Reconciliation of U.S. Federal Statutory Income Tax Rate to Effective Income Tax Rate (Detail)	9 Months Ended	12 Months Ended
	Sep. 28, 2018	Sep. 28, 2018	Dec. 31, 2017	Sep. 29, 2017	Sep. 30, 2016
Income Tax Disclosure [Abstract]
U.S. statutory income tax rate	21.00%	24.60%	35.00%	35.00%	35.00%
Foreign taxes		(1.60%)		(1.50%)	(10.30%)
Difference in foreign tax rates		4.20%		(4.20%)	(4.40%)
Mandatory repatriation tax		25.50%		0.00%	0.00%
Revaluation of deferred tax assets		4.40%		0.00%	0.00%
Unremitted earnings		2.30%		0.00%	0.00%
Change in foreign tax rates and laws		0.30%		(2.90%)	0.00%
Research and development credits		(2.30%)		(3.50%)	(5.20%)
Domestic manufacturing deduction		(1.00%)		(0.30%)	(1.00%)
Net change in tax reserves		0.10%		(0.30%)	(0.20%)
State income taxes		(0.10%)		0.50%	0.20%
Valuation allowance		(3.40%)		(0.30%)	0.80%
Subpart F income		0.70%		0.50%	0.70%
Other, net		0.90%		(1.50%)	0.50%
Effective income tax rate		54.60%		21.50%	16.10%