UNAUDITED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Statement of Comprehensive Income [Abstract]
Net loss	$ (12,631)	$ (21,393)
Other comprehensive (loss) income:
Unrealized (losses) gains on available-for-sale securities (net of tax of $80 and $152, respectively)	(195)	82
Reclassification adjustment for losses on available-for-sale securities included in net income (net of taxes of $0 and $0, respectively)	0	146
Foreign currency translation adjustments	(16,551)	5,823
Other comprehensive (loss) income	(16,746)	6,051
Comprehensive loss	$ (29,377)	$ (15,342)