Income Taxes - Schedule of Reconciliation of Unrecognized Tax Benefits (Detail) - USD ($) $ in Thousands |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2016 |
Dec. 31, 2015 |
Dec. 31, 2014 |
|
| Reconciliation Of Unrecognized Tax Benefits Excluding Amounts Pertaining To Examined Tax Returns Roll Forward | |||
| Balance at beginning of year | $ 2,431 | $ 2,054 | $ 2,196 |
| Additions based on tax positions related to current year | 2,489 | 372 | 83 |
| Additions (reductions) based on tax positions related to prior years | 332 | 5 | (225) |
| Balance at end of year | $ 5,252 | $ 2,431 | $ 2,054 |