Condensed Consolidated Statements of Operations and Comprehensive Loss - USD ($) shares in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Income Statement [Abstract]
Revenue	$ 35,775,000	$ 34,756,000	$ 107,619,000	$ 121,780,000
Cost of goods sold	12,701,000	12,129,000	38,362,000	41,223,000
Gross profit	23,074,000	22,627,000	69,257,000	80,557,000
Operating expenses:
Research and development	4,645,000	5,037,000	13,787,000	16,780,000
Clinical and regulatory affairs	3,632,000	3,208,000	11,064,000	10,507,000
Marketing and sales	16,080,000	17,072,000	48,786,000	59,913,000
General and administrative	9,547,000	10,330,000	27,892,000	34,721,000
Restructuring costs	0	2,899,000	419,000	3,132,000
Total operating expenses	33,904,000	38,546,000	101,948,000	125,053,000
Loss from operations	(10,830,000)	(15,919,000)	(32,691,000)	(44,496,000)
Other income (expense):
Interest expense	(8,527,000)	(7,223,000)	(25,874,000)	(18,888,000)
Other income (expense), net	(380,000)	(113,000)	(541,000)	(433,000)
Change in fair value of contingent consideration related to acquisition	1,000,000	5,000,000	900,000	4,300,000
Change in fair value of derivative liabilities	10,691,000	8,305,000	9,540,000	8,305,000
Loss on debt extinguishment	0	0	(11,756,000)	(2,270,000)
Total other income (expense), net	2,784,000	5,969,000	(27,731,000)	(8,986,000)
Net loss before income taxes	(8,046,000)	(9,950,000)	(60,422,000)	(53,482,000)
Income tax benefit (expense)	281,000	(166,000)	3,495,000	(277,000)
Net loss	(7,765,000)	(10,116,000)	(56,927,000)	(53,759,000)
Comprehensive loss, net of taxes:
Net loss	(7,765,000)	(10,116,000)	(56,927,000)	(53,759,000)
Other comprehensive income (loss) foreign currency translation	(109,000)	32,000	(119,000)	(647,000)
Comprehensive loss	$ (7,874,000)	$ (10,084,000)	$ (57,046,000)	$ (54,406,000)
Basic and diluted net loss per share (in dollars per share)	$ (0.40)	$ (1.19)	$ (3.57)	$ (6.37)
Shares used in computing basic and diluted net loss per share (in shares)	19,244	8,523	15,953	8,445