Balance Sheet Components (Schedule Of Available-For-Sale Short-Term) (Details) - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 28, 2015	Dec. 31, 2014
Schedule of Available-for-sale Securities [Line Items]
Cost	$ 75,123	$ 115,102
Unrealized Gain	19	6
Unrealized Loss	0	(15)
Estimated Fair Value	75,142	115,093
U.S. Treasuries [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost	74,972	114,944
Unrealized Gain	19	6
Unrealized Loss	0	(15)
Estimated Fair Value	74,991	114,935
Certificates Of Deposits [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost	151	158
Unrealized Gain	0	0
Unrealized Loss	0	0
Estimated Fair Value	$ 151	$ 158