Consolidated Statements of Stockholders' Equity (unaudited) - 9 months ended Sep. 30, 2018 - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Accumulated Deficit	Accumulated Other Comprehensive Income (Loss)
Balance at Dec. 31, 2017	$ 55,991	$ 28	$ 164,995	$ (109,252)	$ 220
Balance, shares at Dec. 31, 2017		28,330,460
Cumulative effect of adoption of ASU 2014-09, net of taxes	9,097			9,097
Stock-based compensation	20,257		20,257
Vesting of restricted stock units		671,131
Restricted stock units withheld to settle employee tax withholding liability	(7,921)		(7,921)
Restricted stock units withheld to settle employee tax withholding liability, shares		(154,469)
Exercise of stock options	$ 8,821	$ 1	8,820
Exercise of stock options, shares	703,826	703,826
Issuance of shares under employee stock purchase plan	$ 1,758		1,758
Issuance of shares under employee stock purchase plan, shares		74,517
Other comprehensive income	(2,570)				(2,570)
Net loss	(37,710)			(37,710)
Balance at Sep. 30, 2018	$ 47,723	$ 29	$ 187,909	$ (137,865)	$ (2,350)
Balance, shares at Sep. 30, 2018		29,625,465