Note 6 - Stockholders' Equity (Details Textual) $ / shares in Units, $ in Thousands	Jun. 01, 2020 USD ($) $ / shares shares
Stock Issued During Period, Shares, New Issues (in shares) | shares	22,044
Shares Issued, Price Per Share (in dollars per share)	$ 4.50
Proceeds from Issuance or Sale of Equity, Total | $	$ 108,096
Warrants Issued in Public Offering [Member]
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares) | shares	3,511
Class of Warrant or Right, Warrants Issued, Price Per Warrant (in dollars per share)	$ 4.49
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share)	$ 0.01