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]
Revenues	$ 53,617	$ 51,984	$ 100,518	$ 113,886
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	47,341	45,290	88,685	101,311
Americas, excluding U.S.
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	785	724	1,485	1,303
Europe, Middle East, India, Africa
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	3,620	4,256	6,836	7,899
Other
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	$ 1,871	$ 1,714	$ 3,512	$ 3,373