Note 3 - Summary of Significant Accounting Policies - Computation of Basic Net Income Per Share (Details) - shares	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Weighted average common shares outstanding, basic (in shares)	976,330	1,028,863	975,761	1,028,863
Common shares upon exercise of options and warrants (in shares)	17,140	2,038	11,834	4,268
Weighted average common shares outstanding, diluted (in shares)	993,470	1,030,901	987,595	1,033,131