Note 11 - Information as to Employee Stock Purchase, Savings, and Similar Plans (Details Textual) - USD ($)	3 Months Ended		9 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2020	Dec. 31, 2019
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	$ 22,571	$ 22,456	$ 69,227	$ 68,512