Share-Based Compensation - Stock Option Activity (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Shares
Beginning balance (in shares)	56,966,000
Granted (in shares)	1,130,000	0
Exercised (in shares)	(8,923,000)
Ending balance (in shares)	49,173,000
Exercisable (in shares)	48,105,000
Weighted-Average Exercise Price
Beginning balance (in dollars per share)	$ 2.25
Granted (in dollars per share)	22.35
Exercised (in dollars per share)	2.28
Ending balance (in dollars per share)	2.71
Exercisable (in dollars per share)	$ 2.28
Weighted-Average Remaining Contractual Term, Outstanding	3 years 4 months 24 days	3 years 6 months
Weighted-Average Remaining Contractual Term, Exercisable	3 years 3 months 18 days
Aggregate Intrinsic Value, Outstanding	$ 625,770		$ 933,299
Aggregate Intrinsic Value, Exercisable	$ 632,999