Basis of Presentation and Summary of Significant Accounting Policies (Policies)	3 Months Ended
	Mar. 31, 2016
Accounting Policies [Abstract]
Business	Business Imperva, Inc. (together with its subsidiaries, the “Company”) was incorporated in April 2002 in Delaware. The Company is headquartered in Redwood Shores, California and has subsidiaries located throughout the world including Israel, Asia and Europe. The Company is engaged in the development, marketing, sales, service and support of cyber-security solutions that protect business-critical data and applications whether in the cloud or on premises.
Basis of Presentation	Basis of Presentation The Company has prepared the accompanying unaudited Condensed Consolidated Financial Statements in accordance with Article 10 of Regulation S-X and pursuant to the rules and regulations for Form 10-Q of the Securities and Exchange Commission (the “SEC”). Pursuant to those rules and regulations, the Company has condensed or omitted certain information and footnote disclosure it normally includes in its annual consolidated financial statements prepared in accordance with U.S. generally accepted accounting principles (“GAAP”). In management’s opinion, the Company has made all adjustments (consisting only of normal, recurring adjustments, except as otherwise indicated) necessary to fairly present its consolidated financial position, results of operations, and cash flows. The Company’s interim period operating results do not necessarily indicate the results that may be expected for any other interim period or for the full fiscal year. These financial statements and accompanying notes should be read in conjunction with the consolidated financial statements and notes thereto in the Company’s Annual Report on Form 10-K for the year ended December 31, 2015, which was filed with the SEC on February 26, 2016 (the “Annual Report”). The condensed consolidated financial statements include the accounts of the Company and its wholly-owned subsidiaries. All intercompany balances and transactions have been eliminated in consolidation.
Reclassifications	Reclassifications From time to time the Company reclassifies certain prior period balances to conform to the current year presentation. These reclassifications have no material impact on previously reported total assets, total liabilities, stockholders’ equity, results of operations or cash flows.
Concentration of Revenue and Accounts Receivable	Concentration of Revenue and Accounts Receivable Significant customers are those which represent 10% or more of the Company’s total revenue or gross accounts receivable balance at each respective balance sheet date. For the three months ended March 31, 2016, the Company had one customer that represented 14% of the Company’s total revenue. The same customer represented 17% and 21% of gross accounts receivable as of March 31, 2016 and December 31, 2015 respectively. For the three months ended March 31, 2015, the Company did not have any customers that represented more than 10% of the Company’s total revenue.
Significant Accounting Policies	Significant Accounting Policies There have been no material changes to the Company’s significant accounting policies as compared to the significant accounting policies described in the Company’s Annual Report on Form 10-K for the year ended December 31, 2015.
Recent Accounting Pronouncements	Recent Accounting Pronouncements In March 2016, the Financial Accounting Standards Board (“FASB”) Issued ASU No. 2016-09, Compensation-Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting. The updated guidance changes how companies account for certain aspects of share-based payment awards to employees, including the accounting for income taxes, forfeitures, and statutory tax withholding requirements, as well as classification in the statement of cash flows. The standard will be effective for the Company beginning January 1, 2017, with early application permitted. We are evaluating the impact of adopting this new accounting guidance on our consolidated financial statements. In February 2016, the FASB issued Accounting Standards Update No. 2016-02 regarding ASC Topic 842 "Leases." The amendments in this guidance require balance sheet recognition of lease assets and lease liabilities by lessees for leases classified as operating leases, with an optional policy election to not recognize lease assets and lease liabilities for leases with a term of 12 months or less. The amendments also require new disclosures, including qualitative and quantitative requirements, providing additional information about the amounts recorded in the financial statements. The standard will be effective for the Company beginning January 1, 2019. The amendments require a modified retrospective approach with optional practical expedients. We are evaluating the impact of adopting this new accounting guidance on our consolidated financial statements. In May 2014, the FASB issued ASU No. 2014-09—Revenue (Topic 606): Revenue from Contracts with Customers. ASU No. 2014-09 will replace most existing U.S. GAAP guidance on this topic. The new revenue recognition standard provides a unified model to determine when and how revenue is recognized. The core principle is that a company should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration for which the entity expects to be entitled in exchange for those goods or services. In July 2015, the FASB approved a one-year deferral of the effective date for the new revenue reporting standard for entities reporting under U.S. GAAP. In accordance with the deferral, this guidance will be effective for the Company beginning January 1, 2018 and can be applied either retrospectively to each period presented or as a cumulative-effect adjustment as of the date of adoption. Early adoption is permitted beginning January 1, 2017. The Company is evaluating the impact of adopting this new accounting standard on its consolidated financial statements and has not selected a transition method.