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Document And Entity Information - USD ($)	12 Months Ended
Document And Entity Information - USD ($)	Dec. 31, 2018	Feb. 04, 2019	Jun. 30, 2018
Document and Entity Information [Abstract]
Entity Registrant Name	Vaxart, Inc.
Document Type	10-K
Current Fiscal Year End Date	--12-31
Entity Common Stock, Shares Outstanding		7,141,189
Entity Public Float			$ 12,181,506
Amendment Flag	false
Entity Central Index Key	0000072444
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Filer Category	Non-accelerated Filer
Entity Well-known Seasoned Issuer	No
Document Period End Date	Dec. 31, 2018
Document Fiscal Year Focus	2018
Document Fiscal Period Focus	FY
Entity Small Business	true
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Ex Transition Period	false

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Current assets:
Cash and cash equivalents	$ 11,506	$ 1,571
Short-term investments		1,415
Accounts receivable	1,796	630
Prepaid expenses and other current assets	1,343	137
Total current assets	14,645	3,753
Property and equipment, net	1,066	730
Intangible assets, net	19,413	40
Other long-term assets	103
Total assets	35,227	4,523
Current liabilities:
Accounts payable	962	1,390
Current portion of secured promissory note payable to Oxford Finance	1,667	1,528
Liability related to sale of future royalties, current portion	3,328
Other accrued current liabilities	1,518	1,605
Total current liabilities	7,475	4,523
Convertible promissory notes, long-term, related parties		35,282
Liability related to sale of future royalties, net of current portion	14,413
Secured promissory note payable to Oxford Finance, net of current portion	1,944	3,440
Other long-term liabilities	157
Total liabilities	23,989	43,245
Stockholders’ equity (deficit):
Preferred Stock: $0.10 par value; 5,000,000 shares authorized; none issued and outstanding as of December 31, 2018; 1,221,064 issued and outstanding as of December 31, 2017, with aggregate liquidation value of $39,956		1
Common Stock: $0.10 par value; 200,000,000 shares authorized; 7,141,189 and 138,492 shares issued and outstanding as of December 31, 2018 and 2017, respectively	714
Additional paid-in capital	108,513	41,259
Accumulated deficit	(97,989)	(79,982)
Total stockholders’ equity (deficit)	11,238	(38,722)
Total liabilities and stockholders’ equity (deficit)	$ 35,227	$ 4,523

Condensed Consolidated Balance Sheets (Parentheticals) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Preferred stock, par value (in Dollars per share)	$ 0.10	$ 0.10
Preferred stock, shares authorized	5,000,000	5,000,000
Preferred stock, shares issued	0	1,221,064
Preferred stock, shares outstanding	0	1,221,064
Liquidation Preference (in Dollars)	$ 39,956	$ 39,956
Common stock, par value (in Dollars per share)	$ 0.10	$ 0.10
Common stock, shares authorized	200,000,000	200,000,000
Common stock, shares issued	7,141,189	138,492
Common stock, shares outstanding	7,141,189	138,492

Consolidated Statements of Operations and Comprehensive Loss - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Revenue:
Revenue	$ 4,159	$ 5,839
Operatingexpenses:
Research and development	17,275	12,355
General and administrative	6,681	3,499
Impairment of intangible assets	1,600
Costs of exit from leased premises	359
Total operating expenses	25,915	15,854
Operating loss	(21,756)	(10,015)
Other income and (expenses):
Bargain purchase gain	6,760
Interest income	58	53
Interest expense	(821)	(3,036)
Non-cash interest expense related to sale of future royalties	(1,859)
(Loss) gain on sale of equipment	(11)	69
(Loss) gain on revaluation of financial instruments, net	(3)	3,347
Foreign exchange loss, net	(266)
Total other income and (expenses)	3,858	433
Net loss before provision for income taxes	(17,898)	(9,582)
Provision for income taxes	109
Net loss	(18,007)	(9,582)
Series B and C preferred dividend	(339)	(2,878)
Net comprehensive loss attributable to common stockholders	$ (18,346)	$ (12,460)
Net loss per share – basic and diluted (in Dollars per share)	$ (2.90)	$ (91.65)
Shares used to compute net loss per share – basic and diluted (in Shares)	6,316,065	135,953
Government Contract [Member]
Revenue:
Revenue	$ 1,344	$ 5,839
Royalty [Member]
Revenue:
Revenue	1,340
Non Cash Royalty Revenue [Member]
Revenue:
Revenue	$ 1,475

Consolidated Statements of Stockholders` Equity (Deficit) - USD ($) $ in Thousands	Preferred Stock [Member]	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Total
Balances at Dec. 31, 2016	$ 1		$ 40,758	$ (70,400)	$ (29,641)
Balances (in Shares) at Dec. 31, 2016	1,221,064	135,658
Issuance of common stock upon exercise of stock options			24		$ 24
Issuance of common stock upon exercise of stock options (in Shares)		2,834			2,834
Stock-based compensation			477		$ 477
Net loss				(9,582)	(9,582)
Balances at Dec. 31, 2017	$ 1		41,259	(79,982)	$ (38,722)
Balances (in Shares) at Dec. 31, 2017	1,221,064	138,492			138,492
Issuance of common stock upon conversion of convertible promissory notes, related parties		$ 157	35,420		$ 35,577
Issuance of common stock upon conversion of convertible promissory notes, related parties (in Shares)		1,571,702
Issuance of common stock upon conversion of convertible preferred stock	$ (1)	$ 192	(191)
Issuance of common stock upon conversion of convertible preferred stock (in Shares)	(1,221,064)	1,918,543
Reclassification of warrant to equity			70		70
Issuance of common stock uponreverse merger		$ 365	31,403		31,768
Issuance of common stock uponreverse merger (in Shares)		3,510,439
Issuance of common stock upon exercise of stock options			13		$ 13
Issuance of common stock upon exercise of stock options (in Shares)		2,013			2,013
Stock-based compensation			539		$ 539
Net loss				(18,007)	(18,007)
Balances at Dec. 31, 2018		$ 714	$ 108,513	$ (97,989)	$ 11,238
Balances (in Shares) at Dec. 31, 2018		7,141,189			7,141,189

Consolidated Statements of Cash Flows - USD ($)	12 Months Ended
Consolidated Statements of Cash Flows - USD ($)	Dec. 31, 2018	Dec. 31, 2017
Cash flows from operating activities:
Net loss	$ (18,007,000)	$ (9,582,000)
Adjustments to reconcile net loss to net cash used in operating activities:
Bargain purchase gain	(6,760,000)
Depreciation and amortization	3,203,000	380,000
Loss (gain) on sale of equipment	11,000	(69,000)
Impairment of intangible assets	1,600,000
Impairment of property and equipment	106,000
Stock-based compensation	539,000	477,000
Amortization of discount on short-term investments		24,000
Loss (gain) on revaluation of financial instruments, net	3,000	(3,347,000)
Non-cash interest expense	448,000	2,557,000
Amortization of note discount	18,000	144,000
Non-cash interest expense related to sale of future royalties	1,859,000
Non-cash revenue related to sale of future royalties	(18,000)
Change in operating assets and liabilities:
Accounts receivable	13,500,000	960,000
Prepaid expenses and other assets	(873,000)	52,000
Accounts payable	(3,784,000)	(1,559,000)
Accrued liabilities	(6,393,000)	(77,000)
Net cash used in operating activities	(14,548,000)	(10,040,000)
Cash flows from investing activities:
Purchase of property and equipment	(707,000)	(117,000)
Proceeds from sale of equipment		70,000
Cash acquired in reverse merger	25,525,000
Cash paid for fractional shares in merger	(21,000)
Purchases of short-term investments	(573,000)	(7,351,000)
Proceeds from maturities of short-term investments	1,988,000	10,580,000
Net cash provided by investing activities	26,212,000	3,182,000
Cash flows from financing activities:
Repayment of principal on secured promissory note payable to Oxford Finance	(1,528,000)
Repayment of short-term note	(214,000)
Proceeds from issuance of common stock upon exercise of stock options	13,000	24,000
Net cash (used in) provided by financing activities	(1,729,000)	24,000
Net increase (decrease) in cash and cash equivalents	9,935,000	(6,834,000)
Cash and cash equivalents at beginning of the period	1,571,000	8,405,000
Cash and cash equivalents at end of the period	11,506,000	1,571,000
Supplemental disclosure of cash flow information:
Interest paid	356,000	335,000
Supplemental disclosure of non-cash investing and financing activity:
Issuance of common stock upon reverse merger, net of cash paid for partial shares	31,768,000
Conversion of convertible promissory notes, related parties into common stock upon reverse merger	35,577,000
Reclassification of convertible preferred stock warrant liability to equity	70,000
Acquisition of property and equipment included in accounts payable	$ 52,000

Organization and Basis of Presentation	12 Months Ended
Organization and Basis of Presentation	Dec. 31, 2018
Disclosure Text Block [Abstract]
Organization, Consolidation and Presentation of Financial Statements Disclosure [Text Block]	NOTE 1. Organization and Basis of Presentation General Vaxart Biosciences, Inc. was originally incorporated in California in March 2004, under the name West Coast Biologicals, Inc. The Company changed its name to Vaxart, Inc. (“Private Vaxart”) in July 2007, and reincorporated in the state of Delaware. On February 13, 2018, Private Vaxart completed a business combination with Aviragen Therapeutics, Inc. (“Aviragen”), pursuant to which Aviragen merged with Private Vaxart, with Private Vaxart surviving as a wholly-owned subsidiary of Aviragen (the “Merger”). Pursuant to the terms of the Merger, Aviragen changed its name to Vaxart, Inc. (together with its subsidiaries, the “Company” or “Vaxart”) and Private Vaxart changed its name to Vaxart Biosciences, Inc. All of Private Vaxart’s convertible promissory notes and convertible preferred stock was converted into common stock, following which each share of common stock was converted into approximately 0.22148 shares of the Company’s common stock (the “Conversion”). Except as otherwise noted in these Financial Statements, all shares, equity securities and per share amounts of Private Vaxart are presented to give retroactive effect to the Conversion. Immediately following the completion of the Merger, the Company effected a reverse stock split at a ratio of one new share for every eleven shares of the Company’s common stock outstanding (the “Reverse Stock Split”). Except as otherwise noted in these Financial Statements, all share, equity security and per share amounts are presented to give retroactive effect to the Reverse Stock Split. Immediately after the Reverse Stock Split there were approximately 7.1 million shares of the Company’s common stock outstanding. Private Vaxart’s stockholders, warrantholders and optionholders owned approximately 51% of the fully-diluted common stock of the Company, with Aviragen’s stockholders and optionholders immediately prior to the Merger owning approximately 49% of the fully-diluted common stock of the Company. The Company also assumed all of Private Vaxart’s outstanding stock options and warrants with proportionate adjustments to the number of underlying shares and exercise prices based on an exchange ratio, based on the combined impact of the Conversion and the Reverse Stock Split, of approximately 0.0201346 shares of the Company for each share of Private Vaxart. The Company’s principal operations are based in South San Francisco, California, and it operates in one reportable segment, which is the discovery and development of oral recombinant protein vaccines, based on its proprietary oral vaccine platform. Liquidity and Going Concern Since incorporation, the Company has been involved primarily in performing research and development activities, hiring personnel, and raising capital to support these activities. The Company has experienced losses and negative cash flows from operations since its inception. As of December 31, 2018, the Company had an accumulated deficit of $98.0 million and a loan with an outstanding balance of $3.6 million from Oxford Finance, LLC (“Oxford Finance”), repayable in monthly installments by January 2021 (see Note 9). The Company expects to incur increasing costs as research and clinical trials are advanced and, therefore, expects to continue to incur losses and negative operating cash flows for the next several years. Absent additional funding or adjustments to currently planned operating activities, and in view of the uncertainties regarding future royalty revenue on sales of Relenza and Inavir, management believes that the Company’s cash and cash equivalents of $11.5 million held as of December 31, 2018, are sufficient to fund the Company into, but possibly not beyond, the second quarter of 2019. The Company reviews its operations and clinical plans on a continuing basis, including its commitments for upcoming clinical trials. The Company plans to finance its operations with royalty revenue on sales of Relenza and Inavir, additional equity or debt financing arrangements, and potentially with additional funding from government contracts or strategic alliances with partner companies. The availability and amount of such funding is not certain. The uncertainties inherent in the Company’s future operations and in its ability to obtain additional funding raise substantial doubt about its ability to continue as a going concern beyond one year from the date these financial statements are issued. The financial statements do not include any adjustments that might result from the outcome of this uncertainty. While management believes its plan to raise additional funds will alleviate the conditions that raise substantial doubt, these plans are not entirely within its control and cannot be assessed as being probable of occurring. If adequate funds are not available, the Company may be required to reduce operating expenses, delay or reduce the scope of its product development programs, obtain funds through arrangements with others that may require the Company to relinquish rights to certain of its technologies or products that the Company would otherwise seek to develop or commercialize itself, or cease operations.

Summary of Significant Accounting Policies

12 Months Ended

Dec. 31, 2018

Accounting Policies [Abstract]

Significant Accounting Policies [Text Block]

NOTE 2. Summary of Significant Accounting Policies

Basis of Presentation – The accompanying consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (“U.S. GAAP”).

Basis of Consolidation – The consolidated financial statements include the financial statements of Vaxart, Inc. and its subsidiaries. All significant transactions and balances between Vaxart, Inc. and its subsidiaries have been eliminated in consolidation.

Use of Estimates – The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets, liabilities, revenues and expenses and disclosure of contingent assets and liabilities in the financial statements and accompanying notes. Actual results and outcomes could differ from these estimates and assumptions.

Foreign Currencies – Foreign exchange gains and losses for assets and liabilities of the Company’s non-U.S. subsidiaries for which the functional currency is the U.S. dollar are recorded in foreign exchange gain or loss, net within other income and (expenses) in the Company’s statements of operations and comprehensive loss. The Company has no subsidiaries for which the local currency is the functional currency.

Cash and Cash Equivalents – The Company considers all highly liquid debt investments with an original maturity of three months or less when purchased to be cash equivalents. Cash equivalents, which may consist of amounts invested in money market funds, corporate bonds and commercial paper, are stated at fair value. Cash and cash equivalents as of December 31, 2018 and 2017, includes $50,000 of restricted cash.

Short-Term Investments – The Company’s short-term investments have only comprised commercial paper and corporate bonds. The short-term investments are classified as held-to-maturity based on the Company’s positive intent and ability to hold the securities to maturity. This classification is reevaluated at each balance sheet date. Short-term investments are stated at amortized cost, adjusted for amortization of premiums and accretion of discounts to maturity. Such amortization is presented as interest income in the statement of operations and comprehensive loss. The specific identification method is used to determine the realized gain or loss on securities sold or otherwise disposed. When the fair value of a debt security classified as held-to-maturity is less than its amortized cost, the Company assesses whether or not: (i) it has the intent to sell the security or (ii) it is more likely than not that the Company will be required to sell the security before its anticipated recovery. If either of these conditions is met, the Company must recognize an other-than-temporary impairment through earnings for the difference between the debt security’s amortized cost basis and its fair value. Gains and losses are recognized in earnings when the investments are sold or impaired.

Concentration of Credit Risk – Financial instruments that potentially subject the Company to significant concentrations of credit risk consist principally of cash, cash equivalents, short-term investments and accounts receivable. The Company places its cash, cash equivalents and short‑term investments at financial institutions that management believes are of high credit quality. The Company is exposed to credit risk in the event of default by the financial institutions holding the cash and cash equivalents to the extent such amounts are in excess of the federally insured limits. The Company has not experienced any losses on its deposits since inception.

The primary focus of the Company’s investment strategy is to preserve capital and meet liquidity requirements. The Company’s investment policy addresses the level of credit exposure by limiting the concentration in any one corporate issuer or sector and establishing a minimum allowable credit rating. The Company generally requires no collateral from its customers.

Accounts Receivable – Accounts receivable arise from the Company’s royalty revenue receivable for sales, net of estimated returns, of Inavir and Relenza, and from its contract with the Department of Health and Human Services, Office of Biomedical Advanced Research and Development Authority (“HHS BARDA”) (see Note 6), and are reported at amounts expected to be collected in future periods. An allowance for uncollectible accounts will be recorded based on a combination of historical experience, aging analysis, and information on specific accounts, with related amounts recorded as a reserve against revenue recognized. Account balances will be written off against the allowance after all means of collection have been exhausted and the potential for recovery is considered remote. The Company has provided no allowance for uncollectible accounts as of December 31, 2018 and 2017.

Property and Equipment – Property and equipment is carried at cost less accumulated depreciation. Depreciation is computed using the straight-line method over the estimated useful lives of the respective assets. Depreciation begins at the time the asset is placed in service. Maintenance and repairs are charged to operations as incurred. Upon sale or retirement of assets, the cost and related accumulated depreciation are removed from the balance sheet and the resulting gain or loss is reflected in other income and (expenses) in the period realized.

The useful lives of the property and equipment are as follows:

Laboratory equipment	5 years
Office and computer equipment	3 years
Leasehold improvements	Shorter of remaining lease term or estimated useful life

Intangible Assets – Intangible assets comprise developed technology, intellectual property and, until it was considered fully impaired (see Note 5), in-process research and development. Intangible assets are carried at cost less accumulated amortization. Amortization is computed using the straight-line method over useful lives ranging from 1.3 to 11.75 years for developed technology and 20 years for intellectual property. In-process research and development is considered to be indefinite-lived and is not amortized, but is subject to impairment testing. The Company assessed its in-process research and development as fully impaired in the year ended December 31, 2018 (see Note 5).

Impairment of Long-Lived Assets – The Company reviews its long-lived assets, including property and equipment and intangible assets with finite lives, for impairment whenever events or changes in circumstances indicate the carrying amount of these assets may not be recoverable. Recoverability of these assets is measured by comparison of the carrying amount of each asset to the future undiscounted cash flows the asset is expected to generate over its remaining life. When indications of impairment are present and the estimated undiscounted future cash flows from the use of these assets is less than the assets’ carrying value, the related assets will be written down to fair value. The Company assessed leasehold improvements and furniture at its leased offices in Alpharetta, Georgia as impaired in the year ended December 31, 2018 (see Notes 5 and 10). There have been no other impairments of the Company’s long-lived assets for the periods presented.

