Balance Sheet Components (Schedule Of Available-For-Sale Short-Term) (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Schedule of Available-for-sale Securities [Line Items]
Cost	$ 95,204	$ 115,102
Unrealized Gain	1	6
Unrealized Loss	(65)	(15)
Estimated Fair Value	95,140	115,093
Treasuries [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost	95,057	114,944
Unrealized Gain	1	6
Unrealized Loss	(65)	(15)
Estimated Fair Value	94,993	114,935
Certificates Of Deposits [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost	147	158
Unrealized Gain	0	0
Unrealized Loss	0	0
Estimated Fair Value	$ 147	$ 158