Employee Benefit Plans (Schedule Of Total Stock-Based Compensation Expense Resulting From Stock Options, Restricted Stock Awards, And The Employee Stock Purchase Plan) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Oct. 01, 2017	Oct. 02, 2016	Oct. 01, 2017	Oct. 02, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$ 5,583	$ 4,870	$ 16,412	$ 14,300
Cost Of Revenue [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	499	426	1,477	1,316
Research And Development [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	1,056	1,087	3,748	3,071
Sales And Marketing [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	1,654	1,300	4,339	3,835
General And Administrative [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$ 2,374	$ 2,057	$ 6,848	$ 6,078