Accrued Clinical and Manufacturing Expenses – The Company accrues for estimated costs of research and development activities conducted by third-party service providers, which include the conduct of preclinical studies and clinical trials, and contract manufacturing activities. The Company records the estimated costs of research and development activities based upon the estimated amount of services provided and includes the costs incurred but not yet invoiced within other accrued liabilities in the balance sheets and within research and development expense in the consolidated statements of operations and comprehensive loss. These costs can be a significant component of the Company’s research and development expenses.

The Company estimates the amount of services provided through discussions with internal personnel and external service providers as to the progress or stage of completion of the services and the agreed-upon fee to be paid for such services. The Company makes significant judgments and estimates in determining the accrued balance in each reporting period. As actual costs become known, it adjusts its accrued estimates. Although the Company does not expect its estimates to be materially different from amounts actually incurred, its understanding of the status and timing of services performed, the number of subjects enrolled, and the rate of enrollment may vary from its estimates and could result in the Company reporting amounts that are too high or too low in any particular period. The Company’s accrued expenses are dependent, in part, upon the receipt of timely and accurate reporting from contract research organizations and other third-party service providers. To date, the Company has not experienced any material differences between accrued costs and actual costs incurred.

Convertible Preferred Stock Warrant Liability – The Company has issued certain convertible preferred stock warrants. These warrants were recorded within other accrued liabilities in the balance sheets at fair value due to down-round protection features contained in the convertible preferred stock into which the warrants were exercisable. At the end of each reporting period, changes in fair value of the warrants since the prior period were recorded as a component of (loss) gain on revaluation of financial instruments, net within other income and (expenses) in the consolidated statements of operations and comprehensive loss. In the event that the terms of the warrant change such that liability accounting is no longer required, the fair value on the date of such change is released to equity.

Convertible Promissory Notes Embedded Derivative Liability – The Company recorded derivative instruments related to redemption features embedded within the outstanding convertible promissory notes. The embedded derivatives were accounted for as liabilities at their estimated fair value when the convertible promissory notes were issued and were re-measured to fair value as of each balance sheet date, with the related re-measurement adjustment being recognized as a component of (loss) gain on revaluation of financial instruments in the consolidated statements of operations and comprehensive loss.

Revenue Recognition – The Company recognizes revenue when it transfers control of promised goods or services to its customers, in an amount that reflects the consideration which the Company expects to receive in exchange for those goods or services. To determine revenue recognition, the Company performs the following five steps:

(i) identification of the promised goods or services in the contract;

(ii) determination of whether the promised goods or services are performance obligations including whether they are distinct in the context of the contract;

(iii) measurement of the transaction price, including the constraint on variable consideration;

(iv) allocation of the transaction price to the performance obligations based on estimated selling prices; and

(v) recognition of revenue when (or as) the Company satisfies each performance obligation. A performance obligation is a promise in a contract to transfer a distinct good or service to the customer and is the unit of account.

Revenue from royalties earned as a percentage of sales, including milestone payments based on achieving a specified level of sales, where a license is deemed to be the predominant item to which the royalties relate, is recognized as revenue at the later of (i) when the related sales occur, or (ii) when the performance obligation to which some or all of the royalty has been allocated has been satisfied (or partially satisfied), as required under the sales- and usage-based royalty exception.

The Company performed research and development work under its cost‑plus‑fixed‑fee contract with HHS BARDA. The Company recognizes revenue under research contracts only when a contract has been executed and the contract price is fixed or determinable. Revenue from the HHS BARDA contract is recognized in the period during which the related costs are incurred and the related services are rendered, provided that the applicable conditions under the contract have been met. Costs of contract revenue are recorded as a component of operating expenses in the consolidated statements of operations and comprehensive loss.

Under the cost reimbursable contract with HHS BARDA, the Company is reimbursed for allowable costs, and recognizes revenue as allowable costs are incurred and the fixed-fee is earned. Reimbursable costs under the contract primarily include direct labor, subcontract costs, materials, equipment, travel, and approved overhead and indirect costs. Fixed fees under cost reimbursable contracts are earned in proportion to the allowable costs incurred in performance of the work relative to total estimated contract costs, with such costs incurred representing a reasonable measurement of the proportional performance of the work completed. Under the HHS BARDA contract, certain activities must be pre-approved in order for their costs to be deemed allowable direct costs. The HHS BARDA contract provides the U.S. government the ability to terminate the contract for convenience or to terminate for default if the Company fails to meet its obligations as set forth in the statement of work.

Payments to the Company under cost reimbursable contracts, such as this contract, are provisional payments subject to adjustment upon annual audit by the government. Management believes that revenue for periods not yet audited has been recorded in amounts that are expected to be realized upon final audit and settlement. When the final determination of the allowable costs for any year has been made, revenue and billings may be adjusted accordingly in the period that the adjustment is known.

Research and Development Costs – Research and development costs are expensed as incurred. Research and development costs consist primarily of salaries and benefits, stock-based compensation, consultant fees, third-party costs for conducting clinical trials and the manufacture of clinical trial materials, certain facility costs and other costs associated with clinical trials. Payments made to other entities are under agreements that are generally cancelable by the Company. Advance payments for research and development activities are recorded as prepaid expenses. The prepaid amounts are expensed as the related services are performed.

Stock-Based Compensation – The Company measures the fair value of all stock-based awards, including stock options, to employees and, since April 1, 2018, to nonemployees, on the grant date and records the fair value of these awards, net of estimated forfeitures, to compensation expense over the service period. Prior to April 1, 2018, the fair value of awards to nonemployees was measured on the date of performance at the fair value of the consideration received or the fair value of the equity instruments issued, whichever was more reliably measured. The fair value of options is estimated using the Black-Scholes valuation model. The expected term of each option is estimated by taking the arithmetic average of its original contractual term and its average vesting term.

Net Income (Loss) Per Share Attributable to Common Stockholders – Basic net income (loss) per share is computed by dividing net income (loss), as adjusted for dividends on the Series B and Series C convertible preferred stock in the period, by the weighted average number of common shares outstanding during the period, without consideration of potential common shares.

Diluted net income (loss) per common share is computed giving effect to all potential dilutive common shares, comprising common stock issuable upon exercise of stock options and warrants. The Company uses the treasury-stock method to compute diluted income (loss) per share with respect to its stock options and warrants. For purposes of this calculation, options and warrants to purchase common stock are considered to be potential common shares and are only included in the calculation of diluted net income per share when their effect is dilutive. In the event of a net loss, the effects of all potentially dilutive shares are excluded from the diluted net loss per share calculation as their inclusion would be antidilutive.

Recently Adopted Accounting Pronouncements

In June 2018, the FASB issued ASU 2018-07, Compensation - Stock Compensation (Topic 718): Improvements to Nonemployee Share-Based Payment Accounting. This update simplifies the accounting for share-based payment transactions by changing the guidance for accounting for nonemployee share-based awards so that, instead of revaluing each award at each balance sheet date during the period over which it vests, the value will be fixed on the grant date and expensed over the vesting period in the same way that employee awards are already accounted for. This guidance is effective for annual periods beginning after December 15, 2018, including interim periods within that year, with early adoption permitted for entities that had already adopted Topic 606 (see ASU 2014-09 below). The Company adopted ASU 2018-07 effective April 1, 2018, and since it had no unvested awards granted to nonemployees, its adoption had no effect on the Company’s financial condition or results of operations.

In May 2017, the FASB issued ASU 2017-09, Compensation - Stock Compensation (Topic 718): Scope of Modification Accounting. This update provides guidance about which changes to the terms or conditions of a share-based payment award require an entity to apply modification accounting in Topic 718. This guidance is effective for annual periods beginning after December 15, 2017, including interim periods within that year, and must be applied prospectively to an award modified on or after the adoption date. The Company adopted this standard effective January 1, 2018, and its adoption had no effect on the Company’s financial condition or results of operations.

In January 2017, the FASB issued ASU No. 2017-04, Intangibles-Goodwill and Other (Topic 350) Simplifying the Test for Goodwill Impairment (“ASU 2017-04”), which will simplify the goodwill impairment calculation by eliminating Step 2 from the current goodwill impairment test. The new standard does not change how a goodwill impairment is identified. The standard will be effective January 1, 2020, with early adoption permitted, and is to be applied prospectively from the date of adoption. The Company adopted this standard effective January 1, 2018, and its adoption had no effect on the Company’s financial condition or results of operations.

In January 2017, the FASB issued ASU No. 2017-01, Business Combinations (Topic 805) Clarifying the Definition of a Business (“ASU 2017-01”). The new standard clarifies the definition of a business to help companies evaluate whether acquisition or disposal transactions should be accounted for as asset groups or as businesses. The Company adopted this standard when it became effective on January 1, 2018, and it was applied in connection with the Company’s accounting for the Merger as a business combination.

In August 2016, the FASB issued Accounting Standards Update (ASU) 2016-15, Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments, which provides additional guidance on the presentation and classification of certain items in the statement of cash flows. The standard is effective for fiscal years beginning after December 15, 2017, with early adoption permitted. The Company adopted this standard effective January 1, 2018, and its adoption had no effect on the Company’s financial condition or results of operations.

In May 2014, the FASB issued ASU 2014-09, Revenue from Contracts with Customers (Topic 606), which supersedes nearly all existing revenue recognition guidance under Topic 605, Revenue Recognition. The new standard requires a company to recognize revenue when it transfers goods and services to customers in an amount that reflects the consideration that the company expects to receive for those goods or services. ASU 2014-09 defines a five-step process that includes identifying the contract with the customer, identifying the performance obligations in the contract, determining the transaction price, allocating the transaction price to the performance obligations in the contract and recognizing revenue when (or as) the entity satisfies the performance obligations.

The Company has determined that its HHS BARDA government contract is not within the scope of ASU 2014-09 as the government entity is not a customer under the agreement. The Company adopted ASU 2014-09 with respect to its royalty revenue using the modified retrospective method on January 1, 2018. Under the modified retrospective transition method, the cumulative effect of applying the standard is recognized at the date of initial application for all contracts not completed as of the date of adoption. The adoption of ASU 2014-09 did not have any effect on the Company’s financial condition or results of operations and therefore no cumulative effect adjustment was recorded, although the Company has modified its accounting policies to reflect the requirements of this standard and make additional disclosures.

Recent Accounting Pronouncements

In February 2016, the FASB issued ASU 2016 02 Leases (Topic 842), which replaces most current lease guidance when it becomes effective. This standard update intends to increase transparency and improve comparability by requiring entities to recognize assets and liabilities on the balance sheet for all leases, with certain exceptions. The new standard states that a lessee will recognize a lease liability for the obligation to make lease payments and a right-of-use asset for the right to use the underlying asset for the lease term. Leases will be classified as either finance or operating, with classification affecting the pattern of expense recognition in the statements of operations. The new guidance will be effective for the Company starting in the first quarter of fiscal 2019, with early adoption permitted. The Company plans to adopt the new guidance effective January 1, 2019, using the modified retrospective method, and to use the effective date method of adoption, as permitted by ASU 2018-11, Targeted Improvements, which the FASB issued in July 2018, which reduces the disclosure requirements on transition. The Company has elected the short-term lease recognition exemption for all classes of assets, which means that it will not recognize right-of-use assets or lease liabilities for leases with a duration of one year or less. Further, the Company has elected to use all of the practical expedients available on transition, whereby it has not reassessed under the new standard its prior conclusions about lease identification, lease classification and initial direct costs.

We expect that this standard will have a material effect on our consolidated financial statements. The most significant effects relate to the recognition of new right-of-use assets and lease liabilities on our consolidated balance sheet. The Company currently expects to recognize lease liabilities of $1,207,000, $766,000 of which is current, and right-of-use assets of $941,000 based on the present value of the remaining minimum rental payments under current leasing standards for existing operating leases, to derecognize liabilities of $239,000, $100,000 of which is current, and recognize an increase of $27,000 to accumulated deficit on adoption of the new accounting policy.

The increase in accumulated deficit arises because the right-of-use asset impairment charge that would have been recorded in the three months ended December 31, 2018, under Topic 842 exceeds the lease loss accrual, net of accretion, that was recorded (see Note 10). This impact aside, the adoption will have no effect on the Company’s statements of operations or cash flows, other than on related disclosures.

The Company has reviewed all other significant newly-issued accounting pronouncements and concluded that they either are not applicable to the Company’s operations or no material effect is expected on its consolidated financial statements as a result of future adoption.

Business Combination

12 Months Ended

Dec. 31, 2018

Business Combinations [Abstract]

Business Combination Disclosure [Text Block]

NOTE 3. Business Combination

On February 13, 2018, the Company acquired Aviragen in a reverse merger (see Note 1). On the date of the Merger, Aviragen had in-process research and development as it was conducting a Phase 2 trial, it had previously developed drugs that were licensed to others who brought them to market and it had a workforce that was considered to have the necessary skills, knowledge, and experience to perform a process that, when applied to the in-process research and development, was critical to the ability to convert it into outputs. Based on this evaluation, the Company determined that the Merger should be accounted for as a business combination.

Since the date of the Merger, the results of Aviragen’s operations have been included in the consolidated financial statements. As a result of the acquisition, the Company eliminated the majority of its debt and acquired a significant cash balance in exchange for equity securities.

The total purchase price for Aviragen is summarized as follows (in thousands):

Common stock	$	31,789

Total	$	31,789

In connection with the Aviragen acquisition, the Company allocated the total purchase consideration to the net assets and liabilities acquired, including identifiable intangible assets, based on their respective fair values at the acquisition date.

The following table summarizes the preliminary allocation of the purchase price to the fair value of the respective assets and liabilities acquired, adjustments made since the acquisition date and the final allocation as of December 31, 2018:

	As of February 13, 2018		Adjustments		As of December 31, 2018
			(in thousands)
Cash and cash equivalents	$	25,525	$	—	$	25,525
Accounts receivable		14,666		—		14,666
Prepaid expenses		446		(10)		436
Property and equipment		170		—		170
Intangible assets:
Developed technology ⁽¹⁾		22,400		(300)		22,100
In-process research and development ⁽²⁾		1,600		—		1,600
Total assets		64,807		(310)		64,497

Accounts payable		(3,379)		75		(3,304)
Other current liabilities		(6,351)		(393)		(6,744)
Liability related to sale of future royalties		(16,300)		400		(15,900)
Net assets acquired		38,777		(228)		38,549

Purchase price		(31,789)		—		(31,789)

Bargain purchase gain ⁽³⁾	$	6,988	$	(228)	$	6,760

__________

(1) Developed technology comprises Inavir and Relenza, both influenza vaccines on which the Company is presently receiving royalty revenue, which, based on valuations prepared by an independent third party based on estimated discounted cash flows based on probability-weighted future development expenditures and revenue streams provided by the Company’s management, are being amortized on a straight-line basis over the estimated periods of future royalties of 11.75 and 1.3 years, respectively.

(2) In-process research and development (see Note 5) related to teslexivir, or BTA074, a direct-acting antiviral that, at the time of the Merger, was being actively developed as a treatment for genital warts. The valuation was prepared by an independent third party based on estimated discounted cash flows based on probability-weighted future development expenditures and revenue streams provided by the Company’s management.

(3) The bargain purchase gain represents the excess of the fair value of tangible and identified intangible assets, less liabilities, acquired over the purchase price.

In addition, the Company incurred and expensed costs directly related to the Merger totaling approximately $0.5 million and $0.9 million in the years ended December 31, 2018 and 2017, respectively, which are included in general and administrative expenses in the consolidated statement of operations and comprehensive loss.

Selected amounts related to Aviragen’s business included in the Company’s consolidated statement of operations for the year ended December 31, 2018, are as follows (in thousands):

Revenue	$	2,815

Net loss	$	(3,847)

The unaudited pro forma information in the table below summarizes the combined results of operations of Vaxart Biosciences, Inc. with those of Aviragen as though these entities were combined as of January 1, 2017. The results of Aviragen’s business for the year ended December 31, 2017, are based on information used to prepare its audited consolidated financial statements prepared for the year ended June 30, 2017, as adjusted by information used to prepare its unaudited condensed consolidated financial statements prepared for the six months ended December 31, 2017 and 2016. The results of Aviragen’s business for the year ended December 31, 2018, are based on the Company’s results of operations, with the results increased by Aviragen’s activities in the forty-three days prior to the closing of the Merger. The pro forma financial information for both years presented also includes the removal of direct acquisition-related costs, the reduction in interest expense on borrowing converted into equity in the reverse merger, and the actual depreciation and amortization that would have been charged assuming the fair value adjustments to property and equipment and intangible assets had been applied as of January 1, 2017.

This unaudited pro forma information is summarized as follows:

	Year Ended December 31,
	2018		2017
	(in thousands)
Total revenue	$	15,695	$	13,527

Net loss	$	(13,162)	$	(29,270)

The pro forma financial information as presented above is for informational purposes only and is not indicative of the consolidated results of operations of future periods or the results of operations that would have been achieved had the acquisition had taken place on January 1, 2017.

Fair Value of Financial Instruments

12 Months Ended

Dec. 31, 2018

Fair Value Disclosures [Abstract]

Fair Value Disclosures [Text Block]

NOTE 4. Fair Value of Financial Instruments

Fair value accounting is applied for all financial assets and liabilities and nonfinancial assets and liabilities that are recognized or disclosed at fair value in the financial statements on a recurring basis (at least annually). Financial instruments include cash and cash equivalents, short‑term investments, accounts receivable, accounts payable and accrued liabilities that approximate fair value due to their relatively short maturities. As short‑term investments are classified as held‑to‑maturity, they are recorded at their amortized cost.

