Segment And Geographic Information (Schedule Of Geographic Allocation Of Revenue) (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	Dec. 31, 2016
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	$ 115,567	$ 115,452	$ 105,705	$ 95,374	$ 94,034	$ 90,161	$ 82,692	$ 81,506	$ 432,098	$ 348,393	$ 294,354
United States [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue									154,427	120,558	99,824
Switzerland [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue									50,805	32,430	19,636
France [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue									37,565	34,862	29,273
Korea [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue									31,877	20,755	14,904
Singapore [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue									26,854	19,856	16,172
Other Asia [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue									67,695	64,097	63,190
Other Europe [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue									54,677	45,176	40,170
Other International [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue									$ 8,198	$ 10,659	$ 11,185