Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Statement of Comprehensive Income [Abstract]
Net (loss)	$ (10,983)	$ (17,388)	$ (12,380)
Other comprehensive (loss):
Foreign currency translation adjustments	802	(6)	(1,097)
Unrealized (losses)/gains from marketable securities, net of tax	(2)	(6)	(11)
Total other comprehensive income (loss)	800	(12)	(1,108)
Comprehensive (loss)	$ (10,183)	$ (17,400)	$ (13,488)