Other Financial Statement Data (Schedule Of Equipment And Leasehold Improvements) (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Property, Plant and Equipment [Line Items]
Equipment and leasehold improvements, gross	$ 15,776	$ 15,252
Accumulated depreciation and amortization	(13,469)	(12,814)
Equipment and leasehold improvements, net	2,307	2,438
Equipment [Member]
Property, Plant and Equipment [Line Items]
Equipment and leasehold improvements, gross	14,088	13,624
Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Equipment and leasehold improvements, gross	$ 1,688	$ 1,628