UNAUDITED CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE (LOSS) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Statement of Comprehensive Income [Abstract]
Net (loss)	$ (19,267)	$ (30,338)	$ (65,379)	$ (91,351)
Other comprehensive (loss) income, net of tax
Unrealized (loss) gain on available-for-sale securities	(166)	(216)	(66)	396
Foreign currency translation adjustments	113	(2,201)	1,627	(983)
Total other comprehensive (loss) income, net of tax	(53)	(2,417)	1,561	(587)
Comprehensive (loss)	$ (19,320)	$ (32,755)	$ (63,818)	$ (91,938)