Other Financial Statement Data (Schedule Of Changes In Estimated Warranty Liability) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Movement in Standard Product Warranty Accrual [Roll Forward]
Balance at beginning of period	$ 767	$ 790
Accrual for warranties	619	582
Warranty revision	(34)	7
Settlements made during the period	(563)	(612)
Balance at end of period	789	767
Current portion of estimated warranty liability	(758)	(713)
Long-term estimated warranty liability	$ 31	$ 54