Convertible Preferred Stock - Tabular Disclosure (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2018
Class of Stock [Line Items]
Convertible preferred stock, shares authorized (in shares)	100,000,000	314,930,070
Convertible preferred stock, shares issued (in shares)	0	65,428,088	65,428,088
Convertible preferred stock, shares outstanding (in shares)	0	65,428,088
Convertible preferred stock, aggregate liquidation preference	$ 0	$ 106,369
Series A Preferred Stock
Class of Stock [Line Items]
Convertible preferred stock, shares authorized (in shares)		69,930,070
Convertible preferred stock, shares issued (in shares)		15,384,798
Convertible preferred stock, shares outstanding (in shares)		15,384,798
Convertible preferred stock, aggregate liquidation preference		$ 20,000
Series B Preferred Stock
Class of Stock [Line Items]
Convertible preferred stock, shares authorized (in shares)		245,000,000
Convertible preferred stock, shares issued (in shares)		50,043,290
Convertible preferred stock, shares outstanding (in shares)		50,043,290
Convertible preferred stock, aggregate liquidation preference		$ 86,369