Note 6 - Warrants - Warrants Outstanding (Details)	6 Months Ended
	Jun. 30, 2025 USD ($) $ / shares shares		Jun. 30, 2024 $ / shares shares
Warrants outstanding, balance (in shares) | shares	31,615,616		51,590,300
Warrants outstanding, Granted (in shares) | shares			4,127,516
Warrants outstanding, Exercised (in shares) | shares			(967,748)
Warrants outstanding, Expired (in shares) | shares	(1,888,170)		(5,562,754)
Warrants outstanding, balance (in shares) | shares	29,727,446		49,187,314
Weighted average remaining life, balance (Year)	2 years
Balance, aggregate intrinsic value | $	$ 40,000	[1]
Weighted Average [Member]
Weighted average price, balance (in dollars per share) | $ / shares	$ 0.29		$ 0.27
Weighted average price, Granted (in dollars per share) | $ / shares			0.27
Weighted average price, Exercised (in dollars per share) | $ / shares			0.23
Weighted average price, Expired (in dollars per share) | $ / shares	0.21		0.21
Weighted average price, balance (in dollars per share) | $ / shares	$ 0.29		$ 0.27

[1] Aggregate intrinsic value based on closing common stock price of $0.21 at June 30, 2025.