Share-Based Compensation - Stock Options (Details) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2020 USD ($) $ / shares shares
Number of shares
Outstanding at beginning of period (in shares)	9,423,015
Granted (in shares)	88,838
Exercised (in shares)	(350,461)
Forfeited (in shares)	(24,563)
Outstanding at end of period (in shares)	9,136,829
Options exercisable (in shares)	5,315,110
Options unvested (in shares)	9,136,829
Weighted Average Exercise Price
Outstanding at beginning of period (in dollars per share) | $ / shares	$ 24.58
Granted (in dollars per share) | $ / shares	45.63
Exercised (in dollars per share) | $ / shares	7.44
Forfeited (in dollars per share) | $ / shares	36.95
Outstanding at end of period (in dollars per share) | $ / shares	25.41
Options exercisable (in dollars per share) | $ / shares	16.47
Options unvested (in dollars per share) | $ / shares	$ 25.41
Weighted Average Contractual Term and Aggregate Intrinsic Value
Weighted average remaining contractual term of options outstanding (in years)	7 years 6 months 3 days
Weighted average remaining contractual term of options exercisable (in years)	6 years 7 months 24 days
Weighted average remaining contractual term of options vested and expected to vest (in years)	7 years 6 months 3 days
Aggregate intrinsic value of options outstanding | $	$ 119,446
Aggregate intrinsic value of options exercisable | $	106,407
Aggregate intrinsic value of options vested and expected to vest | $	$ 119,446
Additional Disclosures
Unvested stock options expected to vest (in shares)	3,821,719
Stock options
Additional Disclosures
Share-based award term (in years)	10 years
Total unrecognized compensation cost | $	$ 77,324
Weighted average period for recognition of compensation cost	2 years 4 months 20 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