Other Financial Statement Data (Schedule Of Changes In Deferred Warranty Revenue) (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016
Movement in Extended Product Warranty Accrual [Roll Forward]
Balance at beginning of period	$ 346	$ 199
Revenue deferrals	204	203
Amortization of deferred revenue	(209)	(226)
Total deferred warranty revenue	341	176
Current portion of deferred warranty revenue	(300)	(171)
Long-term deferred warranty revenue	$ 41	$ 5