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Document And Entity Information - shares	6 Months Ended
Document And Entity Information - shares	Jun. 30, 2018	Aug. 08, 2018
Document and Entity Information [Abstract]
Entity Registrant Name	Vaxart, Inc.
Document Type	10-Q
Current Fiscal Year End Date	--12-31
Entity Common Stock, Shares Outstanding		7,141,189
Amendment Flag	false
Entity Central Index Key	0000072444
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Filer Category	Smaller Reporting Company
Entity Well-known Seasoned Issuer	No
Document Period End Date	Jun. 30, 2018
Document Fiscal Year Focus	2018
Document Fiscal Period Focus	Q2

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Current assets:
Cash and cash equivalents	$ 23,921	$ 1,571
Short-term investments		1,415
Accounts receivable, net of allowance	561	630
Prepaid expenses and other current assets	1,021	137
Total current assets	25,503	3,753
Property and equipment, net	1,034	730
Intangible assets, net	21,222	40
Total assets	47,759	4,523
Current liabilities:
Accounts payable	1,449	1,390
Current portion of secured promissory note payable to Oxford Finance	1,667	1,528
Short-term note payable	153
Liability related to sale of future royalties, current portion	3,150
Other accrued liabilities	2,375	1,605
Total current liabilities	8,794	4,523
Convertible promissory notes, long-term, related parties		35,282
Liability related to sale of future royalties, net of current portion	13,916
Secured promissory note payable to Oxford Finance, net of current portion	2,696	3,440
Total liabilities	25,406	43,245
Commitments and contingencies (Note 10)
Stockholders’ equity (deficit):
Preferred Stock: $0.10 par value; 5,000,000 shares authorized; none issued and outstanding as of June 30, 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 June 30, 2018 and December 31, 2017, respectively	714
Additional paid-in capital	108,178	41,259
Accumulated deficit	(86,539)	(79,982)
Total stockholders’ equity (deficit)	22,353	(38,722)
Total liabilities and stockholders’ equity (deficit)	$ 47,759	$ 4,523

Condensed Consolidated Balance Sheets (Parentheticals) - USD ($) $ in Thousands	Jun. 30, 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

Condensed Consolidated Statements of Operations and Comprehensive Loss (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Revenue:
Revenue	$ 608	$ 1,854	$ 2,111	$ 4,164
Operating expenses:
Research and development	5,012	4,324	8,420	8,203
General and administrative	1,771	653	3,781	1,331
Impairment of intangible assets	1,600		1,600
Total operating expenses	8,383	4,977	13,801	9,534
Operating loss	(7,775)	(3,123)	(11,690)	(5,370)
Other income and (expenses):
Bargain purchase gain	(328)		6,660
Interest income	36	20	41	33
Interest expense	(136)	(755)	(573)	(1,499)
Non-cash interest expense related to sale of future royalties	(468)		(766)
Gain (loss) on revaluation of financial instruments, net		320	(3)	502
Foreign exchange loss	(199)		(197)
Total other income and (expenses)	(1,095)	(415)	5,162	(964)
Net loss before provision for income taxes	(8,870)	(3,538)	(6,528)	(6,334)
Provision for income taxes	1		29
Net loss	(8,871)	(3,538)	(6,557)	(6,334)
Series B and C preferred dividend		(718)	(339)	(1,428)
Net comprehensive loss attributable to common stockholders	$ (8,871)	$ (4,256)	$ (6,896)	$ (7,762)
Net loss per share – basic and diluted (in Dollars per share)	$ (1.24)	$ (31.37)	$ (1.26)	$ (57.22)
Shares used to compute net loss per share – basic and diluted (in Shares)	7,141,189	135,658	5,477,265	135,658
Government Contract [Member]
Revenue:
Revenue	$ 520	$ 1,854	$ 1,130	$ 4,164
Royalty [Member]
Revenue:
Revenue	70		963
Non Cash Royalty Revenue [Member]
Revenue:
Revenue	$ 18		$ 18

Condensed Consolidated Statement of Stockholders` Equity (Deficit) (Unaudited) - 6 months ended Jun. 30, 2018 - USD ($) $ in Thousands	Preferred Stock [Member]	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Total
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 upon reverse merger		$ 365	31,403		31,768
Issuance of common stock upon reverse 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			204		$ 204
Net loss				(6,557)	(6,557)
Balances at Jun. 30, 2018		$ 714	$ 108,178	$ (86,539)	$ 22,353
Balances (in Shares) at Jun. 30, 2018		7,141,189			7,141,189

Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
Cash flows from operating activities:
Net loss	$ (6,557)	$ (6,334)
Adjustments to reconcile net loss to net cash used in operating activities:
Bargain purchase gain	(6,660)
Depreciation and amortization	1,437	203
Stock-based compensation	204	253
Amortization of discount on short-term investments		12
Loss (gain) on revaluation of financial instruments, net	3	(502)
Impairment of intangible assets	1,600
Non-cash interest expense	366	1,280
Amortization of note discount	18	71
Non-cash interest expense related to sale of future royalties	766
Change in operating assets and liabilities:
Accounts receivable, net of allowance	14,735	505
Prepaid expenses and other assets	(448)	(37)
Accounts payable	(3,259)	(1,649)
Accrued liabilities	(5,693)	175
Net cash used in operating activities	(3,488)	(6,023)
Cash flows from investing activities:
Purchase of property and equipment	(339)	(95)
Cash acquired in reverse merger	25,525
Cash paid for fractional shares in merger	(21)
Purchases of short-term investments	(573)	(5,765)
Proceeds from maturities of short-term investments	1,988	6,063
Net cash provided by investing activities	26,580	203
Cash flows from financing activities:
Repayment of principal on secured promissory note payable to Oxford Finance	(694)
Repayment of short-term note	(61)
Proceeds from issuance of common stock upon exercise of stock options	13
Net cash used in financing activities	(742)
Net increase (decrease) in cash and cash equivalents	22,350	(5,820)
Cash and cash equivalents at beginning of the period	1,571	8,405
Cash and cash equivalents at end of the period	23,921	2,585
Supplemental disclosure of cash flow information:
Interest paid	189	148
Supplemental disclosure of non-cash financing activity:
Issuance of common stock upon reverse merger, net of cash paid for partial shares	31,768
Conversion of convertible promissory notes, related parties into common stock upon reverse merger	35,577
Reclassification of convertible preferred stock warrant liability to equity	70
Acquisition of property and equipment included in accounts payable	$ 14

Organization and Basis of Presentation

6 Months Ended

Jun. 30, 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, and small-molecule antiviral drugs.

