CONSOLIDATED STATEMENT OF COMPREHENSIVE LOSS - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Revenue
Product revenue	$ 70,481	$ 52,260	$ 48,914
License and other revenue	278	259	360
Total revenue	70,759	52,519	49,274
Cost of revenue	51,278	32,514	19,700
Gross profit	19,481	20,005	29,574
Operating expenses:
Sales and marketing	21,777	20,557	14,734
General and administrative	17,545	16,205	14,363
Research and development	27,931	42,760	49,458
Total operating expenses	67,253	79,522	78,555
Loss from operations	(47,772)	(59,517)	(48,981)
Other income (expense):
Interest income	711	561	176
Interest expense	(3,108)	(3,042)	(1,536)
Other income (expense)	(192)	249	(160)
Total other income (expense)	(2,589)	(2,232)	(1,520)
Loss before provision for income taxes	(50,361)	(61,749)	(50,501)
Income tax expense	139	101	100
Net loss	$ (50,500)	$ (61,850)	$ (50,601)
Net loss per share, basic and diluted	$ (0.91)	$ (1.21)	$ (1.15)
Weighted average number of shares outstanding	55,669	51,169	44,100
Other comprehensive loss
Net loss	$ (50,500)	$ (61,850)	$ (50,601)
Accumulated Other Comprehensive Income (Loss), Foreign Currency Translation Adjustment, Net of Tax	44	(84)	77
Net unrealized gains (losses) on marketable securities, net of tax	27	(2)	(11)
Other Comprehensive Income (Loss), Net of Tax	71	(86)	66
Comprehensive Income (Loss), Net of Tax, Attributable to Parent	$ (50,429)	$ (61,936)	$ (50,535)