Condensed Consolidated Statement of Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-In Capital	Accumulated Deficit	Accumulated other comprehensive income
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative effect of adopting ASC 606 | As Previously Reported	$ (111,939)
Cumulative effect of adopting ASC 606 | Adjustment	(3,494)
Cumulative effect of adopting ASC 606	(115,433)
Beginning Balance (in shares) at Dec. 31, 2017		49,876,000
Beginning Balance (As Previously Reported) at Dec. 31, 2017	311,012
Beginning Balance (Adjustment)	(3,494)
Beginning Balance at Dec. 31, 2017	307,518	$ 50	$ 422,901	$ (115,433)	$ 0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	$ (16,779)			(16,779)
Option exercise, net (in shares)	67,086	66,000
Option exercise, net	$ 346	$ 0	346
Shares withheld for tax withholdings on vesting of restricted stock and exercising of options (in shares)		(4,000)
Shares withheld for tax withholdings on vesting of restricted stock and exercising of options	(31)		(31)
Share-based compensation (in shares)		(79,000)
Share-based compensation	3,501	$ 0	3,501
Settlement of capped call transactions	2,118		2,118
Ending Balance (in shares) at Sep. 30, 2018		49,859,000
Ending Balance at Sep. 30, 2018	296,125	$ 50	$ 428,835	$ (133,208)	448
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Unrecognized gain on derivative instruments, net of taxes	448				$ 448
Cumulative effect of adopting ASC 606	$ (133,208)