Note 6 - Income Taxes - Reconciliation of Income Tax Provisions (Details) - USD ($)	12 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Tax expense at U.S. Statutory rate	$ 3,674,961	$ 2,990,768
State income taxes, net of Federal benefit	136,144	88,909
Research and development credits	(42,688)	(86,223)
Foreign-derived intangible income deduction	(662,467)	(450,912)
Other	(113,638)	4,826
Income tax provision	$ 2,992,312	$ 2,547,368