Note 8 - Stock Warrants - Summary of Warrants (Details) - $ / shares	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Mar. 15, 2021
Number of shares (in shares)	1,402,417	1,429,900	534,067
Exercise price (in dollars per share)	$ 17
Remaining contractual life (Year)	2 years 11 months 4 days
Warrant One [Member]
Number of shares (in shares)	12,833
Exercise price (in dollars per share)	$ 75
Remaining contractual life (Year)	7 days
Warrant Two [Member]
Number of shares (in shares)	431,250
Exercise price (in dollars per share)	$ 10
Remaining contractual life (Year)	2 years 29 days
Warrant Three [Member]
Number of shares (in shares)	958,334
Exercise price (in dollars per share)	$ 20
Remaining contractual life (Year)	3 years 4 months 6 days