CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Revenues:
Net product sales	$ 49,988	$ 27,132	$ 10,033
Net product sales	us-gaap:ProductMember	us-gaap:ProductMember	us-gaap:ProductMember
Cost of goods sold	$ 26,928	$ 14,030	$ 11,734
Cost of goods sold	us-gaap:ProductMember	us-gaap:ProductMember	us-gaap:ProductMember
Gross profit (loss)	$ 23,060	$ 13,102	$ (1,701)
Research and development expenses	8,508	8,957	12,207
Selling and marketing expenses	44,133	46,881	49,291
General and administrative expenses	13,915	13,805	12,625
Loss from operations	(43,496)	(56,541)	(75,824)
Interest expense	(8,974)	(10,085)	(6,937)
Loss on debt extinguishment			(1,187)
Other income, net	795	854	1,197
Net loss	$ (51,675)	$ (65,772)	$ (82,751)
Weighted average common shares outstanding used to compute net loss per share, basic and diluted	32,288,555	24,751,091	16,052,390
Net loss per share of common stock, basic and diluted	$ (1.60)	$ (2.66)	$ (5.16)