Segment And Geographic Information (Summary of Revenue by Category) (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	Dec. 31, 2017
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	$ 27,930	$ 21,915	$ 24,621	$ 16,425	$ 19,526	$ 18,160	$ 21,578	$ 19,362	$ 90,891	$ 78,626	$ 93,468
Product [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue									77,742	66,355	80,030
Instrument [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue									45,126	28,492	38,626
Consumable [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue									32,616	37,863	41,404
Service and Other [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue									13,149	12,271	13,438
North America [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue									44,681	35,598	40,641
Europe (including the Middle East and Africa) [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue									19,600	13,958	14,026
Asia Pacific [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue									$ 26,610	$ 29,070	$ 38,801