Share-Based Compensation - Stock Option Activity (Details) - USD ($) $ / shares in Units, $ in Thousands	6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019
Shares
Beginning balance (in shares)	56,966,000
Granted (in shares)	1,130,000	0
Exercised (in shares)	(15,518,000)
Ending balance (in shares)	42,578,000
Exercisable (in shares)	41,588,000
Weighted-Average Exercise Price
Beginning balance (in dollars per share)	$ 2.25
Granted (in dollars per share)	22.35
Exercised (in dollars per share)	2.11
Ending balance (in dollars per share)	2.84
Exercisable (in dollars per share)	$ 2.38
Weighted-Average Remaining Contractual Term, Outstanding	3 years 2 months 12 days	3 years 6 months
Weighted-Average Remaining Contractual Term, Exercisable	3 years 1 month 6 days
Aggregate Intrinsic Value, Outstanding	$ 823,099		$ 933,299
Aggregate Intrinsic Value, Exercisable	$ 823,087