Note 7 - Stock Option Plans - Summary of Option Activity (Details) - Share-Based Payment Arrangement, Option [Member] - USD ($)	3 Months Ended	12 Months Ended
	Mar. 31, 2025	Dec. 31, 2024
Number of options granted (in shares)	0
Share-Based Payment Arrangement, Employee [Member]
Number of options (in shares)	2,951,989
Weighted average exercise price, outstanding (in dollars per share)	$ 2.29
Weighted average remaining contractual life, outstanding (Year)	4 years 3 months 14 days	4 years 6 months 14 days
Number of options granted (in shares)	0
Weighted average exercise price, granted (in dollars per share)	$ 0
Number of options exercised (in shares)	0
Weighted average exercise price, exercised (in dollars per share)	$ 0
Number of options forfeited and expired (in shares)	0
Weighted average exercise price, forfeited or expired (in dollars per share)	$ 0
Number of options (in shares)	2,951,989	2,951,989
Weighted average exercise price, outstanding (in dollars per share)	$ 2.33	$ 2.29
Number of options exercisable (in shares)	2,103,433
Weighted average exercise price, exercisable (in dollars per share)	$ 2.29
Weighted average remaining contractual life, exercisable (Year)	3 years 8 months 19 days
Number of options, exercised (in shares)	0
Number of options, forfeited or expired (in shares)	0
Share-Based Payment Arrangement, Nonemployee [Member]
Number of options (in shares)	99,996
Weighted average exercise price, outstanding (in dollars per share)	$ 1.74
Weighted average remaining contractual life, outstanding (Year)	2 years 5 months 26 days	2 years 1 month 13 days
Number of options granted (in shares)	16,666
Weighted average exercise price, granted (in dollars per share)	$ 0.94
Number of options exercised (in shares)	(0)
Weighted average exercise price, exercised (in dollars per share)
Number of options forfeited and expired (in shares)	8,333
Weighted average exercise price, forfeited or expired (in dollars per share)	$ 1.65
Number of options (in shares)	108,329	99,996
Weighted average exercise price, outstanding (in dollars per share)	$ 1.62	$ 1.74
Number of options exercisable (in shares)	83,326
Weighted average exercise price, exercisable (in dollars per share)	$ 1.83
Weighted average remaining contractual life, exercisable (Year)	1 year 10 months 13 days
Aggregate intrinsic value, outstanding	$ 4,750	$ 5,750
Weighted average remaining contractual life, granted (Year)	4 years 11 months 8 days
Number of options, exercised (in shares)	0
Number of options, forfeited or expired (in shares)	(8,333)
Aggregate intrinsic value, exercisable	$ 3,722