Convertible Senior Notes - Net carrying value of the liability component (Details) - Senior Notes - Convertible Debt - USD ($) $ in Thousands	Apr. 30, 2020	Jul. 31, 2019
Debt Instrument [Line Items]
Principal	$ 400,000	$ 400,000
Debt discount	65,489	74,213
Debt issuance cost	7,591	8,465
Net carrying amount	$ 326,920	$ 317,322

Face (par) amount of debt instrument at time of issuance.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Amount of unamortized debt discount (premium) and debt issuance costs.

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Amount, after accumulated amortization, of debt issuance costs. Includes, but is not limited to, legal, accounting, underwriting, printing, and registration costs.

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Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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