Asset Acquisition - Additional Information (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Mar. 31, 2019	Sep. 30, 2020	Sep. 30, 2019
Research And Development Assets Acquired Other Than Through Business Combination [Line Items]
In-process research and development expenses		$ 25,600,000		$ 25,591,000
GSK Agreement
Research And Development Assets Acquired Other Than Through Business Combination [Line Items]
Specified clinical and regulatory milestones phase two clinical trial	$ 2,500,000
Direct expenses related to the transaction			$ 100,000
GSK Agreement | Maximum
Research And Development Assets Acquired Other Than Through Business Combination [Line Items]
Specified clinical and regulatory milestones			37,500,000
Specified sales milestone			$ 60,000,000
Series B Convertible Preferred Stock | GSK Agreement
Research And Development Assets Acquired Other Than Through Business Combination [Line Items]
Shares issued for asset acquisition			12,500,000
Shares issued for asset acquisition, estimated fair value			$ 25,500,000
Shares issued, price per share			$ 2.04