Business and Summary of Significant Accounting Policies	6 Months Ended
Business and Summary of Significant Accounting Policies	Jan. 31, 2020
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Business and Summary of Significant Accounting Policies	Business and Summary of Significant Accounting Policies Description of the Business Zscaler, Inc. ("Zscaler," the "Company," "we," "us," or "our") is a cloud security company that developed a platform incorporating core security functionalities needed to enable users to safely utilize authorized applications and services based on an organization’s policies. Our solution is a purpose-built, multi-tenant, distributed cloud security platform that secures access for users and devices to applications and services, regardless of location. We deliver our solutions using a software-as-a-service ("SaaS") business model and sell subscriptions to customers to access our cloud platform, together with related support services. We were incorporated in Delaware in September 2007 and conduct business worldwide, with presence in North America, Europe and Asia. Our headquarters are in San Jose, California. Basis of Presentation The accompanying unaudited condensed consolidated financial statements have been prepared in conformity with accounting principles generally accepted in the United States ("U.S. GAAP") and applicable regulations of the Securities and Exchange Commission ("SEC") regarding interim financial reporting, and include the accounts of the Company and its wholly owned subsidiaries. All intercompany balances and transactions have been eliminated in consolidation. Certain information and note disclosures normally included in the financial statements prepared in accordance with U.S. GAAP have been condensed or omitted pursuant to the applicable required disclosures and regulations of the SEC. Therefore, these unaudited condensed consolidated financial statements and accompanying footnotes should be read in conjunction with the Company's audited consolidated financial statements and related notes in its Annual Report on Form 10-K for the fiscal year ended July 31, 2019 (the "Fiscal 2019 Form 10-K"), as filed with the SEC on September 18, 2019. JOBS Act Extended Transition Period As a result of the market value of our common stock held by our non-affiliates as of January 31, 2019, we ceased to be an "emerging growth company" ("EGC"), as defined in the Jumpstart Our Business Startups Act of 2012 (the "JOBS Act"), with our transition to a large accelerated filer status as of July 31, 2019. As an EGC, we elected not to avail ourselves of the extended transition periods available for complying with new or revised accounting pronouncements applicable to public companies that are not emerging growth companies. Accordingly, the transition to a large accelerated filer did not have an impact to our consolidated financial statements. Interim Unaudited Condensed Consolidated Financial Statements The accompanying condensed consolidated balance sheet as of July 31, 2019 was derived from the audited financial statements as of that date. The accompanying interim condensed consolidated financial statements, including the consolidated balance sheets as of January 31, 2020, the consolidated statements of operations for the three and six months ended January 31, 2020 and 2019, the consolidated statements of comprehensive loss for the three and six months ended January 31, 2020 and 2019, the consolidated statements of stockholders’ equity for the three and six months ended January 31, 2020 and 2019 and the consolidated statements of cash flows for the six months ended January 31, 2020 and 2019 are unaudited. The related financial data and the other financial information disclosed in the accompanying notes to these condensed consolidated financial statements are also unaudited. These interim unaudited condensed consolidated financial statements have been prepared on a basis consistent with our annual consolidated financial statements and, in our opinion, include all normal recurring adjustments necessary to state fairly our quarterly results. The results of operations for the three and six months ended January 31, 2020 are not necessarily indicative of the results to be expected for our fiscal year ending July 31, 2020 or for any other future fiscal year or interim period. Use of Estimates The preparation of condensed consolidated financial statements in conformity with U.S. GAAP requires management to make estimates, judgments and assumptions that affect the amounts reported and disclosed in the financial statements and accompanying notes. Such estimates include, but are not limited to, the determination of revenue recognition, deferred revenue, deferred contract acquisition costs, valuation of acquired intangible assets, the period of benefit generated from our deferred contract acquisition costs, allowance for doubtful accounts, valuation of common stock options and stock-based awards, useful lives of property and equipment, useful lives of acquired intangible assets, loss contingencies related to litigation, valuation of deferred tax assets and the discount rate used for operating leases. Management determines these estimates and assumptions based on historical experience and on various other assumptions that are believed to be reasonable. Actual results could differ significantly from these estimates, and such differences may be material to the condensed consolidated financial statements. Fiscal Year Our fiscal year ends on July 31. References to fiscal 2020, for example, refer to our fiscal year ending July 31, 2020. Significant Accounting Policies Our significant accounting policies are described in the Fiscal 2019 Form 10-K. There have been no significant changes