Condensed Consolidated Statements of Operations (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Revenues:
Total revenue	$ 1,928	$ 1,403	$ 74,634	$ 7,111
Operating expenses:
Research and development	70,684	39,863	215,316	95,541
General and administrative	18,859	9,220	47,894	25,790
Total operating expenses	89,543	49,083	263,210	121,331
Loss from operations	(87,615)	(47,680)	(188,576)	(114,220)
Other income (expense):
Interest income	412	2,012	2,548	6,564
Other income (expense), net	2,616	(2,659)	(6,904)	(3,251)
Total other income (expense)	3,028	(647)	(4,356)	3,313
Loss before benefit from (provision for) income taxes	(84,587)	(48,327)	(192,932)	(110,907)
Benefit from (provision for) income taxes	(22)	13	(84)	(5)
Net loss	$ (84,609)	$ (48,314)	$ (193,016)	$ (110,912)
Net loss per share, basic and diluted	$ (0.67)	$ (4.60)	$ (1.66)	$ (11.53)
Weighted-average shares outstanding, basic and diluted	125,810,907	10,500,848	116,427,529	9,615,379
Grant Revenue [Member]
Revenues:
Total revenue	$ 1,740	$ 1,166	$ 7,690	$ 6,771
License
Revenues:
Total revenue			22,747
Contract Revenue [Member]
Revenues:
Total revenue	$ 188	$ 237	$ 44,197	$ 340