Other Financial Statement Data (Schedule Of Changes In Estimated Warranty Liability) (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Movement in Standard Product Warranty Accrual [Roll Forward]
Balance at beginning of period	$ 790	$ 645
Accrual for warranties	362	615
Warranty revision	(23)	(27)
Settlements made during the period	(413)	(415)
Balance at end of period	716	818
Current portion of estimated warranty liability	(691)	(736)	$ (717)
Long-term estimated warranty liability	$ 25	$ 82