Note 4 - Marketable Securities (Details Textual)	12 Months Ended
	Mar. 31, 2017 USD ($)	Mar. 31, 2016 USD ($)
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Loss	$ 247,149	$ 10,824
Number of Corporate Bonds Resulted in Loss	9
Number of Corporate Bonds	23
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions	10
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions, Greater than or Equal to One Year	0
Number of Other-than-temporarily Impaired Marketable Securities	0