Note 7 - Stock Options - Changes in Options (Details) - USD ($)	3 Months Ended	12 Months Ended
	Mar. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Options outstanding (in shares)	5,315,000	3,850,000
Options outstanding, weighted average exercise price (in dollars per share)	$ 0.49	$ 0.36
Options outstanding, aggregate intrinsic value	$ 745,000	$ 3,910,950	$ 3,363,000
Granted, options (in shares)	100,000	1,465,000
Granted, weighted average exercise price (in dollars per share)	$ 0.80	$ 0.86
Granted, aggregate intrinsic value (in dollars per share)	$ 0	$ 0
Options outstanding (in shares)	5,415,000	5,315,000
Options outstanding, weighted average exercise price (in dollars per share)	$ 0.50	$ 0.49