Share-Based Compensation - Stock Options Activity (Details) - Stock Option - USD ($)	9 Months Ended	12 Months Ended
	Sep. 30, 2021	Dec. 31, 2020
Shares
Beginning balance (in shares)	963,726
Granted (in shares)	278,605
Exercised (in shares)	(131,685)
Forfeited/Expired (in shares)	(37,979)
Ending balance (in shares)	1,072,667	963,726
Vested and expected to vest (in shares)	1,021,851
Exercisable (in shares)	495,853
Weighted Average Price
Beginning Balance, Weighted Average Price (in dollars per share)	$ 125.70
Granted, Weighted Average Price (in dollars per share)	198.21
Exercised, Weighted Average Price (in dollars per share)	111.07
Forfeited, Weighted Average Price (in dollars per share)	165.68
Ending Balance, Weighted Average Price (in dollars per share)	$ 144.92	$ 125.70
Weighted-Average Remaining Contractual Term
Stock options outstanding, Weighted-Average Remaining Contractual Term	7 years 25 days	6 years 11 months 8 days
Aggregate Intrinsic Value
Stock options outstanding, Aggregate intrinsic value	$ 66,728,398	$ 70,829,529
Vested and expected to vest , Weighted Average Price (in dollars per share)	$ 142.97
Exercisable, Weighted Average Price (in dollars per share)	$ 106.25
Weighted-Average Remaining Contractual Term, Vested and expected to vest	6 years 11 months 23 days
Weighted-Average Remaining Contractual Term, Exercisable	5 years 3 months 10 days
Aggregate Intrinsic Value, Vested and expected to vest	$ 65,520,705
Aggregate Intrinsic Value, Exercisable	$ 49,933,371