Summary of Significant Accounting Policies (Policies)	9 Months Ended
Dec. 31, 2016
Notes to Financial Statements
Fiscal Period	The Company's fiscal year ends on March 31 of each calendar year. Each reference to a fiscal year in these notes to the consolidated financial statements refers to the fiscal year ended March 31 of the calendar year indicated (for example, fiscal 2017 refers to the fiscal year ended March 31, 2017).
Use of Estimates	The accompanying interim condensed consolidated financial statements are unaudited and have been prepared on substantially the same basis as our annual consolidated financial statements for the fiscal year ended March 31, 2016. In the opinion of the Company's management, these interim condensed consolidated financial statements reflect all adjustments (consisting only of normal recurring adjustments) considered necessary for a fair statement of our financial position, results of operations and cash flows for the periods presented. The preparation of financial statements in conformity with generally accepted accounting principles 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 condensed consolidated financial statements and the reported amounts of revenue and expenses during the reporting periods. Actual results could differ from these estimates.
Basis of Accounting	The March 31, 2016 year-end condensed consolidated balance sheet data in this document were derived from audited consolidated financial statements and does not include all of the disclosures required by U.S. generally accepted accounting principles. These condensed consolidated financial statements should be read in conjunction with the Company's audited consolidated financial statements as of and for the fiscal year ended March 31, 2016 and notes thereto included in the Company's fiscal 2016 Annual Report on Form 10-K. The results of operations and cash flows for the interim periods included in these condensed consolidated financial statements are not necessarily indicative of the results to be expected for any future period or the entire fiscal year. The significant accounting policies used in preparation of these condensed consolidated financial statements are disclosed in our Annual Report on Form 10-K for the fiscal year ended March 31, 2016 filed with the SEC on May 31, 2016, and there have been no changes to the Company's significant accounting policies during the nine months ended December 31, 2016, except as described in the "Recently Adopted Accounting Pronouncements" section below.
Reclassification	*RECLASSIFICATION* Certain amounts previously reported within the Company's consolidated balance sheets and statements of cash flows have been reclassified to conform to the current period presentation. The reclassification had no impact on the Company's previously reported net loss, cash flows, or basic or diluted net income per share amounts.
Principles of Consolidation	*PRINCIPLES OF CONSOLIDATION* The consolidated financial statements include the accounts of 8x8 and its subsidiaries. All material intercompany accounts and transactions have been eliminated.
Recently Adopted Accounting Pronouncements	*RECENTLY ADOPTED ACCOUNTING PRONOUNCEMENTS* In April 2015, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update (ASU) No. 2015-5, "Intangibles-Goodwill and Other-Internal-Use Software (Subtopic 350-40): Customer's Accounting for Fees Paid in a Cloud Computing Arrangement." This update provides guidance in evaluating whether a cloud computing arrangement includes a software license. If a cloud computing arrangement includes a software license, then the software license element of the arrangement should be accounted for as an acquisition of a software license. If a cloud computing arrangement does not include a software license, the customer should account for the arrangement as a service contract. The guidance does not change generally accepted accounting principles for a customer's accounting for service contracts. This update is effective for annual periods, including interim periods within those annual periods, beginning after December 15, 2015. Therefore, the Company has prospectively adopted this new standard on April 1, 2016. The adoption of this standard did not have a material impact on our consolidated financial statements. In November 2015, the FASB issued ASU No. 2015-17, Income Taxes - Balance Sheet Classification of Deferred Taxes (Topic 740). This ASU requires all deferred tax liabilities and assets to be presented in the balance sheet as noncurrent. As permitted, the Company early adopted this standard prospectively during the quarter ended June 30, 2016. The adoption of this standard resulted in reclassifying current deferred income tax assets to noncurrent deferred income tax assets and current deferred income tax liabilities to noncurrent deferred income tax liabilities. No prior periods were retrospectively adjusted.
Recent Accounting Pronouncements	*RECENT ACCOUNTING PRONOUNCEMENTS* In May 2014, the FASB issued ASU No. 2014-09, Revenue from Contracts with Customers, along with amendments issued in 2015 and 2016, which requires an entity to recognize the amount of revenue to which it expects to be entitled for the transfer of promised goods or services to customers. The ASU will replace most existing revenue recognition guidance in U.S. GAAP when it becomes effective. The new standard will become effective for the Company on April 1, 2018. The standard permits the use of either the retrospective or cumulative effect transition method. The Company has not yet selected a transition method. The Company is currently assessing the impact of this pronouncement and its amendments to its consolidated financial statements. In August 2014, the FASB issued ASU No. 2014-15, Presentation of Financial Statements: Going Concern (Subtopic 205-40), this ASU provides guidance regarding management's responsibility in evaluating whether there is substantial doubt about a company's ability to continue as a going concern. Certain disclosures will be required if conditions give rise to substantial doubt about an entity's ability to continue as a going concern. The amendment is effective for the annual period ending after December 15, 2016, and for annual periods and interim periods thereafter. The Company will apply the requirements of ASU 2014-15 during the fiscal year ended March 31, 2017. In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments, which provides guidance for measurement and recognition of expected credit losses for financial assets held based on historical experience, current