Condensed Consolidated Statements of Operations and Comprehensive Loss - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Income Statement [Abstract]
Revenue	$ 35,606	$ 42,284
Cost of goods sold	12,407	13,958
Gross profit	23,199	28,326
Operating expenses:
Research and development	4,787	5,499
Clinical and regulatory affairs	3,785	3,571
Marketing and sales	16,786	21,725
General and administrative	9,416	10,369
Restructuring costs	419	200
Total operating expenses	35,193	41,397
Loss from operations	(11,994)	(13,071)
Other income (expense):
Interest expense	(8,490)	(5,807)
Other income (expense), net	318	366
Change in fair value of contingent consideration related to acquisition	200	1,100
Change in fair value of derivative liabilities	(2,023)	0
Loss on debt extinguishment	0	(2,270)
Total other expense, net	(9,995)	(6,611)
Net loss before income taxes	(21,989)	(19,682)
Income tax expense	(39)	(85)
Net loss	(22,028)	(19,767)
Other comprehensive loss foreign currency translation	(598)	(127)
Comprehensive loss	$ (22,626)	$ (19,894)
Basic and diluted net loss per share (in dollars per share)	$ (2.12)	$ (2.36)
Shares used in computing basic and diluted net loss per share (in shares)	10,374	8,371