Assets and liabilities recorded at fair value on a recurring basis in the balance sheets are categorized based upon the level of judgment associated with inputs used to measure their fair values. The accounting guidance for fair value provides a framework for measuring fair value and requires certain disclosures about how fair value is determined. Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability (an exit price) in an orderly transaction between market participants at the reporting date. The accounting guidance also establishes a three‑level valuation hierarchy that prioritizes the inputs to valuation techniques used to measure fair value based upon whether such inputs are observable or unobservable. Observable inputs reflect market data obtained from independent sources, while unobservable inputs reflect market assumptions made by the reporting entity.

The three-level hierarchy for the inputs to valuation techniques is briefly summarized as follows:

Level 1 – Inputs are unadjusted, quoted prices in active markets for identical assets or liabilities at the measurement date;

Level 2 – Inputs are observable, unadjusted quoted prices in active markets for similar assets or liabilities, unadjusted quoted prices for identical or similar assets or liabilities 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 significant to the measurement of the fair value of the assets or liabilities that are supported by little or no market data.

The Company’s money market funds are classified within Level 1 of the fair value hierarchy and are valued based on quoted prices in active markets for identical securities. The Company’s corporate bonds and commercial paper are classified within Level 2 of the fair value hierarchy and are valued based on quoted prices for similar assets or prices derived from observable market data. Level 3 liabilities consist of convertible promissory notes embedded derivative liabilities and a convertible preferred stock warrant liability as they are valued by using inputs that are unobservable in the market. The determination of the fair values of the convertible promissory notes embedded derivative is discussed in Note 8.

The following tables present the Company’s financial assets and liabilities that are measured at fair value at December 31, 2018 and 2017:

	Level 1		Level 2		Level 3		Total
December 31, 2018				(in thousands)
Recurring Financial Assets:
Money Market Funds	$	15	$	—	$	—	$	15
Corporate Bonds		—		—		—		—

Total assets	$	15	$	—	$	—	$	15

Recurring Financial Liabilities:
Convertible promissory notes embedded derivative liability	$	—	$	—	$	—	$	—
Convertible preferred stock warrant liability		—		—		—		—

Total liabilities	$	—	$	—	$	—	$	—

	Level 1		Level 2		Level 3		Total
December 31, 2017				(in thousands)
Recurring Financial Assets:
Money Market Funds	$	1,192	$	—	$	—	$	1,192
Corporate Bonds		—		1,415		—		1,415

Total assets	$	1,192	$	1,415	$	—	$	2,607

Recurring Financial Liabilities:
Convertible promissory notes embedded derivative liability	$	—	$	—	$	—	$	—
Convertible preferred stock warrant liability		—		—		67		67

Total liabilities	$	—	$	—	$	67	$	67

The following tables present a reconciliation of all liabilities measured at fair value on a recurring basis using significant unobservable inputs (Level 3) for the years ended December 31, 2018 and 2017:

	Convertible Preferred Stock Warrant Liability		Convertible Promissory Notes Embedded Derivative Liability

					Total
				(in thousands)
Balance at January 1, 2018	$	67	$	—	$	67
Issuances		—		—		—
Revaluation loss included in (loss) gain on revaluation of financial instruments, net		3		—		3
Settlements		(70)		—		(70)
Balance at December 31, 2018	$	—	$	—	$	—

Total losses included in other income and (expenses) attributable to liabilities still held as of December 31, 2018	$	—	$	—	$	—

	Convertible Preferred Stock Warrant Liability		Convertible Promissory Notes Embedded Derivative Liability

					Total
				(in thousands)
Balance at January 1, 2017	$	134	$	3,280	$	3,414
Issuances		—		—		—
Revaluation gains included in (loss) gain on revaluation of financial instruments, net		(67)		(3,280)		(3,347)
Settlements		—		—		—
Balance at December 31, 2017	$	67	$	—	$	67

Total gains included in other income and (expenses) attributable to liabilities still held as of December 31, 2017	$	67	$	3,280	$	3,347

- Definition

The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.

+ References + Details

Balance Sheet Components

12 Months Ended

Dec. 31, 2018

Disclosure Text Block Supplement [Abstract]

Supplemental Balance Sheet Disclosures [Text Block]

NOTE 5. Balance Sheet Components

(a) Cash Equivalents and Short-Term Investments

Cash equivalents and short‑term investments, all of which are classified as held‑to‑maturity securities and mature within one year, consisted of the following:

	December 31, 2018
			Gross Unrecognized Gains		Gross Unrecognized Losses		Estimated Fair Value		Carrying Value
	Amortized Cost
	Amortized Cost
						(in thousands)
Money market funds	$	15	$	—	$	—	$	15	$	15
Corporate bonds		—		—		—		—		—
Total	$	15	$	—	$	—	$	15	$	15
Reported as:
Cash equivalents	$	15	$	—	$	—	$	15	$	15
Short-term investments		—		—		—		—		—
Total	$	15	$	—	$	—	$	15	$	15

	December 31, 2017
			Gross		Gross		Estimated
	Amortized		Unrecognized		Unrecognized		Fair		Carrying
	Cost		Gains		Losses		Value		Value
						(in thousands)
Money market funds	$	1,192	$	—	$	—	$	1,192	$	1,192
Corporate bonds		1,415		—		—		1,415		1,415
Total	$	2,607	$	—	$	—	$	2,607	$	2,607
Reported as:
Cash equivalents	$	1,192	$	—	$	—	$	1,192	$	1,192
Short-term investments		1,415		—		—		1,415		1,415
Total	$	2,607	$	—	$	—	$	2,607	$	2,607

(b) Accounts Receivable

Accounts receivable comprises the following:

	December 31, 2018		December 31, 2017
	(in thousands)
Royalties receivable	$	1,776	$	—
Government contract – billed		20		477
Government contract – unbilled		—		153
Accounts receivable	$	1,796	$	630

(c) Property and Equipment, Net

Property and equipment, net consists of the following:

	December 31, 2018		December 31, 2017
	(in thousands)
Laboratory equipment	$	2,076	$	1,565
Office and computer equipment		227		175
Leasehold improvements		333		226

Total property and equipment		2,636		1,966
Less: accumulated depreciation		(1,570)		(1,236)
Property and equipment, net	$	1,066	$	730

Depreciation expense was $476,000 and $376,000 for the years ended December 31, 2018 and 2017, respectively. Leasehold improvements and furniture at the Company’s leased premises in Georgia, which has been subleased, commencing in November 2018, for less than the rental that the Company is obligated to pay (see Note 10), were assessed as impaired as of September 30, 2018, and accordingly an impairment charge of $106,000 was recorded as a component of costs of exit from leased premises within operating expenses.

(d) Intangible Assets

Intangible assets consist of the following:

	December 31, 2018		February 13, 2018		December 31, 2017
				(in thousands)
Purchased technology	$	22,100	$	22,400	$	—
In-process research and development		—		1,600		—
Intellectual property		80		80		80
Total cost		22,180		24,080		80
Less accumulated amortization		2,767		40		40
Intangible assets, net	$	19,413	$	24,040	$	40

Intangible asset amortization expense was $2,727,000 and $4,000 for the years ended December 31, 2018 and 2017, respectively. Following the results of Phase 2 trials in June 2018, the in-process research and development was assessed as fully impaired in the three months ended June 30, 2018, with the $1.6 million acquired in the Merger (see Note 3) being charged to operating expenses.

As of December 31, 2018, the estimated future amortization expense by year is as follows (in thousands):

Year Ending December 31,
2019	$	2,320
2020		1,732
2021		1,732
2022		1,732
2023		1,731
Thereafter		10,166
Total	$	19,413

(e) Other Accrued Liabilities

Accrued liabilities consist of the following:

	December 31, 2018		December 31, 2017
	(in thousands)
Accrued compensation	$	632	$	1,320
Accrued clinical and manufacturing expenses		75		69
Accrued professional and consulting services		166		113
Reserve for return of royalties		339		—
Deferred rent and lease loss accrual, current portion		111		21
Convertible preferred stock warrant liability		—		67
Other		195		15

Total	$	1,518	$	1,605

Revenue	12 Months Ended
Revenue	Dec. 31, 2018
Revenue [Abstract]
Revenue [Text Block]	NOTE 6. Revenue U.S. Government HHS BARDA Contract In September 2015, HHS BARDA awarded the Company a contract to support the advanced development of a more effective and universal influenza vaccine to improve seasonal and pandemic influenza preparedness. On each of May 25 and July 18, 2017, and June 28, 2018, the Company entered into a Modification of Contract with HHS BARDA, the combined effect being to increase the value of the existing $14 million contract by $1.7 million and to extend it through September 30, 2018. The modified contract is a cost-plus-fixed-fee contract, which reimburses the Company for allowable direct contract costs plus allowable indirect costs and a fixed-fee, totaling $15.7 million. The Company recognized revenue of $1,344,000 and $5,839,000 during the years ended December 31, 2018 and 2017, respectively. As of December 31, 2018, the cumulative revenue recorded from inception under the HHS BARDA contract represents the maximum amount billable under the contract as presently modified, with no further change orders envisaged. Billings under the contract are based on approved provisional indirect billing rates, which permit recovery of fringe benefits, overhead and general and administrative expenses. Indirect rates as well as allowable costs are subject to audit by HHS BARDA on an annual basis. Management believes that revenues recognized to date have been recorded in amounts that are expected to be realized upon final audit and settlement. When the final determination of the allowable costs for any year has been made, revenue and billings may be adjusted accordingly in the period that the adjustments are known and collection is probable. Costs relating to contract acquisition are expensed as incurred. The Company does not consider any of the revenue recorded as of December 31, 2018 or 2017, to be at risk of reversal. Royalty agreements Aviragen entered into a royalty-bearing research and license agreement with GlaxoSmithKline, plc (“GSK”) in 1990 for the development and commercialization of zanamivir, a neuraminidase inhibitor marketed by GSK as Relenza to treat influenza. Most of the Company’s Relenza patents have expired and the only substantial remaining intellectual property related to the Relenza patent portfolio, which is solely owned by the Company and exclusively licensed to GSK, is scheduled to expire in July 2019 in Japan, at which time royalty revenue will cease. The post-Merger royalty revenue related to Relenza recognized in the year ended December 31, 2018, was $788,000, representing 7% of net sales in Japan. The Company also generates royalty revenue from the sale of Inavir in Japan, pursuant to a collaboration and license agreement that Aviragen entered into with Daiichi Sankyo Company, Limited, or Daiichi Sankyo, in 2009. In September 2010, laninamivir octanoate was approved for sale by the Japanese Ministry of Health and Welfare for the treatment of influenza in adults and children, which Daiichi Sankyo markets as Inavir. Under the agreement, the Company currently receives a 4% royalty on net sales of Inavir in Japan and was eligible to earn sales milestone payments, including a one-off payment of $5.0 million if net sales exceeded 20 billion Yen in one year. This target was achieved in the three months ended March 31, 2018, prior to the Merger, and Aviragen recognized the related $5.0 million as royalty revenue prior to the Merger. The last patent related to Inavir is set to expire in December 2029 in Japan, at which time royalty revenue will cease. The post-Merger royalty revenue related to Inavir recognized in the year ended December 31, 2018, was $552,000. In addition, the Company recognized non-cash royalty revenue related to the sale of future royalties (see Note 7) of $1,475,000. Both the royalty revenue and the non-cash royalty revenue related to the sale of future royalties have been subjected to a 5% withholding tax in Japan, for which $102,000 was included in income tax expense in the year ended December 31, 2018.

Liabilities Related to Sale of Future Royalties

12 Months Ended

Dec. 31, 2018

Disclosure Text Block [Abstract]

Deferred Revenue Disclosure [Text Block]

NOTE 7. Liabilities Related to Sale of Future Royalties

In April 2016, Aviragen entered into a Royalty Interest Acquisition Agreement (the “HCRP Agreement”) with HCRP. Under the Agreement, HCRP made a $20.0 million cash payment to Aviragen in consideration for acquiring certain royalty rights (“Royalty Rights”) related to the approved product Inavir in the Japanese market. The Royalty Rights were obtained pursuant to the collaboration and license agreements (the “License Agreement”) and a commercialization agreement that the Company entered into with Daiichi Sankyo. Per the terms of the HCRP Agreement, HCRP is entitled to the first $3.0 million plus 15% of the next $1.0 million in royalties earned in each year commencing on April 1, with any excess revenue being retained by the Company.

Under the relevant accounting guidance, due to a limit on the amount of royalties that HCRP can earn under the arrangement, this transaction was accounted for as a liability that will be amortized using the interest method over the life of the arrangement. The Company has no obligation to pay any amounts to HCRP other than to pass through to HCRP its share of royalties as they are received from Daiichi Sankyo. In order to record the amortization of the liability, the Company is required to estimate the total amount of future royalty payments to be received under the License Agreement and the payments that will be passed through to HCRP over the life of this agreement. The sum of the pass-through amounts less the net proceeds received will be recorded as non-cash interest expense over the life of the liability. Consequently, the Company imputes interest on the unamortized portion of the liability and records non-cash interest expense using an estimated effective interest rate. The Company will periodically assess the expected royalty payments, and to the extent such payments are greater or less than the initial estimate, the Company will adjust the amortization of the liability and interest rate. As a result of this accounting, even though the Company does not retain HCRP’s share of the royalties, it will continue to record non-cash revenue related to those royalties until the amount of the associated liability and related interest is fully amortized.

The following table shows the activity within the liability account since the Merger (in thousands):

Total Liability related to sale of future royalties, February 13, 2018	$	15,900
Non-cash royalty revenue paid to HCRP		(18)
Non-cash interest expense recognized		1,859
Total Liability related to sale of future royalties, December 31, 2018	$	17,741

Convertible Promissory Notes, Related Parties	12 Months Ended
Convertible Promissory Notes, Related Parties	Dec. 31, 2018
Convertible Promissory Notes, Related Party [Abstract]
Convertible Promissory Notes, Related Party [Text Block]	NOTE 8. Convertible Promissory Notes, Related Parties On December 10, 2014, the Company entered into a note purchase agreement with certain existing preferred stockholders under which the Company issued convertible promissory notes during December 2014 for total proceeds of $18.4 million. On November 20, 2015, the Company entered into a second note purchase agreement with certain existing preferred stockholders under which the Company issued convertible promissory notes during November and December 2015 for total proceeds of $11.0 million. These notes were issued with the same terms as the notes issued in 2014. As the holders of the convertible promissory notes each have an equity ownership in the Company, the convertible promissory notes were considered to be a related‑party transaction. The convertible promissory notes bore interest at a rate of 8.0% per annum. The principal and accrued interest on the notes were automatically convertible, upon a future issuance of convertible preferred stock having total proceeds of at least $25.0 million, into that same stock at a conversion price equal to 90% of the price paid by other investors in the financing event. Upon a liquidation event, such as an acquisition or initial public offering, at the election of the majority of the noteholders in each issuance, the principal and accrued interest on the notes could either (i) be paid in full at the initial closing of the liquidation event, or (ii) automatically convert into the Company’s Series C convertible preferred stock at a conversion price based on a specified valuation. After two years, if the notes had not been converted, the holders of a majority of the principal amount had the option to require the entire principal balance and accrued interest to become due and payable. However, in December 2016, in conjunction with the loan agreement with Oxford Finance (see note 9), all of the holders of convertible promissory notes signed subordination agreements, under which they agreed not to demand or receive any payment until all amounts owed to Oxford Finance under the loan agreement were fully paid in cash, thus extending the due dates of the promissory notes potentially to January 2021. This change reflected a debt modification that was not considered substantially significant. Accordingly, the Company did not apply extinguishment accounting, but accounted for the modification on a prospective basis. The convertible promissory notes had redemption features that were determined to be a compound embedded derivative requiring bifurcation and separate accounting at estimated fair value. The estimated fair value of the embedded derivative upon issuance was a liability of $1.9 million for the notes issued in 2014 and $1.3 million for the notes issued in 2015. The estimated fair value of these derivative instruments was recognized as a debt discount and as an embedded derivative liability on the balance sheet upon issuance of the convertible promissory notes. The embedded derivative required periodic re‑measurements to fair value while the instruments were still outstanding (see Note 4). There was no beneficial conversion feature as the conversion feature value was accounted for in the embedded derivative. The Company estimated the fair value of the compound embedded derivative utilizing a Monte Carlo Simulation model. The inputs used to determine the estimated fair value of the embedded derivative instrument included the probability of an underlying event triggering the redemption event and its timing prior to the maturity date of the convertible promissory notes. The fair value measurement was based upon significant inputs not observable in the market, including a valuation of the Company performed by an independent third-party at each balance sheet date. By December 31, 2017, the embedded derivative had zero value because the Merger (see Note 1), which was considered 90% probable of occurring, would not have triggered redemption and, had the Merger not occurred, it was unlikely that the Company would have found an alternative source of financing on favorable terms, so there would have been zero redemption value. The embedded derivative was extinguished when the Merger occurred on February 13, 2018. The Company incurred total debt issuance costs of $20,000 in connection with the 2014 issuance and $7,000 in connection with the 2015 issuance. The debt issuance costs, which were recorded as an additional debt discount, were being amortized over the term of the notes. As of December 31, 2017, the balance of the convertible promissory notes was $35.3 million, comprising principal of $29.4 million plus accrued interest associated with the convertible promissory notes of $6.3 million, offset by unamortized debt discount of $0.4 million. Interest expense related to the convertible promissory notes, including amortization of debt discount, totaled $0.3 million and $2.5 million in the years ended December 31, 2018 and 2017, respectively. The charge in 2018 related to the 43 days prior to the Merger, whereas the charge in 2017 related the full year. On February 13, 2018, the balance of the convertible promissory notes was $35.6 million, comprising accrued interest associated with the convertible promissory notes amounted to $6.6 million plus principal of $29.4 million, offset by the unamortized debt discount to $0.4 million. On that date, in conjunction with the Merger, the convertible promissory notes were exchanged for 1,571,702 shares of the Company’s common stock which, based on the closing stock price of $9.05, had a value of $14.2 million. The difference of $21.4 million was recorded as a capital contribution.

