Note 5 - Reconciliation of Marketable Securities (Details) - USD ($) |
Jun. 30, 2015 |
Mar. 31, 2015 |
|---|---|---|
| Corporate Bond Securities [Member] | ||
| Adjusted Cost | $ 85,929,786 | $ 88,456,886 |
| Gross Unrealized Gains | 724,435 | 1,185,469 |
| Gross Unrealized Losses | (36,779) | (16,371) |
| Available-for-sale Securities | 86,617,442 | 89,625,984 |
| Municipal Bonds [Member] | ||
| Adjusted Cost | 1,373,962 | 1,383,839 |
| Gross Unrealized Gains | $ 185 | $ 3,272 |
| Gross Unrealized Losses | ||
| Available-for-sale Securities | $ 1,374,147 | $ 1,387,111 |
| Adjusted Cost | 87,303,748 | 89,840,725 |
| Gross Unrealized Gains | 724,620 | 1,188,741 |
| Gross Unrealized Losses | (36,779) | (16,371) |
| Available-for-sale Securities | $ 87,991,589 | $ 91,013,095 |