Revenue Concentrations, Significant Customers, and Geographic Areas (Schedule Of Revenue By Geographic Area) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018
Revenue, Major Customer [Line Items]
Revenues	$ 16,852	$ 12,391	$ 15,044	$ 14,976	$ 18,063	$ 16,683	$ 15,854	$ 14,120	$ 59,263	$ 64,720
United States [Member]
Revenue, Major Customer [Line Items]
Revenues									14,459	18,355
Netherlands [Member]
Revenue, Major Customer [Line Items]
Revenues									1,658	3,077
Other Europe [Member]
Revenue, Major Customer [Line Items]
Revenues									8,009	10,041
China [Member]
Revenue, Major Customer [Line Items]
Revenues									11,553	10,438
Singapore [Member]
Revenue, Major Customer [Line Items]
Revenues									4,120	2,948
South Korea [Member]
Revenue, Major Customer [Line Items]
Revenues									4,678	5,375
Japan [Member]
Revenue, Major Customer [Line Items]
Revenues									3,630	8,097
Other Asia [Member]
Revenue, Major Customer [Line Items]
Revenues									8,496	4,464
Other [Member]
Revenue, Major Customer [Line Items]
Revenues									$ 2,660	$ 1,925