Note 5 - Gross Unrealized Losses and Fair Value of Investments (Details) - USD ($)	9 Months Ended	12 Months Ended
	Dec. 31, 2015	Mar. 31, 2015
Corporate Bond Securities [Member]
Fair market value, less than 12 months	$ 39,526,380	$ 3,015,900
Gross unrealized losses, less than 12 months	(132,870)	(163)
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	2,583,664	2,590,240
Gross unrealized losses, greater than 12 months	(20,941)	(16,208)
Total Fair Market Value	42,110,044	5,606,140
Total Gross Unrealized Losses	$ (153,811)	$ (16,371)
Municipal Bonds [Member]
Fair market value, less than 12 months
Gross unrealized losses, less than 12 months
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value
Gross unrealized losses, greater than 12 months
Total Fair Market Value
Total Gross Unrealized Losses
Fair market value, less than 12 months	$ 39,526,380	$ 3,015,900
Gross unrealized losses, less than 12 months	(132,870)	(163)
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	2,583,664	2,590,240
Gross unrealized losses, greater than 12 months	(20,941)	(16,208)
Total Fair Market Value	42,110,044	5,606,140
Total Gross Unrealized Losses	$ (153,811)	$ (16,371)