Note 5 - Income Taxes (Details Textual) - USD ($)	12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent	21.00%	31.50%
Income Tax Expense Reduction (Increase) Due to Blended Rate		$ 1,900,000
Income Tax Expense (Benefit), Continuing Operations, Adjustment of Deferred Tax (Asset) Liability		(430,000)
Effective Income Tax Rate Reconciliation, Tax Expense (Benefit), Share-based Payment Arrangement, Amount	$ (176,000)	(1,086,000)
Tax Adjustments, Settlements, and Unusual Provisions	8,000	$ (150,000)
Domestic Tax Authority [Member]
Operating Loss Carryforwards, Total	$ 0