Warrants - Summary of Warrants Outstanding and Exercisable (Details)	Sep. 30, 2019 $ / shares shares
Series B Convertible Preferred Warrants Exercise Price $16.60
Class Of Warrant Or Right [Line Items]
Number of warrants outstanding	54,396
Warrants exercise price, outstanding \| $ / shares	$ 16.60
Number of warrants exercisable	54,396
Warrants exercise price, exercisable \| $ / shares	$ 16.60
Series B Convertible Preferred Warrants Exercise Price $16.80
Class Of Warrant Or Right [Line Items]
Number of warrants outstanding	17,857
Warrants exercise price, outstanding \| $ / shares	$ 16.80
Number of warrants exercisable	17,857
Warrants exercise price, exercisable \| $ / shares	$ 16.80
Series B Convertible Preferred Warrants Exercise Price $24.30
Class Of Warrant Or Right [Line Items]
Number of warrants outstanding	12,383
Warrants exercise price, outstanding \| $ / shares	$ 24.30
Number of warrants exercisable	12,383
Warrants exercise price, exercisable \| $ / shares	$ 24.30
Series B Convertible Preferred Warrants Exercise Price $28.50
Class Of Warrant Or Right [Line Items]
Number of warrants outstanding	33,393
Warrants exercise price, outstanding \| $ / shares	$ 28.50
Number of warrants exercisable	33,393
Warrants exercise price, exercisable \| $ / shares	$ 28.50
Series B Convertible Preferred Stock Warrants
Class Of Warrant Or Right [Line Items]
Number of warrants outstanding	118,029
Number of warrants exercisable	118,029