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 June 30, 2018, the Company had an accumulated deficit of $86.5 million and a loan with an outstanding balance of $4.4 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 $23.9 million held as of June 30, 3018, 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 and has not yet entered into any commitments for its 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

6 Months Ended

Jun. 30, 2018

Accounting Policies [Abstract]

Significant Accounting Policies [Text Block]

NOTE 2. Summary of Significant Accounting Policies

Basis of Presentation – The Company has prepared the accompanying condensed consolidated financial statements pursuant to the rules and regulations of the Securities and Exchange Commission (“SEC”). Certain information and footnote disclosures normally included in consolidated financial statements prepared in accordance with accounting principles generally accepted in the United States of America (“U.S. GAAP”) have been condensed or omitted pursuant to these rules and regulations. These condensed consolidated financial statements should be read in conjunction with the audited financial statements of Vaxart Biosciences, Inc. and footnotes related thereto for the year ended December 31, 2017, included in our Form 8-K/A filed with the SEC on April 2, 2018. In the opinion of management, the unaudited condensed consolidated financial statements include all adjustments (consisting only of normal recurring adjustments) necessary to present fairly the Company’s financial position and the results of its operations and cash flows. The results of operations for such interim periods are not necessarily indicative of the results to be expected for the full year.

Basis of Consolidation – The condensed 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 (loss), net in the Company’s statement 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 June 30, 2018 and December 31, 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.

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.

Impairment of Long-Lived Assets – The Company reviews its long lived assets, including property and equipment and intangible assets, 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 its in-process research and development as fully impaired in the three months ended June 30, 2018 (see Note 5). 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 condensed 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 are 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 gain (loss) on revaluation of financial instruments in the condensed 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 gain (loss) on revaluation of financial instruments in the condensed 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).

The Company performs 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 condensed 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.

Management believes that if the government were to terminate the HHS BARDA contract for convenience, the costs incurred through the effective date of such termination and any settlement costs resulting from such termination would be allowable costs. 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 to employees, including stock options, on the grant date and records the fair value of these awards, net of estimated forfeitures, to compensation expense over the service period. The fair value of awards to nonemployees is measured on the date of performance at the fair value of the consideration received or the fair value of the equity instruments issued, whichever is more reliably measured. The fair value of options is estimated using the Black-Scholes valuation model.

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

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 loss 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 non-employee 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. The Company adopted this standard effective April 1, 2018, and since it had no unvested awards granted to non-employees, 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 its adoption had no effect on the Company’s financial condition or results of operations, although it was applied in the Company’s determination that the Merger should be accounted for 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. In July 2015, the FASB approved a one‑year deferral of the effective date of the new standard to 2018 for public companies, with an option that would permit companies to adopt the new standard as early as the original effective date of 2017.

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 this standard 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 the 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. The adoption will have no effect on the Company’s statements of operations or cash flows but will increase both its reported assets and reported liabilities in equal amounts that have not yet been quantified.

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 condensed consolidated financial statements as a result of future adoption.

Business Combination

6 Months Ended

Jun. 30, 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 condensed 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 in the three months ended June 30, 2018 and the allocation as of June 30, 2018:

	As of March 31, 2018		Adjustments		As of June 30, 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		—		22,400
In-process research and development ⁽²⁾		1,600		—		1,600
Total assets		64,807		(10)		64,797

Accounts payable		(3,379)		75		(3,304)
Other current liabilities		(6,351)		(393)		(6,744)
Liability related to sale of future royalties		(16,300)		—		(16,300)
Net assets acquired		38,777		(328)		38,449

Purchase price		(31,789)		—		(31,789)

Bargain purchase gain ⁽³⁾	$	6,988	$	(328)	$	6,660

__________

(1) Developed technology comprises Inavir^® and Relenza^®, both influenza vaccines on which the Company is presently receiving royalty revenue, which, based on preliminary valuations, 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 preliminary 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 a preliminary valuation 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 $1.4 million, of which approximately $0.5 million was incurred in the six months ended June 30, 2018, substantially all in the three months ended March 31, 2018, and is included in general and administrative expenses in the condensed consolidated statement of operations and comprehensive loss. The Company is in the process of gathering the information necessary to evaluate the tax impact of the acquisition, including the treatment of the bargain purchase gain, and to finalize accrued expenses and the discount rate and underlying assumptions utilized in the valuation of the intangible assets acquired. The Company expects to complete its evaluation of the impact, if any, during fiscal 2018.

Selected amounts related to Aviragen’s business included in the Company’s condensed consolidated statement of operations for the three and six months ended June 30, 2018, are as follows:

	Period Ended June 30, 2018
	Three Months		Six Months
	(in thousands)
Revenue	$	88	$	981

Net loss	$	(2,280)	$	(2,642)

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 three months and six ended June 30, 2017, are based on the actual unaudited financial statements prepared for the three and six months ended June 30, 2017, and for the three and six months ended June 30, 2018, are based on the Company’s results of operations, with the year-to-date results increased by Aviragen’s activities in the forty-three days prior to the closing of the Merger. The pro forma financial information for all periods 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:

	Three Months Ended June 30,				Six Months Ended June 30,
	2018		2017		2018		2017
	(in thousands)				(in thousands)
Total revenue	$	608	$	1,878	$	13,647	$	9,054

Net income (loss)	$	(8,151)	$	(9,571)	$	(2,252)	$	(17,486)

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

6 Months Ended

Jun. 30, 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 June 30, 2018 and December 31, 2017:

	Level 1		Level 2		Level 3		Total
June 30, 2018	(in thousands)
Recurring Financial Assets:
Money Market Funds	$	13	$	—	$	—	$	13
Corporate Bonds		—		—		—		—

Total assets	$	13	$	—	$	—	$	13

	Level 1		Level 2		Level 3		Total
June 30, 2018	(in thousands)
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

	Level 1		Level 2		Level 3		Total
December 31, 2017				(in thousands)
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 six months ended June 30, 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 gain (loss) on revaluation of financial instruments, net		3		—		3
Settlements		(70)		—		(70)
Balance at June 30, 2018	$	—	$	—	$	—

