Segment and Geographic Information - Additional Information (Details)	9 Months Ended	12 Months Ended
	Sep. 30, 2021 BusinessActivity SegmentManager Segment	Dec. 31, 2020 Segment
Segment Reporting Information [Line Items]
Number of business activity | BusinessActivity	1
Number of segment managers held accountable for operations or operating results | SegmentManager	0
United States
Segment Reporting Information [Line Items]
Number of reportable segments | Segment	1	1