Note 6 - Stockholders' Equity - Share-based Compensation by Award (Details)	9 Months Ended
	Sep. 30, 2025 $ / shares shares	Sep. 30, 2024 $ / shares shares
Options outstanding at beginning of period (in shares) | shares	115,750	119,750
Options outstanding at beginning of period (in dollars per share) | $ / shares	$ 3.27	$ 2.97
Granted (in shares) | shares	0	0
Granted, weighted average exercise price (in dollars per share) | $ / shares	$ 0	$ 0
Exercised (in shares) | shares	(2,000)	0
Exercised, weighted average exercise price (in dollars per share) | $ / shares	$ 3.93	$ 0
Expired (in shares) | shares	(4,000)	(20,000)
Expired, weighted average exercise price (in dollars per share) | $ / shares	$ 3.95	$ 2.42
Options outstanding (in shares) | shares	109,750	99,750
Options outstanding, weighted average exercise price (in dollars per share) | $ / shares	$ 3.24	$ 3.25
Options Exercisable at September 30: (in shares) | shares	109,750	99,750
Options Exercisable at September 30: (in dollars per share) | $ / shares	$ 3.24	$ 3.25