Condensed Consolidated Statements of Operations and Comprehensive Loss - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Income Statement [Abstract]
Revenue	$ 36,238	$ 44,740	$ 71,844	$ 87,024
Cost of goods sold	13,254	15,136	25,661	29,094
Gross profit	22,984	29,604	46,183	57,930
Operating expenses:
Research and development	4,355	6,244	9,142	11,743
Clinical and regulatory affairs	3,647	3,728	7,432	7,299
Marketing and sales	15,920	21,116	32,706	42,841
General and administrative	8,929	14,022	18,345	24,391
Restructuring costs	0	0	419	233
Total operating expenses	32,851	45,110	68,044	86,507
Loss from operations	(9,867)	(15,506)	(21,861)	(28,577)
Other income (expense):
Interest expense	(8,857)	(5,861)	(17,347)	(11,665)
Other income (expense), net	(479)	(683)	(161)	(320)
Change in fair value of contingent consideration related to acquisition	(300)	(1,800)	(100)	(700)
Change in fair value of derivative liabilities	872	0	(1,151)	0
Loss on debt extinguishment	(11,756)	0	(11,756)	(2,270)
Total other expense, net	(20,520)	(8,344)	(30,515)	(14,955)
Net loss before income taxes	(30,387)	(23,850)	(52,376)	(43,532)
Income tax benefit (expense)	3,253	(26)	3,214	(111)
Net loss	(27,134)	(23,876)	(49,162)	(43,643)
Comprehensive loss, net of taxes:
Net loss	(27,134)	(23,876)	(49,162)	(43,643)
Other comprehensive income (loss) foreign currency translation	588	(552)	(10)	(679)
Comprehensive loss	$ (26,546)	$ (24,428)	$ (49,172)	$ (44,322)
Basic and diluted net loss per share (in dollars per share)	$ (1.50)	$ (2.83)	$ (3.44)	$ (5.19)
Shares used in computing basic and diluted net loss per share (in shares)	18,142	8,446	14,280	8,411