Income Tax Expense - Reconciliation of Beginning and Ending Amount of Unrecognized Tax Benefits (Detail) $ in Thousands |
6 Months Ended |
---|---|
Jun. 30, 2018
USD ($)
| |
Income Tax Disclosure [Abstract] | |
Unrecognized tax benefits as of December 31, 2017 | $ 525 |
Additions for tax positions of current year | 48 |
Additions for tax positions of prior years | 5 |
Reductions for settlements with taxing authorities | 0 |
Reductions for lapses of the applicable statutes of limitations | 0 |
Unrecognized tax benefits as of June 30, 2018 | $ 578 |