Total losses included in other income and (expenses) attributable to liabilities still held as of June 30, 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 gain (loss) on revaluation of financial instruments, net		(52)		(450)		(502)
Settlements		—		—		—
Balance at June 30, 2017	$	82	$	2,830	$	2,912

Total gains included in other income and (expenses) attributable to liabilities still held as of June 30, 2017	$	52	$	450	$	502

- 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

6 Months Ended

Jun. 30, 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:

	June 30, 2018
			Gross Unrecognized Gains		Gross Unrecognized Losses		Estimated Fair Value
	Amortized Cost								Carrying Value
	Amortized Cost								Carrying Value
	(in thousands)
Money market funds	$	13	$	—	$	—	$	13	$	13
Corporate bonds		—		—		—		—		—
Total	$	13	$	—	$	—	$	13	$	13
Reported as:
Cash equivalents	$	13	$	—	$	—	$	13	$	13
Short-term investments		—		—		—		—		—
Total	$	13	$	—	$	—	$	13	$	13

	December 31, 2017
			Gross Unrecognized Gains		Gross Unrecognized Losses		Estimated Fair Value
	Amortized Cost								Carrying Value
	Amortized Cost								Carrying 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, Net of Allowance

Accounts receivable, net of allowance, comprises the following:

	June 30, 2018		December 31, 2017
	(in thousands)
Royalties receivable	$	41	$	—
Government contract - billed		164		477
Government contract - unbilled		356		153
Accounts receivable, net of allowance	$	561	$	630

(c) Property and Equipment, Net

Property and equipment, net consists of the following:

	June 30, 2018		December 31, 2017
	(in thousands)
Laboratory equipment	$	1,832	$	1,565
Office and computer equipment		296		175
Leasehold improvements		361		226

Total property and equipment		2,489		1,966
Less: accumulated depreciation		(1,455)		(1,236)
Property and equipment, net	$	1,034	$	730

Depreciation expense was $121,000 and $105,000 for the three months ended June 30, 2018 and 2017, respectively, and $219,000 and $201,000 for the six months ended June 30, 2018 and 2017, respectively.

(d) Intangible Assets

Intangible assets consist of the following:

	June 30, 2018		February 13, 2018			December 31, 2017
			(in thousands)
Purchased technology	$	22,400	$	22,400	$	—
In-process research and development		—		1,600		—
Intellectual property		80		80		80
Total cost		22,480		24,080		80
Less accumulated amortization		1,258		40		40
Intangible assets, net	$	21,222	$	24,040	$	40

Intangible asset amortization expense was $805,000 and $1,000 for the three months ended June 30, 2018 and 2017, respectively, and $1,218,000 and $2,000 for the six months ended June 30, 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 June 30, 2018, the estimated future amortization expense by year is as follows (in thousands):

Year Ending December 31,
2018 (six months remaining)	$	1,623
2019		2,254
2020		1,757
2021		1,758
2022		1,757
Thereafter		12,073
Total	$	21,222

(e) Other Accrued Liabilities

Accrued liabilities consist of the following:

	June 30, 2018		December 31, 2017
	(in thousands)
Accrued compensation	$	1,375	$	1,320
Accrued clinical and manufacturing expenses		58		69
Accrued professional and consulting services		254		113
Reserve for return of royalties		327		—
Deferred rent		31		21
Convertible preferred stock warrant liability		—		67
Other		330		15

Total	$	2,375	$	1,605

Revenue

6 Months Ended

Jun. 30, 2018

Revenue from Contract with Customer [Abstract]

Revenue from Contract with Customer [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 $520,000 and $1,854,000 during the three months ended June 30, 2018 and 2017, respectively, and $1,130,000 and $4,164,000 during the six months ended June 30, 2018 and 2017, respectively. 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 June 30, 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. The post-Merger royalty revenue related to Relenza^®recognized in the three and six months ended June 30, 2018, was $70,000 and $411,000, respectively.

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 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 post-Merger royalty revenue related to Inavir^®recognized in the six months ended June 30, 2018, was $552,000. No such revenue was recognized in the three months ended June 30, 2018, since the $18,000 receivable is payable to HealthCare Royalty Partners III, L.P. (“HCRP”) (See Note 7). Such royalty revenue is subject to a 5% withholding tax in Japan, for which $1,000 and $29,000 was included in income tax expense in the three and six months ended June 30, 2018, respectively.

Under the Inavir^® collaboration and license agreement, the Company and Daiichi Sankyo have cross-licensed the world-wide rights to develop and commercialize the related intellectual property, and have agreed to share equally in any royalties, license fees, or milestone or other payments received from any third-party licenses outside of Japan. Patents on the composition of matter for LANI in Japan generally expire in 2024.

Liabilities Related to Sale of Future Royalties

6 Months Ended

Jun. 30, 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 Company, Limited. 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	$	16,300
Non-cash interest expense recognized		766
Total Liability related to sale of future royalties, June 30, 2018	$	17,066

In June 2018, the Company paid a royalty of $275,000 to HCRP, which had been recorded as an accrued liability as of March 31, 2018.

Convertible Promissory Notes, Related Parties

6 Months Ended

Jun. 30, 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.

The Company’s accrued interest associated with the convertible promissory notes amounted to $6.3 million and the unamortized debt discount to $0.4 million as of December 31, 2017.

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

6 Months Ended

Jun. 30, 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 $122,000 and $129,000 during the three months ended June 30, 2018 and 2017, respectively, of which $94,000 and $91,000 was paid, respectively, and recorded interest expense of $252,000 and $255,000 during the six months ended June 30, 2018 and 2017, respectively, of which $189,000 and $148,000 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 the gain (loss) on revaluation of financial instruments line 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 transferred to equity.

