Industry Segment, Geographic Information and Significant Customers - Segment Information about Revenue, Cost of Revenue, Gross Margin and Income before Income Taxes (Detail) $ in Thousands		3 Months Ended		9 Months Ended
		Oct. 01, 2016 USD ($)	Sep. 26, 2015 USD ($)	Oct. 01, 2016 USD ($) segment	Sep. 26, 2015 USD ($)
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Number of Reportable Segments | segment				1
Revenue		$ 168,610	$ 143,609	$ 448,110	$ 410,358
Cost of revenue	[1]	87,550	73,751	235,437	216,759
Gross margin		81,060	69,858	212,673	193,599
Research and development	[1]	19,672	18,122	57,944	55,886
Selling and marketing	[1]	17,925	19,379	66,972	60,896
General and administrative	[1]	16,012	13,701	48,919	39,195
Other income (expense), net		523	(93)	2,142	(948)
Income before income taxes		$ 27,974	$ 18,563	$ 40,980	$ 36,674

[1] Total stock-based compensation recorded in the three and nine months ended October 1, 2016 and September 26, 2015 included in the above figures breaks down by expense classification as follows: Three Months Ended Nine Months Ended October 1, 2016 September 26, 2015 October 1, 2016 September 26, 2015Cost of revenue$184 $270 $555 662Research and development1,028 963 2,598 2,737Selling and marketing444 474 1,316 1,089General and administrative2,247 2,193 7,312 5,974