Note 4 - Net Income Per Share - Components of Common Shares Outstanding (Details) - shares |
3 Months Ended | 9 Months Ended | ||
|---|---|---|---|---|
Dec. 31, 2018 |
Dec. 31, 2017 |
Dec. 31, 2018 |
Dec. 31, 2017 |
|
| Weighted average common shares outstanding – basic (in shares) | 4,845,010 | 4,841,369 | 4,843,355 | 4,841,130 |
| Dilutive effect of stock options (in shares) | 5,497 | 5,921 | 6,765 | 4,906 |
| Shares used in computing net income per share – diluted (in shares) | 4,850,507 | 4,847,290 | 4,850,120 | 4,846,036 |