Commitments and Contingencies

6 Months Ended

Jun. 30, 2018

Commitments and Contingencies Disclosure [Abstract]

Commitments and Contingencies Disclosure [Text Block]

NOTE 10. Commitments and Contingencies

(a) Leases

The Company has five 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 four leases all expire between December 31, 2018 and 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. 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 $368,000 and $323,000 for the six months ended June 30, 2018 and 2017, respectively. Under the terms of the lease agreements, the Company is also responsible for certain insurance, property tax and maintenance expenses. Future minimum payments under the facility leases as of June 30, 2018, are as follows (in thousands):

Year ending December 31,
2018 (six months remaining)	$	506
2019		774
2020		411
2021		56
Thereafter		—
Total	$	1,747

(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

6 Months Ended

Jun. 30, 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 we have 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 condensed 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 June 30, 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:

	June 30, 2018	December 31, 2017

Convertible preferred stock outstanding	—	1,221,064
Options issued and outstanding	997,223	304,850
Available for future grants of equity awards	93,278	—
Cumulative convertible preferred stock dividends	—	441,096
Common stock warrants	10,914	10,914
Total	1,101,415	1,977,924

Equity Incentive Plans

6 Months Ended

Jun. 30, 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. As of June 30, 2018, the Company had no shares of common stock available for issuance under the 2007 Plan. Equity awards under the 2007 Plan do not become available for future issuance if such awards are forfeited or otherwise terminate. Each stock option to acquire shares of Private Vaxart stock, whether vested or unvested, that had not previously been exercised was assumed in the Merger.

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. The number of shares of the Company’s common stock available under the 2016 Equity Plan will be 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 the six months ended June 30, 2018, is as follows:

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



Balance at January 1, 2018	—	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	—	(18,403)	$	8.72
Canceled	210,549	(345,417)	$	35.82
			$
Balance at June 30, 2018	70,551	997,223	$	9.11

In addition, the 2016 Equity Plan has a reserve of 22,727 shares available for future issuance as RSAs and RSUs. As of June 30, 2018, no such awards have been granted under the 2016 Equity Plan.

The weighted average grant date fair value of options awarded in the six months ended June 30, 2018 and 2017, was $3.59 and $2.99, respectively. Fair values were estimated using the following assumptions:

	Six Months Ended June 30,
	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:

	Three Months Ended June 30,				Six Months Ended June 30,
	2018		2017		2018		2017
	(in thousands)				(in thousands)
Research and development	$	59	$	69	$	103	$	138
General and administrative		59		60		101		115
Total stock-based compensation	$	118	$	129	$	204	$	253

As of June 30, 2018, the unrecognized stock‑based compensation cost related to outstanding stock options that are expected to vest was 1.5 million, which the Company expects to recognize over an estimated weighted average period of 3.16 years.

Net Income (Loss) Per Share Attributable to Common Stockholders

6 Months Ended

Jun. 30, 2018

Earnings Per Share [Abstract]

Earnings Per Share [Text Block]

NOTE 13. 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):

	Three Months Ended June 30,				Six Months Ended June 30,
	2018		2017		2018		2017

Net loss	$	(8,871)	$	(3,538)	$	(6,557)	$	(6,334)

Series B and C preferred dividend		—		(718)		(339)		(1,428)

Net loss attributable to common stockholders	$	(8,871)	$	(4,256)	$	(6,896)	$	(7,762)

Shares used to compute net loss per share, basic and diluted		7,141,189		135,658		5,477,265		135,658

Net loss per share attributable to common stockholders, basic and diluted	$	(1.24)	$	(31.37)	$	(1.26)	$	(57.22)

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:

	Three Months Ended June 30,		Six Months Ended June 30,
	2018	2017	2018	2017

Options to purchase common stock	878,555	271,955	765,702	272,120

Warrant to purchase common stock	10,794	—	8,230	—

Warrant to purchase convertible preferred stock	—	7,563	1,797	7,563

Series B and C convertible preferred stock outstanding, including cumulative dividends	—	1,523,276	431,064	1,523,276

Series A convertible preferred stock outstanding	—	94,988	24,723	94,988

Convertible promissory notes, related party (as converted)	—	709,509	373,388	709,509

Total potentially dilutive securities excluded from denominator of the diluted earnings per share computation	889,349	2,607,291	1,604,904	2,607,456

Accounting Policies, by Policy (Policies)

6 Months Ended

Jun. 30, 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)

6 Months Ended

Jun. 30, 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)

6 Months Ended

Jun. 30, 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 March 31, 2018		Adjustments		As of June 30, 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		—		22,400
In-process research and development ⁽²⁾		1,600		—		1,600
Total assets		64,807		(10)		64,797

Accounts payable		(3,379)		75		(3,304)
Other current liabilities		(6,351)		(393)		(6,744)
Liability related to sale of future royalties		(16,300)		—		(16,300)
Net assets acquired		38,777		(328)		38,449

Purchase price		(31,789)		—		(31,789)

Bargain purchase gain ⁽³⁾	$	6,988	$	(328)	$	6,660

Business Combination, Separately Recognized Transactions [Table Text Block]

	Period Ended June 30, 2018
	Three Months		Six Months
	(in thousands)
Revenue	$	88	$	981

Net loss	$	(2,280)	$	(2,642)

Business Acquisition, Pro Forma Information [Table Text Block]

	Three Months Ended June 30,				Six Months Ended June 30,
	2018		2017		2018		2017
	(in thousands)				(in thousands)
Total revenue	$	608	$	1,878	$	13,647	$	9,054

Net income (loss)	$	(8,151)	$	(9,571)	$	(2,252)	$	(17,486)

Fair Value of Financial Instruments (Tables)

6 Months Ended

Jun. 30, 2018

Fair Value Disclosures [Abstract]

Fair Value, Assets Measured on Recurring Basis [Table Text Block]

	Level 1		Level 2		Level 3		Total
June 30, 2018	(in thousands)
Recurring Financial Assets:
Money Market Funds	$	13	$	—	$	—	$	13
Corporate Bonds		—		—		—		—

Total assets	$	13	$	—	$	—	$	13

	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

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

	Level 1		Level 2		Level 3		Total
June 30, 2018	(in thousands)
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 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 gain (loss) on revaluation of financial instruments, net		3		—		3
Settlements		(70)		—		(70)
Balance at June 30, 2018	$	—	$	—	$	—

Total losses included in other income and (expenses) attributable to liabilities still held as of June 30, 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 gain (loss) on revaluation of financial instruments, net		(52)		(450)		(502)
Settlements		—		—		—
Balance at June 30, 2017	$	82	$	2,830	$	2,912

Total gains included in other income and (expenses) attributable to liabilities still held as of June 30, 2017	$	52	$	450	$	502

Balance Sheet Components (Tables)

