Segment Information and Enterprise Reporting - Analysis of Product Revenues Based upon Geographic Area Shipped (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Oct. 01, 2016	Sep. 30, 2017	Oct. 01, 2016
Analysis of Product Revenues Based upon the Geographic Area Shipped
Total product revenue	$ 181,271	$ 160,286	$ 542,170	$ 488,183
Total product revenue, in percentage	100.00%	100.00%	100.00%	100.00%
United States | Reportable Geographical Components
Analysis of Product Revenues Based upon the Geographic Area Shipped
Total product revenue	$ 119,266	$ 114,563	$ 370,403	$ 345,113
Total product revenue, in percentage	65.80%	71.50%	68.30%	70.70%
Europe, Middle East and Africa | Reportable Geographical Components
Analysis of Product Revenues Based upon the Geographic Area Shipped
Total product revenue	$ 38,127	$ 23,929	$ 102,322	$ 81,887
Total product revenue, in percentage	21.00%	14.90%	18.90%	16.80%
Asia and Austrialia | Reportable Geographical Components
Analysis of Product Revenues Based upon the Geographic Area Shipped
Total product revenue	$ 18,078	$ 16,630	$ 51,801	$ 46,815
Total product revenue, in percentage	10.00%	10.40%	9.60%	9.60%
North and South America (excluding United States) | Reportable Geographical Components
Analysis of Product Revenues Based upon the Geographic Area Shipped
Total product revenue	$ 5,800	$ 5,164	$ 17,644	$ 14,368
Total product revenue, in percentage	3.20%	3.20%	3.20%	2.90%