Balance Sheet Components (Schedule Of Available-For-Sale Short-Term) (Details) - USD ($) $ in Thousands	Sep. 27, 2015	Dec. 31, 2014
Available-for-sale Securities, Amortized Cost Basis [Abstract]
Cost	$ 60,336	$ 115,102
Unrealized Gain	26	6
Unrealized Loss	0	(15)
Estimated Fair Value	60,362	115,093
U.S. Treasuries [Member]
Available-for-sale Securities, Amortized Cost Basis [Abstract]
Cost	60,067	114,944
Unrealized Gain	26	6
Unrealized Loss	0	(15)
Estimated Fair Value	60,093	114,935
Certificates Of Deposits [Member]
Available-for-sale Securities, Amortized Cost Basis [Abstract]
Cost	269	158
Unrealized Gain	0	0
Unrealized Loss	0	0
Estimated Fair Value	$ 269	$ 158