock (in shares) | shares	192,824	2,000,000
Share Price | $ / shares	$ 13	$ 13
IPO | IPO
Description of Business and Basis of Presentation
underwriting discounts and commissions	$ 175,000	$ 1,800,000

Summary of Significant Accoun_4

Summary of Significant Accounting Policies - Concentration of Risk (Details)	12 Months Ended
	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)
Summary of Significant Accounting Policies
Accounts receivable	$ 0	$ 1,660,000
Contract revenue | Customer risk
Summary of Significant Accounting Policies
Number of customers	1	2
Contract revenue | Customer 1 | Customer risk
Summary of Significant Accounting Policies
Concentration risk percentage	100.00%	58.00%
Contract revenue | Customer 2 | Customer risk
Summary of Significant Accounting Policies
Concentration risk percentage		42.00%
Accounts receivable | Customer risk
Summary of Significant Accounting Policies
Number of customers		2
Accounts receivable | Customer 1 | Customer risk
Summary of Significant Accounting Policies
Concentration risk percentage	60.00%	60.00%
Accounts receivable | Customer 2 | Customer risk
Summary of Significant Accounting Policies
Concentration risk percentage		40.00%

Summary of Significant Accoun_5

Summary of Significant Accounting Policies - Accounts Receivable and Allowance for Doubtful Accounts (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Summary of Significant Accounting Policies
Allowance for doubtful accounts	$ 0	$ 0

Summary of Significant Accoun_6

Summary of Significant Accounting Policies - Property and Equipment and Impairment of Long-Lived Assets (Details)	12 Months Ended
	Dec. 31, 2019
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_7

Summary of Significant Accounting Policies - Impairment of Long-Lived Assets (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Summary of Significant Accounting Policies
Impairments of long-lived assets	$ 0	$ 0

Summary of Significant Accoun_8

Summary of Significant Accounting Policies - Revenue Recognition (Details) - USD ($)	1 Months Ended		12 Months Ended
	Sep. 30, 2019	Jul. 31, 2019	Dec. 31, 2019	Dec. 31, 2018
Summary of Significant Accounting Policies
Deferred revenue, current			$ 14,602,000	$ 22,000
Amortization of contract assets			0
Impairments of contract assets			0
Upfront payment
Summary of Significant Accounting Policies
Deferred revenue, current			200,000
License Agreement with SIBV
Summary of Significant Accounting Policies
Upfront payment received		$ 5,000,000
License Agreement with SAMR
Summary of Significant Accounting Policies
Upfront payment received	$ 15,000,000	$ 5,000,000	42,500,000
License Agreement
Summary of Significant Accounting Policies
Deferred revenue, current			$ 14,600,000

Summary of Significant Accoun_9

Summary of Significant Accounting Policies - Costs for Collaborative Arrangements (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Summary of Significant Accounting Policies
Research and Development Expense	$ 24,083,000	$ 23,000,000
Collaboration revenue
Summary of Significant Accounting Policies
Research and Development Expense		$ 604,000

Summary of Significant Accou_10

Summary of Significant Accounting Policies - Stock-Based Compensation (Details)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Options
Common Stock for future issuance
Dividend yield (in percent)	0.00%	0.00%

Summary of Significant Accou_11

Summary of Significant Accounting Policies - Loss Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Summary of Significant Accounting Policies
Potentially dilutive securities excluded from computation of diluted net loss per share	3,113,634	2,792,135
Numerator:
Net loss available to common stockholders (basic and diluted)	$ (29,681)	$ (23,462)
Denominator:
Weighted-average common shares outstanding used in computing net loss per share available to common stockholders, basic and diluted:	8,458,277	3,146,632
Basic and diluted net loss per share	$ (3.51)	$ (7.45)
Options
Summary of Significant Accounting Policies
Potentially dilutive securities excluded from computation of diluted net loss per share	1,380,312	825,205
Warrants | Common Stock
Summary of Significant Accounting Policies
Potentially dilutive securities excluded from computation of diluted net loss per share	1,733,322	1,966,930

Summary of Significant Accou_12

Summary of Significant Accounting Policies - Recently Issued Accounting Pronouncements (Details) - USD ($)	Dec. 31, 2019	Dec. 31, 2018
Summary of Significant Accounting Policies
Deferred revenue, current	$ 14,602,000	$ 22,000
Upfront payment
Summary of Significant Accounting Policies
Deferred revenue, current	$ 200,000

Fair Value Disclosure (Details)

