Revenue Concentrations, Significant Customers And Geographic Areas (Schedule Of Sales By Geographic Area) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Revenue, Major Customer [Line Items]
Total export sales	$ 11,886	$ 7,764	$ 33,424	$ 29,270
Americas
Revenue, Major Customer [Line Items]
Total export sales	355	159	568	976
Europe
Revenue, Major Customer [Line Items]
Total export sales	4,093	2,543	9,360	9,114
Asia
Revenue, Major Customer [Line Items]
Total export sales	7,090	4,959	22,948	18,933
Other
Revenue, Major Customer [Line Items]
Total export sales	$ 348	$ 103	$ 548	$ 247