Business Segment, Geographic and Major Customer Information - Geographic Information (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	$ 85,177	$ 64,079	$ 165,131	$ 127,890
U.S.
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	71,836	49,381	136,485	101,987
Other countries
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	$ 13,341	$ 14,698	$ 28,646	$ 25,903