Condensed Consolidated Statements of Operations and Comprehensive Loss - 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]
Revenue	$ 24,841	$ 36,238	$ 53,351	$ 71,844
Cost of goods sold	10,688	13,254	24,066	25,661
Gross profit	14,153	22,984	29,285	46,183
Operating expenses:
Research and development	3,624	4,355	7,160	9,142
Clinical and regulatory affairs	3,071	3,647	6,236	7,432
Marketing and sales	11,610	15,920	26,106	32,706
General and administrative	13,197	8,929	23,316	18,345
Restructuring costs	0	0	0	419
Total operating expenses	31,502	32,851	62,818	68,044
Loss from operations	(17,349)	(9,867)	(33,533)	(21,861)
Other income (expense):
Interest expense	(10,863)	(8,857)	(21,390)	(17,347)
Other expense, net	(65)	(479)	(1,187)	(161)
Change in fair value of contingent consideration related to acquisition	(100)	(300)	200	(100)
Change in fair value of derivative liabilities	2,330	872	12,505	(1,151)
Loss on debt extinguishment	0	(11,756)	(730)	(11,756)
Total other expense, net	(8,698)	(20,520)	(10,602)	(30,515)
Net loss before income taxes	(26,047)	(30,387)	(44,135)	(52,376)
Income tax benefit (expense)	(46)	3,253	(73)	3,214
Net loss	(26,093)	(27,134)	(44,208)	(49,162)
Comprehensive loss, net of taxes:
Net loss	(26,093)	(27,134)	(44,208)	(49,162)
Other comprehensive income (loss) foreign currency translation	222	588	970	(10)
Comprehensive loss	$ (25,871)	$ (26,546)	$ (43,238)	$ (49,172)
Basic and diluted net loss per share (in dollars per share)	$ (1.26)	$ (1.50)	$ (2.17)	$ (3.44)
Shares used in computing basic and diluted net loss per share (in shares)	20,717	18,142	20,392	14,280