conditions, and reasonable and supportable forecasts that affect the collectability of the reported amount. The amendment is effective for fiscal years beginning after December 15, 2020. Early adoption is permitted for fiscal years beginning after December 15, 2018. The Company is currently assessing the impact of this pronouncement to its consolidated financial statements. In August 2016, the FASB issued ASU No. 2016-15, Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments, which provides guidance on how certain cash receipts and cash payments are to be presented and classified in the statement of cash flows. This amendment is effective for fiscal years beginning after December 15, 2017, and interim periods within those fiscal years. Early adoption is permitted. The Company is currently assessing the impact of this pronouncement to its Consolidated Statements of Cash Flows. In October 2016, the FASB has issued ASU No. 2016-16, Income Taxes (Topic 740): Intra-Entity Transfers of Assets Other Than Inventory, which provides guidance on how an entity should recognize the income tax consequences of an intra-entity transfer of an asset other than inventory when the transfer occurs. This amendment is effective for fiscal years beginning after December 15, 2017, and interim periods within those fiscal years. Early adoption is permitted. The Company is currently assessing the impact of this pronouncement to its consolidated financial statements. In November 2016, the FASB has issued ASU No. 2016-18, Statement of Cash Flows (Topic 230), which provides guidance on how restricted cash or restricted cash equivalents should be included with cash and cash equivalents when reconciling the beginning-of-period and end-of-period total amounts shown on the statement of cash flows. This amendment is effective for fiscal years beginning after December 15, 2017, and interim periods within those fiscal years. Early adoption is permitted. The Company is currently assessing the impact of this pronouncement to its Consolidated Statements of Cash Flows. In January 2017, the FASB has issued ASU No. 2017-01, Business Combinations (Topic 805): Clarifying the Definition of a Business, which clarifies the definition of a business with the objective of adding guidance to assist entities with evaluating whether transactions should be accounted for as acquisitions (or disposals) of assets or businesses. This amendment is effective for fiscal years beginning after December 15, 2017, and interim periods within those fiscal years. Early adoption is permitted. The Company is currently assessing the impact of this pronouncement to its consolidated financial statements. In January 2017, the FASB has issued ASU No. 2017-04, Intangibles and Other (Topic 350): Simplifying the Test for Goodwill Impairment, which eliminates the requirement to calculate the implied fair value of goodwill but rather require an entity to record an impairment charge based on the excess of a reporting unit's carrying value over its fair value. This amendment is effective for annual or interim goodwill impairment tests in fiscal years beginning after December 15, 2019. Early adoption is permitted. The Company is currently assessing the impact of this pronouncement to its consolidated financial statements.
Research, Development and Software Costs	*RESEARCH, DEVELOPMENT AND SOFTWARE COSTS* In the first nine months of fiscal 2017 and 2016, the Company expensed all research and development costs in accordance with ASC 985-20, Costs of Software to be Sold, Leased or Marketed (ASC 985-20). The Company accounts for computer software developed or obtained for internal use in accordance with ASC 350-40, Internal Use Software (ASC 350-40). Capitalized costs are classified as either long-term assets or property and equipment on the consolidated balance sheets.
Indemnifications	Indemnifications In the normal course of business, the Company may agree to indemnify other parties, including customers, lessors and parties to other transactions with the Company, with respect to certain matters such as breaches of representations or covenants or intellectual property infringement or other claims made by third parties. These agreements may limit the time within which an indemnification claim can be made and the amount of the claim. In addition, the Company has entered into indemnification agreements with its officers and directors. It is not possible to determine the maximum potential amount of the Company's exposure under these indemnification agreements due to the limited history of prior indemnification claims and the unique facts and circumstances involved in each particular agreement. Historically, payments made by the Company under these agreements have not had a material impact on the Company's operating results, financial position or cash flows. Under some of these agreements, however, the Company's potential indemnification liability might not have a contractual limit.
Warranty Expense	*WARRANTY EXPENSE* The Company accrues for the estimated costs that may be incurred under its product warranties upon revenue recognition.
Segment Reporting	SEGMENT REPORTING ASC 280, Segment Reporting, establishes annual and interim reporting standards for an enterprise's business segments and related disclosures about its products, services, geographic areas and major customers. Under ASC 280, the method for determining what information to report is based upon the way management organizes the operating segments within the Company for making operating decisions and assessing financial performance. The Company manages its operations primarily on a geographic basis. The Chief Executive Officer, the Chief Financial Officer, and the Chief Technology Officer or the Company's Chief Operating Decision Makers (CODMs), evaluate performance of the Company and make decisions regarding allocation of resources based on geographic results. The Company's reportable segments are the Americas and Europe. The Americas segment is primarily North America. The Europe segment is primarily the United Kingdom. Each operating segment provides similar products and services. The Company's CODMs evaluate the performance of its operating segments based on revenues and net income. Revenues are attributed to each segment based on the ordering location of the customer or ship to location. The Company allocates corporate overhead costs such as research and development, sales and marketing, general and administrative, amortization expense, stock-based compensation expense, and commitment and contingencies to the Americas segment.

