Note 9 - Warrants - Warrant Activity (Details) - Warrants Issued in Connection with the Merger [Member] - $ / shares	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Warrants exercisable, balance (in shares)	602,392	602,392
Warrants exercisable, weighted average exercise price (in dollars per share)	$ 24.00	$ 24.00
Warrants granted, shares (in shares)	0
Warrants, granted, weighted average exercise price (in dollars per share)	$ 0
Warrants exercised, shares (in shares)	0	0
Warrants, exercised, weighted average exercise price (in dollars per share)	$ 0	$ 0
Warrants exercisable, balance (in shares)	602,392	602,392
Warrants exercisable, weighted average exercise price ( (in dollars per share)	$ 24.00	$ 24.00