Preferred and Common Stock Warrants - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands					12 Months Ended
	Nov. 29, 2019	Nov. 26, 2019	Apr. 16, 2019	Apr. 12, 2019	Dec. 31, 2019	Mar. 31, 2019	Mar. 13, 2019	Dec. 31, 2018
Class of Stock [Line Items]
Fair value of warrants						$ 288	$ 5,200
Warrants issued (in shares)					13,201,667
Warrant expiration period		30 days		5 years
Common stock par value (in dollars per share)					$ 0.001			$ 0.001
Class A Warrant
Class of Stock [Line Items]
Warrants issued (in shares)			3,900,000
Convertible preferred stock exercise price (in dollars per share)			$ 13.20	$ 13.20
Class B Warrants
Class of Stock [Line Items]
Warrants issued (in shares)	5,416,667
Convertible preferred stock exercise price (in dollars per share)	$ 15.00	$ 15.00
Pre Funded Warrant
Class of Stock [Line Items]
Warrants issued (in shares)	1,750,000		2,130,000
Convertible preferred stock exercise price (in dollars per share)	$ 11.999	$ 11.999	$ 10.999	$ 10.999
Warrants available to purchase (in shares)			1
Common stock par value (in dollars per share)			$ 0.001