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
	Sep. 27, 2015	Sep. 28, 2014	Sep. 27, 2015	Sep. 28, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$ 4,111	$ 5,162	$ 12,517	$ 15,226
Cost Of Revenue [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	358	573	1,190	1,533
Research And Development [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	877	1,255	2,495	3,878
Sales And Marketing [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	1,173	1,409	3,838	4,759
General And Administrative [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$ 1,703	$ 1,925	$ 4,994	$ 5,056