Note 11 - Income Taxes (Details Textual) - USD ($)	3 Months Ended		6 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Income Tax Expense (Benefit), Total	$ 6,000	$ (1,000)	$ 6,000	$ (4,000)
Effective Income Tax Rate Reconciliation, Percent, Total	3.80%	0.20%	1.90%	3.80%
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent			21.00%
Unrecognized Tax Benefits, Ending Balance	$ 0	$ 0	$ 0	$ 0