Fair Value Disclosure (Details) $ in Thousands	Dec. 31, 2018USD ($)
Fair value
Assets	$ 455
Liabilities	455
Stock option liability
Fair value
Liabilities	455
Deferred charge related to stock options
Fair value
Assets	455
Level 2
Fair value
Assets	455
Liabilities	455
Level 2 | Stock option liability
Fair value
Liabilities	455
Level 2 | Deferred charge related to stock options
Fair value
Assets	$ 455

Balance Sheet Components - Prop

Balance Sheet Components - Property and Equipment, net (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Property and Equipment, net
Total property and equipment	$ 1,829,000	$ 1,762,000
Less: Accumulated depreciation	(823,000)	(491,000)
Property and equipment, net	1,006,000	1,271,000
Depreciation expense	332,000	278,000
Lab equipment
Property and Equipment, net
Total property and equipment	1,804,000	1,737,000
Computer equipment and software
Property and Equipment, net
Total property and equipment	$ 25,000	$ 25,000

Balance Sheet Components - Inta

Balance Sheet Components - Intangible Assets, net (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Intangible Assets, net
Less: Accumulated amortization	$ (49,000)	$ (43,000)
Intangible assets, net	32,000	38,000
Amortization of Intangible Assets	6,000	5,000
License Agreement
Intangible Assets, net
Finite-Lived Intangible Assets, Gross	$ 81,000	$ 81,000

Balance Sheet Components - In_2

Balance Sheet Components - Intangible Assets, Net- Amortization expense (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Acquired intangible amortization expense
2020	$ 5
2021	5
2022	5
2023	5
2024 and thereafter	12
Intangible assets, net	$ 32	$ 38

Balance Sheet Components - In_3

Balance Sheet Components - Intangible Assets, Net - Licenses (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
The University of Chicago Agreement
Intangible Assets, net
Maximum contingent milestone payments	$ 1,600,000
Milestone payments accrued	0	$ 0
The Brigham and Women's Hospital, Inc
Intangible Assets, net
Maximum contingent milestone payments	860,000
Milestone payments accrued	0	0
The University of Iowa Research Foundation
Intangible Assets, net
Maximum contingent milestone payments	712,500
Milestone payments accrued	0	0
Brigham Young University
Intangible Assets, net
Maximum contingent milestone payments	400,000
Milestone payments accrued	$ 0	0
Reimbursement of 3rd party costs (in percent)	0.33%
National Institutes of Health
Intangible Assets, net
Maximum contingent milestone payments	$ 850,000
Milestone payments accrued	0	0
Kenta Biotech Ltd
Intangible Assets, net
Accrued royalty obligation	488,000	$ 0
Maximum royalty base for royalty payments	50,000,000
Emergent Product Development Gaithersburg Inc
Intangible Assets, net
Milestone payments under the agreement	$ 2,800,000

Balance Sheet Components - Accr

Balance Sheet Components - Accrued Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Accrued Liabilities
Research and development services	$ 2,709	$ 2,179
Stock option liability		455
Payroll related expenses	150	254
Professional services	115	56
Accrued liabilities	$ 2,974	$ 2,944

Equity Method Investment (Detai

Equity Method Investment (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Aug. 06, 2018	Feb. 11, 2018
Equity Method Investment
Contributions owed to the joint venture	$ 1,000,000
Loss from equity method investment	951,000	$ 40,000
Equity method investment	9,000	960,000
SABC
Equity Method Investment
Percentage of ownership interest				49.00%
Carryover basis of license contributed	0
JV Entity
Equity Method Investment
Loss from equity method investment	$ 951,000	$ 40,000
Hepalink | SABC
Equity Method Investment
Percentage of ownership interest			51.00%
Minimum amount obligated to make an additional equity investment at first future financing			$ 10,800,000
Hepalink | JV Entity
Equity Method Investment
Contribution obligated			$ 7,200,000	$ 1,000,000

Collaboration, Development an_2

Collaboration, Development and License Agreements (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
License Agreement with GSK
License agreement
Deferred revenue	$ 440,000
GSK
License agreement
Collaboration revenue		$ 1,200,000
Deferred revenue on additional work performed recognized		$ 440,000

