Revenue Concentrations, Significant Customers And Geographic Areas (Schedule Of Sales By Geographic Area) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Revenue, Major Customer [Line Items]
Total export sales	$ 20,523	$ 14,467
Americas
Revenue, Major Customer [Line Items]
Total export sales	707	783
Europe
Revenue, Major Customer [Line Items]
Total export sales	3,186	3,500
China
Revenue, Major Customer [Line Items]
Total export sales	8,863	5,163
Taiwan
Revenue, Major Customer [Line Items]
Total export sales	1,012	730
Other Asia
Revenue, Major Customer [Line Items]
Total export sales	6,729	4,143
Other
Revenue, Major Customer [Line Items]
Total export sales	$ 26	$ 148