Condensed Consolidated Statement of Operations and Comprehensive Loss - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Revenue	$ 14,944	$ 10,591	$ 40,816	$ 26,755
Cost of goods sold:
Total costs of goods sold and services	7,911	4,996	20,847	14,016
Gross profit	7,033	5,595	19,969	12,739
Operating expense:
Research and development (including stock compensation of $175 and $152 for the three months ended September 30, 2019 and 2018, respectively, and $523 and $361 for the nine months ended September 30, 2019 and 2018, respectively)	3,924	4,411	11,792	11,759
Selling, general and administrative (including stock compensation of $1,564 and $1,657 for the three months ended September 30, 2019 and 2018, respectively, and $3,940 and $2,862 for the nine months ended September 30, 2019 and 2018, respectively)	13,352	8,846	38,293	23,117
Total operating expenses	17,276	13,257	50,085	34,876
Loss from operations	(10,243)	(7,662)	(30,116)	(22,137)
Interest income (expense), net	282	30	346	21
Other income (expense), net	(34)	(25)	(149)	(86)
Loss before income tax	(9,995)	(7,657)	(29,919)	(22,202)
Income tax benefit	(125)		(81)
Net loss	$ (9,870)	$ (7,657)	$ (29,838)	$ (22,202)
Net loss per share, basic and diluted	$ (0.37)	$ (0.35)	$ (1.24)	$ (1.01)
Weighted-average common shares outstanding, basic and diluted	26,627,831	22,070,786	24,102,887	21,917,823
Product revenue
Revenue	$ 10,737	$ 5,962	$ 29,059	$ 15,907
Cost of goods sold:
Total costs of goods sold and services	5,513	3,277	14,217	8,995
Service and other revenue
Revenue	4,207	3,017	11,757	8,699
Cost of goods sold:
Total costs of goods sold and services	$ 2,398	1,719	$ 6,630	5,021
Collaboration and license revenue
Revenue		$ 1,612		$ 2,149