Accumulated Other Comprehensive Income (Loss) - Schedule of Components of Accumulated Other Comprehensive Income (Loss) (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	$ (3,228)	$ (4,515)	$ (4,826)	$ (1,613)
Foreign currency translation	(1,429)	1,067	52	(1,933)
Foreign currency translation before reclassification		749		(2,251)
Reclassification adjustment for write-off of foreign currency translation loss		318		318
Unrealized gain (Loss) on investments, net of tax	3	(51)	120	47
Ending Balance	(4,654)	(3,499)	(4,654)	(3,499)
Net Unrealized Gain (Loss) on Marketable Investments [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	17	24	(100)	(74)
Unrealized gain (Loss) on investments, net of tax	3	(51)	120	47
Ending Balance	20	(27)	20	(27)
Cumulative Translation Adjustment [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	(3,245)	(4,539)	(4,726)	(1,539)
Foreign currency translation	(1,429)		52
Foreign currency translation before reclassification		749		(2,251)
Reclassification adjustment for write-off of foreign currency translation loss		318		318
Ending Balance	$ (4,674)	$ (3,472)	$ (4,674)	$ (3,472)