Note 11 - Stockholders' Deficit - Stock Options Rollforward (Details) - $ / shares	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Nonvested shares (in shares)	899,672	439,194
Nonvested, Beginning balance, Weighted Average Grant-Date Fair Value (in dollars per share)	$ 8.71	$ 19.38
Granted, shares (in shares)	640,748	700,853
Granted, Weighted Average Grant-Date Fair Value (in dollars per share)	$ 7.90	$ 7.81	$ 12.08
Vested/Issued, shares (in shares)	(518,784)	(240,375)
Vested/Issued, Weighted Average Grant-Date Fair Value (in dollars per share)	$ 9.51	$ 25.57
Forfeited, shares (in shares)	(186,339)
ForfeitedForfeited, Weighted Average Grant-Date Fair Value (in dollars per share)	$ 7.96
Nonvested shares (in shares)	835,297	899,672	439,194
Nonvested, Beginning balance, Weighted Average Grant-Date Fair Value (in dollars per share)	$ 7.76	$ 8.71	$ 19.38