Condensed Consolidated Statements of Operations - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Revenue	$ 13,130	$ 13,536	$ 28,857	$ 25,872
Cost of goods sold:
Total costs of goods sold and services	7,917	6,605	16,831	12,936
Gross profit	5,213	6,931	12,026	12,936
Operating expenses:
Research and development	4,312	4,016	8,580	7,868
Selling, general and administrative	13,102	13,429	27,375	24,941
Total operating expenses	17,414	17,445	35,955	32,809
Loss from operations	(12,201)	(10,514)	(23,929)	(19,873)
Interest income (expense), net	(108)	42	53	64
Other income (expense), net	(11)	(68)	(178)	(115)
Loss before income taxes	(12,320)	(10,540)	(24,054)	(19,924)
Income tax benefit (provision)	18	(23)	142	(44)
Net loss	$ (12,302)	$ (10,563)	$ (23,912)	$ (19,968)
Reconciliation of net loss to net loss attributable to common stockholders:
Net loss per share, basic and diluted	$ (0.43)	$ (0.46)	$ (0.85)	$ (0.88)
Weighted-average common shares outstanding, basic and diluted	28,312,925	23,213,653	28,246,028	22,820,502
Product revenue
Revenue	$ 6,790	$ 8,776	$ 16,623	$ 18,322
Cost of goods sold:
Total costs of goods sold and services	5,416	4,455	11,602	8,704
Service and other revenue
Revenue	6,317	4,760	12,079	7,550
Cost of goods sold:
Total costs of goods sold and services	2,501	$ 2,150	5,229	$ 4,232
Collaboration and license revenue
Revenue	$ 23		$ 155