Segment Information - Geographical Information (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	$ 24,413	$ 35,093	$ 50,603	$ 72,703
Property and equipment, net	3,569		3,569		$ 4,728
Total Intangible Assets, Net	2,613		2,613		6,862
UNITED STATES
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	10,366	14,776	18,987	37,928
Property and equipment, net	2,332		2,332		2,974
Total Intangible Assets, Net					6,862
Foreign Countries [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	14,047	20,317	31,616	34,775
Property and equipment, net	1,237		1,237		1,754
Other North America
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	142	415	294	434
Property and equipment, net	6		6		33
Asia Pacific [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	4,243	6,697	9,446	12,116
Property and equipment, net	1,231		1,231		1,721
CHINA [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Property and equipment, net	53		53		163
INDIA
Revenues from External Customers and Long-Lived Assets [Line Items]
Property and equipment, net	1,178		1,178		$ 1,558
Netherlands [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	4,409	8,378	12,113	13,601
Other EMEA [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	5,253	4,827	9,763	8,624
Europe, the Middle East and Africa [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	$ 9,662	$ 13,205	$ 21,876	$ 22,225