Unaudited Consolidated Statements of Comprehensive Loss - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Statement of Comprehensive Income [Abstract]
Net loss	$ (16,987)	$ (7,317)	$ (64,114)	$ (35,046)
Other comprehensive income (loss):
Unrealized income (loss) on marketable securities, net of tax	(13)	6	37	33
Gains (losses) on marketable securities reclassified into earnings, net of tax	4	(4)	(2)	(20)
Total	(9)	2	35	13
Unrealized income (loss) on derivative instruments, net of tax	883	(100)	4,199	(3,985)
Losses (gains) on derivative instruments reclassified into earnings, net of tax	(361)	1,194	170	2,094
Total	522	1,094	4,369	(1,891)
Total other comprehensive income	513	1,096	4,404	(1,878)
Comprehensive loss	$ (16,474)	$ (6,221)	$ (59,710)	$ (36,924)