Note 9 - Common and Preferred Stock (Details Textual) - shares		6 Months Ended
	Mar. 05, 2020	Jun. 30, 2021	Dec. 31, 2020
Preferred Stock, Shares Issued, Total (in shares)		6,281	7,531
Preferred Stock, Shares Outstanding, Ending Balance (in shares)		6,281	7,531
Conversion of Series 1 Preferred Stock in to Common Stock [Member]
Conversion of Stock, Shares Converted (in shares)		3,719
Conversion of Stock, Shares Issued (in shares)		1,506,380
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