Note 13 - Profit Sharing and 401k Plan (Details Textual) - USD ($)	12 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2018
Profit Sharing Defined Contribution Plan [Member]
Defined Contribution Plan, Cost	$ 34,000	$ 9,100	$ 91,000
Defined Contribution 401K Plan [Member]
Defined Contribution Plan, Cost	$ 96,000	$ 116,000	$ 117,000
Defined Contribution Plan, Employer Matching Contribution, Percent of Employees' Gross Pay	2.00%