Consolidated Statements of Operations - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Revenue:
Subscription and returns	$ 64,219	$ 51,668	$ 181,764	$ 145,825
Professional services and other	5,308	3,600	12,849	9,299
Total revenue	69,527	55,268	194,613	155,124
Cost of revenue:
Subscription and returns	17,330	12,330	47,984	35,683
Professional services and other	2,906	2,329	8,393	6,906
Total cost of revenue	20,236	14,659	56,377	42,589
Gross profit	49,291	40,609	138,236	112,535
Operating expenses:
Research and development	13,285	10,401	38,332	30,374
Sales and marketing	41,276	33,151	119,187	96,642
General and administrative	10,235	8,092	28,787	26,189
Restructuring charges		793		793
Goodwill impairment	9,174		9,174
Total operating expenses	73,970	52,437	195,480	153,998
Operating loss	(24,679)	(11,828)	(57,244)	(41,463)
Other (income) expense:
Interest income	(1,068)	(23)	(1,373)	(48)
Interest expense	534	635	2,495	1,817
Other (income) expense, net	49	(2,003)	(423)	(1,058)
Total other (income) expense, net	(485)	(1,391)	699	711
Loss before income taxes	(24,194)	(10,437)	(57,943)	(42,174)
Provision for (benefit from) income taxes	(91)	(172)	(825)	(462)
Net loss	$ (24,103)	$ (10,265)	$ (57,118)	$ (41,712)
Net loss per share attributable to common shareholders, basic and diluted	$ (0.36)	$ (1.80)	$ (1.95)	$ (7.54)
Weighted average shares of common stock outstanding, basic and diluted	66,590	5,706	29,269	5,531