Note 4 - Net Income Per Share - Components of Common Shares Outstanding (Details) - shares |
3 Months Ended | |
|---|---|---|
Jun. 30, 2020 |
Jun. 30, 2019 |
|
| Basic (in shares) | 4,835,038 | 4,846,010 |
| Dilutive effect of stock options (in shares) | 119 | 4,378 |
| Shares used in computing net income per share – diluted (in shares) | 4,835,157 | 4,850,388 |