Note 2 - Summary of Significant Accounting Policies - Weighted Average Number of Shares (Details) - shares	12 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Basic (in shares)	4,833,661	4,834,054
Dilutive effect of stock options (in shares)	1,978	408
Shares used in computing net income per share – diluted (in shares)	4,835,639	4,834,462