Commitments and Contingencies - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2012	Dec. 31, 2010
Loss Contingencies [Line Items]
Rent expense	$ 6,100,000	$ 4,600,000	$ 3,900,000
Tenant improvement allowances	700,000			$ 300,000	$ 600,000
Restricted cash	1,884,000	1,665,000
Purchase commitments	$ 3,800,000	5,800,000
Period of purchase commitment of inventory from specified date	6 months
Loss contingency accrual	$ 0	0
Cancelable Lease Agreement [Member]
Loss Contingencies [Line Items]
Motor vehicle lease expenses	$ 2,700,000	$ 2,400,000	$ 2,600,000
Minimum [Member]
Loss Contingencies [Line Items]
Operating lease expiration year	2017
Maximum [Member]
Loss Contingencies [Line Items]
Operating lease expiration year	2021
Maximum [Member] | Cancelable Lease Agreement [Member]
Loss Contingencies [Line Items]
Penalties	$ 100,000