Stockholders' Equity (Deficit) - Common Stock Warrants (Details) - Warrants to purchase common stock - $ / shares		1 Months Ended	12 Months Ended
	Sep. 29, 2017	Sep. 30, 2017	Dec. 31, 2019
Class Of Stock [Line Items]
Warrants exercise price per share	$ 63.14	$ 6.13
Warrants issued expiration period			The warrants expire on various dates in September, November and December 2022.
Number of common stock warrants exercised			196
Private Placement, September 2017
Class Of Stock [Line Items]
Number of common stock warrants exercised			0
Warrants issued to purchase shares under private placement	469,996
Warrant term	5 years
Common stock warrants expiration date	Sep. 29, 2022
Series B-2 Convertible Preferred Stock
Class Of Stock [Line Items]
Warrants issued		371,624