Convertible Senior Notes, Net - Schedule of Liability and Equity Component of Notes (Details) - Senior Notes $ in Thousands	Oct. 31, 2020 USD ($)
Convertible Senior Notes Due 2023
Liability component:
Principal	$ 40,246
Less: unamortized debt issuance costs and debt discount	(5,115)
Net carrying amount	35,131
Convertible Senior Notes Due 2025
Liability component:
Principal	1,060,000
Less: unamortized debt issuance costs and debt discount	(196,126)
Net carrying amount	863,874
Convertible Senior Notes Due 2026
Liability component:
Principal	1,150,000
Less: unamortized debt issuance costs and debt discount	(304,097)
Net carrying amount	845,903
Additional Paid-in Capital | Convertible Senior Notes Due 2023
Equity component:
Equity component	9,328
Less: issuance costs	(271)
Carrying amount of the equity component	9,057
Additional Paid-in Capital | Convertible Senior Notes Due 2025
Equity component:
Equity component	221,387
Less: issuance costs	(4,040)
Carrying amount of the equity component	217,347
Additional Paid-in Capital | Convertible Senior Notes Due 2026
Equity component:
Equity component	310,311
Less: issuance costs	(4,090)
Carrying amount of the equity component	$ 306,221