Unaudited Consolidated Statements of Comprehensive Loss - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Statement of Comprehensive Income [Abstract]
Net loss	$ (22,639)	$ (15,046)
Other comprehensive income (loss):
Unrealized income (loss) on marketable securities, net of tax	18	(9)
Gains (losses) on marketable securities reclassified into earnings, net of tax	(8)	1
Total	10	(8)
Unrealized income (loss) on derivative instruments, net of tax	2,484	(2,053)
Losses (gains) on derivative instruments reclassified into earnings, net of tax	451	(48)
Total	2,935	(2,101)
Total other comprehensive income (loss)	2,945	(2,109)
Comprehensive loss	$ (19,693)	$ (17,155)