Stock-Based Compensation Expense and Employee Benefit Plans - Number of Shares Available for Grant (Details)	12 Months Ended
	Dec. 31, 2021 shares
Options/ RSUs Available for Grant
Beginning balance (in shares)	20,233,754
Added to plan (in shares)	8,102,014
Granted (in shares)	6,475,536
Cancelled (in shares)	2,778,276
Expired (in shares)	491,724
Ending Balance (in shares)	24,146,784