| Description of Stock Plans - Intrinsic Value of Options Exercised and Fair Value of Options Vested (Detail) - USD ($) $ in Thousands | 12 Months Ended | ||
|---|---|---|---|
| Mar. 31, 2017 | Mar. 31, 2016 | Mar. 31, 2015 | |
| Disclosure of Compensation Related Costs, Share-based Payments [Abstract] | |||
| Total fair value of options vested | $ 3,519 | $ 5,288 | $ 3,155 | 
| Total intrinsic value of options exercised | $ 10 | $ 3 | $ 71 | 
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- References No definition available. 
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- Definition Amount of accumulated difference between fair value of underlying shares on dates of exercise and exercise price on options exercised (or share units converted) into shares. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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- Definition Fair value of options vested. Excludes equity instruments other than options, for example, but not limited to, share units, stock appreciation rights, restricted stock. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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