Note 3 - Net Income Per Share Computations - Reconciliation of Net Common Share Computation (Details) - USD ($)	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Net income	$ 2,770,508	$ 1,773,913
Basic (in shares)	4,893,324	4,818,339
Plus dilutive effect of stock options (in shares)	29,808	45,907
Weighted average diluted shares (in shares)	4,923,132	4,864,247
Basic earnings per share (in dollars per share)	$ 0.57	$ 0.37
Diluted earnings per share (in dollars per share)	$ 0.56	$ 0.36