CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS (unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Income Statement [Abstract]
Revenues	$ 19,495	$ 15,825	$ 38,656	$ 29,900
Costs and expenses
Costs of revenues	14,823	9,923	29,945	20,014
Research and development	6,465	4,497	12,855	9,742
Selling, general and administrative	7,705	5,466	14,979	9,636
Total costs and expenses	28,993	19,886	57,779	39,392
Loss from operations	(9,498)	(4,061)	(19,123)	(9,492)
Interest income	246	200	756	284
Interest expense		(745)	(2)	(929)
Other income (expense), net	1	(1,261)	9	(1,413)
Loss before income taxes	(9,251)	(5,867)	(18,360)	(11,550)
Provision for income taxes	(4)	(2)	(34)	(4)
Net loss	$ (9,255)	$ (5,869)	$ (18,394)	$ (11,554)
Net loss per share, basic and diluted	$ (0.29)	$ (0.89)	$ (0.58)	$ (2.38)
Weighted-average shares outstanding, basic and diluted	31,731,628	6,597,007	31,538,329	4,853,325