GEOGRAPHIC AND CUSTOMER CONCENTRATION INFORMATION - Summary of Geographic Information Relating to Property and Equipment, Net (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Revenues from External Customers and Long-Lived Assets [Line Items]
Property and equipment, net	$ 7,534	$ 9,216
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Property and equipment, net	4,140	4,949
Germany
Revenues from External Customers and Long-Lived Assets [Line Items]
Property and equipment, net	3,185	4,129
Others
Revenues from External Customers and Long-Lived Assets [Line Items]
Property and equipment, net	$ 209	$ 138