Asset Acquisition - Additional Information (Details) - USD ($) $ / shares in Units, shares in Millions	1 Months Ended	6 Months Ended
	Aug. 31, 2019	Jun. 30, 2019
Research And Development Assets Acquired Other Than Through Business Combination [Line Items]
In-process research and development expenses		$ 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 | Subsequent Event
Research And Development Assets Acquired Other Than Through Business Combination [Line Items]
Specified clinical and regulatory milestones phase two clinical trial achieved	$ 2,500,000
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