Note 11 - Information As to Employee Stock Purchase, Savings, and Similar Plans (Details Textual) - USD ($)	12 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Mar. 31, 2016
Defined Contribution Plan, Employer Matching Contribution, Percent of Employees' Gross Pay	100.00%
Defined Contribution Plan, Maximum Annual Contributions Per Employee, Percent	3.00%
Defined Benefit Plan, Plan Assets, Contributions by Employer	$ 100,904	$ 104,643	$ 94,831