Note 3 - Net Income (Loss) Per Common Share - Basic and Diluted Income (Loss) Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2021	Sep. 30, 2020
Net income (loss)	$ 490	$ 11,266	$ (1,885)	$ (626)	$ (2,902)	$ (3,124)	$ 9,871	$ (6,652)
Preferred dividends, deemed dividends and accretion	(1,935)			(2,529)			(6,260)	(5,275)
Net income (loss)available to common shareholders	(1,445)			(3,155)			3,611	(11,927)
Preferred dividends, deemed dividends and accretion	0			0			0	0
Net income (loss) available to common shareholders after assumed conversions	$ (1,445)			$ (3,155)			$ 3,611	$ (11,927)
Denominator for basic income (loss) per share – weighted-average shares outstanding (in shares)	340,384,468			133,341,134			326,458,778	125,558,524
Options (in shares)	0			0			82,942,500	0
Warrants (in shares)	0			0			2,919,631	0
Convertible preferred stock (in shares)	0			0			0	0
Denominator for diluted income (loss) – adjusted weighted average shares and assumed conversions (in shares)	340,384,468			133,341,134			412,320,909	125,558,524
Basic income (loss) per share available to common shareholders (in dollars per share)	$ (0.00)			$ (0.02)			$ 0.01	$ (0.09)
Diluted income (loss) per share available to common shareholders (in dollars per share)	$ (0.00)			$ (0.02)			$ 0.01	$ (0.09)