Related Party Transactions (Details) - Affiliated Entity - Purchase of Common Stock from Founders - USD ($)	1 Months Ended	3 Months Ended	9 Months Ended
Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Related Party Transaction [Line Items]
Number of shares purchased (in shares)	8,909,092
Purchase price	$ 98,000,000.0
Stock-based compensation expense recorded		$ 0	$ 23,300,000	$ 0	$ 23,300,000

Amount of transactions with related party during the financial reporting period.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 850
-SubTopic 10
-Section 50
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-URI http://asc.fasb.org/extlink&oid=6457730&loc=d3e39549-107864

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
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Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
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-Name Accounting Standards Codification
-Topic 850
-SubTopic 10
-Section 50
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