Note 9 - Warrants - Warrants Outstanding and Activity (Details)	3 Months Ended
	Mar. 31, 2023 $ / shares shares
Balance (in shares)	403,846
Issued (in shares)	0
Exercised (in shares)	0
Expired (in shares)	0
Balance (in shares)	403,846
Warrants [Member]
Exercise price (in dollars per share) | $ / shares	$ 52.40
Balance (in shares)	403,846
Issued (in shares)	0
Exercised (in shares)	0
Expired (in shares)	0
Balance (in shares)	403,846