Condensed Consolidated Statements of Operations (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Income Statement [Abstract]
Revenue	$ 27,312	$ 19,932	$ 75,177	$ 55,566
Cost of revenue	8,076	6,173	22,969	17,324
Gross profit	19,236	13,759	52,208	38,242
Operating expenses:
Sales and marketing	11,626	8,605	33,589	25,659
Research and development	5,626	3,917	16,082	10,560
General and administrative	6,375	3,666	16,640	10,252
Total operating expenses	23,627	16,188	66,311	46,471
Operating loss	(4,391)	(2,429)	(14,103)	(8,229)
Other income (expense), net:
Interest and investment income	106		234
Interest expense	(2)	(195)	(5)	(506)
Other income (expense), net	(23)	30	(61)	2
Total other income (expense), net	81	(165)	168	(504)
Loss before income taxes	(4,310)	(2,594)	(13,935)	(8,733)
(Provision for) benefit from income taxes	79	(35)	65	75
Net loss	$ (4,231)	$ (2,629)	$ (13,870)	$ (8,658)
Net loss per share attributable to common stockholders:
Basic	$ (0.15)	$ (0.18)	$ (0.50)	$ (0.66)
Diluted	$ (0.15)	$ (0.18)	$ (0.50)	$ (0.66)
Weighted-average common shares outstanding:
Basic	28,100,172	14,772,006	27,719,519	13,124,480
Diluted	28,100,172	14,772,006	27,719,519	13,124,480