Note 8 - Shareholders' Equity - Stock Option Activity (Details) - $ / shares	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Options outstanding, options (in shares)	410,615	427,580
Options outstanding, weighted average exercise price (in dollars per share)	$ 3.5	$ 3.5
Granted to employees and directors, options (in shares)	46,400	19,600
Granted to employees and directors, weighted average exercise price (in dollars per share)	$ 4.23	$ 3.99
Exercised, options (in shares)	(140,916)	(21,665)
Exercised, weighted average exercise price (in dollars per share)	$ 3.29	$ 3.7
Canceled/expired/forfeited, options (in shares)	(23,333)	(14,900)
Canceled/expired/forfeited, weighted average exercise price (in dollars per share)	$ 3.53	$ 3.93
Options outstanding, options (in shares)	292,766	410,615
Options outstanding,, weighted average exercise price (in dollars per share)	$ 3.71	$ 3.5
Options exercisable, options (in shares)	236,565
Options exercisable, weighted average exercise price (in dollars per share)	$ 3.6