CONSOLIDATED 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
Operating expenses:
Research and development	$ 22,997	$ 35,308	$ 45,501	$ 58,069
Selling, general, and administrative	8,921	8,841	21,717	16,600
Total operating expenses	31,918	44,149	67,218	74,669
Loss from operations	(31,918)	(44,149)	(67,218)	(74,669)
Other income (expense):
Interest income, net	801	1,353	1,937	2,899
Total other income, net	801	1,353	1,937	2,899
Net loss	$ (31,117)	$ (42,796)	$ (65,281)	$ (71,770)
Net loss per share, basic and diluted	$ (0.71)	$ (1.24)	$ (1.48)	$ (2.08)
Weighted-average common shares outstanding, basic and diluted	44,098,860	34,452,661	44,074,352	34,435,023
Other comprehensive loss:
Net loss	$ (31,117)	$ (42,796)	$ (65,281)	$ (71,770)
Unrealized gain on marketable securities	567		630
Comprehensive loss	$ (30,550)	$ (42,796)	$ (64,651)	$ (71,770)