Secured Promissory Note Payable to Oxford Finance	12 Months Ended
Secured Promissory Note Payable to Oxford Finance	Dec. 31, 2018
Secured Promissory Note Payable [Abstract]
Secured Promissory Note Payable [Text Block]	NOTE 9. Secured Promissory Note Payable to Oxford Finance On December 22, 2016, the Company entered into a loan and security agreement (the “Loan Agreement”) with Oxford Finance, under which the Company borrowed $5.0 million. The $5.0 million loan, which bears interest at 30-day U.S. LIBOR plus 6.17%, is evidenced by a secured promissory note and is repayable over four years, with interest only payable over the first 12 months and the balance fully amortized over the subsequent 36 months. The loan is secured by substantially all the Company’s assets, except for intellectual property. In conjunction with the execution of the Loan Agreement, all the holders of convertible promissory notes signed subordination agreements, under which they agreed to subordinate in favor of Oxford Finance all amounts due under their promissory notes and any security interest in the Company’s property. In addition, the holders of the notes agreed that they would not demand or receive any payment until all amounts owed to Oxford Finance under the Loan Agreement have been fully paid in cash. Upon repayment, an additional final payment equal to $325,000 is due, which is being accreted as interest expense over the term of the loan using the effective‑interest method. In connection with the Loan Agreement, the Company issued a warrant to Oxford Finance to purchase 7,563 shares of its Series C convertible preferred stock at an exercise price of $33.11 per share (the “Warrant”). The fair value of the Warrant at the date of issuance was approximately $134,000, which was recorded as debt discount and is being amortized as interest expense over the term of the loan using the effective‑interest method. The annual effective interest rate of the note, including the accretion of the final payment and the amortization of the debt discount, is approximately 10.5%. The Company recorded interest expense related to the Loan Agreement of $469,000 and $518,000 during the years ended December 31, 2018 and 2017, respectively, of which $356,000 and $335,000 was paid, respectively. The Warrant provided that if the share price at the next equity financing was less than the Warrant exercise price, then the Warrant would be for the new class of shares, the exercise price would be the new class share price, and the number of shares would be calculated by dividing $250,000 by the new class share price. Due to this anti-dilution protection, the Company determined that the Warrant needed to be recorded as a liability, and therefore estimated the fair value of the Warrant upon issuance and at each balance sheet date, with any changes in the fair value being recorded within (loss) gain on revaluation of financial instruments, net in other income and (expenses) in the statements of operations and comprehensive loss. Due to the antidilution protection, following the Merger, the Warrant was amended to allow the holder to purchase 10,914 shares of common stock at an exercise price of $22.99 per share. Since the amended Warrant contains no non-standard antidilution protections or similar features, the fair value of approximately $70,000 on February 13, 2018, was reclassified to equity.

Commitments and Contingencies

12 Months Ended

Dec. 31, 2018

Commitments and Contingencies Disclosure [Abstract]

Commitments and Contingencies Disclosure [Text Block]

NOTE 10. Commitments and Contingencies

(a) Leases

The Company has four office and research and development facilities in South San Francisco, California, under noncancelable operating leases. The principal lease, for office and research and development premises, expires on April 30, 2020, subject to the Company’s option to extend the lease at the then market rate for an additional five‑year period. The remaining three leases all expire on August 31, 2019. In addition, as a result of the Merger, the Company also leases office space in Alpharetta, Georgia, under a lease expiring on February 28, 2021, which, commencing in November 2018, the Company has subleased for the remainder of the lease term for less than it is required to pay under the head lease and accordingly it recorded a lease loss charge of $253,000 on the cease-use date in the three months ending December 31, 2018, which, along with the related impairment of property and equipment (see Note 5), was recorded as a component of costs of exit from leased premises within operating expenses.

Liabilities related to costs of exit from leased premises are summarized as follows (in thousands):


Balance as of January 1, 2018	$	—
Costs of exit from leased premises		359
Deferred rent on cease-use date		19
Impairment of property and equipment		(106)
Cash paid, net of receipts		(41)
Accretion charges, included in rent expense		2
Balance as of December 31, 2018	$	233

Rent expense is recognized on a straight‑line basis over the noncancelable term of each operating lease and, accordingly, the Company records the difference between cash rent payments and the recognition of rent expense as a deferred rent liability, which is included within accrued expenses. Rent expense was $875,000 and $564,000 for the years ended December 31, 2018 and 2017, respectively. Under the terms of the lease agreements, the Company is also responsible for certain insurance, property tax and maintenance expenses. The Company also leases equipment under three operating leases that expire between May and September 2019.

Future minimum payments and sublease income under operating leases as of December 31, 2018, are as follows:

Years Ending December 31,	Lease Payments		Sublease Income
	(in thousands)
2019	$	859	$	213
2020		411		219
2021		56		38
Thereafter		—		—
Total	$	1,326	$	470

(b) Indemnifications

In the ordinary course of business, the Company enters into agreements that may include indemnification provisions. Pursuant to such agreements, the Company may indemnify, hold harmless and defend indemnified parties for losses suffered or incurred by the indemnified party. Some of the provisions will limit losses to those arising from third‑party actions. In some cases, the indemnification will continue after the termination of the agreement. The maximum potential amount of future payments the Company could be required to make under these provisions is not determinable. The Company has never incurred material costs to defend lawsuits or settle claims related to these indemnification provisions. The Company has also entered into indemnification agreements with its directors and officers that may require the Company to indemnify its directors and officers against liabilities that may arise by reason of their status or service as directors or officers to the fullest extent permitted by Delaware corporate law. The Company currently has directors’ and officers’ insurance.

(c) Litigation

From time to time the Company may be involved in claims arising in connection with its business. Based on information currently available, the Company believes that the amount, or range, of reasonably possible losses in connection with any pending actions against it in excess of established reserves, in the aggregate, not to be material to its consolidated financial condition or cash flows. However, losses may be material to the Company’s operating results for any particular future period, depending on the level of income or loss for such period.

Stockholders' Equity

12 Months Ended

Dec. 31, 2018

Stockholders' Equity Note [Abstract]

Stockholders' Equity Note Disclosure [Text Block]

NOTE 11. Stockholders’ Equity

(a) Convertible Preferred Stock

The Company is authorized to issue 5,000,000 shares of preferred stock, $0.10 par value per share. The Company’s board of directors may, without further action by the stockholders, fix the rights, preferences, privileges and restrictions of up to an aggregate of 5,000,000 shares of preferred stock in one or more series and authorize their issuance. These rights, preferences and privileges could include dividend rights, conversion rights, voting rights, terms of redemption, liquidation preferences, sinking fund terms and the number of shares constituting any series or the designation of such series, any or all of which may be greater than the rights of our common stock. The issuance of preferred stock could adversely affect the voting power of holders of common stock and the likelihood that such holders will receive dividend payments and payments upon liquidation. In addition, the issuance of preferred stock could have the effect of delaying, deterring or preventing a change of control or other corporate action. No shares of preferred stock are currently outstanding, and the Company has no present plan to issue any shares of preferred stock.

All of Private Vaxart’s convertible preferred stock was converted into common stock on February 13, 2018, in conjunction with the Merger.

As of December 31, 2017, convertible preferred stock consisted of the following:

	Shares authorized	Shares outstanding	Net carrying value		Liquidation preference
			(in thousands)		(in thousands)
Series A	94,988	94,988	$	2,949	$	2,737
Series B	747,095	520,973		16,115		17,219
Series C	820,088	605,103		19,877		20,000
Total	1,662,171	1,221,064	$	38,941	$	39,956

Significant provisions of the convertible preferred stock were as follows:

Dividends – The holders of Series C convertible preferred stock were entitled to receive non-compounding cumulative dividends, in preference to any dividends payable to holders of Series B and Series A convertible preferred stock or common stock, at an annual dividend rate of $2.64416 per share, as adjusted for any stock splits, stock dividends, recapitalizations, or the like. Such cumulative dividends were payable within ten days of demand of the holders of at least a majority of the then outstanding Series C convertible preferred stock, or automatically upon a liquidation event. Dividends accumulated from the date of issuance and were payable, whether or not declared, before any dividend on Series B and Series A convertible preferred stock or common stock could be paid or declared. Series C convertible preferred stock shares issued as stock dividends were not entitled to cumulative dividends. The holders of Series C convertible preferred stock could elect whether the cumulative dividends would be paid in cash or in shares of Series C convertible preferred stock based on the original issue price of Series C convertible preferred stock of $33.05196 per share. In the event the board of directors declared a cash dividend in addition to the above cumulative dividends (a Special Dividend), the holders of Series C convertible preferred stock would have been entitled to receive, in preference to any dividends payable to the holders of Series B and Series A convertible preferred stock or common stock, a per share amount equal to the sum of: (a) the original issue price of Series C convertible preferred stock, and (b) all accrued and/or declared but unpaid dividends on such Series C convertible preferred stock, including the cumulative dividends. No dividends were declared during any of the periods presented. As of February 13, 2018, when the convertible preferred stock was converted into common stock, and December 31, 2017, accumulated and undeclared dividends for Series C convertible preferred stock were $7.3 million and $7.1 million, respectively ($12.06 per share and $11.74 per share, respectively, of the outstanding Series C convertible preferred stock). On February 13, 2018, in conjunction with the Merger, the Series C convertible preferred stock and the related accumulated dividends were converted into 696,028 and 253,851 shares of common stock, respectively.

The holders of Series B convertible preferred stock were entitled to receive non-compounding cumulative dividends, in preference to any dividends payable to holders of Series A convertible preferred stock or common stock, at the annual dividend rate of $2.64416 per share, as adjusted for any stock splits, stock dividends, recapitalizations, or the like. Such cumulative dividends were payable within ten days of demand of the holders of at least a majority of the then outstanding Series B convertible preferred stock or automatically upon a liquidation event. Dividends accumulated from the date of issuance and were payable, whether or not declared, before any dividend on Series A convertible preferred stock or common stock could be paid or declared. Series B convertible preferred shares issued as stock dividends were not entitled to cumulative dividends. The holders of Series B convertible preferred stock could elect whether the cumulative dividends would be paid in cash or in shares of Series B convertible preferred stock based on the original issue price of Series B convertible preferred stock of $33.05196 per share. In the event the board of directors declared a cash dividend in addition to the above cumulative dividends (a Special Dividend), the holders of Series B convertible preferred stock would have been entitled to receive, in preference to any dividends payable to the holders of Series A convertible preferred stock or common stock, a per share amount equal to the sum of: (a) the original issue price of Series B convertible preferred stock, and (b) all accrued and/or declared but unpaid dividends on such Series B convertible preferred stock, including the cumulative dividends. No dividends were declared during any of the periods presented. As of February 13, 2018, when the convertible preferred stock was converted into common stock, and December 31, 2017, accumulated and undeclared dividends for Series B convertible preferred stock were $7.6 million and $7.5 million, respectively ($15.78 per share and $15.46 per share, respectively, of the 483,387 shares of outstanding Series B convertible preferred stock on which dividends accrued). On February 13, 2018, in conjunction with the Merger, the Series B convertible preferred stock and the related accumulated dividends were converted into 599,259 and 265,340 shares of common stock, respectively.

The holders of Series A convertible preferred stock were entitled to receive noncumulative dividends, in preference to any dividends payable to holders of common stock, at the annual dividend rate of $2.30449 per share, as adjusted for any stock splits, stock dividends, recapitalizations, or the like, if declared by the board of directors. On February 13, 2018, in conjunction with the Merger, the Series A convertible preferred stock was converted into 104,065 shares of common stock.

Conversion – At the option of the holder, each share of convertible preferred stock was convertible, one‑for‑one, subject to adjustment for anti‑dilution protection, into shares of common stock. Each share automatically converted into the number of shares of common stock into which the shares were convertible at the then applicable conversion ratio upon: (1) the closing of the sale of the Company’s common stock in a public offering provided the offering price per share was not less than three times the Series C convertible preferred stock original issue price of $33.05196 and the aggregate gross proceeds were not less than $30.0 million, or (2) upon receipt of a written consent of the holders of a majority of the then outstanding shares of convertible preferred stock voting as a single class on an as‑converted basis.

Liquidation – In the event of any liquidation, dissolution or winding up of the Company, including a merger or acquisition where the beneficial owners of the Company’s common and convertible preferred stock owned less than 50% of the surviving entity, or a sale of all or substantially all assets, the holders of Series C convertible preferred stock would have been entitled to receive a per share amount equal to $33.05196 (subject to adjustment for stock splits, stock dividends, recapitalizations, or the like), plus all dividends accrued, payable and/or in arrears (whether or not declared) minus the amount of any Special Dividends previously paid. After payment of the full liquidation preference of Series C convertible preferred stock, the holders of Series B convertible preferred stock would have been entitled to receive a per share amount equal to $33.05196 (subject to adjustment for stock splits, stock dividends, recapitalizations, or the like), plus all dividends accrued, payable and/or in arrears (whether or not declared) minus the amount of any Special Dividends previously paid. After payment of the full liquidation preference of Series B convertible preferred stock, the holders of Series A convertible preferred stock would have been entitled to receive an amount equal to $28.80613 per share, as adjusted, plus all declared but unpaid dividends prior and in preference to any distribution to the holders of common stock. In each case, if the proceeds of such an event were insufficient to permit the liquidation payment to a particular class, any proceeds legally available for distribution to that class would have been distributed ratably among the holders of that class in proportion to the preferential amounts that each holder was entitled to receive. Following payment of all convertible preferred stock preferences, any remaining legally available assets of the Company would have been distributed to the holders of common stock and convertible preferred stock pro rata, based on the greatest number of shares of common stock held on an as‑converted basis.

Voting – The holders of convertible preferred stock were entitled to the number of votes equal to the number of shares of common stock into which each share of Series A, Series B, and Series C convertible preferred stock could have been converted on the record date for the vote or consent of the stockholders, except as otherwise required by law, and had voting rights and powers equal to the voting rights and powers of the common stockholders. The holders of Series A convertible preferred stock, voting as a separate class, were entitled to elect one member of the board of directors. As long as a specified investor held at least one share of Series C convertible preferred stock, the specified investor was able to designate one member of the board of directors, who would have been elected by the holders of Series C convertible preferred stock voting as a separate class. As long as a specified investor held least one share of Series B convertible preferred stock, the specified investor was able to designate one member of the board of directors, who would have been elected by the holders of Series B convertible preferred stock voting as a separate class. The holders of common stock, voting as a separate class, were entitled to elect two members of the board of directors, one of whom was the duly appointed chief executive officer of the Company.

Protective Provisions – So long as at least 20,134 shares of Series C convertible preferred stock remained outstanding and for so long as at least 20,134 shares of Series B convertible preferred stock remained outstanding, Series C holders and Series B holders, voting as a single class on an as‑converted basis, needed to approve certain specified corporate actions such as amending the certificate of incorporation, authorizing additional shares of stock or additional directors, redeeming stock and entering into certain strategic relationships.

Redemption – The convertible preferred stock was not redeemable. There were no liquidation events under the control of preferred stockholders that could have resulted in liquidation in which only the preferred stockholders would have participated. Accordingly, the convertible preferred stock was classified within stockholders’ equity (deficit) on the Company’s consolidated balance sheets.

(b) Common Stock

Except as otherwise required by law or as otherwise provided in any certificate of designation for any series of preferred stock, the holders of common stock possess all voting power for the election of the Company’s directors and all other matters requiring stockholder action. Holders of common stock are entitled to one vote per share on matters to be voted on by stockholders. Holders of common stock are entitled to receive such dividends, if any, as may be declared from time to time by the Company’s board of directors in its discretion out of funds legally available therefore. In no event will any stock dividends or stock splits or combinations of stock be declared or made on common stock unless the shares of common stock at the time outstanding are treated equally and identically. As of December 31, 2018, no dividends had been declared by the board of directors.

In the event of the Company’s voluntary or involuntary liquidation, dissolution, distribution of assets or winding-up, the holders of the common stock will be entitled to receive an equal amount per share of all of the Company’s assets of whatever kind available for distribution to stockholders, after the rights of the holders of the preferred stock have been satisfied. There are no sinking fund provisions applicable to the common stock.

The Company had shares of common stock reserved for issuance as follows:

	December 31, 2018	December 31, 2017

Convertible preferred stock outstanding	—	1,221,064
Options issued and outstanding	865,163	304,850
Available for future grants of equity awards	223,377	—
Cumulative convertible preferred stock dividends	—	441,096
Common stock warrants	10,914	10,914
Total	1,099,454	1,977,924

Equity Incentive Plans

12 Months Ended

Dec. 31, 2018

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

Disclosure of Compensation Related Costs, Share-based Payments [Text Block]

NOTE 12. Equity Incentive Plans

Prior to the Merger, the Company issued equity awards for compensation purposes to employees, directors and consultants under the Company’s 2007 Equity Incentive Plan (the “2007 Plan”). The 2007 Plan expired in July 2017, since when the Company has had no shares of common stock available for issuance under the 2007 Plan since awards under the 2007 Plan no longer become available for future issuance if such awards are forfeited or otherwise terminate. Each outstanding stock option to acquire shares of Private Vaxart stock, whether vested or unvested, was assumed in the Merger after adjustment for the impact of the Conversion and the Reverse Stock Split.

In November 2016, Aviragen’s stockholders approved the 2016 Equity Incentive Plan (“2016 Equity Plan”), under which all outstanding awards under their previous plans became available for issuance under the 2016 Equity Plan if such awards are forfeited or otherwise terminate. The purpose of the 2016 Equity Plan is to assist the Company in attracting and retaining valued employees, consultants and non-employee directors by offering them a greater stake in the Company’s success and a closer identity with it, and to encourage ownership of the Company’s shares by such persons.

