Segment And Geographic Information (Schedule Of Geographic Allocation Of Revenue) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	$ 75,725	$ 80,748	$ 150,641	$ 164,140
Switzerland [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	12,472	12,339	24,988	26,387
Singapore [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	10,098	10,316	19,948	20,350
Korea [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	9,899	10,684	19,138	20,554
France [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	7,730	8,881	15,360	17,814
United States [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	7,439	8,128	14,478	17,778
Other Europe [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	13,593	15,324	28,833	30,523
Other Asia [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	13,676	14,667	26,263	29,975
Other International [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	$ 818	$ 409	$ 1,633	$ 759