Note 4 - Net Income Per Share - Components of Common Shares Outstanding (Details) - shares |
3 Months Ended | 6 Months Ended | ||
|---|---|---|---|---|
Sep. 30, 2017 |
Sep. 30, 2016 |
Sep. 30, 2017 |
Sep. 30, 2016 |
|
| Weighted average common shares outstanding – basic (in shares) | 4,841,010 | 4,835,564 | 4,841,010 | 4,835,289 |
| Dilutive effect of stock options (in shares) | 4,622 | 2,255 | 4,897 | 2,004 |
| Shares used in computing net income per share – diluted (in shares) | 4,845,632 | 4,837,819 | 4,845,907 | 4,837,293 |