Under the 2016 Equity Plan, the Company is authorized to issue incentive stock options (“ISOs”), non-qualified stock options (“NQSOs”), restricted stock (“RSAs”) and restricted stock units (“RSUs”). Awards that expire or are canceled generally become available for issuance again under the 2016 Equity Plan. All awards outstanding, along with the number of shares of the Company’s common stock available under the 2016 Equity Plan, were adjusted for the impact of the Reverse Stock Split and remain subject to adjustment in the event of a stock split, stock dividend or other extraordinary dividend, or other similar change in the Company’s common stock or capital structure. Awards may vest over varying periods, as specified by the Company’s Board of Directors for each grant, and have a maximum term of ten years from the grant date.

A summary of stock option transactions in each of the two years ended December 31, 2018, is as follows:

			Weighted Average Exercise Price
	Shares Available For Grant	Number of Options Outstanding



Balance at January 1, 2017	99,644	275,539	$	11.32
Granted	(78,406)	78,406	$	4.07
Exercised	—	(2,834)	$	8.58
Forfeited	33,012	(33,012)	$	11.49
Canceled	13,249	(13,249)	$	12.00
Termination of Plan	(67,499)	—	$	—

Balance at December 31, 2017	—	304,850	$	9.50

Assumed on consummation of Merger	291,102	627,106	$	26.33
Granted	(431,100)	431,100	$	5.17
Exercised	—	(2,013)	$	6.49
Forfeited	71,500	(89,903)	$	5.90
Canceled	269,148	(405,977)	$	34.64
			$
Balance at December 31, 2018	200,650	865,163	$	8.13

In addition, the 2016 Equity Plan has a reserve of 22,727 shares available for future issuance as RSAs and RSUs. As of December 31, 2018, no such awards have been granted under the 2016 Equity Plan.

As of December 31, 2018, there were 865,163 options outstanding with a weighted average exercise price of $8.13, a weighted average remaining term of 6.14 years and zero aggregate intrinsic value. Of these options, 452,905 were vested, with a weighted average exercise price of $10.58, a weighted average remaining term of 3.35 years and zero aggregate intrinsic value.

The aggregate intrinsic value represents the total pre-tax value (i.e., the difference between the Company’s stock price and the exercise price) of stock options outstanding as of December 31, 2018, based on our common stock closing price of $1.88, which would have been received by the option holders had all their in-the-money options been exercised as of that date.

The grant date fair value of options vested in the years ended December 31, 2018 and 2017, was $332,000 and $533,000, respectively. The intrinsic value of options exercised in the years ended December 31, 2018 and 2017, was zero and $1,000, respectively.

The weighted average grant date fair value of options awarded in the years ended December 31, 2018 and 2017, was $3.59 and $2.99, respectively. Fair values were estimated using the following assumptions:

	Year Ended December 31,
	2018	2017

Risk-free interest rate	2.80%	1.87%
Expected term	5.96 Years	6.09 Years
Expected volatility	79%	91%
Dividend yield	0%	0%

Total stock‑based compensation recognized for options was as follows:

	Year Ended December 31,
	2018		2017
	(in thousands)
Research and development	$	254	$	262
General and administrative		285		215
Total stock-based compensation	$	539	$	477

As of December 31, 2018, the unrecognized stock-based compensation cost related to outstanding stock options that are expected to vest was $1.1 million, which the Company expects to recognize over an estimated weighted average period of 2.75 years.

Income Taxes

12 Months Ended

Dec. 31, 2018

Income Tax Disclosure [Abstract]

Income Tax Disclosure [Text Block]

NOTE 13. Income Taxes

The provision for income taxes consists of the following for the years ended December 31, 2018 and 2017:

	Year Ended December 31,
	2018		2017
	(In thousands)
Current:
Federal	$	—	$	—
State		3		—
Foreign		106		—

Total Current	$	109	$	—

Deferred:
Federal	$	—	$	—
State		—		—
Foreign		—		—

Total Deferred	$	—	$	—

Provision for income taxes	$	109	$	—

The components of the deferred tax assets as of December 31, 2018 and 2017, are as follows:

	December 31, 2018		December 31, 2017
Deferred tax assets:	(In thousands)
Net operating loss carry-forwards	$	43,822	$	19,441
Research and development tax credits		3,357		2,979
Capitalized research and development		2,326		—
Sale of future royalties		8,383		—
Accruals, reserves and other		714		544
Total deferred tax assets		58,602		22,964
Valuation allowance		(48,626)		(22,964)
Deferred tax assets net of valuation allowance		9,976		—
Deferred tax liabilities:
Intangible assets		(9,976)		—
Total deferred tax liabilities		(9,976)		—

Net deferred tax assets	$	—	$	—

A reconciliation of the provision for income taxes with the expected provision for income taxes computed by applying the federal statutory income tax rate of 21% and 34% to the net loss before provision for income taxes for the years ended December 31, 2018 and 2017, respectively:

	Year Ended December 31,
	2018		2017

U.S. federal taxes at statutory rate		21.0 %		34.0 %
State taxes (net of federal benefit)		0.6		14.2
Foreign rate differential		3.1		—
Global intangible low-taxed income		(8.8)		—
Permanent items:
Convertible note interest		(0.4)		(10.8)
Revaluation of derivative liabilities		—		11.9
Others		(2.1)		(1.4)
Tax credits		2.1		8.0
Change in valuation allowance		(20.4)		43.4
Impact of tax reform rate change		—		(97.0)
NOL and credit adjustments		(3.8)		(2.4)
Bargain purchase gain		8.1		—
Other		—		0.1

Provision for income taxes		(0.6)%		— %

The Company’s actual tax expense differed from the statutory federal income tax expense using a tax rate of 21% for the year ended December 31, 2018, primarily due to, state and foreign income taxes, nondeductible expenses, research and development tax credits, and the change in valuation allowance. The Company’s actual tax expense differed from the statutory federal income tax expense using a tax rate of 21% for the year ended December 31, 2017, primarily due to remeasurement of deferred taxes due to change in federal tax rate under the Tax Cuts and Jobs Act (the "TCJA"), state income taxes, nondeductible expenses, research and development tax credits, and the change in valuation allowance.

On December 22, 2017, the TCJA was signed into law. The TCJA decreased the U.S. corporate federal income tax rate from 35% to 21% effective January 1, 2018. The TCJA also includes a number of other provisions including the elimination of loss carrybacks and limitations on the use of future losses, repeal of the Alternative Minimum Tax regime, and the introduction of a base erosion, anti-abuse tax and 100% expense allowance for certain properties. These provisions are not expected to have immediate effect on the Company.

The key impact of the TCJA on the Company’s financial statements was the re-measurement of the deferred tax balances to the new corporate tax rate in the year ended December 31, 2017. U.S. GAAP requires the re-measurement of the Company’s deferred tax balances as of the enactment date of the TCJA, based on the rates at which the balances are expected to reverse in the future. The TCJA reduced the corporate tax rate to 21%, effective January 1, 2018. The Company recorded a decrease in its deferred tax assets of $4.2 million with a corresponding reduction to its valuation allowance of $4.2 million for the year ending December 31, 2017, primarily related to the impact of the TCJA.

As of December 31, 2018 and 2017, the Company had a net operating loss (“NOL”) carryforwards of $92.3 million and $69.5 million for federal purposes, and $76.9 million and $75.0 million for state purposes, respectively. If not utilized, these carryforwards will begin to expire in 2024 for federal, and 2028 for state purposes.

As of December 31, 2018, the Company also has accumulated tax losses of $14.4 million for Australia, $24.7 million for the United Kingdom and $37.7 million for France available for carry forward against future earnings, which under relevant tax laws do not expire but may not be available under certain circumstances. As of December 31, 2018, the Company’s foreign subsidiaries have no positive accumulated earnings. As such, no federal or state income taxes have been provided on the losses of its foreign subsidiaries. If in the future there are positive earnings generated from the Company’s foreign subsidiaries, the Company will evaluate whether to record any applicable federal and state income taxes on such earnings.

As of December 31, 2018 and 2017, the Company had federal research and development tax credit carryforwards of $3.0 million and $2.7 million, respectively and state research and development tax credit carryforwards of $2.3 million and $2.0 million, respectively, before offset for unrecognized tax benefits, to offset future income tax liabilities. The federal research and development tax credits will start to expire in 2027, if not utilized, while the state research and development tax credit can be carried forward indefinitely.

Sections 382 and 383 of the Internal Revenue Code provides for a limitation on the annual use of NOL and research and development tax credit carryforwards following certain ownership changes that could limit the Company’s ability to utilize these carryforwards. The Company’s losses and credit carryforwards may be subject to these limitations. The Company has not performed an analysis to determine if such ownership changes have occurred. An analysis will be performed prior to recognizing the benefits of any losses or credits in the financial statements.

The Company is required to reduce its deferred tax assets by a valuation allowance if it is more likely than not that some or all of its deferred tax assets will not be realized. Management must use judgment in assessing the potential need for a valuation allowance, which requires an evaluation of both negative and positive evidence. The weight given to the potential effect of negative and positive evidence should be commensurate with the extent to which it can be objectively verified. In determining the need for and amount of the valuation allowance, if any, the Company assesses the likelihood that it will be able to recover its deferred tax assets using historical levels of income, estimates of future income and tax planning strategies. As a result of historical cumulative losses, the Company determined that, based on all available evidence, there was substantial uncertainty as to whether it will recover recorded net deferred taxes in future periods. Accordingly, the Company recorded a valuation allowance against all of its net deferred tax assets as of December 31, 2018 and 2017. The net change in total valuation allowance was an increase of approximately $25.7 million for the year ended December 31, 2018

A reconciliation of the beginning and ending amount of unrecognized tax benefits is as follows:

	Year Ended December 31,
	2018		2017
	(in thousands)
Beginning Balance	$	1,404	$	1,231
Additions based on tax positions related to the current year		181		173
Decreases related to prior years’ tax positions		(3)		—

Ending Balance	$	1,582	$	1,404

The Company’s policy is to recognize interest and penalties accrued on any unrecognized tax benefits as a component of income tax expense. During the year ended December 31, 2017 and 2018, the Company recognized no interest and penalties associated with unrecognized tax benefits. There are no tax positions for which it is reasonably possible that the total amounts of unrecognized tax benefits will significantly increase or decrease within twelve months of the reporting date.

The Company files income tax returns in the U.S, Australia, France and the United Kingdom, as well as with various U.S. states. The Company is subject to tax audits in all jurisdictions in which it files income tax returns. Tax audits by their very nature are often complex and can require several years to complete. There are currently no tax audits that have commenced with respect to income tax returns in any jurisdiction.

Under the tax statute of limitations applicable to the Internal Revenue Code, the Company and its U.S. subsidiary, either standalone or as part of the consolidated group, is no longer subject to U.S. federal income tax examinations by the Internal Revenue Service for tax years before tax year 2016. Under the statute of limitations applicable to most state income tax laws, the Company is no longer subject to state income tax examinations by tax authorities for tax years before 2015 in states in which it has filed income tax returns. However, because the Company is carrying forward income tax attributes, such as net operating losses and tax credits from 2004 and earlier tax years, these attributes can still be audited when utilized on returns filed in the future. The Company is subject to foreign tax examinations by tax authorities for fiscal year 2014 and forward.

Net Loss Per Share Attributable to Common Stockholders

12 Months Ended

Dec. 31, 2018

Earnings Per Share [Abstract]

Earnings Per Share [Text Block]

NOTE 14. Net Loss Per Share Attributable to Common Stockholders

The following table presents the calculation of basic and diluted net loss per share (in thousands, except share and per share amounts):

	Year Ended December 31,
	2018		2017

Net loss	$	(18,007)	$	(9,582)

Series B and C preferred dividend		(339)		(2,878)

Net loss attributable to common stockholders	$	(18,346)	$	(12,460)

Shares used to compute net loss per share, basic and diluted		6,316,065		135,953

Net loss per share attributable to common stockholders, basic and diluted	$	(2.90)	$	(91.65)

No adjustment has been made to the net loss attributable to common stockholders as the effect would be anti-dilutive due to the net loss.

The following potentially dilutive securities were excluded from the computation of diluted weighted average shares outstanding because they would have been antidilutive:

	Year Ended December 31,
	2018		2017

Options to purchase common stock	839,396	295,243

Warrant to purchase common stock	9,658	—

Warrant to purchase convertible preferred stock	891	7,563

Series B and C convertible preferred stock outstanding, including cumulative dividends	213,760	1,567,172

Series A convertible preferred stock outstanding	12,260	94,988

Convertible promissory notes, related party (as converted)	185,159	754,289

Total potentially dilutive securities excluded from denominator of the diluted earnings per share computation	1,261,124	2,719,255

Quarterly Financial Data (Unaudited)

12 Months Ended

Dec. 31, 2018

Quarterly Financial Information Disclosure [Abstract]

Quarterly Financial Information [Text Block]

NOTE 15. Quarterly Financial Data (Unaudited)

Selected summarized quarterly financial information for fiscal 2018 and 2017 is as follows:

	Year Ended December 31, 2018
	First		Second		Third		Fourth

Revenue	$	1,503	$	608	$	281	$	1,767
Operating expenses	$	5,418	$	8,383	$	6,161	$	5,953
Net income (loss)	$	2,314	$	(8,871)	$	(6,548)	$	(4,902)
Net income (loss) attributable to common stockholders	$	1,975	$	(8,871)	$	(6,548)	$	(4,902)
Net income (loss) per share – basic	$	0.54	$	(1.24)	$	(0.92)	$	(0.69)
Net income (loss) per share – diluted	$	0.49	$	(1.24)	$	(0.92)	$	(0.69)

	Year Ended December 31, 2017
	First		Second		Third		Fourth

Revenue	$	2,310	$	1,854	$	915	$	760
Operating expenses	$	4,557	$	4,977	$	2,871	$	3,449
Net loss	$	(2,796)	$	(3,538)	$	(2,173)	$	(1,075)
Net loss attributable to common stockholders	$	(3,506)	$	(4,256)	$	(2,898)	$	(1,800)
Net loss per share – basic and diluted	$	(25.84)	$	(31.37)	$	(21.36)	$	(13.16)

Accounting Policies, by Policy (Policies)

12 Months Ended

Dec. 31, 2018

Accounting Policies [Abstract]

Basis of Accounting, Policy [Policy Text Block]

Consolidation, Policy [Policy Text Block]

Use of Estimates, Policy [Policy Text Block]

Foreign Currency Transactions and Translations Policy [Policy Text Block]

Cash and Cash Equivalents, Policy [Policy Text Block]

Investment, Policy [Policy Text Block]

Concentration Risk, Credit Risk, Policy [Policy Text Block]

Receivables, Policy [Policy Text Block]

Property, Plant and Equipment, Policy [Policy Text Block]

The useful lives of the property and equipment are as follows:

Laboratory equipment	5 years
Office and computer equipment	3 years
Leasehold improvements	Shorter of remaining lease term or estimated useful life

Goodwill and Intangible Assets, Policy [Policy Text Block]

Impairment or Disposal of Long-Lived Assets, Policy [Policy Text Block]

Accrued Clinical And Manufacturing Expenses Policy [Policy Text Block]

Convertible Preferred Stock Warrant Liability Policy [Policy Text Block]

Derivatives, Policy [Policy Text Block]

Revenue Recognition, Policy [Policy Text Block]

(i) identification of the promised goods or services in the contract;

(ii) determination of whether the promised goods or services are performance obligations including whether they are distinct in the context of the contract;

(iii) measurement of the transaction price, including the constraint on variable consideration;

(iv) allocation of the transaction price to the performance obligations based on estimated selling prices; and

Research and Development Expense, Policy [Policy Text Block]

Share-based Compensation, Option and Incentive Plans Policy [Policy Text Block]

Earnings Per Share, Policy [Policy Text Block]

New Accounting Pronouncements, Policy [Policy Text Block]

Recently Adopted Accounting Pronouncements

Recent Accounting Pronouncements

Summary of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2018

Accounting Policies [Abstract]

Schedule Of Property Plant And Equipment Useful Life [Table Text Block]

Laboratory equipment	5 years
Office and computer equipment	3 years
Leasehold improvements	Shorter of remaining lease term or estimated useful life

Business Combination (Tables)

12 Months Ended

Dec. 31, 2018

Business Combinations [Abstract]

Schedule of Business Acquisitions by Acquisition, Equity Interest Issued or Issuable [Table Text Block]

Common stock	$	31,789

Total	$	31,789

Schedule of Recognized Identified Assets Acquired and Liabilities Assumed [Table Text Block]

	As of February 13, 2018		Adjustments		As of December 31, 2018
			(in thousands)
Cash and cash equivalents	$	25,525	$	—	$	25,525
Accounts receivable		14,666		—		14,666
Prepaid expenses		446		(10)		436
Property and equipment		170		—		170
Intangible assets:
Developed technology ⁽¹⁾		22,400		(300)		22,100
In-process research and development ⁽²⁾		1,600		—		1,600
Total assets		64,807		(310)		64,497

Accounts payable		(3,379)		75		(3,304)
Other current liabilities		(6,351)		(393)		(6,744)
Liability related to sale of future royalties		(16,300)		400		(15,900)
Net assets acquired		38,777		(228)		38,549

Purchase price		(31,789)		—		(31,789)

Bargain purchase gain ⁽³⁾	$	6,988	$	(228)	$	6,760

Business Combination, Separately Recognized Transactions [Table Text Block]

Revenue	$	2,815

Net loss	$	(3,847)

Business Acquisition, Pro Forma Information [Table Text Block]

	Year Ended December 31,
	2018		2017
	(in thousands)
Total revenue	$	15,695	$	13,527

Net loss	$	(13,162)	$	(29,270)

Fair Value of Financial Instruments (Tables)

12 Months Ended

Dec. 31, 2018

Fair Value Disclosures [Abstract]

Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block]

	Level 1		Level 2		Level 3		Total
December 31, 2018				(in thousands)
Recurring Financial Assets:
Money Market Funds	$	15	$	—	$	—	$	15
Corporate Bonds		—		—		—		—

Total assets	$	15	$	—	$	—	$	15

Recurring Financial Liabilities:
Convertible promissory notes embedded derivative liability	$	—	$	—	$	—	$	—
Convertible preferred stock warrant liability		—		—		—		—

