Organization and Basis of Presentation (Details) $ in Thousands		3 Months Ended
	Feb. 13, 2018 shares	Mar. 31, 2018 USD ($) shares	Dec. 31, 2017 USD ($)
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) | $		$ (77,668)	$ (79,982)
Private Vaxarts Stockholderrs 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]
Retained Earnings (Accumulated Deficit) | $		$ 77,700
Loan Agreement, Borrowed Amount | $		$ 4,700
Common Stock [Member]
Organization and Basis of Presentation (Details) [Line Items]
Convertible Preferred Stock, Shares Issued upon Conversion | shares	0.22148