Note 8 - Stock-based Compensation - Stock Option Activity (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Outstanding at beginning of year, options (in shares)	270,500	384,500
Outstanding at beginning of year, option, weighted average exercise price (in dollars per share)	$ 3.09	$ 2.98
Granted, options (in shares)	0	0
Granted, option, weighted average exercise price (in dollars per share)	$ 0	$ 0
Exercised, options (in shares)	0	(44,000)
Exercised, option, weighted average exercise price (in dollars per share)	$ 0	$ 0.96
Expired or forfeited, options (in shares)	(94,500)	(70,000)
Expired or forfeited, option, weighted average exercise price (in dollars per share)	$ 5.22	$ 3.85
Outstanding at end of year, options (in shares)	176,000	270,500
Outstanding at end of year, option, weighted average exercise price (in dollars per share)	$ 1.94	$ 3.09
Exercisable, options (in shares)	176,000	270,500
Exercisable, option, weighted average exercise price (in dollars per share)	$ 1.94	$ 3.09
Weighted-Average Remaining Contractual Life (years) (Year)	1 year 2 months 4 days	1 year 6 months 21 days
Aggregate Intrinsic Value	$ 4	$ 4