Total liabilities	$	—	$	—	$	—	$	—

	Level 1		Level 2		Level 3		Total
December 31, 2017				(in thousands)
Recurring Financial Assets:
Money Market Funds	$	1,192	$	—	$	—	$	1,192
Corporate Bonds		—		1,415		—		1,415

Total assets	$	1,192	$	1,415	$	—	$	2,607

Recurring Financial Liabilities:
Convertible promissory notes embedded derivative liability	$	—	$	—	$	—	$	—
Convertible preferred stock warrant liability		—		—		67		67

Total liabilities	$	—	$	—	$	67	$	67

Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Table Text Block]

	Convertible Preferred Stock Warrant Liability		Convertible Promissory Notes Embedded Derivative Liability

					Total
				(in thousands)
Balance at January 1, 2018	$	67	$	—	$	67
Issuances		—		—		—
Revaluation loss included in (loss) gain on revaluation of financial instruments, net		3		—		3
Settlements		(70)		—		(70)
Balance at December 31, 2018	$	—	$	—	$	—

Total losses included in other income and (expenses) attributable to liabilities still held as of December 31, 2018	$	—	$	—	$	—

	Convertible Preferred Stock Warrant Liability		Convertible Promissory Notes Embedded Derivative Liability

					Total
				(in thousands)
Balance at January 1, 2017	$	134	$	3,280	$	3,414
Issuances		—		—		—
Revaluation gains included in (loss) gain on revaluation of financial instruments, net		(67)		(3,280)		(3,347)
Settlements		—		—		—
Balance at December 31, 2017	$	67	$	—	$	67

Total gains included in other income and (expenses) attributable to liabilities still held as of December 31, 2017	$	67	$	3,280	$	3,347

Balance Sheet Components (Tables)

12 Months Ended

Dec. 31, 2018

Disclosure Text Block Supplement [Abstract]

Cash, Cash Equivalents and Investments [Table Text Block]

	December 31, 2018
			Gross Unrecognized Gains		Gross Unrecognized Losses		Estimated Fair Value		Carrying Value
	Amortized Cost
	Amortized Cost
						(in thousands)
Money market funds	$	15	$	—	$	—	$	15	$	15
Corporate bonds		—		—		—		—		—
Total	$	15	$	—	$	—	$	15	$	15
Reported as:
Cash equivalents	$	15	$	—	$	—	$	15	$	15
Short-term investments		—		—		—		—		—
Total	$	15	$	—	$	—	$	15	$	15

	December 31, 2017
			Gross		Gross		Estimated
	Amortized		Unrecognized		Unrecognized		Fair		Carrying
	Cost		Gains		Losses		Value		Value
						(in thousands)
Money market funds	$	1,192	$	—	$	—	$	1,192	$	1,192
Corporate bonds		1,415		—		—		1,415		1,415
Total	$	2,607	$	—	$	—	$	2,607	$	2,607
Reported as:
Cash equivalents	$	1,192	$	—	$	—	$	1,192	$	1,192
Short-term investments		1,415		—		—		1,415		1,415
Total	$	2,607	$	—	$	—	$	2,607	$	2,607

Schedule of Accounts, Notes, Loans and Financing Receivable [Table Text Block]

	December 31, 2018		December 31, 2017
	(in thousands)
Royalties receivable	$	1,776	$	—
Government contract – billed		20		477
Government contract – unbilled		—		153
Accounts receivable	$	1,796	$	630

Property, Plant and Equipment [Table Text Block]

	December 31, 2018		December 31, 2017
	(in thousands)
Laboratory equipment	$	2,076	$	1,565
Office and computer equipment		227		175
Leasehold improvements		333		226

Total property and equipment		2,636		1,966
Less: accumulated depreciation		(1,570)		(1,236)
Property and equipment, net	$	1,066	$	730

Schedule of Finite-Lived Intangible Assets [Table Text Block]

	December 31, 2018		February 13, 2018		December 31, 2017
				(in thousands)
Purchased technology	$	22,100	$	22,400	$	—
In-process research and development		—		1,600		—
Intellectual property		80		80		80
Total cost		22,180		24,080		80
Less accumulated amortization		2,767		40		40
Intangible assets, net	$	19,413	$	24,040	$	40

Schedule of Finite-Lived Intangible Assets, Future Amortization Expense [Table Text Block]

Year Ending December 31,
2019	$	2,320
2020		1,732
2021		1,732
2022		1,732
2023		1,731
Thereafter		10,166
Total	$	19,413

Schedule of Accrued Liabilities [Table Text Block]

	December 31, 2018		December 31, 2017
	(in thousands)
Accrued compensation	$	632	$	1,320
Accrued clinical and manufacturing expenses		75		69
Accrued professional and consulting services		166		113
Reserve for return of royalties		339		—
Deferred rent and lease loss accrual, current portion		111		21
Convertible preferred stock warrant liability		—		67
Other		195		15

Total	$	1,518	$	1,605

Liabilities Related to Sale of Future Royalties (Tables)

12 Months Ended

Dec. 31, 2018

Disclosure Text Block [Abstract]

Deferred Revenue, by Arrangement, Disclosure [Table Text Block]

Total Liability related to sale of future royalties, February 13, 2018	$	15,900
Non-cash royalty revenue paid to HCRP		(18)
Non-cash interest expense recognized		1,859
Total Liability related to sale of future royalties, December 31, 2018	$	17,741

Commitments and Contingencies (Tables)

12 Months Ended

Dec. 31, 2018

Commitments and Contingencies Disclosure [Abstract]

Restructuring and Related Costs [Table Text Block]


Balance as of January 1, 2018	$	—
Costs of exit from leased premises		359
Deferred rent on cease-use date		19
Impairment of property and equipment		(106)
Cash paid, net of receipts		(41)
Accretion charges, included in rent expense		2
Balance as of December 31, 2018	$	233

Schedule of Future Minimum Rental Payments for Operating Leases [Table Text Block]

Years Ending December 31,	Lease Payments		Sublease Income
	(in thousands)
2019	$	859	$	213
2020		411		219
2021		56		38
Thereafter		—		—
Total	$	1,326	$	470

Stockholders' Equity (Tables)

12 Months Ended

Dec. 31, 2018

Stockholders' Equity Note [Abstract]

Schedule Of Convertible Preferred Stock [Table Text Block]

	Shares authorized	Shares outstanding	Net carrying value		Liquidation preference
			(in thousands)		(in thousands)
Series A	94,988	94,988	$	2,949	$	2,737
Series B	747,095	520,973		16,115		17,219
Series C	820,088	605,103		19,877		20,000
Total	1,662,171	1,221,064	$	38,941	$	39,956

Schedule Of Common Stock Reserved For Issuance [Table Text Block]

	December 31, 2018	December 31, 2017

Convertible preferred stock outstanding	—	1,221,064
Options issued and outstanding	865,163	304,850
Available for future grants of equity awards	223,377	—
Cumulative convertible preferred stock dividends	—	441,096
Common stock warrants	10,914	10,914
Total	1,099,454	1,977,924

Equity Incentive Plans (Tables)

12 Months Ended

Dec. 31, 2018

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

Share-based Compensation, Stock Options, Activity [Table Text Block]

			Weighted Average Exercise Price
	Shares Available For Grant	Number of Options Outstanding



Balance at January 1, 2017	99,644	275,539	$	11.32
Granted	(78,406)	78,406	$	4.07
Exercised	—	(2,834)	$	8.58
Forfeited	33,012	(33,012)	$	11.49
Canceled	13,249	(13,249)	$	12.00
Termination of Plan	(67,499)	—	$	—

Balance at December 31, 2017	—	304,850	$	9.50

Assumed on consummation of Merger	291,102	627,106	$	26.33
Granted	(431,100)	431,100	$	5.17
Exercised	—	(2,013)	$	6.49
Forfeited	71,500	(89,903)	$	5.90
Canceled	269,148	(405,977)	$	34.64
			$
Balance at December 31, 2018	200,650	865,163	$	8.13

Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions [Table Text Block]

	Year Ended December 31,
	2018	2017

Risk-free interest rate	2.80%	1.87%
Expected term	5.96 Years	6.09 Years
Expected volatility	79%	91%
Dividend yield	0%	0%

Schedule of Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Table Text Block]

	Year Ended December 31,
	2018		2017
	(in thousands)
Research and development	$	254	$	262
General and administrative		285		215
Total stock-based compensation	$	539	$	477

Income Taxes (Tables)

12 Months Ended

Dec. 31, 2018

Income Tax Disclosure [Abstract]

Schedule of Components of Income Tax Expense (Benefit) [Table Text Block]

	Year Ended December 31,
	2018		2017
	(In thousands)
Current:
Federal	$	—	$	—
State		3		—
Foreign		106		—

Total Current	$	109	$	—

Deferred:
Federal	$	—	$	—
State		—		—
Foreign		—		—

Total Deferred	$	—	$	—

Provision for income taxes	$	109	$	—

Schedule of Deferred Tax Assets and Liabilities [Table Text Block]

	December 31, 2018		December 31, 2017
Deferred tax assets:	(In thousands)
Net operating loss carry-forwards	$	43,822	$	19,441
Research and development tax credits		3,357		2,979
Capitalized research and development		2,326		—
Sale of future royalties		8,383		—
Accruals, reserves and other		714		544
Total deferred tax assets		58,602		22,964
Valuation allowance		(48,626)		(22,964)
Deferred tax assets net of valuation allowance		9,976		—
Deferred tax liabilities:
Intangible assets		(9,976)		—
Total deferred tax liabilities		(9,976)		—

Net deferred tax assets	$	—	$	—

Schedule of Effective Income Tax Rate Reconciliation [Table Text Block]

	Year Ended December 31,
	2018		2017

U.S. federal taxes at statutory rate		21.0 %		34.0 %
State taxes (net of federal benefit)		0.6		14.2
Foreign rate differential		3.1		—
Global intangible low-taxed income		(8.8)		—
Permanent items:
Convertible note interest		(0.4)		(10.8)
Revaluation of derivative liabilities		—		11.9
Others		(2.1)		(1.4)
Tax credits		2.1		8.0
Change in valuation allowance		(20.4)		43.4
Impact of tax reform rate change		—		(97.0)
NOL and credit adjustments		(3.8)		(2.4)
Bargain purchase gain		8.1		—
Other		—		0.1

Provision for income taxes		(0.6)%		— %

Schedule of Unrecognized Tax Benefits Roll Forward [Table Text Block]

	Year Ended December 31,
	2018		2017
	(in thousands)
Beginning Balance	$	1,404	$	1,231
Additions based on tax positions related to the current year		181		173
Decreases related to prior years’ tax positions		(3)		—

Ending Balance	$	1,582	$	1,404

Net Loss Per Share Attributable to Common Stockholders (Tables)

12 Months Ended

Dec. 31, 2018

Earnings Per Share [Abstract]

Schedule of Earnings Per Share, Basic and Diluted [Table Text Block]

	Year Ended December 31,
	2018		2017

Net loss	$	(18,007)	$	(9,582)

Series B and C preferred dividend		(339)		(2,878)

Net loss attributable to common stockholders	$	(18,346)	$	(12,460)

Shares used to compute net loss per share, basic and diluted		6,316,065		135,953

Net loss per share attributable to common stockholders, basic and diluted	$	(2.90)	$	(91.65)

Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table Text Block]

	Year Ended December 31,
	2018		2017

Options to purchase common stock	839,396	295,243

Warrant to purchase common stock	9,658	—

Warrant to purchase convertible preferred stock	891	7,563

Series B and C convertible preferred stock outstanding, including cumulative dividends	213,760	1,567,172

Series A convertible preferred stock outstanding	12,260	94,988

Convertible promissory notes, related party (as converted)	185,159	754,289

Total potentially dilutive securities excluded from denominator of the diluted earnings per share computation	1,261,124	2,719,255

Quarterly Financial Data (Unaudited) (Tables)

12 Months Ended

Dec. 31, 2018

Quarterly Financial Information Disclosure [Abstract]

Quarterly Financial Information [Table Text Block]

	Year Ended December 31, 2018
	First		Second		Third		Fourth

Revenue	$	1,503	$	608	$	281	$	1,767
Operating expenses	$	5,418	$	8,383	$	6,161	$	5,953
Net income (loss)	$	2,314	$	(8,871)	$	(6,548)	$	(4,902)
Net income (loss) attributable to common stockholders	$	1,975	$	(8,871)	$	(6,548)	$	(4,902)
Net income (loss) per share – basic	$	0.54	$	(1.24)	$	(0.92)	$	(0.69)
Net income (loss) per share – diluted	$	0.49	$	(1.24)	$	(0.92)	$	(0.69)

	Year Ended December 31, 2017
	First		Second		Third		Fourth

Revenue	$	2,310	$	1,854	$	915	$	760
Operating expenses	$	4,557	$	4,977	$	2,871	$	3,449
Net loss	$	(2,796)	$	(3,538)	$	(2,173)	$	(1,075)
Net loss attributable to common stockholders	$	(3,506)	$	(4,256)	$	(2,898)	$	(1,800)
Net loss per share – basic and diluted	$	(25.84)	$	(31.37)	$	(21.36)	$	(13.16)

Organization and Basis of Presentation (Details) $ in Thousands		12 Months Ended
	Feb. 13, 2018 shares	Dec. 31, 2018 USD ($) shares	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)
Organization and Basis of Presentation (Details) [Line Items]
Stockholders' Equity, Reverse Stock Split	the Company effected a reverse stock split at a ratio of one new share for every eleven shares of the Company’s common stock outstanding
Stock Issued During Period, Shares, Reverse Stock Splits \| shares		7,100,000
Exchange Ratio, Number of Shares Exchanged Per Share \| shares		0.0201346
Number of Reportable Segments		1
Retained Earnings (Accumulated Deficit) \| $		$ (97,989)	$ (79,982)
Cash and Cash Equivalents, at Carrying Value \| $		$ 11,506	$ 1,571	$ 8,405
Private Vaxarts Stockholders Warrantholders And Optionsholders [Member]
Organization and Basis of Presentation (Details) [Line Items]
Equity Method Investment, Ownership Percentage		51.00%
Aviragens Stockholderrs And Optionsholders [Member]
Organization and Basis of Presentation (Details) [Line Items]
Equity Method Investment, Ownership Percentage		49.00%
Oxford Finance [Member]
Organization and Basis of Presentation (Details) [Line Items]
Loan Agreement, Borrowed Amount \| $		$ 3,600
Conversion [Member]
Organization and Basis of Presentation (Details) [Line Items]
Conversion of Stock, Shares Issued \| shares	0.22148

Summary of Significant Accounting Policies (Details) - USD ($)		12 Months Ended
	Jan. 01, 2019	Dec. 31, 2018	Dec. 31, 2017
Summary of Significant Accounting Policies (Details) [Line Items]
Restricted Cash		$ 50,000	$ 50,000
Intellectual Property [Member]
Summary of Significant Accounting Policies (Details) [Line Items]
Finite-Lived Intangible Asset, Useful Life		20 years
Minimum [Member]
Summary of Significant Accounting Policies (Details) [Line Items]
Finite-Lived Intangible Asset, Useful Life		1 year 109 days
Maximum [Member]
Summary of Significant Accounting Policies (Details) [Line Items]
Finite-Lived Intangible Asset, Useful Life		11 years 9 months
Recognize Lease Liabilities [Member]
Summary of Significant Accounting Policies (Details) [Line Items]
Operating Lease, Liability	$ 1,207,000
Operating Lease, Liability, Current	766,000
Operating Lease, Right-of-Use Asset	941,000
Derecognize Lease Liabilities [Member]
Summary of Significant Accounting Policies (Details) [Line Items]
Operating Lease, Liability	239,000
Operating Lease, Liability, Current	100,000
Increase (Decrease) In Accumulated Deficit	$ 27,000

Summary of Significant Accounting Policies (Details) - Estimated Useful Lives	12 Months Ended
	Dec. 31, 2018
Laboratory Equipment [Member]
Summary of Significant Accounting Policies (Details) - Estimated Useful Lives [Line Items]
Property, Plant and Equipment, Useful Lives	5 years
Office Equipment [Member]
Summary of Significant Accounting Policies (Details) - Estimated Useful Lives [Line Items]
Property, Plant and Equipment, Useful Lives	3 years
Leasehold Improvements [Member]
Summary of Significant Accounting Policies (Details) - Estimated Useful Lives [Line Items]
Property, Plant and Equipment, Useful Lives, Description	Shorter of remaining lease term or estimated useful life

Business Combination (Details) - USD ($) $ in Millions	12 Months Ended
Business Combination (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Business Combination (Details) [Line Items]
Business Combination, Acquisition Related Costs	$ 0.5	$ 0.9
Maximum [Member]
Business Combination (Details) [Line Items]
Finite-Lived Intangible Asset, Useful Life	11 years 9 months
Minimum [Member]
Business Combination (Details) [Line Items]
Finite-Lived Intangible Asset, Useful Life	1 year 109 days

Business Combination (Details) - Total purchase price for Aviragen $ in Thousands	12 Months Ended
	Dec. 31, 2018 USD ($)
Total purchase price for Aviragen [Abstract]
Common stock	$ 31,789
Total	$ 31,789

