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 |