Summary of Significant Accounting Policies (Policies)

9 Months Ended

Dec. 31, 2016

The Company's fiscal year ends on March 31 of each calendar year. Each reference to a fiscal year in these notes to the consolidated financial statements refers to the fiscal year ended March 31 of the calendar year indicated (for example, fiscal 2017 refers to the fiscal year ended March 31, 2017).

Use of Estimates

The accompanying interim condensed consolidated financial statements are unaudited and have been prepared on substantially the same basis as our annual consolidated financial statements for the fiscal year ended March 31, 2016. In the opinion of the Company's management, these interim condensed consolidated financial statements reflect all adjustments (consisting only of normal recurring adjustments) considered necessary for a fair statement of our financial position, results of operations and cash flows for the periods presented. The preparation of financial statements in conformity with generally accepted accounting principles 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 condensed consolidated financial statements and the reported amounts of revenue and expenses during the reporting periods. Actual results could differ from these estimates.

Basis of Accounting

The March 31, 2016 year-end condensed consolidated balance sheet data in this document were derived from audited consolidated financial statements and does not include all of the disclosures required by U.S. generally accepted accounting principles. These condensed consolidated financial statements should be read in conjunction with the Company's audited consolidated financial statements as of and for the fiscal year ended March 31, 2016 and notes thereto included in the Company's fiscal 2016 Annual Report on Form 10-K.

The results of operations and cash flows for the interim periods included in these condensed consolidated financial statements are not necessarily indicative of the results to be expected for any future period or the entire fiscal year.

