Consolidated Statements of Operations - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Revenue:
Total revenue	$ 29,533	$ 21,671	$ 57,445	$ 44,745
Cost of revenue:
Gross profit	3,514	2,744	7,232	5,554
Operating expenses:
Research and development	1,868	1,638	3,796	3,243
Sales and marketing	3,509	3,721	7,020	7,220
General and administrative	3,352	4,240	7,592	8,696
Total operating expenses	8,729	9,599	18,408	19,159
Loss from operations	(5,215)	(6,855)	(11,176)	(13,605)
Interest expense, net	(103)	(103)	(144)	(195)
Total interest expense, net	(103)	(103)	(144)	(195)
Net loss	$ (5,318)	$ (6,958)	$ (11,320)	$ (13,800)
Net loss per share:
Basic and diluted	$ (0.22)	$ (0.29)	$ (0.47)	$ (0.58)
Weighted-average common shares outstanding:
Basic and diluted	24,118,620	23,743,358	24,025,136	23,655,676
Product [Member]
Revenue:
Total revenue	$ 28,908	$ 21,115	$ 55,693	$ 43,636
Cost of revenue:
Cost of revenue	25,715	18,676	49,193	38,699
Research Services [Member]
Revenue:
Total revenue	625	556	1,752	1,109
Cost of revenue:
Cost of revenue	$ 304	$ 251	$ 1,020	$ 492