STATEMENTS OF OPERATIONS - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Operating expenses:
Research and development	$ 12,051	$ 9,998	$ 24,757	$ 19,474
General and administrative	6,555	4,755	12,509	8,900
Total operating expenses	18,606	14,753	37,266	28,374
Loss from operations	(18,606)	(14,753)	(37,266)	(28,374)
Other income, net	10	133	377	320
Net loss	$ (18,596)	$ (14,620)	$ (36,889)	$ (28,054)
Basic and diluted net loss per share	$ (0.09)	$ (0.09)	$ (0.18)	$ (0.17)
Weighted average common shares outstanding used to compute basic and diluted net loss per share	212,792,403	160,789,272	206,303,586	160,718,313