Business Combination (Details) - Allocation of the purchase price to the fair value of the respective assets and liabilities acquired - USD ($) $ in Thousands		11 Months Ended	12 Months Ended
	Feb. 13, 2018	Dec. 31, 2018	Dec. 31, 2018	Dec. 31, 2017
Business Combination (Details) - Allocation of the purchase price to the fair value of the respective assets and liabilities acquired [Line Items]
Cash and cash equivalents		$ 25,525	$ 25,525
Accounts receivable		14,666	14,666
Prepaid expenses		436	436
Property and equipment		170	170
Intangible assets:
Developed technology (1)		22,100	22,100
In-process research and development (2)		1,600	1,600
Total assets		64,497	64,497
Accounts payable		(3,304)	(3,304)
Other current liabilities		(6,744)	(6,744)
Liability related to sale of future royalties		(15,900)	(15,900)
Net assets acquired		38,549	38,549
Purchase price			(31,789)
Bargain purchase gain (3)			6,760
Previously Reported [Member]
Business Combination (Details) - Allocation of the purchase price to the fair value of the respective assets and liabilities acquired [Line Items]
Cash and cash equivalents	$ 25,525
Accounts receivable	14,666
Prepaid expenses	446
Property and equipment	170
Intangible assets:
Developed technology (1)	22,400
In-process research and development (2)	1,600
Total assets	64,807
Accounts payable	(3,379)
Other current liabilities	(6,351)
Liability related to sale of future royalties	(16,300)
Net assets acquired	38,777
Purchase price	(31,789)
Bargain purchase gain (3)	$ 6,988
Restatement Adjustment [Member]
Business Combination (Details) - Allocation of the purchase price to the fair value of the respective assets and liabilities acquired [Line Items]
Prepaid expenses		(10)	(10)
Intangible assets:
Developed technology (1)		(300)	(300)
Total assets		(310)	(310)
Accounts payable		75	75
Other current liabilities		(393)	(393)
Liability related to sale of future royalties		400	400
Net assets acquired		(228)	$ (228)
Bargain purchase gain (3)		$ (228)

Business Combination (Details) - Selected amounts related to Aviragen's business included in the Company's consolidated statement of operations $ in Thousands	12 Months Ended
	Dec. 31, 2018 USD ($)
Selected amounts related to Aviragen's business included in the Company's consolidated statement of operations [Abstract]
Revenue	$ 2,815
Net loss	$ (3,847)

Business Combination (Details) - Unaudited pro forma information is summarized - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Unaudited pro forma information is summarized [Abstract]
Total revenue	$ 15,695	$ 13,527
Net loss	$ (13,162)	$ (29,270)

Fair Value of Financial Instruments (Details) - Company's financial assets and liabilities measured at fair value - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Recurring Financial Assets:
Financial Assets	$ 15	$ 2,607
Recurring Financial Liabilities:
Financial Liability		67
Fair Value, Inputs, Level 1 [Member]
Recurring Financial Assets:
Financial Assets	15	1,192
Recurring Financial Liabilities:
Financial Liability
Fair Value, Inputs, Level 2 [Member]
Recurring Financial Assets:
Financial Assets		1,415
Recurring Financial Liabilities:
Financial Liability
Fair Value, Inputs, Level 3 [Member]
Recurring Financial Assets:
Financial Assets
Recurring Financial Liabilities:
Financial Liability		67
Convertible Promissory Notes Embedded Derivative Liability [Member]
Recurring Financial Liabilities:
Financial Liability
Convertible Promissory Notes Embedded Derivative Liability [Member] \| Fair Value, Inputs, Level 1 [Member]
Recurring Financial Liabilities:
Financial Liability
Convertible Promissory Notes Embedded Derivative Liability [Member] \| Fair Value, Inputs, Level 2 [Member]
Recurring Financial Liabilities:
Financial Liability
Convertible Promissory Notes Embedded Derivative Liability [Member] \| Fair Value, Inputs, Level 3 [Member]
Recurring Financial Liabilities:
Financial Liability
Convertible Preferred Stock Warrant Liability [Member]
Recurring Financial Liabilities:
Financial Liability		67
Convertible Preferred Stock Warrant Liability [Member] \| Fair Value, Inputs, Level 1 [Member]
Recurring Financial Liabilities:
Financial Liability
Convertible Preferred Stock Warrant Liability [Member] \| Fair Value, Inputs, Level 2 [Member]
Recurring Financial Liabilities:
Financial Liability
Convertible Preferred Stock Warrant Liability [Member] \| Fair Value, Inputs, Level 3 [Member]
Recurring Financial Liabilities:
Financial Liability		67
Money Market Funds [Member]
Recurring Financial Assets:
Financial Assets	15	1,192
Money Market Funds [Member] \| Fair Value, Inputs, Level 1 [Member]
Recurring Financial Assets:
Financial Assets	15	1,192
Money Market Funds [Member] \| Fair Value, Inputs, Level 2 [Member]
Recurring Financial Assets:
Financial Assets
Money Market Funds [Member] \| Fair Value, Inputs, Level 3 [Member]
Recurring Financial Assets:
Financial Assets
Corporate Bonds [Member]
Recurring Financial Assets:
Financial Assets		1,415
Corporate Bonds [Member] \| Fair Value, Inputs, Level 1 [Member]
Recurring Financial Assets:
Financial Assets
Corporate Bonds [Member] \| Fair Value, Inputs, Level 2 [Member]
Recurring Financial Assets:
Financial Assets		1,415
Corporate Bonds [Member] \| Fair Value, Inputs, Level 3 [Member]
Recurring Financial Assets:
Financial Assets

Fair Value of Financial Instruments (Details) - A reconciliation of all liabilities measured at fair value on a recurring basis using significant unobservable inputs (Level 3) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Balance at January 1	$ 67	$ 3,414
Issuances
Revaluation loss gains included in (loss) gain on revaluation of financial instruments, net	3	(3,347)
Settlements	(70)
Balance at December 31		67
Total gain (losses) included in other income and (expenses) attributable to liabilities still held		3,347
Convertible Preferred Stock Warrant Liability [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Balance at January 1	67	134
Issuances
Revaluation loss gains included in (loss) gain on revaluation of financial instruments, net	3	(67)
Settlements	(70)
Balance at December 31		67
Total gain (losses) included in other income and (expenses) attributable to liabilities still held		67
Convertible Promissory Notes Embedded Derivative Liability [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Balance at January 1		3,280
Issuances
Revaluation loss gains included in (loss) gain on revaluation of financial instruments, net		(3,280)
Settlements
Balance at December 31
Total gain (losses) included in other income and (expenses) attributable to liabilities still held		$ 3,280

Balance Sheet Components (Details) - USD ($)	3 Months Ended	12 Months Ended
Balance Sheet Components (Details) - USD ($)	Jun. 30, 2018	Dec. 31, 2018	Dec. 31, 2017
Disclosure Text Block Supplement [Abstract]
Depreciation		$ 476,000	$ 376,000
Impairment of property and equipment		106,000
Amortization of Intangible Assets		$ 2,727,000	$ 4,000
Research and Development in Process	$ 1,600,000

Balance Sheet Components (Details) - Cash equivalents and short-term investments - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Balance Sheet Components (Details) - Cash equivalents and short-term investments [Line Items]
Amortized Cost	$ 15	$ 2,607
Gross Unrecognized Gains
Gross Unrecognized Losses
Estimated Fair Value	15	2,607
Carrying Value	15	2,607
Corporate Bonds [Member]
Balance Sheet Components (Details) - Cash equivalents and short-term investments [Line Items]
Amortized Cost		1,415
Gross Unrecognized Gains
Gross Unrecognized Losses
Estimated Fair Value		1,415
Carrying Value		1,415
Short-term Investments [Member]
Balance Sheet Components (Details) - Cash equivalents and short-term investments [Line Items]
Amortized Cost		1,415
Gross Unrecognized Gains
Gross Unrecognized Losses
Estimated Fair Value		1,415
Carrying Value		1,415
Money Market Funds [Member]
Balance Sheet Components (Details) - Cash equivalents and short-term investments [Line Items]
Amortized Cost	15	1,192
Gross Unrecognized Gains
Gross Unrecognized Losses
Estimated Fair Value	15	1,192
Carrying Value	15	1,192
Cash Equivalents [Member]
Balance Sheet Components (Details) - Cash equivalents and short-term investments [Line Items]
Amortized Cost	15	1,192
Gross Unrecognized Gains
Gross Unrecognized Losses
Estimated Fair Value	15	1,192
Carrying Value	$ 15	$ 1,192

Balance Sheet Components (Details) - Accounts receivable net of allowance - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Accounts receivable net of allowance [Abstract]
Royalties receivable	$ 1,776
Government contract – billed	20	477
Government contract – unbilled		153
Accounts receivable	$ 1,796	$ 630

Balance Sheet Components (Details) - Property and equipment, net - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Property and equipment, net [Abstract]
Laboratory equipment	$ 2,076	$ 1,565
Office and computer equipment	227	175
Leasehold improvements	333	226
Total property and equipment	2,636	1,966
Less: accumulated depreciation	(1,570)	(1,236)
Property and equipment, net	$ 1,066	$ 730

Balance Sheet Components (Details) - Intangible assets - USD ($) $ in Thousands	Dec. 31, 2018	Feb. 13, 2018	Dec. 31, 2017
Finite-Lived Intangible Assets [Line Items]
Intangible assets, gross	$ 22,180	$ 24,080	$ 80
Less accumulated amortization	2,767	40	40
Intangible assets, net	19,413	24,040	40
Purchased Technology [Member]
Finite-Lived Intangible Assets [Line Items]
Intangible assets, gross	22,100	22,400
In Process Research and Development [Member]
Finite-Lived Intangible Assets [Line Items]
Intangible assets, gross		1,600
Intellectual Property [Member]
Finite-Lived Intangible Assets [Line Items]
Intangible assets, gross	$ 80	$ 80	$ 80

Balance Sheet Components (Details) - The estimated future amortization expense by year $ in Thousands	Dec. 31, 2018 USD ($)
The estimated future amortization expense by year [Abstract]
2019	$ 2,320
2020	1,732
2021	1,732
2022	1,732
2023	1,731
Thereafter	10,166
Total	$ 19,413

Balance Sheet Components (Details) - Accrued liabilities - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Accrued liabilities [Abstract]
Accrued compensation	$ 632	$ 1,320
Accrued clinical and manufacturing expenses	75	69
Accrued professional and consulting services	166	113
Reserve for return of royalties	339
Deferred rent and lease loss accrual, current portion	111	21
Convertible preferred stock warrant liability		67
Other	195	15
Total	$ 1,518	$ 1,605

Revenue (Details) ¥ in Billions		3 Months Ended	12 Months Ended
Revenue (Details) ¥ in Billions	May 25, 2017 USD ($)	Mar. 31, 2018 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2018 JPY (¥)	Dec. 31, 2017 USD ($)
Entity Loan Modification Program [Member] \| HHSBARDA [Member]
Revenue (Details) [Line Items]
Contract with Customer, Liability	$ 14,000,000
Contract with Customer, Liability, Cumulative Catch-up Adjustment to Revenue, Modification of Contract	1,700,000
Cost of Goods and Services Sold	$ 15,700,000
Contract with Customer, Liability, Revenue Recognized			$ 1,344,000		$ 5,839,000
Royalty [Member] \| Relenza Recognized [Member]
Revenue (Details) [Line Items]
Revenues			$ 788,000
Royalty Percentage			7.00%	7.00%
Royalty [Member] \| Aviragen Therapeutics Inc [Member]
Revenue (Details) [Line Items]
Revenues		$ 5,000,000	$ 5,000,000	¥ 20
Royalty Percentage			4.00%	4.00%
Royalty [Member] \| Inavir Recognized [Member]
Revenue (Details) [Line Items]
Revenues			$ 552,000
Non Cash Royalty Revenue			1,475,000
Royalty [Member] \| JAPAN
Revenue (Details) [Line Items]
Revenues			$ 102,000
Royalty Percentage			5.00%	5.00%

Liabilities Related to Sale of Future Royalties (Details) - HCRP [Member] - Royalty Arrangement [Member] $ in Millions	1 Months Ended
	Apr. 30, 2016 USD ($)
Liabilities Related to Sale of Future Royalties (Details) [Line Items]
Debt, Additions	$ 20.0
HCRP Agreement, Revenue Terms	HCRP is entitled to the first $3.0 million plus 15% of the next $1.0 million in royalties earned in each year commencing on April 1
Revenues	$ 3.0
Royalty Percentage	15.00%
Royalty Income, Nonoperating	$ 1.0

Liabilities Related to Sale of Future Royalties (Details) - Liability related to sale of future Royalties $ in Thousands	12 Months Ended
	Dec. 31, 2018 USD ($)
Liability related to sale of future Royalties [Abstract]
Total Liability related to sale of future royalties, February 13, 2018	$ 15,900
Non-cash royalty revenue paid to HCRP	(18)
Non-cash interest expense recognized	1,859
TotalLiability related to sale of future royalties, December 31, 2018	$ 17,741

Convertible Promissory Notes, Related Parties (Details) - USD ($)				12 Months Ended
	Feb. 13, 2018	Nov. 20, 2015	Dec. 10, 2014	Dec. 31, 2018	Dec. 31, 2017
Convertible Promissory Notes, Related Parties (Details) [Line Items]
Proceeds from Convertible Debt				$ 25.0
Debt Instrument, Interest Rate, Stated Percentage				8.00%
Debt Instrument, Unamortized Discount				$ 300,000	$ 2,500,000
Debt Conversion, Converted Instrument, Shares Issued (in Shares)	1,571,702
Debt Instrument, Convertible, Conversion Price (in Dollars per share)	$ 9.05
Debt Conversion, Converted Instrument, Amount	$ 14,200,000
Other Ownership Interests, Contributed Capital	21,400,000
Note Purchase Agreement [Member]
Convertible Promissory Notes, Related Parties (Details) [Line Items]
Proceeds from Convertible Debt			$ 18.4
Second Note Purchase Agreement [Member]
Convertible Promissory Notes, Related Parties (Details) [Line Items]
Proceeds from Convertible Debt		$ 11.0
Convertible Promissory Notes [Member]
Convertible Promissory Notes, Related Parties (Details) [Line Items]
Debt Instrument, Face Amount	35,600,000				35,300,000
Debt Instrument, Periodic Payment, Interest	6.6				29,400,000
Debt Instrument, Increase, Accrued Interest					6.3
Debt Instrument, Unamortized Discount	400,000				$ 400,000
Debt Instrument, Periodic Payment, Principal	$ 29,400,000
Notes Issued In 2014 [Member]
Convertible Promissory Notes, Related Parties (Details) [Line Items]
Embedded Derivative, Fair Value of Embedded Derivative Liability				1.9
Debt Issuance Costs, Net				20,000
Notes Issued In 2015 [Member]
Convertible Promissory Notes, Related Parties (Details) [Line Items]
Embedded Derivative, Fair Value of Embedded Derivative Liability				1.3
Debt Issuance Costs, Net				$ 7,000

Secured Promissory Note Payable to Oxford Finance (Details) - Loan Agreement [Member] - Oxford Finance [Member] - USD ($)		12 Months Ended
	Dec. 22, 2016	Dec. 31, 2018	Dec. 31, 2017
Secured Promissory Note Payable to Oxford Finance (Details) [Line Items]
Long-term Debt, Gross	$ 5.0
Debt Instrument, Payment Terms	a secured promissory note and is repayable over four years, with interest only payable over the first 12 months and the balance fully amortized over the subsequent 36 months
Debt Instrument, Periodic Payment Terms, Balloon Payment to be Paid		$ 325,000
Interest Expense, Debt		469,000	$ 518,000
Interest Paid, Including Capitalized Interest, Operating and Investing Activities		356,000	$ 335,000
Debt Conversion, Converted Instrument, Amount		$ 250,000
Convertible Preferred Stock [Member] \| Series C Preferred Stock [Member]
Secured Promissory Note Payable to Oxford Finance (Details) [Line Items]
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in Shares)		7,563
Class of Warrant or Right, Exercise Price of Warrants or Rights (in Dollars per share)		$ 33.11
Warrants Not Settleable in Cash, Fair Value Disclosure		$ 134,000
Debt Instrument, Interest Rate, Stated Percentage		10.50%
London Interbank Offered Rate (LIBOR) [Member]
Secured Promissory Note Payable to Oxford Finance (Details) [Line Items]
Debt Instrument, Description of Variable Rate Basis	30-day U.S. LIBOR plus 6.17%
Debt Instrument, Basis Spread on Variable Rate	6.17%
Warrant [Member] \| Common Stock [Member]
Secured Promissory Note Payable to Oxford Finance (Details) [Line Items]
Class of Warrant or Right, Exercise Price of Warrants or Rights (in Dollars per share)		$ 22.99
Warrants Not Settleable in Cash, Fair Value Disclosure		$ 70,000
Class of Warrant or Right, Number of Securities Called by Each Warrant or Right (in Shares)		10,914
Debt Conversion, Converted Instrument, Issuance Date		Feb. 13, 2018

Commitments and Contingencies (Details) - USD ($)	3 Months Ended	12 Months Ended
Commitments and Contingencies (Details) - USD ($)	Dec. 31, 2018	Dec. 31, 2018	Dec. 31, 2017
Commitments and Contingencies (Details) [Line Items]
Operating Lease, Impairment Loss	$ 253,000
Operating Leases, Rent Expense		$ 875,000	$ 564,000
Office Space In San Francisco California [Member] \| The First Lease [Member]
Commitments and Contingencies (Details) [Line Items]
Lease Expiration Date		Apr. 30, 2020
Office Space In San Francisco California [Member] \| Remaining Three Leases [Member]
Commitments and Contingencies (Details) [Line Items]
Lease Expiration Date		Aug. 31, 2019
Office Space In Alpharetta Georgia [Member]
Commitments and Contingencies (Details) [Line Items]
Lease Expiration Date		Feb. 28, 2021

Commitments and Contingencies (Details) - Liabilities related to costs of exit from leased premises - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Liabilities related to costs of exit from leased premises [Abstract]
Balance
Balance	233
Costs of exit from leased premises	359
Deferred rent on cease-use date	19
Impairment of property and equipment	(106)
Cash paid, net of receipts	(41)
Accretion charges, included in rent expense	$ 2

Commitments and Contingencies (Details) - Future minimum payments and sublease income under operating leases $ in Thousands	Dec. 31, 2018 USD ($)
Future minimum payments and sublease income under operating leases [Abstract]
2019	$ 859
2019	213
2020	411
2020	219
2021	56
2021	38
Thereafter
Thereafter
Total	1,326
Total	$ 470

