Note 7 - Stock Options - Changes in Options (Details) - USD ($)	12 Months Ended
	Dec. 31, 2021	Mar. 31, 2023	Dec. 31, 2020
Options outstanding (in shares)	5,315,000
Options outstanding, weighted average exercise price (in dollars per share)	$ 0.49
Options outstanding, aggregate intrinsic value		$ 0	$ 0
Granted, options (in shares)	100,000
Granted, weighted average exercise price (in dollars per share)	$ 0.80
Granted, aggregate intrinsic value (in dollars per share)	$ 0