Condensed Statements of Operations and Comprehensive Loss - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Income Statement [Abstract]
Revenue	$ 14,675	$ 11,908	$ 28,225	$ 23,126
Operating expenses:
Cost of revenue	6,301	5,139	12,580	9,705
Research and development	4,267	3,103	7,728	5,890
Selling and marketing	8,263	6,937	15,329	12,557
General and administrative	6,071	5,536	12,299	11,334
Intangible asset amortization	267	267	534	267
Total operating expenses	25,169	20,982	48,470	39,753
Loss from operations	(10,494)	(9,074)	(20,245)	(16,627)
Interest expense	(785)	(90)	(1,152)	(177)
Other income, net	36	28	79	58
Net loss	(11,243)	(9,136)	(21,318)	(16,746)
Comprehensive loss	$ (11,243)	$ (9,136)	$ (21,318)	$ (16,746)
Net loss per common share, basic and diluted (in usd per share)	$ (0.40)	$ (0.35)	$ (0.77)	$ (0.69)
Shares used to compute net loss per common share, basic and diluted	27,859,918	26,048,934	27,838,955	24,304,022