Stock-Based Compensation - Schedule of Shares Available for Grant and Stock Option Activity (Details) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended		3 Months Ended	12 Months Ended
	Apr. 30, 2019	Mar. 31, 2019	Mar. 31, 2020	Dec. 31, 2019
Shares Available for Grant
Balance as of December 31, 2019 (in shares)			8,160,000
Shares authorized (in shares)			3,812,000
Forfeited/cancelled (in shares)			144,000
Balance as of March 31, 2020 (in shares)			11,866,000	8,160,000
Shares Subject to Options Outstanding
Balance as of December 31, 2019 (in shares)			14,020,000
Exercised (in shares)			(1,247,000)
Forfeited/cancelled (in shares)			(144,000)
Balance as of March 31, 2020 (in shares)			12,629,000	14,020,000
Options vested and exercisable as of March 31, 2020 (in shares)			9,176,000
Weighted- Average Exercise Price
Balance as of December 31, 2019 (in USD per share)			$ 1.85
Exercised (in USD per share)			1.38
Forfeited/cancelled (in USD per share)			1.88
Balance as of March 31, 2020 (in USD per share)			1.89	$ 1.85
Options vested and exercisable as of June 30, 2019 (in USD per share)			$ 1.53
Weighted- Average Remaining Contractual Life (Years) and Aggregate Intrinsic Value
Weighted- Average Remaining Contractual Life (Years), Options outstanding			6 years 4 months 24 days	6 years 8 months 12 days
Weighted- Average Remaining Contractual Life (Years), Options vested and exercisable			6 years
Aggregate Intrinsic Value, Options outstanding			$ 336,424	$ 325,474
Aggregate Intrinsic Value, Options vested and exercisable			$ 247,727
Restricted Stock Awards
Shares Available for Grant
Granted (in shares)		(982,301)
Restricted stock units
Shares Available for Grant
Granted (in shares)			(726,000)
Performance stock units
Shares Available for Grant
Forfeited (in shares)			375,000
Performance-Based RSUs
Shares Available for Grant
Granted (in shares)	(100,000)		(23,196)
Forfeited (in shares)			101,000