Balance Sheet Components (Schedule Of Property And Equipment, Net) (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Total property and equipment, gross	$ 123,241	$ 123,493
Accumulated depreciation and amortization	(102,581)	(104,020)
Total property and equipment, net	20,660	19,473	$ 22,384
Computer Equipment [Member]
Total property and equipment, gross	10,114	10,557
Furniture, Fixtures And Leasehold Improvements [Member]
Total property and equipment, gross	21,640	20,827
Software [Member]
Total property and equipment, gross	28,997	28,663
Machinery and Equipment [Member]
Total property and equipment, gross	$ 62,490	$ 63,446