Revenue Concentrations, Significant Customers, and Geographic Areas (Schedule Of Long-lived Assets Attributable To Each Geographic Area's Operations) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Revenues from External Customers and Long-Lived Assets [Line Items]
Total long-lived assets	$ 3,195	$ 2,687
United States [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total long-lived assets	2,867	2,348
Europe [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total long-lived assets	2	4
Asia And Other [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total long-lived assets	$ 326	$ 335