Collaboration, Development an_3

Collaboration, Development and License Agreements - Cystic Fibrosis Foundation Development Agreement (Details) - USD ($)	1 Months Ended		12 Months Ended
	Nov. 30, 2018	Dec. 31, 2016	Dec. 31, 2019	Dec. 31, 2018
Collaborative Arrangements and Non-collaborative Arrangement Transactions
Deferred revenue, current			$ 14,602,000	$ 22,000
Upfront payment
Collaborative Arrangements and Non-collaborative Arrangement Transactions
Deferred revenue, current			200,000
CFF
Collaborative Arrangements and Non-collaborative Arrangement Transactions
Collaboration revenue		$ 2,900,000
Grant revenue			1,000,000	$ 1,600,000
Amount of increase in award	$ 7,500,000
Remaining milestones related to clinical research activities			$ 4,800,000
CFF | Upfront payment
Collaborative Arrangements and Non-collaborative Arrangement Transactions
Deferred revenue, current		$ 200,000

Collaboration, Development an_4

Collaboration, Development and License Agreements - Serum License Agreement (Details) - USD ($)	1 Months Ended		12 Months Ended
	Sep. 30, 2019	Jul. 31, 2019	Dec. 31, 2019	Dec. 31, 2018
Collaborative Arrangements and Non-collaborative Arrangement Transactions
Total revenue			$ 1,022,000	$ 2,757,000
Deferred revenue, current			14,602,000	$ 22,000
Deferred revenue, noncurrent			5,000,000
Capitalized contract cost, Current			1,537,000
Capitalized contract cost, Noncurrent			$ 526,000
Minimum
Collaborative Arrangements and Non-collaborative Arrangement Transactions
Royalty payments			4.00%
Maximum
Collaborative Arrangements and Non-collaborative Arrangement Transactions
Royalty payments			6.00%
License Agreement
Collaborative Arrangements and Non-collaborative Arrangement Transactions
Capitalized contract costs			$ 2,100,000
Total revenue			0
Deferred revenue, current			14,600,000
Deferred revenue, noncurrent			5,000,000
Capitalized incremental costs of obtaining the License Agreement			2,100,000
Capitalized contract cost, Current			1,500,000
Capitalized contract cost, Noncurrent			526,000
Licenses and know-how
Collaborative Arrangements and Non-collaborative Arrangement Transactions
Deferred revenue			14,500,000
Development support services
Collaborative Arrangements and Non-collaborative Arrangement Transactions
Deferred revenue			79,000
Research and Development Option
Collaborative Arrangements and Non-collaborative Arrangement Transactions
Deferred revenue			892,000
Manufacturing rights option
Collaborative Arrangements and Non-collaborative Arrangement Transactions
Deferred revenue			$ 4,100,000
Products in EU
Collaborative Arrangements and Non-collaborative Arrangement Transactions
Royalty payments			20.00%
License Agreement with SIBV
Collaborative Arrangements and Non-collaborative Arrangement Transactions
Upfront payment received		$ 5,000,000
Issuance costs from equity allocation			$ 376,000
License Agreement with SAMR
Collaborative Arrangements and Non-collaborative Arrangement Transactions
Buy back manufacturing rights			5,000,000
Upfront payment received	$ 15,000,000	$ 5,000,000	42,500,000
License Agreement and Option Agreement
Collaborative Arrangements and Non-collaborative Arrangement Transactions
Proceeds from sale of restricted common stock and upfront payment			22,500,000
Fair value of net proceeds			5,000,000
Fair value of gross proceeds			5,400,000
Deferred revenue			19,600,000
Deferred revenue based on upfront payments			15,000,000
Deferred revenue from equity allocation			4,600,000
Capitalized contract costs			2,100,000
Issuance costs from equity allocation			441,000
Direct costs related to license agreement			1,700,000
Capitalized incremental costs of obtaining the License Agreement			$ 2,100,000
Serum International B.V. ("SIBV")
Collaborative Arrangements and Non-collaborative Arrangement Transactions
Issuance of common stock (in shares)		801,820
Issuance of common stock		$ 10,000,000
Restricted common stock | Serum International B.V. ("SIBV")
Collaborative Arrangements and Non-collaborative Arrangement Transactions
Issuance of common stock (in shares)		801,820
Issuance of common stock		$ 10,000,000

Warrants (Details)

Warrants (Details) - USD ($)	Dec. 12, 2016	Nov. 30, 2015	Dec. 31, 2019	Dec. 31, 2018	Aug. 13, 2019	Dec. 31, 2017
Warrants to Purchase Common Stock
Total fair value of warrants						$ 11,868,000
Number of unvested warrants cancelled					109,601
Share-based Compensation			$ 2,010,000	$ 1,658,000
Change in fair value of warrants				(1,632,000)
Reclassification into equity upon initial public offering				10,236,000
Performance Award
Warrants to Purchase Common Stock
Minimum gross proceeds for meeting performance requirement		$ 25,000,000
Warrants potentially issued for meeting performance requirement		234,860
Number of warrants issued	234,860
Warrants exercise price	$ 14.50
Total fair value of warrants	$ 661,000
Vesting period	5 years
Share-based Compensation			$ 82,000	132,000
Change in fair value of warrants				$ 1,600,000

