Redeemable Convertible Preferred Stock and Common Stock (Details)		1 Months Ended		12 Months Ended
	Jul. 30, 2018 shares	Dec. 31, 2015 $ / shares shares	Oct. 31, 2012 shares	Dec. 31, 2018 shares	Dec. 31, 2019 shares
Class of Stock [Line Items]
Redeemable convertible preferred stock, conversion ratio		1
Issuance of common stock upon conversion of redeemable convertible preferred stock (in shares)	55,385,854
Common stock, authorized (in shares)	500,000,000			500,000,000	500,000,000
Preferred stock, authorized (in shares)	10,000,000
Preferred stock, issued (in shares)				0	0
Preferred stock, outstanding (in shares)				0	0
Series A Redeemable Convertible Preferred Stock
Class of Stock [Line Items]
Stock sold (in shares)		15,847,500	15,847,500
Redeemable convertible preferred stock, par value (in usd per share) | $ / shares		$ 0.01
Series B Redeemable Convertible Preferred Stock
Class of Stock [Line Items]
Stock sold (in shares)		39,538,354
Redeemable convertible preferred stock, par value (in usd per share) | $ / shares		$ 0.01
Redeemable convertible preferred stock, shares authorized (in shares)		42,000,000
Common Stock
Class of Stock [Line Items]
Issuance of common stock upon conversion of redeemable convertible preferred stock (in shares)				55,386,000
Common Stock | IPO
Class of Stock [Line Items]
Stock sold (in shares)	12,535,000
Issuance of common stock upon conversion of redeemable convertible preferred stock (in shares)	55,385,854