Other Financial Statement Data (Schedule Of Changes In Estimated Warranty Liability) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Movement in Standard Product Warranty Accrual [Roll Forward]
Balance at beginning of period	$ 798	$ 789
Accrual for warranties	230	174
Warranty revision	1	17
Settlements made during the period	(244)	(154)
Balance at end of period	785	826
Current portion of estimated warranty liability	(748)	(795)	$ (761)
Long-term estimated warranty liability	$ 37	$ 31