Schedule of Effective Income Tax Rate Reconciliation (Detail)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Income tax expense at federal statutory rate	21.00%	21.00%	21.00%	35.00%
State taxes, net of federal tax effect	18.00%	(1.70%)	(1.30%)
Foreign earnings taxed at different rates	21.70%	(6.10%)	(20.50%)
Book tax difference in amortization of intangible property	(0.00%)	(4.60%)	(0.00%)
Withholding tax	(12.50%)	3.10%	5.50%
Foreign tax credit	3.80%	(3.00%)	(5.20%)
Other international components	(3.50%)	0.20%	0.30%
Change in valuation allowance	2.70%	1.60%	2.50%
Deferred tax adjustments and rate changes	(3.40%)	1.00%	(1.70%)
Meals and entertainment	(1.30%)	1.30%	2.60%
Non-deductible officers compensation	(12.50%)	1.40%	2.10%
Subpart F income	(2.00%)	3.20%	7.00%
Research and development tax credit	19.90%	(9.30%)	(11.80%)
Stock compensation	11.80%	1.80%	5.80%
GILTI, net of foreign tax credit	(1.10%)	0.90%	0.50%
FDII	3.10%	(1.90%)	(4.50%)
Transition Tax	0.00%	0.00%	(15.20%)
Other permanent differences	(3.40%)	1.30%	3.00%
Total	62.30%	10.20%	(9.90%)