Note 11 - Fair Value Accounting - Derivative Liabilities (Details) - USD ($)	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Change in fair value included in earnings	$ (667,000)	$ 1,172,000
Fair value at end of period	6,024,000
Fair Value, Inputs, Level 3 [Member]
Fair value at beginning of period	5,292,000	24,128,000
Change in fair value included in earnings	667,000	(1,172,000)
Fair value at end of period	6,024,000	22,850,000
Fair Value, Inputs, Level 3 [Member] | Series D Preferred Stock [Member]
Derivative liability from issuance of Preferred Series D	65,000	248,000
Decrease in derivative liability from conversions of Preferred Series D	$ 0	$ (354,000)