Other Financial Statement Data (Schedule Of Changes In Estimated Warranty Liability) (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020
Movement in Standard Product Warranty Accrual [Roll Forward]
Balance at beginning of period	$ 839	$ 798
Accrual for warranties	527	429
Warranty revision	3	9
Settlements made during the period	(392)	(474)
Balance at end of period	977	762
Current portion of estimated warranty liability	(920)	(729)	$ (793)
Long-term estimated warranty liability	$ 57	$ 33