6 Months Ended

Jun. 30, 2018

Disclosure Text Block Supplement [Abstract]

Cash, Cash Equivalents and Investments [Table Text Block]

	June 30, 2018
			Gross Unrecognized Gains		Gross Unrecognized Losses		Estimated Fair Value
	Amortized Cost								Carrying Value
	Amortized Cost								Carrying Value
	(in thousands)
Money market funds	$	13	$	—	$	—	$	13	$	13
Corporate bonds		—		—		—		—		—
Total	$	13	$	—	$	—	$	13	$	13
Reported as:
Cash equivalents	$	13	$	—	$	—	$	13	$	13
Short-term investments		—		—		—		—		—
Total	$	13	$	—	$	—	$	13	$	13

	December 31, 2017
			Gross Unrecognized Gains		Gross Unrecognized Losses		Estimated Fair Value
	Amortized Cost								Carrying Value
	Amortized Cost								Carrying 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]

	June 30, 2018		December 31, 2017
	(in thousands)
Royalties receivable	$	41	$	—
Government contract - billed		164		477
Government contract - unbilled		356		153
Accounts receivable, net of allowance	$	561	$	630

Property, Plant and Equipment [Table Text Block]

	June 30, 2018		December 31, 2017
	(in thousands)
Laboratory equipment	$	1,832	$	1,565
Office and computer equipment		296		175
Leasehold improvements		361		226

Total property and equipment		2,489		1,966
Less: accumulated depreciation		(1,455)		(1,236)
Property and equipment, net	$	1,034	$	730

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

	June 30, 2018		February 13, 2018			December 31, 2017
			(in thousands)
Purchased technology	$	22,400	$	22,400	$	—
In-process research and development		—		1,600		—
Intellectual property		80		80		80
Total cost		22,480		24,080		80
Less accumulated amortization		1,258		40		40
Intangible assets, net	$	21,222	$	24,040	$	40

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

Year Ending December 31,
2018 (six months remaining)	$	1,623
2019		2,254
2020		1,757
2021		1,758
2022		1,757
Thereafter		12,073
Total	$	21,222

Schedule of Accrued Liabilities [Table Text Block]

	June 30, 2018		December 31, 2017
	(in thousands)
Accrued compensation	$	1,375	$	1,320
Accrued clinical and manufacturing expenses		58		69
Accrued professional and consulting services		254		113
Reserve for return of royalties		327		—
Deferred rent		31		21
Convertible preferred stock warrant liability		—		67
Other		330		15

Total	$	2,375	$	1,605

Liabilities Related to Sale of Future Royalties (Tables)

6 Months Ended

Jun. 30, 2018

Disclosure Text Block [Abstract]

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

Total Liability related to sale of future royalties, February 13, 2018	$	16,300
Non-cash interest expense recognized		766
Total Liability related to sale of future royalties, June 30, 2018	$	17,066

Commitments and Contingencies (Tables)

6 Months Ended

Jun. 30, 2018

Commitments and Contingencies Disclosure [Abstract]

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

Year ending December 31,
2018 (six months remaining)	$	506
2019		774
2020		411
2021		56
Thereafter		—
Total	$	1,747

Stockholders' Equity (Tables)

6 Months Ended

Jun. 30, 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]

	June 30, 2018	December 31, 2017

Convertible preferred stock outstanding	—	1,221,064
Options issued and outstanding	997,223	304,850
Available for future grants of equity awards	93,278	—
Cumulative convertible preferred stock dividends	—	441,096
Common stock warrants	10,914	10,914
Total	1,101,415	1,977,924

Equity Incentive Plans (Tables)

6 Months Ended

Jun. 30, 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, 2018	—	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	—	(18,403)	$	8.72
Canceled	210,549	(345,417)	$	35.82
			$
Balance at June 30, 2018	70,551	997,223	$	9.11

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

	Six Months Ended June 30,
	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]

	Three Months Ended June 30,				Six Months Ended June 30,
	2018		2017		2018		2017
	(in thousands)				(in thousands)
Research and development	$	59	$	69	$	103	$	138
General and administrative		59		60		101		115
Total stock-based compensation	$	118	$	129	$	204	$	253

Net Income (Loss) Per Share Attributable to Common Stockholders (Tables)

6 Months Ended

Jun. 30, 2018

Earnings Per Share [Abstract]

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

	Three Months Ended June 30,				Six Months Ended June 30,
	2018		2017		2018		2017

Net loss	$	(8,871)	$	(3,538)	$	(6,557)	$	(6,334)

Series B and C preferred dividend		—		(718)		(339)		(1,428)

Net loss attributable to common stockholders	$	(8,871)	$	(4,256)	$	(6,896)	$	(7,762)

Shares used to compute net loss per share, basic and diluted		7,141,189		135,658		5,477,265		135,658

Net loss per share attributable to common stockholders, basic and diluted	$	(1.24)	$	(31.37)	$	(1.26)	$	(57.22)

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

	Three Months Ended June 30,		Six Months Ended June 30,
	2018	2017	2018	2017

Options to purchase common stock	878,555	271,955	765,702	272,120

Warrant to purchase common stock	10,794	—	8,230	—

Warrant to purchase convertible preferred stock	—	7,563	1,797	7,563

Series B and C convertible preferred stock outstanding, including cumulative dividends	—	1,523,276	431,064	1,523,276

Series A convertible preferred stock outstanding	—	94,988	24,723	94,988

Convertible promissory notes, related party (as converted)	—	709,509	373,388	709,509

Total potentially dilutive securities excluded from denominator of the diluted earnings per share computation	889,349	2,607,291	1,604,904	2,607,456

Organization and Basis of Presentation (Details) $ in Thousands		6 Months Ended
	Feb. 13, 2018 shares	Jun. 30, 2018 USD ($) shares	Dec. 31, 2017 USD ($)	Jun. 30, 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) \| $		$ (86,539)	$ (79,982)
Cash and Cash Equivalents, at Carrying Value \| $		$ 23,921	$ 1,571	$ 2,585	$ 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 \| $		$ 4,400
Common Stock [Member]
Organization and Basis of Presentation (Details) [Line Items]
Convertible Preferred Stock, Shares Issued upon Conversion \| shares	0.22148

