Reconciliations Between Statutory Federal Income Tax Rate and Effective Rate (Detail)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Statutory Federal income tax rate	21.00%	34.00%	34.00%
Increase (Decrease) resulting from:
U.S. Taxes on foreign income, net of taxes paid credit			1.30%
Change in valuation allowance	(6.60%)	10.60%	5.30%
Foreign, state and local tax, net of Federal benefit	1.80%	0.80%	1.10%
Nondeductible expenses	3.40%	2.40%	2.40%
Stock option compensation		(2.20%)
Research and development credits	(2.50%)	(4.60%)	(0.70%)
Effect of different tax rates of foreign jurisdictions	(6.60%)	(20.80%)	(15.00%)
Undistributed profits of subsidiaries	1.20%	5.80%	7.90%
Tax reform items	10.80%	29.10%
Tax effects of intercompany transfers	0.80%	(5.00%)	(5.30%)
Other	4.60%	(1.00%)	(0.30%)
Effective rate	27.90%	49.10%	30.70%