The significant accounting policies used in preparation of these condensed consolidated financial statements are disclosed in our Annual Report on Form 10-K for the fiscal year ended March 31, 2016 filed with the SEC on May 31, 2016, and there have been no changes to the Company's significant accounting policies during the nine months ended December 31, 2016, except as described in the "Recently Adopted Accounting Pronouncements" section below.

Reclassification

RECLASSIFICATION

Certain amounts previously reported within the Company's consolidated balance sheets and statements of cash flows have been reclassified to conform to the current period presentation. The reclassification had no impact on the Company's previously reported net loss, cash flows, or basic or diluted net income per share amounts.

Principles of Consolidation

PRINCIPLES OF CONSOLIDATION

The consolidated financial statements include the accounts of 8x8 and its subsidiaries. All material intercompany accounts and transactions have been eliminated.

Recently Adopted Accounting Pronouncements

RECENTLY ADOPTED ACCOUNTING PRONOUNCEMENTS

In April 2015, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update (ASU) No. 2015-5, "Intangibles-Goodwill and Other-Internal-Use Software (Subtopic 350-40): Customer's Accounting for Fees Paid in a Cloud Computing Arrangement." This update provides guidance in evaluating whether a cloud computing arrangement includes a software license. If a cloud computing arrangement includes a software license, then the software license element of the arrangement should be accounted for as an acquisition of a software license. If a cloud computing arrangement does not include a software license, the customer should account for the arrangement as a service contract. The guidance does not change generally accepted accounting principles for a customer's accounting for service contracts. This update is effective for annual periods, including interim periods within those annual periods, beginning after December 15, 2015. Therefore, the Company has prospectively adopted this new standard on April 1, 2016. The adoption of this standard did not have a material impact on our consolidated financial statements.

In November 2015, the FASB issued ASU No. 2015-17, Income Taxes - Balance Sheet Classification of Deferred Taxes (Topic 740). This ASU requires all deferred tax liabilities and assets to be presented in the balance sheet as noncurrent. As permitted, the Company early adopted this standard prospectively during the quarter ended June 30, 2016. The adoption of this standard resulted in reclassifying current deferred income tax assets to noncurrent deferred income tax assets and current deferred income tax liabilities to noncurrent deferred income tax liabilities. No prior periods were retrospectively adjusted.

Recent Accounting Pronouncements

RECENT ACCOUNTING PRONOUNCEMENTS

In May 2014, the FASB issued ASU No. 2014-09, Revenue from Contracts with Customers, along with amendments issued in 2015 and 2016, which requires an entity to recognize the amount of revenue to which it expects to be entitled for the transfer of promised goods or services to customers. The ASU will replace most existing revenue recognition guidance in U.S. GAAP when it becomes effective. The new standard will become effective for the Company on April 1, 2018. The standard permits the use of either the retrospective or cumulative effect transition method. The Company has not yet selected a transition method. The Company is currently assessing the impact of this pronouncement and its amendments to its consolidated financial statements.

In August 2014, the FASB issued ASU No. 2014-15, Presentation of Financial Statements: Going Concern (Subtopic 205-40), this ASU provides guidance regarding management's responsibility in evaluating whether there is substantial doubt about a company's ability to continue as a going concern. Certain disclosures will be required if conditions give rise to substantial doubt about an entity's ability to continue as a going concern. The amendment is effective for the annual period ending after December 15, 2016, and for annual periods and interim periods thereafter. The Company will apply the requirements of ASU 2014-15 during the fiscal year ended March 31, 2017.

In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments, which provides guidance for measurement and recognition of expected credit losses for financial assets held based on historical experience, current conditions, and reasonable and supportable forecasts that affect the collectability of the reported amount. The amendment is effective for fiscal years beginning after December 15, 2020. Early adoption is permitted for fiscal years beginning after December 15, 2018. The Company is currently assessing the impact of this pronouncement to its consolidated financial statements.

