Note 5 - Marketable Securities (Details Textual)	3 Months Ended	6 Months Ended	12 Months Ended
	Sep. 30, 2015 USD ($)	Sep. 30, 2015 USD ($)	Mar. 31, 2015 USD ($)
Corporate Bond Securities [Member]
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Loss	$ 17,615	$ 17,615	$ 16,371
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	$ 2,597,444	$ 2,597,444	2,590,240
Severity of Unrealized Loss, Percentage of Adjusted Cost	0.30%	0.30%
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Loss		$ 17,615	16,371
Number of Corporate Bonds Resulted in Loss	4	4
Number of Corporate Bonds	27	27
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	$ 2,595,544	$ 2,595,544	$ 2,590,240