Note 5 - Gross Unrealized Losses and Fair Value of Investments (Details) - USD ($)	3 Months Ended	12 Months Ended
	Jun. 30, 2016	Mar. 31, 2016
Corporate Bond Securities [Member]
Fair market value, less than 12 months		$ 3,003,606
Gross unrealized losses, less than 12 months		(6,703)
Fair market value, greater than 12 months		2,599,870
Gross unrealized losses, greater than 12 months		(4,121)
Total Fair Market Value		5,603,476
Total Gross Unrealized Losses		(10,824)
Municipal Bonds [Member]
Fair market value, less than 12 months
Gross unrealized losses, less than 12 months
Fair market value, greater than 12 months
Gross unrealized losses, greater than 12 months
Total Fair Market Value
Total Gross Unrealized Losses
Fair market value, less than 12 months		3,003,606
Gross unrealized losses, less than 12 months		(6,703)
Fair market value, greater than 12 months		2,599,870
Gross unrealized losses, greater than 12 months		(4,121)
Total Fair Market Value		5,603,476
Total Gross Unrealized Losses	$ 0	$ (10,824)