Segment And Geographic Information (Schedule Of Geographic Allocation Of Revenue) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	$ 105,022	$ 111,108
United States [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	37,145	37,366
Switzerland [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	12,516	14,048
Singapore [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	9,850	10,034
Korea [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	9,239	9,870
France [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	7,630	8,933
Other Europe [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	15,240	15,199
Other Asia [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	12,587	15,308
Other International [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	$ 815	$ 350