Convertible Preferred Stock (De

Convertible Preferred Stock (Details) $ in Millions	Aug. 13, 2018USD ($)shares	Aug. 03, 2018shares	Jun. 30, 2016
Series A Convertible Preferred Stock
Convertible Preferred Stock
Dividend rate (in percentage)			3.00%
Preferred stock dividend shares issued (in shares)	669,489
Preferred stock dividend shares fair value | $	$ 1.4
Common Stock
Convertible Preferred Stock
Stock issued upon conversion of convertible shares		5,744,586
Ratio of reverse stock split		0.155814

Common Stock (Details)

Common Stock (Details) - USD ($)	1 Months Ended	12 Months Ended
	Jul. 31, 2019	Dec. 31, 2019	Dec. 31, 2018	Sep. 30, 2019
Common Stock for future issuance
Proceeds from issuance of common stock, net		$ 4,958,000	$ 25,079,000
Total common stock for future issuance		3,310,616
License Agreement and Option Agreement
Common Stock for future issuance
Proceeds from sale of restricted common stock and upfront payment		$ 22,500,000
Deferred revenue		19,600,000
Deferred revenue based on upfront payments		15,000,000
Deferred revenue from equity allocation		4,600,000
Capitalized contract costs		2,100,000
Issuance costs from equity allocation		441,000
Direct costs related to license agreement		1,700,000
Fair value of net proceeds		5,000,000
Fair value of gross proceeds		$ 5,400,000
Maximum
Common Stock for future issuance
Valuation (term of years)			9 years 8 months 12 days
Options
Common Stock for future issuance
Valuation (term of years)		6 years 3 months
Dividend yield (in percent)		0.00%	0.00%
Shares reserved for issuance of future options		196,982
Total common stock for future issuance		1,380,312
Serum International B.V. ("SIBV")
Common Stock for future issuance
Issuance of common stock (in shares)	801,820
Issuance of common stock	$ 10,000,000
Serum International B.V. ("SIBV") | Restricted common stock
Common Stock for future issuance
Issuance of common stock (in shares)	801,820
Issuance of common stock	$ 10,000,000
Commission payment	816,000
Proceeds from issuance of common stock, net	$ 9,200,000
Expected volatility		84.00%
Risk-free interest-rate		1.94%
Dividend yield (in percent)		0.00%
ATM Agreement
Common Stock for future issuance
Maximum aggregate offering price				$ 25,000,000
Maximum value of shares under prospectus supplement covering				$ 100,000,000
Warrants
Common Stock for future issuance
Total common stock for future issuance		1,733,322

Stock-Based Compensation - Stoc

Stock-Based Compensation - Stock option activity (Details) - $ / shares	1 Months Ended	12 Months Ended
	May 31, 2014	Dec. 31, 2019
Shares Available for Grant
Additional shares reserved (in shares)	77,908	763,973
Options granted (in shares)		(696,874)
Options cancelled (in shares)		129,883
End of the period (in shares)		196,982
Number of options
Number of Shares, beginning of the period (in shares)		825,205
Stock option granted		696,874
Number of Shares, Options exercised (in shares)		(11,884)
Number of Shares, Options cancelled (in shares)		(129,883)
Number of Shares, end of the period (in shares)		1,380,312
Weighted average exercise price
Weighted-Average Exercise Price, beginning of the period (in dollars per share)		$ 12.15
Weighted-Average Exercise Price, Options granted (in dollars per share)		8.52
Weighted-Average Exercise Price, Options exercised (in dollars per share)		2.89
Weighted-Average Exercise Price, Options cancelled (in dollars per share)		11.67
Weighted-Average Exercise Price, end of the period (in dollars per share)		$ 10.06

