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Intangible Assets, Net - Additional Information (Detail) - USD ($)
$ in Thousands
3 Months Ended
Mar. 31, 2018
Mar. 31, 2017
Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract]    
Definite-lived assets amortization period 3 years  
Amortization expense of definite-lived assets $ 306 $ 48