Note 5 - Investments in Securities (Details Textual) - USD ($)	1 Months Ended	12 Months Ended
	Jun. 30, 2018	Mar. 31, 2019	Mar. 31, 2018
Equity Securities, FV-NI, Unrealized Gain		$ 71,000
Equity Securities, FV-NI, Unrealized Loss		617,000
Debt Securities, Held-to-maturity, Total	$ 2,000,000
Debt Securities, Held-to-Maturity, Term	3 years
Other than Temporary Impairment Losses, Investments, Total		$ 2,000,000	$ 1,559,972