Consolidated Statements of Operations - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Statement [Abstract]
Net sales	$ 3,985	$ 8,950	$ 3,398
Cost of sales	10,076	5,293	3,558
Gross profit (loss)	(6,091)	3,657	(160)
Operating expenses:
Research and development, net of grants	5,347	3,036	5,041
Clinical and regulatory	2,703	3,510	2,622
Selling and marketing	8,989	8,935	6,845
General and administrative	10,080	8,223	6,565
Total operating expenses	27,119	23,704	21,073
Loss from operations	(33,210)	(20,047)	(21,233)
Interest income	31	2	9
Other income, net		27	12
Interest expense on convertible promissory notes and loan payable			(1,957)
Amortization of discount on convertible promissory notes			(5,077)
Write-off of unamortized discount on conversion of convertible promissory notes			(6,955)
Net loss	$ (33,179)	$ (20,018)	$ (35,201)
Net loss per common share - basic and diluted (in dollars per share)	$ (0.84)	$ (0.56)	$ (1.41)
Weighted average shares outstanding - basic and diluted (in shares)	39,554	35,637	25,053