STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Expenses:
Research and development	$ 11,752	$ 10,010	$ 26,756	$ 18,882
General and administrative	4,130	2,502	7,980	6,169
Loss from operations	(15,882)	(12,512)	(34,736)	(25,051)
Interest income	212	90	398	186
Other expense, net	(5)	(1)	(9)	(41)
Net loss	(15,675)	(12,423)	(34,347)	(24,906)
Deemed divideds on convertible preferred stock			(8,880)
Net loss applicable to common shareholders	$ (15,675)	$ (12,423)	$ (43,227)	$ (24,906)
Per share information:
Net loss per share of common stock-basic and diluted	$ (0.16)	$ (0.24)	$ (0.46)	$ (0.47)
Basic and diluted weighted average shares outstanding	99,770,498	52,522,225	93,180,795	52,493,874
Net loss	$ (15,675)	$ (12,423)	$ (34,347)	$ (24,906)
Other comprehensive income:
Unrealized gain on available-for-sale securities			27
Total comprehensive loss	$ (15,675)	$ (12,423)	$ (34,320)	$ (24,906)