Description of Business and Summary of Significant Accounting Policies (Policies)	6 Months Ended
	Jun. 30, 2015
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation and Consolidation	Basis of Presentation and Consolidation The accompanying unaudited condensed consolidated financial statements include the accounts of FireEye, Inc. and its wholly owned subsidiaries. All intercompany balances and transactions have been eliminated in consolidation. The accompanying unaudited condensed consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America ("U.S. GAAP"), and following the requirements of the Securities and Exchange Commission ("SEC"), for interim reporting. As permitted under those rules, certain footnotes or other financial information that are normally required by U.S. GAAP can be condensed or omitted. These unaudited condensed consolidated financial statements have been prepared on the same basis as our annual consolidated financial statements and, in the opinion of management, reflect all adjustments, consisting only of normal recurring adjustments, that are necessary for a fair statement of our financial information. The results of operations for the three and six months ended June 30, 2015 are not necessarily indicative of the results to be expected for the year ending December 31, 2015 or for any other interim period or for any other future year. The balance sheet as of December 31, 2014 has been derived from audited consolidated financial statements at that date but does not include all of the information required by U.S. GAAP for annual consolidated financial statements. The accompanying unaudited condensed consolidated financial statements and related financial information should be read in conjunction with the audited consolidated financial statements and the related notes thereto for the year ended December 31, 2014 included in our Annual Report on Form 10-K, which was filed with the SEC on March 2, 2015.
Use of Estimates	Use of Estimates The preparation of condensed consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenue and expenses during the reporting period. Such management estimates include, but are not limited to, the best estimate of selling price for our products and services, commissions expense, future taxable income, contract manufacturer liabilities, litigation and settlement costs and other loss contingencies, fair value of our stock options and the purchase price allocation of acquired businesses. We base our estimates on historical experience and also on assumptions that we believe are reasonable. Changes in facts or circumstances may cause us to change our assumptions and estimates in future periods, and it is possible that actual results could differ from current or revised future estimates.
Recent Accounting Pronouncements	Recent Accounting Pronouncements In April 2015, the FASB issued ASU No. 2015-03, Interest - Imputation of Interest (Subtopic 835-30) - Simplifying the Presentation of Debt Issuance Costs. This standard requires companies to present debt issuance costs on the balance sheet as a direct deduction from the related liability, consistent with the presentation of debt discounts, rather than as an asset. Amortization of such costs will continue to be reported as interest expense. The guidance is effective for us beginning in the first quarter of 2016, and requires retrospective application to all prior periods presented in the financial statements. Early adoption is permitted. We have elected to early adopt this standard in the current fiscal quarter, concurrent with the issuance of our Convertible Senior Notes. As such, the issuance costs determined attributable to the liability component of our Convertible Senior Notes have been recorded as a direct deduction from the carrying amount of the notes liability (See Note 8). The adoption of this standard has no impact on any prior period financial statements presented, as we did not previously incur any debt issuance costs. In May 2014, the FASB issued ASU No. 2014-09, Revenue from Contracts with Customers (Topic 606). This standard provides a single model for revenue arising from contracts with customers and supersedes current revenue recognition guidance. The core principle of the guidance is that an entity should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. In July 2015, the FASB decided to defer the effective date by one year, and as a result, the guidance is effective for us beginning in the first quarter of 2018. Early adoption as of the original effective date would be permitted. The guidance permits companies to either apply the requirements retrospectively to all prior periods presented, or apply the requirements in the year of adoption, through a cumulative adjustment. We are currently evaluating the impact the adoption will have on our consolidated financial statements and related disclosures. In August 2014, the FASB issued ASU 2014-15, Disclosures of Uncertainties About an Entity’s Ability to Continue as a Going Concern. This standard provides guidance on how and when reporting entities must disclose going-concern uncertainties in their financial statements. The guidance is effective for us beginning in the first quarter of 2017. Early adoption is permitted. The adoption of this standard is not expected to have an impact on our consolidated financial statements.
Litigation	Litigation We accrue for contingencies when we believe that a loss is probable and that we can reasonably estimate the amount of any such loss. We have made an assessment of the probability of incurring any such losses and whether or not those losses are estimable.