Note 5 - Unrealized Losses and Fair Value of Investments (Details) - USD ($)	3 Months Ended	12 Months Ended
	Jun. 30, 2015	Mar. 31, 2015
Corporate Bond Securities [Member]
Corporate bonds, fair market value less than 12 months	$ 12,352,085	$ 3,015,900
Corporate bonds, gross unrealized losses less than 12 months	(26,489)	(163)
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	2,595,544	2,590,240
Corporate bonds, gross unrealized losses greater than 12 months	(10,290)	(16,208)
Corporate bonds, total fair market value	14,947,629	5,606,140
Corporate bonds, total gross unrealized losses	(36,779)	(16,371)
Municipal bonds, gross unrealized losses less than 12 months	26,489	163
Municipal bonds, gross unrealized losses greater than 12 months	10,290	16,208
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Loss	$ 36,779	$ 16,371
Municipal Bonds [Member]
Corporate bonds, fair market value less than 12 months
Corporate bonds, gross unrealized losses less than 12 months
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value
Corporate bonds, gross unrealized losses greater than 12 months
Corporate bonds, total fair market value
Corporate bonds, total gross unrealized losses
Municipal bonds, gross unrealized losses less than 12 months
Municipal bonds, gross unrealized losses greater than 12 months
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Loss
Corporate bonds, fair market value less than 12 months	$ 12,352,085	$ 3,015,900
Corporate bonds, gross unrealized losses less than 12 months	(26,489)	(163)
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	2,595,544	2,590,240
Corporate bonds, gross unrealized losses greater than 12 months	(10,290)	(16,208)
Corporate bonds, total fair market value	14,947,629	5,606,140
Corporate bonds, total gross unrealized losses	(36,779)	(16,371)
Municipal bonds, gross unrealized losses less than 12 months	26,489	163
Municipal bonds, gross unrealized losses greater than 12 months	10,290	16,208
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Loss	$ 36,779	$ 16,371