Condensed Consolidated Statements of Operations and Comprehensive Loss - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Operating expenses:
Research and development	$ 35,676	$ 7,930	$ 60,659	$ 10,554
In process research and development	1,000	20,500	2,000	41,398
General and administrative	9,673	4,606	17,707	7,210
Total operating expenses	46,349	33,036	80,366	59,162
Loss from operations	(46,349)	(33,036)	(80,366)	(59,162)
Other income, net	1,851	300	3,257	389
Net loss	(44,498)	(32,736)	(77,109)	(58,773)
Other comprehensive income:
Unrealized gain on marketable securities, net of tax	417	3	557	3
Other comprehensive income	417	3	557	3
Comprehensive loss	$ (44,081)	$ (32,733)	$ (76,552)	$ (58,770)
Net loss per share, basic and diluted	$ (0.74)	$ (5.65)	$ (1.59)	$ (10.14)
Weighted average common shares outstanding, basic and diluted	60,265,046	5,795,053	48,357,294	5,796,370