Business and Summary of Significant Accounting Policies - Initial Public Offering (Details) - USD ($) $ / shares in Units, $ in Millions		12 Months Ended
	Jul. 30, 2018	Dec. 31, 2018	Dec. 31, 2019
Subsidiary, Sale of Stock [Line Items]
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
IPO
Subsidiary, Sale of Stock [Line Items]
Stock sold, price per share (in usd per share)	$ 23.00
Net proceeds from sale of stock	$ 264.6
Common Stock
Subsidiary, Sale of Stock [Line Items]
Issuance of common stock upon conversion of redeemable convertible preferred stock (in shares)		55,386,000
Common Stock | IPO
Subsidiary, Sale 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
Common Stock | Over-allotment option
Subsidiary, Sale of Stock [Line Items]
Stock sold (in shares)	1,635,000
Redeemable convertible Series A preferred stock | IPO
Subsidiary, Sale of Stock [Line Items]
Issuance of common stock upon conversion of redeemable convertible preferred stock (in shares)	15,847,500
Redeemable convertible Series B preferred stock | IPO
Subsidiary, Sale of Stock [Line Items]
Issuance of common stock upon conversion of redeemable convertible preferred stock (in shares)	39,538,354