Stock-Based Compensation Expense and Employee Benefit Plans - Employee Stock Purchase Plan (Details)		12 Months Ended
	Jul. 05, 2018	Dec. 31, 2021 USD ($) shares	Dec. 31, 2020 USD ($)	Jul. 25, 2018 shares	Apr. 30, 2018 shares
Employee Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of share maximum per employee		2,500
Share-Based Compensation Arrangement By Share-based Payment Award, Purchase Period		6 months
Share-based Compensation Arrangement by Share-based Payment Award, Maximum Employee Subscription Amount | $		$ 25,000
2018 ESPP
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of common stock reserved for issuance (in shares)		2,544,668
Employee stock ownership plan (ESOP), compensation expense | $		$ 7,700,000	$ 5,700,000
Share-based compensation arrangement by share-based payment award, shares issued in period		1,945,305
Number of additional shares authorized (in shares)		1,902,572
Unrecognized stock-based compensation cost | $		$ 9,800,000
Expense expected to be recognized over a weighted-average period		6 months
2018 ESPP | Employee Stock | Class A common stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of common stock reserved for issuance (in shares)					33,333,333
Number of common stock reserved for issuance (in shares)				3,333,333
Employee Purchase Plan, Number Of Share Reserved For Issuance Increase, Term	9 years
Employee Purchase Plan, Percentage Of Total Outstanding Shares				0.01
Purchase price of common stock, percentage of fair market value			85.00%