Description of Stock Plans - Intrinsic Value of Options Exercised and Fair Value of Options Vested (Detail) - USD ($) $ in Thousands |
6 Months Ended | |
|---|---|---|
Sep. 30, 2016 |
Sep. 30, 2015 |
|
| Disclosure of Compensation Related Costs, Share-based Payments [Abstract] | ||
| Total fair value of options vested | $ 2,452 | $ 2,847 |
| Total intrinsic value of options exercised | $ 8 | $ 110 |