Note 6 - Mezzanine Equity (Details Textual) - USD ($)			3 Months Ended		12 Months Ended
	Dec. 23, 2020	Nov. 12, 2020	Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2021
Conversion of Series D Preferred Stock into Common Stock [Member]
Conversion of Stock, Shares Converted (in shares)			0		646
Conversion of Stock, Shares Issued (in shares)					11,149,123
Dividends, Common Stock, Stock					$ 70,221
Bridge Note [Member]
Proceeds from Issuance of Debt		$ 2,200,000
Series D Preferred Stock [Member]
Preferred Stock, Dividend Rate, Percentage		4.00%
Preferred Stock, Convertible, Conversion Price (in dollars per share)		$ 0.0583
Stock Issued During Period, Shares, New Issues (in shares)	500	11,560
Proceeds from Issuance or Sale of Equity, Total	$ 500,000	$ 11,560,000
Shares Issued, Price Per Share (in dollars per share)		$ 1,000
Dividends, Preferred Stock, Stock			$ 253		999
Conversion of Stock, Shares Converted (in shares)			(0)
Conversion of Stock, Shares Issued (in shares)			253
Embedded Derivative, Fair Value of Embedded Derivative Liability			$ 26,011,000
Dividends, Preferred Stock, Total			1,531,000	$ 1,817,000
Preferred Stock, Value, Outstanding			10,478,000		8,759,000
Preferred Stock, Discount on Shares			$ 12,991,000		$ 14,458,000