Note 9 - Stockholders' Equity - Option Activity (Details)	3 Months Ended
	Mar. 31, 2022 $ / shares shares
Outstanding (in shares) | shares	45,468
Outstanding, weighted average exercise price (in dollars per share)	$ 14.28
Granted, weighted average exercise price (in dollars per share)	$ 0
Vested (in shares) | shares	0
Vested, weighted average exercise price (in dollars per share)	$ 0
Forfeited, canceled (in shares) | shares	(2,813)
Forfeited, canceled, weighted average exercise price (in dollars per share)	$ 67.00
Outstanding (in shares) | shares	42,655
Outstanding, weighted average exercise price (in dollars per share)	$ 10.81