Stock-Based Compensation - Summary of RSUs Granted under Award Plan (Parenthetical) (Detail) - RSUs/Restricted Stock [Member] |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2015 |
Dec. 31, 2014 |
Dec. 31, 2013 |
|
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||
| Restricted stock units vesting period, years | 3 years | 3 years | 3 years |
| RSUs to employees that cliff vest, date | Jan. 31, 2018 | Jan. 31, 2017 | Jan. 31, 2016 |
| RSUs to employees that cliff vest, percentage | 100.00% | 100.00% | 100.00% |