Note 15 - Warrants - Outstanding Warrants (Details)	9 Months Ended
	Sep. 30, 2021 $ / shares shares
Warrants outstanding (in shares) | shares	371,340
Warrants outstanding, weighted average exercise price (in dollars per share) | $ / shares	$ 7.28
Warrants granted (in shares) | shares	3,022,340
Warrants granted, weighted average exercise price (in dollars per share) | $ / shares	$ 4.94
Warrants exercised (in shares) | shares	(92,883)
Warrants exercised, weighted average exercise price (in dollars per share) | $ / shares	$ 2.03
Warrants forfeited, canceled (in shares) | shares	(128,938)
Warrants forfeited, canceled, weighted average exercise price (in dollars per share) | $ / shares	$ 16.63
Warrants outstanding (in shares) | shares	3,171,859
Warrants outstanding, weighted average exercise price (in dollars per share) | $ / shares	$ 4.82