Note 3 - Net Income Per Share Computations - Reconciliation of Net Common Share Computation (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Net income	$ 2,921,120	$ 2,757,398	$ 6,450,102	$ 5,177,975
Basic (in shares)	4,872,674	4,786,283	4,845,743	4,769,201
Plus dilutive effect of stock options (in shares)	28,515	0	34,060	2
Weighted average diluted shares (in shares)	4,901,189	4,786,283	4,879,803	4,769,203
Basic earnings per share (in dollars per share)	$ 0.60	$ 0.58	$ 1.33	$ 1.09
Diluted earnings per share (in dollars per share)	$ 0.60	$ 0.58	$ 1.32	$ 1.09