Note 11 - Information As to Employee Stock Purchase, Savings, and Similar Plans (Details Textual) - USD ($)	3 Months Ended		9 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2019	Dec. 31, 2018
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	$ 22,456	$ 21,733	$ 68,512	$ 67,327