Balance Sheets (Current Period Unaudited) (Parentheticals) - USD ($) |
Dec. 31, 2018 |
Mar. 31, 2018 |
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|---|---|---|---|---|---|
| Allowance for uncollectible accounts | $ 15,000 | $ 15,000 | [1] | ||
| 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) | 4,846,010 | 4,842,010 | |||
| Common stock, shares outstanding (in shares) | 4,846,010 | 4,842,010 | |||
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