Share-Based Compensation - Stock Options (Details) $ / shares in Units, $ in Thousands	9 Months Ended
	Sep. 30, 2020 USD ($) $ / shares shares
Number of shares
Outstanding at beginning of period (in shares)	9,423,015
Granted (in shares)	311,338
Exercised (in shares)	(1,700,357)
Forfeited (in shares)	(87,876)
Outstanding at end of period (in shares)	7,946,120
Options exercisable (in shares)	4,474,848
Options unvested (in shares)	7,946,120
Weighted Average Exercise Price
Outstanding at beginning of period (in dollars per share) | $ / shares	$ 24.58
Granted (in dollars per share) | $ / shares	53.60
Exercised (in dollars per share) | $ / shares	11.69
Forfeited (in dollars per share) | $ / shares	42.32
Outstanding at end of period (in dollars per share) | $ / shares	28.28
Options exercisable (in dollars per share) | $ / shares	20.13
Options unvested (in dollars per share) | $ / shares	$ 28.28
Weighted Average Contractual Term and Aggregate Intrinsic Value
Weighted average remaining contractual term of options outstanding (in years)	7 years 2 months 23 days
Weighted average remaining contractual term of options exercisable (in years)	6 years 5 months 4 days
Weighted average remaining contractual term of options vested and expected to vest (in years)	7 years 2 months 23 days
Aggregate intrinsic value of options outstanding | $	$ 292,267
Aggregate intrinsic value of options exercisable | $	200,903
Aggregate intrinsic value of options vested and expected to vest | $	$ 292,267
Additional Disclosures
Unvested stock options expected to vest (in shares)	3,471,272
Stock options
Additional Disclosures
Share-based award term (in years)	10 years
Total unrecognized compensation cost | $	$ 65,128
Weighted average period for recognition of compensation cost	1 year 11 months 12 days
Stock options | Minimum
Additional Disclosures
Share-based award vesting period (in years)	3 years
Stock options | Maximum
Additional Disclosures
Share-based award vesting period (in years)	4 years