Stock-Based Compensation - Stat

Stock-Based Compensation - Status of options (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Number of options
Options outstanding	1,380,312	825,205
Options vested and expected to vest	1,380,312
Options vested and exercisable	699,519
Weighted average exercise price
Options outstanding (in dollars per share)	$ 10.06	$ 12.15
Options vested and expected to vest (in dollars per share)	10.06
Options vested and exercisable (in dollars per share)	$ 10.48
Weighted average contractual term and aggregate intrinsic value
Options outstanding (in years)	7 years 10 months 21 days
Options vested and expected to vest (in years)	7 years 10 months 21 days
Options vested and exercisable (in years)	6 years 8 months 19 days
Options outstanding (in dollars)	$ 258
Options vested and expected to vest (in dollars)	258
Options vested and exercisable (in dollars)	$ 258

Stock-Based Compensation - Expe

Stock-Based Compensation - Expenses (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Stock-Based Compensation
Total stock-based compensation expense	$ 1,928	$ 1,526
Research and development
Stock-Based Compensation
Total stock-based compensation expense	662	461
General and administrative
Stock-Based Compensation
Total stock-based compensation expense	$ 1,266	$ 1,065

Stock-Based Compensation - Assu

Stock-Based Compensation - Assumptions (Details)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Minimum
Fair value of the options granted, estimated using assumptions
Expected term (in years)		6 years 3 months
Maximum
Fair value of the options granted, estimated using assumptions
Expected term (in years)		9 years 8 months 12 days
Options
Fair value of the options granted, estimated using assumptions
Expected term (in years)	6 years 3 months
Expected volatility, minimum	79.00%	77.00%
Expected volatility, maximum	95.00%	84.00%
Risk-free interest-rate, minimum	1.59%	2.22%
Risk-free interest-rate, maximum	2.67%	3.01%
Dividend yield (in percent)	0.00%	0.00%
Options | Number of shares excess granted under the 2014 Plan
Fair value of the options granted, estimated using assumptions
Expected term (in years)	6 years 3 months
Expected volatility, minimum	77.00%
Expected volatility, maximum	79.00%
Risk-free interest-rate, minimum	2.22%
Risk-free interest-rate, maximum	2.99%
Dividend yield (in percent)	0.00%

Stock-Based Compensation - Addi

Stock-Based Compensation - Additional information (Details) - USD ($)	1 Months Ended		12 Months Ended
	Dec. 31, 2018	May 31, 2014	Dec. 31, 2019	Dec. 31, 2018
Stock-Based Compensation
Reserved for issuance (in shares)		233,722
Voting rights of all classes of stock (in percent)		10.00%
Exercise price for incentive stock options to the percentage of fair market value		110.00%
Annual increase in the number of shares to the shares of common stock		77,908	763,973
Stock option granted			696,874
Weighted-average exercise price of stock option granted			$ 8.52
Options outstanding (in dollars)			$ 258,000
Stock-based compensation expense			1,928,000	$ 1,526,000
Stock-based compensation expense			$ 2,010,000	1,658,000
Assets	$ 455,000			455,000
Liabilities	455,000			$ 455,000
Employee
Stock-Based Compensation
Stock option granted			550,582	351,516
Weighted-average exercise price of stock option granted			$ 5.97	$ 9.89
Total unrecognized compensation costs			$ 4,300,000
Unrecognized stock-based compensation expenses expected to be recognized			2 years 7 months 21 days
Aggregate intrinsic value			$ 51,000	$ 3,000
Stock-based compensation expense			$ 1,900,000	$ 1,500,000
Non employee
Stock-Based Compensation
Stock option granted			69,875	16,000
Weighted-average exercise price of stock option granted			$ 5.47	$ 12.37
Total unrecognized compensation costs			$ 289,000
Unrecognized stock-based compensation expenses expected to be recognized			3 years 2 months 16 days
Stock-based compensation expense			$ 77,000	$ 38,000
Stock option liability
Stock-Based Compensation
Liabilities	455,000			455,000
Deferred charge related to stock options
Stock-Based Compensation
Assets	$ 455,000			455,000
Options
Stock-Based Compensation
Annual increase in the number of shares to the percentage of the issued and outstanding common stock		20.00%
Vesting period (in years)		4 years
Expiration period (in years)		10 years
Options | Number of shares excess granted under the 2014 Plan
Stock-Based Compensation
Stock option granted	76,417
Options | Stock option liability | Accrued liabilities | Number of shares excess granted under the 2014 Plan
Stock-Based Compensation
Liabilities	$ 455,000			455,000
Options | Deferred charge related to stock options | Prepaid expenses and other current assets | Number of shares excess granted under the 2014 Plan
Stock-Based Compensation
Assets	$ 455,000			$ 455,000

