Subsequent Events - Merger Agreement and Stock Purchase Agreement (Details) - USD ($)		12 Months Ended
	Jan. 28, 2021	Dec. 31, 2020	Dec. 31, 2019
Subsequent Events
Aggregate shares sold under purchase agreement		$ 16,270,000	$ 6,996,000
Common Stock
Subsequent Events
Aggregate shares sold under purchase agreement		$ 3,000	$ 1,000
Subsequent Events | Series X Preferred Stock | Quellis Biosciences, Inc
Subsequent Events
Shares issued upon merger (in shares)	50,504
Warrants to purchase number of shares	2,805
Exercise Price (in dollars per share)	$ 341.70
Subsequent Events | Common Stock | Quellis Biosciences, Inc
Subsequent Events
Shares issued upon merger (in shares)	3,332,669
Share price (in dollars per share)	$ 0.001
Warrants to purchase number of shares	185,136
Exercise Price (in dollars per share)	$ 0.35
Conversion value	$ 122,700,000
Subsequent Events | Stock Purchase Agreement | Series X Preferred Stock
Subsequent Events
Aggregate shares sold under purchase agreement	35,573
Purchase price	110,000,000
Subsequent Events | Stock Purchase Agreement | Common Stock | Series X Preferred Stock
Subsequent Events
Purchase price	$ 1,000