Note 6 - Income Taxes (Details Textual) - USD ($)		3 Months Ended		6 Months Ended
	Dec. 22, 2017	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Income Tax Expense (Benefit), Total		$ (393,000)	$ 281,000	$ (6,000)	$ 655,000
Effective Income Tax Rate Reconciliation, Percent, Total				(0.30%)	27.70%
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent	21.00%