CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Income Statement [Abstract]
Revenue	$ 40,762	$ 34,405	$ 112,015	$ 88,015
Cost of revenue	20,981	17,857	57,945	46,045
Gross profit	19,781	16,548	54,070	41,970
Operating expenses:
Research and development	10,344	8,804	27,678	25,170
Sales and marketing	7,842	7,864	24,579	24,746
General and administrative	5,503	6,695	16,653	16,981
Restructuring costs				3,749
Total operating expenses	23,689	23,363	68,910	70,646
Loss from operations	(3,908)	(6,815)	(14,840)	(28,676)
Other income, net	317	204	947	561
Interest expense	(413)	(390)	(1,263)	(970)
Loss before income taxes	(4,004)	(7,001)	(15,156)	(29,085)
Income tax expense	(77)	(69)	(151)	(159)
Net loss	$ (4,081)	$ (7,070)	$ (15,307)	$ (29,244)
Net loss per share — basic and diluted	$ (0.19)	$ (0.33)	$ (0.70)	$ (1.37)
Weighted-average shares outstanding — basic and diluted	21,961	21,403	21,738	21,287