CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Revenue
Total revenue	$ 13,398	$ 3,335	$ 12,926
Expenses
Research and development	299,349	182,866	93,872
General and administrative	83,412	42,573	21,681
Total operating expenses	382,761	225,439	115,553
Loss from operations	(369,363)	(222,104)	(102,627)
Other income, net	11,426	8,848	4,209
Net loss	(357,937)	(213,256)	(98,418)
Unrealized (loss) gain on available-for-sale investments	130	(410)	0
Comprehensive loss	$ (358,067)	$ (212,846)	$ (98,418)
Basic and diluted net loss per share (USD per share)	$ (7.96)	$ (5.69)	$ (3.19)
Weighted average common shares outstanding, basic and diluted (shares)	44,987,555	37,467,505	30,897,717