Note 3 - Net Income Per Share Computations - Reconciliation of Net Common Share Computation (Details) - USD ($)	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Net income	$ 1,773,913	$ 551,493
Basic (in shares)	4,818,339	4,754,496
Plus dilutive effect of stock options (in shares)	45,907	8
Weighted average diluted shares (in shares)	4,864,247	4,754,504
Basic earnings per share (in dollars per share)	$ 0.37	$ 0.12
Diluted earnings per share (in dollars per share)	$ 0.36	$ 0.12