Summary of Significant Accounting Policies (Details) - USD ($)	3 Months Ended	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2018	Dec. 31, 2017
Summary of Significant Accounting Policies (Details) [Line Items]
Restricted Cash (in Dollars)	$ 50,000	$ 50,000	$ 50,000
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
Developed Technology Rights [Member] \| Minimum [Member]
Summary of Significant Accounting Policies (Details) [Line Items]
Finite-Lived Intangible Asset, Useful Life	1 year 109 days
Developed Technology Rights [Member] \| Maximum [Member]
Summary of Significant Accounting Policies (Details) [Line Items]
Finite-Lived Intangible Asset, Useful Life	11 years 9 months
Intellectual Property [Member]
Summary of Significant Accounting Policies (Details) [Line Items]
Finite-Lived Intangible Asset, Useful Life	20 years

Summary of Significant Accounting Policies (Details) - Estimated Useful Lives	6 Months Ended
	Jun. 30, 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		6 Months Ended
Business Combination (Details) - USD ($) $ in Millions	Feb. 13, 2018	Jun. 30, 2018
Business Combination (Details) [Line Items]
Business Combination, Acquisition Related Costs	$ 1.4	$ 0.5
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	6 Months Ended
	Jun. 30, 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	3 Months Ended			6 Months Ended
	Jun. 30, 2018	Mar. 31, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 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
Developed technology (1)	22,400			22,400
In-process research and development (2)	1,600			1,600
Total assets	64,797			64,797
Accounts payable	(3,304)			(3,304)
Other current liabilities	(6,744)			(6,744)
Liability related to sale of future royalties	(16,300)			(16,300)
Net assets acquired	38,449			38,449
Purchase price				(31,789)
Bargain purchase gain (3)	(328)			6,660
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
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
Scenario, Adjustment [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
Accounts receivable
Prepaid expenses	(10)			(10)
Property and equipment
Developed technology (1)
In-process research and development (2)
Total assets	(10)			(10)
Accounts payable	75			75
Other current liabilities	(393)			(393)
Liability related to sale of future royalties
Net assets acquired	(328)			$ (328)
Purchase price
Bargain purchase gain (3)	$ (328)

Business Combination (Details) - Selected amounts related to Aviragen`s business included in the Company`s condensed consolidated sta - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2018
Selected amounts related to Aviragen`s business included in the Company`s condensed consolidated sta [Abstract]
Revenue	$ 88	$ 981
Net loss	$ (2,280)	$ (2,642)

Business Combination (Details) - Unaudited pro forma information is summarized - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Unaudited pro forma information is summarized [Abstract]
Total revenue	$ 608	$ 1,878	$ 13,647	$ 9,054
Net income (loss)	$ (8,151)	$ (9,571)	$ (2,252)	$ (17,486)

Fair Value of Financial Instruments (Details) - Company's financial assets measured at fair value - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Recurring Financial Assets:
Financial Assets	$ 13	$ 2,607
Fair Value, Inputs, Level 1 [Member]
Recurring Financial Assets:
Financial Assets	13	1,192
Fair Value, Inputs, Level 2 [Member]
Recurring Financial Assets:
Financial Assets		1,415
Fair Value, Inputs, Level 3 [Member]
Recurring Financial Assets:
Financial Assets
Money Market Funds [Member]
Recurring Financial Assets:
Financial Assets	13	1,192
Money Market Funds [Member] \| Fair Value, Inputs, Level 1 [Member]
Recurring Financial Assets:
Financial Assets	13	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) - Company's financial liabilities measured at fair value - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Recurring Financial Liabilities:
Financial Liability		$ 67
Fair Value, Inputs, Level 1 [Member]
Recurring Financial Liabilities:
Financial Liability
Fair Value, Inputs, Level 2 [Member]
Recurring Financial Liabilities:
Financial Liability
Fair Value, Inputs, Level 3 [Member]
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

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	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Balance	$ 67	$ 3,414
Issuances
Revaluation (gains) loss included in (loss) gain on revaluation of financial instruments, net	3	(502)
Settlements	(70)
Balance		2,912
Total gains or loss included in other income and (expenses) attributable to liabilities still held		502
Convertible Preferred Stock Warrant Liability [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Balance	67	134
Issuances
Revaluation (gains) loss included in (loss) gain on revaluation of financial instruments, net	3	(52)
Settlements	(70)
Balance		82
Total gains or loss included in other income and (expenses) attributable to liabilities still held		52
Convertible Promissory Notes Embedded Derivative Liability [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Balance		3,280
Issuances
Revaluation (gains) loss included in (loss) gain on revaluation of financial instruments, net		(450)
Settlements
Balance		2,830
Total gains or loss included in other income and (expenses) attributable to liabilities still held		$ 450

Balance Sheet Components (Details) - USD ($)	3 Months Ended		6 Months Ended
Balance Sheet Components (Details) - USD ($)	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Disclosure Text Block Supplement [Abstract]
Depreciation	$ 121,000	$ 105,000	$ 219,000	$ 201,000
Amortization of Intangible Assets	805,000	$ 1,000	$ 1,218,000	$ 2,000
Research and Development in Process	$ 1,600,000

Balance Sheet Components (Details) - Cash equivalents and short‑term investments - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Balance Sheet Components (Details) - Cash equivalents and short‑term investments [Line Items]
Amortized Cost	$ 13	$ 2,607
Gross Unrecognized Gains
Gross Unrecognized Losses
Estimated Fair Value	13	2,607
Carrying Value	13	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	13	1,192
Gross Unrecognized Gains
Gross Unrecognized Losses
Estimated Fair Value	13	1,192
Carrying Value	13	1,192
Cash Equivalents [Member]
Balance Sheet Components (Details) - Cash equivalents and short‑term investments [Line Items]
Amortized Cost	13	1,192
Gross Unrecognized Gains
Gross Unrecognized Losses
Estimated Fair Value	13	1,192
Carrying Value	$ 13	$ 1,192

Balance Sheet Components (Details) - Accounts receivable net of allowance - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Accounts receivable net of allowance [Abstract]
Royalties receivable	$ 41
Government contract - billed	164	477
Government contract - unbilled	356	153
Accounts receivable, net of allowance	$ 561	$ 630

Balance Sheet Components (Details) - Property and equipment, net - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Property and equipment, net [Abstract]
Laboratory equipment	$ 1,832	$ 1,565
Office and computer equipment	296	175
Leasehold improvements	361	226
Total property and equipment	2,489	1,966
Less: accumulated depreciation	(1,455)	(1,236)
Property and equipment, net	$ 1,034	$ 730

