Note 6 - Stockholders' Equity - Share-based Compensation by Award (Details) - $ / shares				3 Months Ended		12 Months Ended
	Dec. 16, 2022	Dec. 17, 2021	May 14, 2021	Mar. 31, 2023	Mar. 31, 2022	Dec. 31, 2022
Options Outstanding (in shares)				101,500	85,000
Options Outstanding, Weighted Average Exercise Price (in dollars per share)				$ 2.97	$ 2.52
Granted (in shares)	16,500	15,000	70,000	0	0
Granted, weighted average exercise price (in dollars per share)				$ 0	$ 0
Exercised (in shares)				0	0	0
Exercised (in dollars per share)				$ 0	$ 0
Forfeited (in shares)				0	0
Forfeited (in dollars per share)				$ 0	$ 0
Options outstanding (in shares)				101,500	85,000
Options outstanding, weighted average exercise price (in dollars per share)				$ 2.97	$ 2.52
Options Exercisable (in shares)				76,500	32,500
Options Exercisable, Weighted Average Exercise Price (in dollars per share)				$ 3.15	$ 2.52