Note 3 - Shareholders' Equity - Summary of Stock Option Activity (Details) - $ / shares	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Balance, number of shares (in shares)	11,407,772	3,369,322
Balance, weighted average exercise price (in dollars per share)	$ 0.26	$ 0.41
Options granted, number of shares (in shares)	2,200,000	3,506,500
Options granted, weighted average exercise price (in dollars per share)	$ 0.24	$ 0.26
Options forfeited/expired, number of shares (in shares)	(41,250)	(108,542)
Options forfeited/expired, weighted average exercise price (in dollars per share)	$ 0.41	$ 0.3
Balance, number of shares (in shares)	13,566,522	6,767,280
Balance, weighted average exercise price (in dollars per share)	$ 0.25	$ 0.33
Exercisable, number of shares (in shares)	4,459,388	3,447,666
Exercisable, weighted average exercise price (in dollars per share)	$ 0.3	$ 0.34
Vested and expected to vest, number of shares (in shares)	11,519,254	5,862,975
Vested and expected to vest, weighted average exercise price (in dollars per share)	$ 0.26	$ 0.33