Balance Sheet Components (Details) - Intangible assets - USD ($) $ in Thousands	Jun. 30, 2018	Feb. 13, 2018	Dec. 31, 2017
Finite-Lived Intangible Assets [Line Items]
Intangible assets, gross	$ 22,480	$ 24,080	$ 80
Less accumulated amortization	1,258	40	40
Intangible assets, net	21,222	24,040	40
Purchased Technology [Member]
Finite-Lived Intangible Assets [Line Items]
Intangible assets, gross	22,400	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	Jun. 30, 2018 USD ($)
The estimated future amortization expense by year [Abstract]
2018 (six months remaining)	$ 1,623
2019	2,254
2020	1,757
2021	1,758
2022	1,757
Thereafter	12,073
Total	$ 21,222

Balance Sheet Components (Details) - Accrued liabilities - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Accrued liabilities [Abstract]
Accrued compensation	$ 1,375	$ 1,320
Accrued clinical and manufacturing expenses	58	69
Accrued professional and consulting services	254	113
Reserve for return of royalties	327
Deferred rent	31	21
Convertible preferred stock warrant liability		67
Other	330	15
Total	$ 2,375	$ 1,605

Revenue (Details) ¥ in Billions		3 Months Ended			6 Months Ended
Revenue (Details) ¥ in Billions	May 25, 2017 USD ($)	Jun. 30, 2018 USD ($)	Mar. 31, 2018 USD ($)	Jun. 30, 2017 USD ($)	Jun. 30, 2018 USD ($)	Jun. 30, 2018 JPY (¥)	Jun. 30, 2017 USD ($)
Revenue (Details) [Line Items]
Revenues		$ 608,000		$ 1,854,000	$ 2,111,000		$ 4,164,000
Entity Loan Modification Program [Member] \| HHS BARDA [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		520,000		1,854,000	1,130,000		4,164,000
Royalty [Member]
Revenue (Details) [Line Items]
Revenues		70,000			963,000
Royalty [Member] \| Relenza Recognized [Member]
Revenue (Details) [Line Items]
Revenues		70,000			411,000
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
Royalty [Member] \| HCRP [Member]
Revenue (Details) [Line Items]
Accrued Royalties		18,000			18,000
Royalty [Member] \| JAPAN
Revenue (Details) [Line Items]
Revenues		$ 1,000			$ 29,000
Royalty Percentage					5.00%	5.00%

Liabilities Related to Sale of Future Royalties (Details) - USD ($)	1 Months Ended		3 Months Ended		6 Months Ended
	Jun. 30, 2018	Apr. 30, 2016	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Liabilities Related to Sale of Future Royalties (Details) [Line Items]
Revenues			$ 608,000	$ 1,854,000	$ 2,111,000	$ 4,164,000
HCRP [Member] \| Royalty Arrangement [Member]
Liabilities Related to Sale of Future Royalties (Details) [Line Items]
Debt, Additions		$ 20,000,000
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		$ 3,000,000
Royalty Percentage		15.00%
Royalty Income, Nonoperating		$ 1,000,000
Royalty Expense	$ 275,000

Liabilities Related to Sale of Future Royalties (Details) - Liability related to sale of future Royalties $ in Thousands	6 Months Ended
	Jun. 30, 2018 USD ($)
Liability related to sale of future Royalties [Abstract]
Total Liability related to sale of future royalties, February 13, 2018	$ 16,300
Non-cash interest expense recognized	766
Total Liability related to sale of future royalties, June 30, 2018	$ 17,066

Convertible Promissory Notes, Related Parties (Details) - USD ($)				6 Months Ended	12 Months Ended
	Feb. 13, 2018	Nov. 20, 2015	Dec. 10, 2014	Jun. 30, 2018	Dec. 31, 2017
Convertible Promissory Notes, Related Parties (Details) [Line Items]
Proceeds from Convertible Debt				$ 25,000,000
Debt Instrument, Interest Rate, Stated Percentage				8.00%
Debt Instrument, Increase, Accrued Interest					$ 6,300,000
Debt Instrument, Unamortized Discount	$ 400,000				$ 400,000
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			$ 18,400,000
Second Note Purchase Agreement [Member]
Convertible Promissory Notes, Related Parties (Details) [Line Items]
Proceeds from Convertible Debt		$ 11,000,000
Convertible Promissory Notes [Member]
Convertible Promissory Notes, Related Parties (Details) [Line Items]
Debt Instrument, Face Amount	35,600,000
Debt Instrument, Periodic Payment, Interest	6,600,000
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				$ 1,900,000
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				1,300,000
Debt Issuance Costs, Net				$ 7,000

Secured Promissory Note Payable to Oxford Finance (Details) - USD ($)			3 Months Ended		6 Months Ended
	Feb. 13, 2018	Dec. 22, 2016	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Secured Promissory Note Payable to Oxford Finance (Details) [Line Items]
Debt Instrument, Interest Rate, Stated Percentage			8.00%		8.00%
Interest Paid, Including Capitalized Interest, Operating and Investing Activities					$ 189,000	$ 148,000
Debt Conversion, Converted Instrument, Amount	$ 14,200,000
Loan Agreement [Member] \| Oxford Finance [Member]
Secured Promissory Note Payable to Oxford Finance (Details) [Line Items]
Long-term Debt, Gross		$ 5,000,000
Debt Instrument, Payment Terms		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		325,000
Interest Expense, Debt			122,000	$ 129,000	252,000	255,000
Interest Paid, Including Capitalized Interest, Operating and Investing Activities			$ 94,000	$ 91,000	189,000	$ 148,000
Debt Conversion, Converted Instrument, Amount					$ 250,000
Convertible Preferred Stock [Member] \| Series C Preferred Stock [Member] \| Loan Agreement [Member] \| Oxford Finance [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		7,563
Class of Warrant or Right, Exercise Price of Warrants or Rights (in Dollars per share)			$ 33.11		$ 33.11
Warrants Not Settleable in Cash, Fair Value Disclosure			$ 134,000		$ 134,000
Debt Instrument, Interest Rate, Stated Percentage			10.50%		10.50%
London Interbank Offered Rate (LIBOR) [Member] \| Loan Agreement [Member] \| Oxford Finance [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] \| Loan Agreement [Member] \| Oxford Finance [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)			10,914		10,914
Class of Warrant or Right, Exercise Price of Warrants or Rights (in Dollars per share)			$ 22.99		$ 22.99
Warrants Not Settleable in Cash, Fair Value Disclosure			$ 70,000		$ 70,000
Debt Conversion, Converted Instrument, Issuance Date					Feb. 13, 2018