Stockholders' Equity (Details) - USD ($) $ / shares in Units, $ in Millions			12 Months Ended
	Feb. 13, 2018	Dec. 31, 2017	Dec. 31, 2018
Stockholders' Equity (Details) [Line Items]
Preferred Stock, Shares Authorized (in Shares)		5,000,000	5,000,000
Preferred Stock, Par or Stated Value Per Share		$ 0.10	$ 0.10
Preferred Stock, Shares Outstanding (in Shares)		1,221,064	0
Convertible Preferred Stock, Terms of Conversion			At the option of the holder, each share of convertible preferred stock was convertible, one‑for‑one, subject to adjustment for anti‑dilution protection, into shares of common stock. Each share automatically converted into the number of shares of common stock into which the shares were convertible at the then applicable conversion ratio upon: (1) the closing of the sale of the Company’s common stock in a public offering provided the offering price per share was not less than three times the Series C convertible preferred stock original issue price of $33.05196 and the aggregate gross proceeds were not less than $30.0 million, or (2) upon receipt of a written consent of the holders of a majority of the then outstanding shares of convertible preferred stock voting as a single class on an as‑converted basis
Convertible Preferred Stock [Member]
Stockholders' Equity (Details) [Line Items]
Preferred Stock, Shares Authorized (in Shares)		1,662,171
Preferred Stock, Shares Outstanding (in Shares)		1,221,064
Preferred Stock, Voting Rights			The holders of convertible preferred stock were entitled to the number of votes equal to the number of shares of common stock into which each share of Series A, Series B, and Series C convertible preferred stock could have been converted on the record date for the vote or consent of the stockholders, except as otherwise required by law, and had voting rights and powers equal to the voting rights and powers of the common stockholders. The holders of Series A convertible preferred stock, voting as a separate class, were entitled to elect one member of the board of directors. As long as a specified investor held at least one share of Series C convertible preferred stock, the specified investor was able to designate one member of the board of directors, who would have been elected by the holders of Series C convertible preferred stock voting as a separate class. As long as a specified investor held least one share of Series B convertible preferred stock, the specified investor was able to designate one member of the board of directors, who would have been elected by the holders of Series B convertible preferred stock voting as a separate class. The holders of common stock, voting as a separate class, were entitled to elect two members of the board of directors, one of whom was the duly appointed chief executive officer of the Company
Convertible Preferred Stock [Member] \| Series C Preferred Stock [Member]
Stockholders' Equity (Details) [Line Items]
Preferred Stock, Shares Authorized (in Shares)		820,088
Preferred Stock, Dividend Rate, Per-Dollar-Amount			$ 2.64416
Preferred Stock, Per Share Amounts of Preferred Dividends in Arrears			33.05196
Dividends, Preferred Stock (in Dollars)	$ 7.3	$ 7.1
Preferred Stock, Dividends Per Share, Declared	$ 12.06	$ 11.74
Preferred Stock, Shares Outstanding (in Shares)		605,103
Shares Issued, Price Per Share			33.05196
Preferred Stock, Liquidation Preference Per Share			$ 33.05196
Convertible Preferred Stock [Member] \| Series C Preferred Stock [Member] \| Minimum [Member]
Stockholders' Equity (Details) [Line Items]
Preferred Stock, Shares Outstanding (in Shares)			20,134
Proceeds from Issuance of Convertible Preferred Stock (in Dollars)			$ 30.0
Convertible Preferred Stock [Member] \| Series B Preferred Stock [Member]
Stockholders' Equity (Details) [Line Items]
Preferred Stock, Shares Authorized (in Shares)		747,095
Preferred Stock, Dividend Rate, Per-Dollar-Amount			$ 2.64416
Preferred Stock, Per Share Amounts of Preferred Dividends in Arrears	$ 15.78		33.05196
Dividends, Preferred Stock (in Dollars)	$ 7.6	$ 7.5
Preferred Stock, Dividends Per Share, Declared		$ 15.46
Preferred Stock, Shares Outstanding (in Shares)	483,387	520,973
Preferred Stock, Liquidation Preference Per Share			$ 33.05196
Convertible Preferred Stock [Member] \| Series B Preferred Stock [Member] \| Minimum [Member]
Stockholders' Equity (Details) [Line Items]
Preferred Stock, Shares Outstanding (in Shares)			20,134
Convertible Preferred Stock [Member] \| Series A Preferred Stock [Member]
Stockholders' Equity (Details) [Line Items]
Preferred Stock, Shares Authorized (in Shares)		94,988
Preferred Stock, Dividend Rate, Per-Dollar-Amount			$ 2.30449
Preferred Stock, Shares Outstanding (in Shares)		94,988
Preferred Stock, Liquidation Preference Per Share			$ 28.80613
Common Stock [Member]
Stockholders' Equity (Details) [Line Items]
Stock Issued During Period, Shares, Acquisitions (in Shares)			3,510,439
Common Stock, Voting Rights			Holders of common stock are entitled to one vote per share on matters to be voted on by stockholders
Common Stock [Member] \| Convertible Preferred Stock [Member] \| Series C Preferred Stock [Member]
Stockholders' Equity (Details) [Line Items]
Stock Issued During Period, Shares, Acquisitions (in Shares)	696,028
Common Stock [Member] \| Convertible Preferred Stock [Member] \| Series C Preferred Stock [Member] \| Dividend Paid [Member]
Stockholders' Equity (Details) [Line Items]
Stock Issued During Period, Shares, Acquisitions (in Shares)	253,851
Common Stock [Member] \| Convertible Preferred Stock [Member] \| Series B Preferred Stock [Member]
Stockholders' Equity (Details) [Line Items]
Stock Issued During Period, Shares, Acquisitions (in Shares)	599,259
Common Stock [Member] \| Convertible Preferred Stock [Member] \| Series B Preferred Stock [Member] \| Dividend Paid [Member]
Stockholders' Equity (Details) [Line Items]
Stock Issued During Period, Shares, Acquisitions (in Shares)	265,340
Common Stock [Member] \| Convertible Preferred Stock [Member] \| Series A Preferred Stock [Member]
Stockholders' Equity (Details) [Line Items]
Stock Issued During Period, Shares, Acquisitions (in Shares)	104,065

Stockholders' Equity (Details) - Convertible preferred stock - Convertible Preferred Stock [Member] - USD ($)	Feb. 13, 2018	Dec. 31, 2017
Stockholders' Equity (Details) - Convertible preferred stock [Line Items]
Preferred stock, shares authorized		1,662,171
Preferred stock, shares outstanding		1,221,064
Preferred stock, net carrying value		$ 38,941
Preferred stock, liquidation preference		$ 39,956
Series A Preferred Stock [Member]
Stockholders' Equity (Details) - Convertible preferred stock [Line Items]
Preferred stock, shares authorized		94,988
Preferred stock, shares outstanding		94,988
Preferred stock, net carrying value		$ 2,949
Preferred stock, liquidation preference		$ 2,737
Series B Preferred Stock [Member]
Stockholders' Equity (Details) - Convertible preferred stock [Line Items]
Preferred stock, shares authorized		747,095
Preferred stock, shares outstanding	483,387	520,973
Preferred stock, net carrying value		$ 16,115
Preferred stock, liquidation preference		$ 17,219
Series C Preferred Stock [Member]
Stockholders' Equity (Details) - Convertible preferred stock [Line Items]
Preferred stock, shares authorized		820,088
Preferred stock, shares outstanding		605,103
Preferred stock, net carrying value		$ 19,877
Preferred stock, liquidation preference		$ 20,000

Stockholders' Equity (Details) - Common stock reserved for issuance - shares	Dec. 31, 2018	Dec. 31, 2017
Stockholders' Equity (Details) - Common stock reserved for issuance [Line Items]
Common stock reserved for issuance	1,099,454	1,977,924
Convertible Preferred Stock Outstanding [Member]
Stockholders' Equity (Details) - Common stock reserved for issuance [Line Items]
Common stock reserved for issuance		1,221,064
Options Issued And Outstanding [Member]
Stockholders' Equity (Details) - Common stock reserved for issuance [Line Items]
Common stock reserved for issuance	865,163	304,850
Options Available For Future Grants [Member]
Stockholders' Equity (Details) - Common stock reserved for issuance [Line Items]
Common stock reserved for issuance	223,377
Cumulative Convertible Preferred Stock Dividends [Member]
Stockholders' Equity (Details) - Common stock reserved for issuance [Line Items]
Common stock reserved for issuance		441,096
Common Stock Warrants [Member]
Stockholders' Equity (Details) - Common stock reserved for issuance [Line Items]
Common stock reserved for issuance	10,914	10,914

Equity Incentive Plans (Details) - USD ($)	12 Months Ended
Equity Incentive Plans (Details) - USD ($)	Dec. 31, 2018	Dec. 31, 2017
Employee Stock Option [Member]
Equity Incentive Plans (Details) [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number (in Shares)	865,163
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price (in Dollars per share)	$ 8.13
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term	6 years 51 days
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Intrinsic Value	$ 0
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Number (in Shares)	452,905
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Weighted Average Exercise Price (in Dollars per share)	$ 10.58
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Weighted Average Remaining Contractual Term	3 years 127 days
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Aggregate Intrinsic Value	$ 0
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Grant Date Intrinsic Value (in Dollars per share)	$ 1.88
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested in Period, Fair Value	$ 332,000	$ 533,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Intrinsic Value	$ 0	$ 1,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value (in Dollars per share)	$ 3.59	$ 2.99
Employee Service Share-based Compensation, Nonvested Awards, Compensation Not yet Recognized, Stock Options	$ 1,100,000
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition	2 years 9 months
Restricted Stock [Member]
Equity Incentive Plans (Details) [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized (in Shares)	22,727
Maximum [Member] \| Employee Stock Option [Member]
Equity Incentive Plans (Details) [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period	10 years

Equity Incentive Plans (Details) - Summary of stock option - $ / shares	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Summary of stock option [Abstract]
Balance		99,644
Balance	304,850	275,539
Balance (in Dollars per share)	$ 9.50	$ 11.32
Assumed on consummation of Merger	291,102
Assumed on consummation of Merger	627,106
Assumed on consummation of Merger (in Dollars per share)	$ 26.33
Granted	(431,100)	(78,406)
Granted	431,100	78,406
Granted (in Dollars per share)	$ 5.17	$ 4.07
Exercised	(2,013)	(2,834)
Exercised (in Dollars per share)	$ 6.49	$ 8.58
Forfeited	71,500	33,012
Forfeited	(89,903)	(33,012)
Forfeited (in Dollars per share)	$ 5.90	$ 11.49
Canceled	269,148	13,249
Canceled	(405,977)	(13,249)
Canceled (in Dollars per share)	$ 34.64	$ 12.00
Balance	200,650
Balance	865,163	304,850
Balance (in Dollars per share)	$ 8.13	$ 9.50
Termination of Plan		(67,499)

Equity Incentive Plans (Details) - Fair values estimated assumptions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Fair values estimated assumptions [Abstract]
Risk-free interest rate	2.80%	1.87%
Expected term	5 years 350 days	6 years 32 days
Expected volatility	79.00%	91.00%
Dividend yield	0.00%	0.00%

Equity Incentive Plans (Details) - Total stock-based compensation recognized for options - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation	$ 539	$ 477
Research and Development Expense [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation	254	262
General and Administrative Expense [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation	$ 285	$ 215

Income Taxes (Details) - USD ($) $ in Millions	12 Months Ended
Income Taxes (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Income Taxes (Details) [Line Items]
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent	21.00%	34.00%
Effective Income Tax Rate Reconciliation, Deduction, Percent	21.00%	21.00%
Increase (Decrease) in Deferred Taxes		$ 4.2
Valuation Allowance, Deferred Tax Asset, Increase (Decrease), Amount	$ 25.7	4.2
Domestic Tax Authority [Member]
Income Taxes (Details) [Line Items]
Operating Loss Carryforwards	92.3	69.5
Tax Credit Carryforward, Amount	3.0	2.7
State and Local Jurisdiction [Member]
Income Taxes (Details) [Line Items]
Operating Loss Carryforwards	76.9	75.0
Tax Credit Carryforward, Amount	2.3	$ 2.0
AUSTRALIA
Income Taxes (Details) [Line Items]
Tax Credit Carryforward, Amount	14.4
UNITED KINGDOM
Income Taxes (Details) [Line Items]
Tax Credit Carryforward, Amount	24.7
FRANCE
Income Taxes (Details) [Line Items]
Tax Credit Carryforward, Amount	$ 37.7

Income Taxes (Details) - Components of income taxes - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Current:
Federal
State	3
Foreign	106
Total Current	109
Deferred:
Federal
State
Foreign
Total Deferred
Provision for income taxes	$ 109

Income Taxes (Details) - Components of the deferred tax assets - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Components of the deferred tax assets [Abstract]
Net operating loss carry-forwards	$ 43,822	$ 19,441
Research and development tax credits	3,357	2,979
Capitalized research and development	2,326
Sale of future royalties	8,383
Accruals, reserves and other	714	544
Total deferred tax assets	58,602	22,964
Valuation allowance	(48,626)	(22,964)
Deferred tax assets net of valuation allowance	9,976
Deferred tax liabilities:
Intangible assets	(9,976)
Total deferred tax liabilities	(9,976)
Net deferred tax assets

Income Taxes (Details) - Reconciliation of the provision for income taxes	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Reconciliation of the provision for income taxes [Abstract]
U.S. federal taxes at statutory rate	21.00%	34.00%
State taxes (net of federal benefit)	0.60%	14.20%
Foreign rate differential	3.10%
Global intangible low-taxed income	(8.80%)
Permanent items:
Convertible note interest	(0.40%)	(10.80%)
Revaluation of derivative liabilities		11.90%
Others	(2.10%)	(1.40%)
Tax credits	2.10%	8.00%
Change in valuation allowance	(20.40%)	43.40%
Impact of tax reform rate change		(97.00%)
NOL and credit adjustments	(3.80%)	(2.40%)
Bargain purchase gain	8.10%
Other		0.10%
Provision for income taxes	(0.60%)

Income Taxes (Details) - Reconciliation of the unrecognized tax benefits - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Reconciliation of the unrecognized tax benefits [Abstract]
Beginning Balance	$ 1,404	$ 1,231
Additions based on tax positions related to the current year	181	173
Decreases related to prior years’ tax positions	(3)
Ending Balance	$ 1,582	$ 1,404

Net Loss Per Share Attributable to Common Stockholders (Details) - Calculation of basic and diluted net loss per share - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017
Calculation of basic and diluted net loss per share [Abstract]
Net loss	$ (4,902)	$ (6,548)	$ (8,871)	$ 2,314	$ (1,075)	$ (2,173)	$ (3,538)	$ (2,796)	$ (18,007)	$ (9,582)
Series B and C preferred dividend									(339)	(2,878)
Net loss attributable to common stockholders	$ (4,902)	$ (6,548)	$ (8,871)	$ 1,975	$ (1,800)	$ (2,898)	$ (4,256)	$ (3,506)	$ (18,346)	$ (12,460)
Shares used to compute net loss per share, basic and diluted (in Shares)									6,316,065	135,953
Net loss per share attributable to common stockholders, basic and diluted (in Dollars per share)					$ (13.16)	$ (21.36)	$ (31.37)	$ (25.84)	$ (2.90)	$ (91.65)

- Definition

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

+ References + Details

Net Loss Per Share Attributable to Common Stockholders (Details) - Potentially dilutive securities excluded from the computation of diluted weighted average shares - shares	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potentially dilutive securities excluded from denominator of the diluted earnings per share computation	1,261,124	2,719,255
Employee Stock Option [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potentially dilutive securities excluded from denominator of the diluted earnings per share computation	839,396	295,243
Warrant [Member] \| Convertible Preferred Stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potentially dilutive securities excluded from denominator of the diluted earnings per share computation	891	7,563
Warrant [Member] \| Common Stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potentially dilutive securities excluded from denominator of the diluted earnings per share computation	9,658
Cumulative Convertible Preferred Stock Dividends [Member] \| Series B And C Preferred Stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potentially dilutive securities excluded from denominator of the diluted earnings per share computation	213,760	1,567,172
Convertible Preferred Stock Outstanding [Member] \| Series A Preferred Stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potentially dilutive securities excluded from denominator of the diluted earnings per share computation	12,260	94,988
Convertible Promissory Notes Related Party [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potentially dilutive securities excluded from denominator of the diluted earnings per share computation	185,159	754,289

Quarterly Financial Data (Unaudited) (Details) - Selected summarized quarterly financial - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017
Selected summarized quarterly financial [Abstract]
Revenue	$ 1,767	$ 281	$ 608	$ 1,503	$ 760	$ 915	$ 1,854	$ 2,310	$ 4,159	$ 5,839
Operating expenses	5,953	6,161	8,383	5,418	3,449	2,871	4,977	4,557
Net income (loss)	(4,902)	(6,548)	(8,871)	2,314	(1,075)	(2,173)	(3,538)	(2,796)	(18,007)	(9,582)
Net income (loss) attributable to common stockholders	$ (4,902)	$ (6,548)	$ (8,871)	$ 1,975	$ (1,800)	$ (2,898)	$ (4,256)	$ (3,506)	$ (18,346)	$ (12,460)
Net loss per share – basic and diluted (in Dollars per share)					$ (13.16)	$ (21.36)	$ (31.37)	$ (25.84)	$ (2.90)	$ (91.65)
Net income (loss) per share – basic (in Dollars per share)	$ (0.69)	$ (0.92)	$ (1.24)	$ 0.54
Net income (loss) per share – diluted (in Dollars per share)	$ (0.69)	$ (0.92)	$ (1.24)	$ 0.49

- Definition

The amount of net income (loss) for the period per each share of common stock or unit outstanding during the reporting period.

+ References

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+ Details

- Definition

The amount of net income (loss) for the period available to each share of common stock or common unit outstanding during the reporting period and to each share or unit that would have been outstanding assuming the issuance of common shares or units for all dilutive potential common shares or units outstanding during the reporting period.

+ References

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+ Details

- Definition

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

+ References + Details