Condensed Consolidated Statements of Operations - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2019	Mar. 31, 2018
Operating expenses:
Research and development	$ 10,137	$ 8,334
General and administrative	3,365	3,420
Total operating expenses	13,502	11,754
Loss from operations	(13,502)	(11,754)
Other income, net	325	272
Loss before provision for (benefit from) income taxes, net	(13,177)	(11,482)
Provision for (benefit from) income taxes, net	(145)	43
Net loss	$ (13,032)	$ (11,525)
Net loss per common share, basic and diluted	$ (0.17)	$ (0.19)
Weighted-average shares used in computing net loss per common share, basic and diluted	74,485,295	59,722,743

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