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, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017
Revenue, Major Customer [Line Items]
Revenues	$ 18,063	$ 16,683	$ 15,854	$ 14,120	$ 13,176	$ 11,828	$ 16,409	$ 11,920	$ 64,720	$ 53,333
United States [Member]
Revenue, Major Customer [Line Items]
Revenues									18,355	15,361
Netherlands [Member]
Revenue, Major Customer [Line Items]
Revenues									3,077	2,786
Other Europe [Member]
Revenue, Major Customer [Line Items]
Revenues									10,041	8,948
China [Member]
Revenue, Major Customer [Line Items]
Revenues									10,438	6,899
Singapore [Member]
Revenue, Major Customer [Line Items]
Revenues									2,948	4,424
South Korea [Member]
Revenue, Major Customer [Line Items]
Revenues									5,375	2,643
Japan [Member]
Revenue, Major Customer [Line Items]
Revenues									8,097	7,177
Other Asia [Member]
Revenue, Major Customer [Line Items]
Revenues									4,464	3,685
Other [Member]
Revenue, Major Customer [Line Items]
Revenues									$ 1,925	$ 1,410