Note 4 - Net Income Per Share - Components of Common Shares Outstanding (Details) - shares |
3 Months Ended | 6 Months Ended | ||
|---|---|---|---|---|
Sep. 30, 2020 |
Sep. 30, 2019 |
Sep. 30, 2020 |
Sep. 30, 2019 |
|
| Basic (in shares) | 4,834,709 | 4,846,010 | 4,834,872 | 4,846,010 |
| Dilutive effect of stock options (in shares) | 100 | 1,871 | 114 | 3,347 |
| Shares used in computing net income per share – diluted (in shares) | 4,834,809 | 4,847,881 | 4,834,986 | 4,849,357 |