Note 11 - Stock Compensation Plans - Stock Option Activity (Details) - $ / shares	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2023
Options outstanding, beginning of year (in shares)	59,000
Options outstanding, end of year (in shares)	59,000
Options available for grant (in shares)	932,369	926,348
Options exercisable (in shares)	59,000	59,000
Outstanding, exercise price range (in dollars per share)	$ 17.35	$ 17.35
Exercisable, weighted average exercise price (in dollars per share)	17.35	17.35
Minimum [Member]
Exercised, exercise price range (in dollars per share)	1.52
Outstanding, exercise price range (in dollars per share)	3.5	3.5
Maximum [Member]
Exercised, exercise price range (in dollars per share)	1.72
Outstanding, exercise price range (in dollars per share)	$ 39.11	$ 39.11