Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Revenues	$ 17,607	$ 9,634
Operating expenses:
Total cost of revenue	10,638	9,862
Gross profit	6,969	(228)
Research and development expense	24,666	15,096
Sales, marketing, general and administrative expense	9,523	10,156
Total operating expenses	34,189	25,252
Loss from operations	(27,220)	(25,480)
Other expense, net	(30)	(6)
Net loss	$ (27,250)	$ (25,486)
Net loss per share - basic and diluted	$ (0.31)	$ (0.35)
Weighted-average shares outstanding - basic and diluted	86,983	72,786
Product revenue
Revenue from Contract with Customer, Including Assessed Tax	$ 0	$ 2,300
Operating expenses:
Cost of Goods and Services Sold	5,468	4,359
License and royalty
Revenue from Contract with Customer, Including Assessed Tax	10,011	350
Contract
Revenue from Contract with Customer, Including Assessed Tax	7,596	6,984
Operating expenses:
Cost of Goods and Services Sold	$ 5,170	$ 5,503