CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
CONSOLIDATED STATEMENT OF COMPREHENSIVE LOSS
Revenue	$ 4,774		$ 12,919
Operating expenses:
Research and development	15,699	$ 8,061	40,153	$ 26,185
General and administrative	6,181	3,173	14,961	8,947
Total operating expenses	21,880	11,234	55,114	35,132
Loss from operations	(17,106)	(11,234)	(42,195)	(35,132)
Other income (expense), net	959	472	2,768	772
Net loss	$ (16,147)	$ (10,762)	$ (39,427)	$ (34,360)
Net loss per share, basic and diluted (in dollars per share)	$ (0.55)	$ (0.44)	$ (1.46)	$ (2.72)
Weighted average common shares outstanding, basic and diluted (in shares)	29,232,158	24,310,681	26,929,215	12,647,032
Comprehensive loss:
Net loss	$ (16,147)	$ (10,762)	$ (39,427)	$ (34,360)
Other comprehensive income (loss):
Unrealized gain (loss) on marketable securities	(32)		34	2
Total other comprehensive income (loss)	(32)		34	2
Comprehensive loss	$ (16,179)	$ (10,762)	$ (39,393)	$ (34,358)