Condensed Consolidated Statements of Operations and Comprehensive Loss (Unaudited) - 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	$ 38,684	$ 35,676	$ 80,098	$ 60,659
In process research and development	15,000	1,000	17,805	2,000
General and administrative	11,655	9,673	22,403	17,707
Total operating expenses	65,339	46,349	120,306	80,366
Loss from operations	(65,339)	(46,349)	(120,306)	(80,366)
Other income (expense), net	(1,531)	1,851	(638)	3,257
Net loss	(66,870)	(44,498)	(120,944)	(77,109)
Other comprehensive income:
Foreign currency translation, net of tax	78	0	(9)	0
Unrealized gain on marketable securities, net of tax	994	417	318	557
Other comprehensive income	1,072	417	309	557
Comprehensive loss	$ (65,798)	$ (44,081)	$ (120,635)	$ (76,552)
Net loss per share, basic and diluted	$ (1.00)	$ (0.74)	$ (1.88)	$ (1.59)
Weighted average common shares outstanding, basic and diluted	66,599,915	60,265,046	64,245,119	48,357,294