Share-Based Compensation - Stock Options (Details) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2021 USD ($) $ / shares shares
Number of shares
Outstanding at beginning of period (in shares)	7,545,907
Granted (in shares)	1,135,850
Exercised (in shares)	(76,072)
Forfeited (in shares)	(56,102)
Outstanding at end of period (in shares)	8,549,583
Options exercisable (in shares)	5,298,569
Options vested and expected to vest (in shares)	8,549,583
Weighted Average Exercise Price
Outstanding at beginning of period (in dollars per share) | $ / shares	$ 28.21
Granted (in dollars per share) | $ / shares	83.31
Exercised (in dollars per share) | $ / shares	35.06
Forfeited (in dollars per share) | $ / shares	59.17
Outstanding at end of period (in dollars per share) | $ / shares	35.27
Options exercisable (in dollars per share) | $ / shares	25.14
Options vested and expected to vest (in dollars per share) | $ / shares	$ 35.27
Weighted Average Contractual Term and Aggregate Intrinsic Value
Weighted average remaining contractual term of options outstanding (in years)	7 years 1 month 20 days
Weighted average remaining contractual term of options exercisable (in years)	6 years 4 months 6 days
Weighted average remaining contractual term of options vested and expected to vest (in years)	7 years 1 month 20 days
Aggregate intrinsic value of options outstanding | $	$ 300,544
Aggregate intrinsic value of options exercisable | $	233,353
Aggregate intrinsic value of options vested and expected to vest | $	$ 300,544
Additional Disclosures
Unvested options expected to vest (in shares)	3,251,014
Stock options
Additional Disclosures
Share-based award term (in years)	10 years
Total unrecognized compensation cost | $	$ 85,068
Weighted average period for recognition of compensation cost	2 years 25 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