CONDENSED CONSOLIDATED STATEMENTS OF 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
Revenues:
Total revenues	$ 4,122	$ 7,210	$ 11,611	$ 9,222
Operating expenses:
Cost of sales, excluding amortization of acquired intangible assets	502	706	1,482	1,035
Research and development	3,276	3,955	8,129	7,753
Sales and marketing	6,089	7,284	14,214	14,595
General and administrative	4,792	4,815	9,152	9,425
Amortization of acquired intangible assets	615	615	1,230	1,230
Total operating expenses	15,274	17,375	34,207	34,038
Loss from operations	(11,152)	(10,165)	(22,596)	(24,816)
Other income (expense):
Interest and other income, net	8	266	62	509
Interest expense	(1,806)	(1,599)	(3,590)	(2,619)
Loss on extinguishment of debt	0	0	0	(3,810)
Total other expense, net	(1,798)	(1,333)	(3,528)	(5,920)
Net loss	$ (12,950)	$ (11,498)	$ (26,124)	$ (30,736)
Net loss per share - basic and diluted	$ (0.10)	$ (0.11)	$ (0.22)	$ (0.30)
Weighted average shares outstanding - basic and diluted	124,771	106,238	120,151	100,847
Net loss	$ (12,950)	$ (11,498)	$ (26,124)	$ (30,736)
Foreign currency translation adjustments	0	1	0	1
Comprehensive loss	(12,950)	(11,497)	(26,124)	(30,735)
Product [Member]
Revenues:
Total revenues	3,706	6,705	8,393	7,932
License and Collaboration Agreement [Member]
Revenues:
Total revenues	35	5	2,055	70
Royalty Income [Member]
Revenues:
Total revenues	$ 381	$ 500	$ 1,163	$ 1,220