Stock-Based Compensation - Schedule of Shares Available for Future Grants (Details)	9 Months Ended
	Sep. 30, 2021 shares
Share-based Compensation Activity [Roll Forward]
Options available for future grant at beginning of period (in shares)	142,693,665
Awards granted (in shares)	(6,951,470)
Options forfeited and canceled (in shares)	647,791
Options available for future grant at end of period (in shares)	63,939,109