Note 4 - Marketable Securities (Details Textual)	12 Months Ended
	Mar. 31, 2016 USD ($)	Mar. 31, 2015 USD ($)
Corporate Bond Securities [Member] | Maximum [Member]
Severity of Unrealized Loss, Percentage of Adjusted Cost	0.20%
Corporate Bond Securities [Member]
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Loss	$ 10,824	$ 16,371
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	$ 2,599,870	2,590,240
Number of Corporate Bonds Resulted in Loss	2
Number of Corporate Bonds	25
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions, Greater than or Equal to One Year	1
Number of Other-than-temporarily Impaired Marketable Securities	0
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Loss	$ 10,824	16,371
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	$ 2,599,870	$ 2,590,240