Condensed Consolidated Statements of Operations and Comprehensive Loss - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Revenues:
Cost of revenue		$ 464
Gross profit		1,856
Operating expenses:
Research and development	$ 20,381	13,350
General and administrative	5,117	6,191
Total operating expenses	25,498	19,541
Loss from operations	(25,498)	(17,685)
Interest expense	(1,434)
Other income (expense), net	790	670
Loss before provision for income taxes	(26,142)	(17,015)
Provision for income taxes	2	4
Net loss	$ (26,144)	$ (17,019)
Net loss per common share, basic and diluted	$ (0.42)	$ (0.36)
Shares used in computing net loss per share - basic and diluted	62,546,295	47,559,366
Comprehensive loss:
Net loss	$ (26,144)	$ (17,019)
Unrealized gain (loss) on available-for-sale securities, net of tax	50	(44)
Comprehensive loss	$ (26,094)	(17,063)
Licensing
Revenues:
Total revenues		$ 2,320