to these policies that have had a material impact on our condensed consolidated financial statements and related notes for the three and six months ended January 31, 2020 other than for the adoption of new accounting guidance related to leases effective August 1, 2019 further described below. Operating Leases We enter into operating lease arrangements for real estate assets related to office space and co-location assets related to space and racks at data center facilities. We determine if an arrangement contains a lease at its inception by assessing whether there is an identified asset and whether the arrangement conveys the right to control the use of the identified asset in exchange for consideration. Operating leases related balances are included in "operating lease right-of-use assets," "operating lease liabilities," and "operating lease liabilities, noncurrent" in our condensed consolidated balance sheets. Right-of-use assets represent our right to use an underlying asset for the lease term and lease liabilities represent our obligation to make payments arising from the lease. Operating lease right-of-use assets and lease liabilities are recognized at the lease commencement date based on the present value of lease payments over the lease term. Lease payments consist of the fixed payments under the arrangement, less any lease incentives, such as tenant improvement allowances. Variable costs, such as maintenance and utilities based on actual usage, are not included in the measurement of right-to-use assets and lease liabilities but are expensed when the event determining the amount of variable consideration to be paid occurs. As the implicit rate of our leases is not determinable, we use an incremental borrowing rate ("IBR") based on the information available at the lease commencement date in determining the present value of lease payments. The lease expense is recognized on a straight-line basis over the lease term. We generally use the base, non-cancelable lease term when recognizing the right-of-use assets and lease liabilities, unless it is reasonably certain that a renewal or termination option will be exercised. We account for lease components and non-lease components as a single lease component. Leases with a term of twelve months or less are not recognized on the consolidated balance sheets. We recognize lease expense for these leases on a straight-line basis over the term of the lease. Recently Adopted Accounting Pronouncements In February 2016, the FASB issued ASU No. 2016-02, Leases (Topic 842) ("ASU 2016-02"), as amended, which requires recognition of lease assets and liabilities for leases with terms of more than 12 months. This standard is effective for fiscal years beginning after December 15, 2018, with early adoption permitted. We adopted this standard effective August 1, 2019 using the transitional provision which allows for the adoption of Topic 842 to be applied prospectively at the beginning of the fiscal year of adoption. As such, the condensed consolidated balance sheets for prior periods are not comparable to our fiscal 2020 periods. The adoption of this new standard resulted in the recognition of operating lease right-of-use assets of $16.9 million and operating lease liabilities of $18.0 million. We have elected the package of practical expedients permitted under the transition guidance, which allows us to carryforward our historical lease classification, our assessment on whether a contract is or contains a lease, and our initial direct costs for any leases that existed prior to adoption of the new standard. We have also elected to combine lease and non-lease components for real estate and co-location arrangements. In addition, we elected not to recognize lease liabilities and related right-of-use assets for leases that, at the lease commencement date, have a lease term of 12 months or less. In December 2019, the FASB issued ASU No. 2019-12, Income Taxes (Topic 740) ("ASU 2019-12"): Simplifying the Accounting for Income Taxes. The new standard eliminates certain exceptions related to the approach for intraperiod tax allocation, the methodology for calculating income taxes in an interim period, and the recognition of deferred tax liabilities for outside basis differences related to changes in ownership of equity method investments and foreign subsidiaries. The guidance also simplifies aspects of accounting for franchise taxes and enacted changes in tax laws or rates, and clarifies the accounting for transactions that result in a step-up in the tax basis of goodwill. For public business entities, it is effective for fiscal years beginning after December 15, 2020, including interim periods within those fiscal years. Early adoption is permitted. We early adopted this standard as of November 1, 2019, and it did not have a material impact to our consolidated financial statements. Recently Issued Accounting Pronouncements Not Yet Adopted In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments-Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments. This standard amends guidance on reporting credit losses for assets held at amortized cost basis and available-for-sale debt securities to require that credit losses on available-for-sale debt securities be presented as an allowance rather than as a write-down. The measurement of credit losses for newly recognized financial assets and subsequent changes in the allowance for credit losses are recorded in the statements of operations. For public business entities, it is effective for fiscal years beginning after December 15, 2019, including interim periods within those fiscal years. Early adoption is permitted. We are currently evaluating the potential impact of this standard on our consolidated financial statements.