Summary of Significant Accounting Policies - Components of Accumulated Other Comprehensive Income (Loss) (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance	$ (1,613)	$ 2,454	$ 588
Foreign currency translation	(3,187)	(3,977)	826
Foreign currency translation before reclassification	(3,505)
Reclassification adjustment for write-off of foreign currency translation loss	318
Unrealized loss on investments before reclassification, net of tax	(26)	(84)	(111)
Reclassification adjustment for net gain (losses) realized in net income, net of tax		(6)	1,151
Ending Balance	(4,826)	(1,613)	2,454
Accumulated Net Unrealized Investment Gain (Loss) [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance	(74)	16	(1,024)
Unrealized loss on investments before reclassification, net of tax	(26)	(84)	(111)
Reclassification adjustment for net gain (losses) realized in net income, net of tax		(6)	1,151
Ending Balance	(100)	(74)	16
Accumulated Translation Adjustment [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance	(1,539)	2,438	1,612
Foreign currency translation		(3,977)	826
Foreign currency translation before reclassification	(3,505)
Reclassification adjustment for write-off of foreign currency translation loss	318
Ending Balance	$ (4,726)	$ (1,539)	$ 2,438