Note 14 - Subsequent Events (Details Textual) - USD ($) $ / shares in Units, $ in Millions		1 Months Ended		3 Months Ended
	Jul. 30, 2021	Apr. 30, 2021	Mar. 31, 2021	Mar. 31, 2021
Series C Convertible Preferred Stock [Member]
Temporary Equity, Stock Issued During Period, Shares, New Issues (in shares)		10,000		24,500
Temporary Equity, Issued Price Per Share (in dollars per share)			$ 1,000	$ 1,000
Temporary Equity, Stock Issued During Period, Value, New Issues		$ 10.0	$ 24.5
Temporary Equity, Stock Issued During Period, Shares Issued for Services (in shares)		200	490
Subsequent Event [Member] | Series C Warrants [Member]
Exercise of Warrants, Percent of Fully Diluted Common Stock Acquirable	0.071%
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share)	$ 0.01
Subsequent Event [Member] | Series C Convertible Preferred Stock [Member]
Temporary Equity, Stock Issued During Period, Shares, New Issues (in shares)	5,000
Temporary Equity, Issued Price Per Share (in dollars per share)	$ 1,000
Temporary Equity, Stock Issued During Period, Value, New Issues	$ 5.0
Temporary Equity, Stock Issued During Period, Shares Issued for Services (in shares)	100