CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Income Statement [Abstract]
Product sales, net	$ 20,014	$ 26,151	$ 46,692	$ 47,961
Revenue, Product and Service [Extensible List]			us-gaap:ProductMember
Cost of product sales	8,660	9,022	$ 18,582	17,662
Cost, Product and Service [Extensible List]			us-gaap:ProductMember
Gross profit	11,354	17,129	$ 28,110	30,299
Research and development	3,226	21,070	6,989	24,078
Selling, general and administrative	16,486	16,259	34,555	29,779
Total operating expenses	19,712	37,329	41,544	53,857
Loss from operations	(8,358)	(20,200)	(13,434)	(23,558)
Other income (expense):
Interest income	147	428	453	908
Other income (expense)	(1)	(2)	(3)	(4)
Interest expense	(57)	(18)	10	18
Total other income (expense)	89	408	460	922
Net loss	$ (8,269)	$ (19,792)	$ (12,974)	$ (22,636)
Net loss per share attributable to common shareholders (Basic and Diluted) (in dollars per share)	$ (0.18)	$ (0.45)	$ (0.29)	$ (0.52)
Weighted average number of common shares outstanding (Basic and Diluted) (in shares)	45,137	43,956	45,031	43,841