Note 8 - Common Stock and Preferred Stock (Details Textual) - shares		12 Months Ended
	Mar. 05, 2020	Dec. 31, 2020	Mar. 31, 2021
Preferred Stock, Shares Issued, Total (in shares)		7,531	7,531
Preferred Stock, Shares Outstanding, Ending Balance (in shares)		7,531	7,531
Conversion of Series 1 Preferred Stock in to Common Stock [Member]
Conversion of Stock, Shares Converted (in shares)		2,469
Conversion of Stock, Shares Issued (in shares)		1,000,068
Preferred Class A [Member]
Convertible Preferred Stock, Shares Issued upon Conversion (in shares)	405.05
Conversion of Convertible Senior Notes 2020 into Preferred Stock [Member]
Debt Conversion, Converted Instrument, Shares Issued (in shares)	10,000