Balance Sheets (Parentheticals) - USD ($) |
Mar. 31, 2018 |
Mar. 31, 2017 |
|---|---|---|
| Allowance for uncollectible accounts | $ 15,000 | $ 15,000 |
| Common stock, par value (in dollars per share) | $ 0.01 | $ 0.01 |
| Common stock, shares authorized (in shares) | 6,000,000 | 6,000,000 |
| Common stock, shares issued (in shares) | 4,842,010 | 4,841,010 |
| Common stock, shares outstanding (in shares) | 4,842,010 | 4,841,010 |