| Income Taxes - Schedule of Reconciliation of Beginning and Ending Amount of Unrecognized Tax Benefits (Detail) - USD ($) $ in Thousands | 12 Months Ended | ||
|---|---|---|---|
| Mar. 31, 2017 | Mar. 31, 2016 | Mar. 31, 2015 | |
| Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward] | |||
| Balance at April 1 | $ 783 | $ 905 | $ 61 | 
| Additions for tax position of prior years | 158 | 0 | 844 | 
| Reductions for tax positions of prior years | 0 | (122) | 0 | 
| Balance at March 31 | $ 941 | $ 783 | $ 905 | 
| X | ||||||||||
| 
- Definition A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period. No definition available. 
 | 
| X | ||||||||||
| 
- Definition Amount of unrecognized tax benefits. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
 | 
| X | ||||||||||
| 
- Definition Amount of decrease in unrecognized tax benefits resulting from tax positions taken in prior period tax returns. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
 | 
| X | ||||||||||
| 
- Definition Amount of increase in unrecognized tax benefits resulting from tax positions taken in prior period tax returns. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
 |