Unaudited Condensed Consolidated Statements of Operations - USD ($) shares in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Income Statement [Abstract]
Net revenues	$ 31,904,000	$ 40,877,000	$ 59,388,000	$ 70,861,000
Cost of product sales	15,703,000	14,277,000	29,208,000	30,722,000
Operating expenses:
Selling, general and administrative	23,735,000	26,514,000	47,424,000	50,965,000
Research and development	10,360,000	10,824,000	22,126,000	20,124,000
Restructuring charges	0	1,034,000	0	2,485,000
Total operating expenses	34,095,000	38,372,000	69,550,000	73,574,000
Loss from operations	(17,894,000)	(11,772,000)	(39,370,000)	(33,435,000)
Interest expense, net	(11,594,000)	(9,613,000)	(22,480,000)	(18,825,000)
Other (expense) income, net	(728,000)	75,000	(1,035,000)	127,000
Loss before provision for income taxes	(30,216,000)	(21,310,000)	(62,885,000)	(52,133,000)
Provision for income taxes	(1,046,000)	(126,000)	(1,205,000)	(265,000)
Net loss	$ (31,262,000)	$ (21,436,000)	$ (64,090,000)	$ (52,398,000)
Net loss per common share—basic and diluted (in usd per share)	$ (1.67)	$ (1.15)	$ (3.42)	$ (2.82)
Weighted-average shares outstanding—basic and diluted (in shares)	18,759	18,609	18,731	18,575