Supplemental Financial Information (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Quarterly Financial Information Disclosure [Abstract]
Revenues	$ 593	$ 2,361	$ 1,483	$ 437	$ 1,071	$ 1,169	$ 483	$ 1,726	$ 4,874	$ 4,449
Operating expenses
Cost of product sales	4,702	8,231	7,185	4,681	6,272	6,453	4,600	5,436	24,799	22,761
Research and development cost	315	282	338	620	857	967	1,203	1,475	1,555	4,502
General and administrative expense	5,856	5,107	4,335	4,016	6,352	2,174	3,913	1,775	19,314	14,214	$ 600
Total operating expenses	10,873	13,620	11,858	9,317	13,481	9,594	9,716	8,686	45,668	41,477
Loss from operations	(10,280)	(11,259)	(10,375)	(8,880)	(12,410)	(8,425)	(9,233)	(6,960)	(40,794)	(37,028)
Other income and expense
Insurance proceeds net of related expenses	(792)	0	0	0					(792)	0
Interest expense	(243)	(142)	(203)	(2,889)	(1,222)	(919)	(719)	(587)	(3,477)	(3,447)
Interest and other income	45	85	77	63	100	81	25	17	270	223
Total other expense, net	(990)	(57)	(126)	(2,826)	(1,122)	(838)	(694)	(570)	(3,999)	(3,224)
Loss before income tax expense	(11,270)	(11,316)	(10,501)	(11,706)	(13,532)	(9,263)	(9,927)	(7,530)	(44,793)	(40,252)
Income tax expense	0	0	0	(2)	0	0	0	(2)	(2)	(2)
Net loss	$ (11,270)	$ (11,316)	$ (10,501)	$ (11,708)	$ (13,532)	$ (9,263)	$ (9,927)	$ (7,532)	$ (44,795)	$ (40,254)
Weighted average shares outstanding, basic and diluted (in shares)	57,523,283	57,053,982	50,757,448	43,514,225	38,905,282	38,779,710	30,134,995	27,768,008	52,263,885	34,154,826
Basic and diluted net loss per share (in dollars per share)	$ (0.20)	$ (0.20)	$ (0.21)	$ (0.27)	$ (0.35)	$ (0.24)	$ (0.33)	$ (0.27)	$ (0.86)	$ (1.18)