Commitments and Contingencies (Details) - USD ($)	6 Months Ended
Commitments and Contingencies (Details) - USD ($)	Jun. 30, 2018	Jun. 30, 2017
Commitments and Contingencies (Details) [Line Items]
Operating Leases, Rent Expense	$ 368,000	$ 323,000
Office Space In Alpharetta, Georgia [Member]
Commitments and Contingencies (Details) [Line Items]
Lease Expiration Date	Feb. 28, 2021
The First Lease [Member] \| Office Space In San Francisco California [Member]
Commitments and Contingencies (Details) [Line Items]
Lease Expiration Date	Apr. 30, 2020
Remaining Four Leases [Member] \| Minimum [Member] \| Office Space In San Francisco California [Member]
Commitments and Contingencies (Details) [Line Items]
Lease Expiration Date	Dec. 31, 2018
Remaining Four Leases [Member] \| Maximum [Member] \| Office Space In San Francisco California [Member]
Commitments and Contingencies (Details) [Line Items]
Lease Expiration Date	Aug. 31, 2019

Commitments and Contingencies (Details) - The future minimum lease payments $ in Thousands	Jun. 30, 2018 USD ($)
The future minimum lease payments [Abstract]
2018 (six months remaining)	$ 506
2019	774
2020	411
2021	56
Thereafter
Total	$ 1,747

Stockholders' Equity (Details) - USD ($) $ / shares in Units, $ in Millions			6 Months Ended
	Feb. 13, 2018	Dec. 31, 2017	Jun. 30, 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 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 - USD ($) $ in Thousands	Jun. 30, 2018	Feb. 13, 2018	Dec. 31, 2017
Stockholders' Equity (Details) - Convertible preferred stock [Line Items]
Preferred stock, shares authorized	5,000,000		5,000,000
Preferred stock, shares outstanding	0		1,221,064
Preferred stock, net carrying value			$ 1
Preferred stock, liquidation preference	$ 39,956		$ 39,956
Convertible Preferred Stock [Member]
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
Convertible Preferred Stock [Member] \| 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
Convertible Preferred Stock [Member] \| 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
Convertible Preferred Stock [Member] \| 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	Jun. 30, 2018	Dec. 31, 2017
Stockholders' Equity (Details) - Common stock reserved for issuance [Line Items]
Common stock reserved for issuance	1,101,415	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	997,223	304,850
Options Available For Future Grants [Member]
Stockholders' Equity (Details) - Common stock reserved for issuance [Line Items]
Common stock reserved for issuance	93,278
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) - 2016 Equity Plan [Member] - USD ($) $ / shares in Units, $ in Millions	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
Employee Stock Option [Member]
Equity Incentive Plans (Details) [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value	$ 3.59	$ 2.99
Employee Service Share-based Compensation, Nonvested Awards, Compensation Not yet Recognized, Stock Options	$ 1.5
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition	3 years 58 days
Restricted Stock [Member]
Equity Incentive Plans (Details) [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized	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	6 Months Ended
	Jun. 30, 2018 $ / shares shares
Summary of stock option [Abstract]
Balance at January 1, 2018
Balance at January 1, 2018	304,850
Balance at January 1, 2018 (in Dollars per share) \| $ / shares	$ 9.50
Assumed on consummation of Merger	291,102
Assumed on consummation of Merger	627,106
Assumed on consummation of Merger (in Dollars per share) \| $ / shares	$ 26.33
Granted	(431,100)
Granted	431,100
Granted (in Dollars per share) \| $ / shares	$ 5.17
Exercised	(2,013)
Exercised (in Dollars per share) \| $ / shares	$ 6.49
Forfeited	(18,403)
Forfeited (in Dollars per share) \| $ / shares	$ 8.72
Canceled	210,549
Canceled	(345,417)
Canceled (in Dollars per share) \| $ / shares	$ 35.82
Balance at June 30, 2018	70,551
Balance at June 30, 2018	997,223
Balance at June 30, 2018 (in Dollars per share) \| $ / shares	$ 9.11

Equity Incentive Plans (Details) - Fair values estimated assumptions	6 Months Ended
	Jun. 30, 2018	Jun. 30, 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	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation	$ 118	$ 129	$ 204	$ 253
Research and Development Expense [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation	59	69	103	138
General and Administrative Expense [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation	$ 59	$ 60	$ 101	$ 115

Net Income (Loss) Per Share Attributable to Common Stockholders (Details) - Calculation of basic and diluted net income (loss) per share - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Net Income (Loss) Per Share Attributable to Common Stockholders (Details) - Calculation of basic and diluted net income (loss) per share [Line Items]
Net loss	$ (8,871)	$ (3,538)	$ (6,557)	$ (6,334)
Net loss attributable to common stockholders	$ (8,871)	$ (4,256)	$ (6,896)	$ (7,762)
Shares used to compute net loss per share, basic and diluted (in Shares)	7,141,189	135,658	5,477,265	135,658
Net loss per share attributable to common stockholders, basic and diluted (in Dollars per share)	$ (1.24)	$ (31.37)	$ (1.26)	$ (57.22)
Series B And C Preferred Stock [Member]
Net Income (Loss) Per Share Attributable to Common Stockholders (Details) - Calculation of basic and diluted net income (loss) per share [Line Items]
Series B and C preferred dividend		$ (718)	$ (339)	$ (1,428)

- Definition

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

+ References + Details

Net Income (Loss) Per Share Attributable to Common Stockholders (Details) - Potentially dilutive securities excluded from the computation of diluted weighted average shares - shares	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 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	889,349	2,607,291	1,604,904	2,607,456
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	878,555	271,955	765,702	272,120
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	10,794		8,230
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		7,563	1,797	7,563
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		1,523,276	431,064	1,523,276
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		94,988	24,723	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		709,509	373,388	709,509