STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Revenue:
Total revenue			$ 20,000
Revenue from Contract with Customer, Product and Service [Extensible List]	us-gaap:LicenseMember	us-gaap:LicenseMember	us-gaap:LicenseMember	us-gaap:LicenseMember
Operating expenses:
Research and development	$ 38,700	$ 13,928	$ 72,113	$ 28,892
General and administrative	10,230	2,401	24,575	4,399
Acquisition of in-process research and development				143,333
Total operating expenses	48,930	16,329	96,688	176,624
Loss from operations	(48,930)	(16,329)	(76,688)	(176,624)
Other income:
Interest income	520	647	1,829	1,408
Total other income	520	647	1,829	1,408
Net loss	$ (48,410)	$ (15,682)	$ (74,859)	$ (175,216)
Net loss per share attributable to common stockholders— basic and diluted	$ (65)	$ (1,568,200)	$ (150)	$ (17,521,600)
Weighted average common shares outstanding— basic and diluted	749,539	10	497,924	10
Other comprehensive loss
Change in unrealized gains losses on marketable securities, net	$ (30)		$ (30)
Total other comprehensive loss	(30)		(30)
Total comprehensive loss	$ (48,440)	$ (15,682)	$ (74,889)	$ (175,216)