Summary of Significant Accounting Policies - Schedule of Components of Accumulated Other Comprehensive Income (Loss) (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	$ 151,600	$ 141,189	$ 150,036
Foreign currency translation	401	(3,257)	5,593
Reclassification of stranded tax effects from tax reform		(26)
Unrealized (gain) loss on investments before reclassification, net of tax		12	(32)
Reclassification adjustment for net losses realized in net income, net of tax		129
Unrealized loss on interest rate swap, net of tax	(104)
Ending Balance	158,088	151,600	141,189
Net Unrealized Loss on Marketable Investments [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance		(115)	(83)
Reclassification of stranded tax effects from tax reform		(26)
Unrealized (gain) loss on investments before reclassification, net of tax		12	(32)
Reclassification adjustment for net losses realized in net income, net of tax		129
Ending Balance			(115)
Net Unrealized Gain (Loss) on Interest Rate Swaps [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Unrealized loss on interest rate swap, net of tax	(104)
Ending Balance	(104)
Cumulative Translation Adjustment [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	(5,154)	(1,897)	(7,490)
Foreign currency translation	401	(3,257)	5,593
Ending Balance	(4,753)	(5,154)	(1,897)
Total Accumulated Other Comprehensive Income (Loss) [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	(5,154)	(2,012)	(7,573)
Foreign currency translation	401	(3,257)	5,593
Unrealized loss on interest rate swap, net of tax	(104)
Ending Balance	$ (4,857)	$ (5,154)	$ (2,012)