Income Taxes - Effective income

Income Taxes - Effective income tax rate reconciliation, Amount (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Income tax expense benefit reconciliation
Federal income tax at statutory rate	$ (6,233)	$ (4,642)
State income tax, net of federal benefit	(1,293)	(1,300)
Foreign tax differential	2,346	733
Permanent differences	394	178
Tax credits generated in current year	(732)	(783)
Other	840	1
Valuation allowance	$ 4,678	$ 5,813

Income Taxes - Components of de

Income Taxes - Components of deferred tax assets (liabilities) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Components of deferred tax assets
Net operating loss carryforwards	$ 14,519	$ 10,228
Accruals and reserves	1,292	1,053
Research and development credits	1,534	1,368
Deferred Revenue		6
Depreciation and amortization	(34)	(23)
Total	17,311	12,632
Valuation allowance	(17,311)	(12,632)
Net change in the valuation allowance	$ 4,700	$ 5,800

Income Taxes - Uncertain tax po

Income Taxes - Uncertain tax positions (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Income Taxes
Balance at the beginning of the year	$ 486	$ 213
Increase based on current year tax positions	254	271
Increase (decrease) for prior year tax positions	(206)	2
Balance at the beginning of the year	$ 534	$ 486

Income Taxes - Tax Cuts and Job

Income Taxes - Tax Cuts and Jobs Act of 2017 (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Income Taxes
Net change in the valuation allowance	$ 4.7	$ 5.8

Income Taxes - Net operating lo

Income Taxes - Net operating loss carryforwards and Tax credit carryforwards (Details)	Dec. 31, 2019USD ($)
Income Taxes
Net operating loss carryforwards	$ 53,600,000
Federal
Income Taxes
Net operating loss carryforwards	19,500,000
Research credit carryforwards | Federal
Income Taxes
Tax credit carryforwards	1,700,000
Research credit carryforwards | State
Income Taxes
Tax credit carryforwards	437,000
After tax year 2017 | Federal
Income Taxes
Net operating loss carryforwards	$ 31,800,000

Related Parties (Details)

Related Parties (Details) - USD ($)	1 Months Ended	12 Months Ended
	Jul. 31, 2019	Dec. 31, 2019	Dec. 31, 2018
Related parties
Revenue		$ 1,022,000	$ 2,757,000
Deferred revenue, current		14,602,000	22,000
Deferred revenue, noncurrent		5,000,000
Capitalized contract cost, Current		1,537,000
Capitalized contract cost, Noncurrent		526,000
License Agreement
Related parties
Revenue		0
Deferred revenue, current		14,600,000
Deferred revenue, noncurrent		5,000,000
Capitalized contract costs		2,100,000
Capitalized contract cost, Current		1,500,000
Capitalized contract cost, Noncurrent		526,000
Shenzen Hepalink Pharmaceutical Group Co., Ltd.("Hepalink")
Related parties
Reduction to operating expenses on reimbursed to JV entity		(1,500,000)	(360,000,000)
Serum International B.V. ("SIBV") | License Agreement
Related parties
Deferred revenue, current		14,600,000
Deferred revenue, noncurrent		5,000,000
Capitalized contract costs		2,100,000
Capitalized contract cost, Current		1,500,000
Capitalized contract cost, Noncurrent		526,000
Serum International B.V. ("SIBV")
Related parties
Issuance of common stock (in shares)	801,820
Issuance of stock	$ 10,000,000
Other receivables | Shenzen Hepalink Pharmaceutical Group Co., Ltd.("Hepalink")
Related parties
Outstanding receivable for reimbursable expenses		$ 152,000	$ 360,000

Commitments and Contingencies -

Commitments and Contingencies - Leases and Contingencies (Details)	12 Months Ended
	Dec. 31, 2019USD ($)claim	Dec. 31, 2018USD ($)claim
Commitments and Contingencies
Notice period for termination of lease	90 days
Rent expense | $	$ 341,000	$ 314,000
Number of pending legal proceedings | claim	0	0

Commitments and Contingencies_2

Commitments and Contingencies - Cystic Fibrosis Foundation Agreement and Joint Venture Agreement (Details) - CF Foundation $ in Millions	1 Months Ended
	Dec. 31, 2016USD ($)iteminstallment	Nov. 30, 2018USD ($)
Cystic Fibrosis Foundation Agreement
Amount of award received for advance research on potential drugs | $	$ 2.9	$ 7.5
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

Subsequent Events (Details)

Subsequent Events (Details)	1 Months Ended
	Feb. 29, 2020USD ($)
Subsequent event
Subsequent Events
Compensatory damages	$ 277,000