CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	[2]
Statement of Comprehensive Income [Abstract]
Net loss	$ (29,325)	$ (25,081)	[1],[3]
Other comprehensive gain (loss), before tax:
Net unrealized gain (loss) on available-for-sale investments	(636)	119
Foreign currency translation gain (loss)	(12)	576
Net unrealized gain (loss) on derivative instruments	(742)	1,526
Other comprehensive gain (loss), before tax	(1,390)	2,221
Tax effect	0	(816)
Other comprehensive gain (loss), net of tax	(1,390)	1,405
Comprehensive loss	$ (30,715)	$ (23,676)

[1] See Note 1 for a summary of adjustments.

[2] See Note 1 for a summary of adjustments.

[3] See Note 1 for a summary of adjustments.