Income Taxes - Reconciliation Between Income Tax Provision (Benefit) Computed at Federal Statutory Rate and Actual Tax Provision (Benefit) (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Effective Income Tax Rate Reconciliation, Amount [Abstract]
Tax provision at federal statutory rate	$ 235	$ 4,246	$ 13,527
State income taxes, net of federal benefit	(1,002)	(1,426)	62
Research and development credits	(1,511)	(1,508)	(2,627)
Effect of foreign operations	2,923	(1,344)	(3,320)
Deemed repatriation transition tax	(831)	16,976	0
Provision for remeasuring deferred tax balances	(343)	10,450	0
Reduction in accrual for estimated potential tax assessments	(2,047)	(1,676)	(15,404)
Non-deductible stock-based compensation	3,940	1,249	1,288
Domestic manufacturing deduction	0	0	(831)
Acquisition and integration costs	285	168	(103)
Meals and entertainment	497	500	475
Other	(54)	(160)	632
Provision for (benefit from) income taxes	$ 2,092	$ 27,475	$ (6,301)
Effective Income Tax Rate Reconciliation, Percent [Abstract]
Tax provision at federal statutory rate	21.00%	35.00%	35.00%
State income taxes, net of federal benefit	(89.40%)	(11.80%)	0.20%
Research and development credits	(134.80%)	(12.40%)	(6.80%)
Effect of foreign operations	260.70%	(11.10%)	(8.50%)
Deemed repatriation transition tax	(74.20%)	139.80%	0.00%
Provision for remeasuring deferred tax balances	(30.60%)	86.10%	0.00%
Reduction in accrual for estimated potential tax assessments	(182.50%)	(13.70%)	(39.90%)
Non-deductible stock-based compensation	351.50%	10.30%	3.30%
Domestic manufacturing deduction	(0.00%)	(0.00%)	(2.20%)
Acquisition and integration costs	25.40%	1.40%	(0.20%)
Meals and entertainment	44.30%	4.10%	1.20%
Other	(4.80%)	(1.30%)	1.60%
Provision for (benefit from) income taxes	186.60%	226.40%	(16.30%)