Note 7 - Warrants (Details Textual) $ / shares in Units, $ in Thousands		12 Months Ended
	Feb. 11, 2021 USD ($) $ / shares shares	Dec. 31, 2021 USD ($) $ / shares shares	Dec. 31, 2020 USD ($)
Class of Warrant or Right, Number of Warrants Issued (in shares)		2,850,000
Proceeds from Issuance of Private Placement | $		$ 25,812	$ 0
Payments of Stock Issuance Costs | $	$ 1,783	$ 1,783	$ (0)
Warrants and Rights Outstanding | $	$ 7,337
Measurement Input, Risk Free Interest Rate [Member]
Warrants and Rights Outstanding, Measurement Input	0.0059
Measurement Input, Price Volatility [Member]
Warrants and Rights Outstanding, Measurement Input	0.9466
Measurement Input, Expected Term [Member]
Warrants and Rights Outstanding, Measurement Input	5.5
Warrants Issued in Connection with Private Placement [Member]
Class of Warrant or Right, Number of Warrants Issued (in shares)	2,500,000
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares)	2,500,000
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share) | $ / shares	$ 5.10	$ 5.10
Warrants and Rights Outstanding, Term (Year)	5 years 6 months
The Placement Agent Warrants [Member]
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares)	350,000
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share) | $ / shares	$ 6.45	$ 6.45
Warrants and Rights Outstanding, Term (Year)	5 years 6 months
Private Placement [Member]
Stock Issued During Period, Shares, New Issues (in shares)	5,000,000
Shares Issued, Price Per Share (in dollars per share) | $ / shares	$ 5.1625
Proceeds from Issuance of Private Placement | $	$ 25,812
Payments of Stock Issuance Costs | $	$ 1,783
Private Placement [Member] | Warrants Issued in Connection with Private Placement [Member]
Class of Warrant or Right, Number of Warrants Issued (in shares)	2,500,000
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares)	2,500,000
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share) | $ / shares	$ 5.10