Note 14 - Income Taxes - Reconciliation of Provision for Taxes (Details) - USD ($)	12 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Tax at statutory federal income tax rate	$ 615,952	$ (573,507)
Tax-exempt income	(491,456)	(260,637)
State income taxes, net of federal impact	42,442	(90,427)
Valuation allowance on income tax benefits	5,790,102
Impact of the Tax Act	2,318,118
Nondeductible expenses and other	55,397	166,566
Other	(278,517)
Income tax expense (benefit)	$ 8,052,038	$ (758,005)