Reconciliation of Unrecognized Tax Benefits (Detail) $ in Thousands |
12 Months Ended |
---|---|
Dec. 31, 2017
USD ($)
| |
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items] | |
Unrecognized tax benefits at January 1, 2017 | $ 1,407 |
Gross increases - tax positions in prior period | 679 |
Gross increases - tax positions in current period | 199 |
Gross decreases - release | (479) |
Unrecognized tax benefits at December 31, 2017 | $ 1,806 |