In August 2016, the FASB issued ASU No. 2016-15, Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments, which provides guidance on how certain cash receipts and cash payments are to be presented and classified in the statement of cash flows. This amendment is effective for fiscal years beginning after December 15, 2017, and interim periods within those fiscal years. Early adoption is permitted. The Company is currently assessing the impact of this pronouncement to its Consolidated Statements of Cash Flows.

In October 2016, the FASB has issued ASU No. 2016-16, Income Taxes (Topic 740): Intra-Entity Transfers of Assets Other Than Inventory, which provides guidance on how an entity should recognize the income tax consequences of an intra-entity transfer of an asset other than inventory when the transfer occurs. This amendment is effective for fiscal years beginning after December 15, 2017, and interim periods within those fiscal years. Early adoption is permitted. The Company is currently assessing the impact of this pronouncement to its consolidated financial statements.

In November 2016, the FASB has issued ASU No. 2016-18, Statement of Cash Flows (Topic 230), which provides guidance on how restricted cash or restricted cash equivalents should be included with cash and cash equivalents when reconciling the beginning-of-period and end-of-period total amounts shown on the statement of cash flows. This amendment is effective for fiscal years beginning after December 15, 2017, and interim periods within those fiscal years. Early adoption is permitted. The Company is currently assessing the impact of this pronouncement to its Consolidated Statements of Cash Flows.

In January 2017, the FASB has issued ASU No. 2017-01, Business Combinations (Topic 805): Clarifying the Definition of a Business, which clarifies the definition of a business with the objective of adding guidance to assist entities with evaluating whether transactions should be accounted for as acquisitions (or disposals) of assets or businesses. This amendment is effective for fiscal years beginning after December 15, 2017, and interim periods within those fiscal years. Early adoption is permitted. The Company is currently assessing the impact of this pronouncement to its consolidated financial statements.

In January 2017, the FASB has issued ASU No. 2017-04, Intangibles and Other (Topic 350): Simplifying the Test for Goodwill Impairment, which eliminates the requirement to calculate the implied fair value of goodwill but rather require an entity to record an impairment charge based on the excess of a reporting unit's carrying value over its fair value. This amendment is effective for annual or interim goodwill impairment tests in fiscal years beginning after December 15, 2019. Early adoption is permitted. The Company is currently assessing the impact of this pronouncement to its consolidated financial statements.

Research, Development and Software Costs

RESEARCH, DEVELOPMENT AND SOFTWARE COSTS

In the first nine months of fiscal 2017 and 2016, the Company expensed all research and development costs in accordance with ASC 985-20, Costs of Software to be Sold, Leased or Marketed (ASC 985-20).

The Company accounts for computer software developed or obtained for internal use in accordance with ASC 350-40, Internal Use Software (ASC 350-40). Capitalized costs are classified as either long-term assets or property and equipment on the consolidated balance sheets.

Indemnifications

Indemnifications

In the normal course of business, the Company may agree to indemnify other parties, including customers, lessors and parties to other transactions with the Company, with respect to certain matters such as breaches of representations or covenants or intellectual property infringement or other claims made by third parties. These agreements may limit the time within which an indemnification claim can be made and the amount of the claim. In addition, the Company has entered into indemnification agreements with its officers and directors.

It is not possible to determine the maximum potential amount of the Company's exposure under these indemnification agreements due to the limited history of prior indemnification claims and the unique facts and circumstances involved in each particular agreement. Historically, payments made by the Company under these agreements have not had a material impact on the Company's operating results, financial position or cash flows. Under some of these agreements, however, the Company's potential indemnification liability might not have a contractual limit.

Warranty Expense

WARRANTY EXPENSE

The Company accrues for the estimated costs that may be incurred under its product warranties upon revenue recognition.

Segment Reporting

SEGMENT REPORTING

ASC 280, Segment Reporting, establishes annual and interim reporting standards for an enterprise's business segments and related disclosures about its products, services, geographic areas and major customers. Under ASC 280, the method for determining what information to report is based upon the way management organizes the operating segments within the Company for making operating decisions and assessing financial performance.

The Company manages its operations primarily on a geographic basis. The Chief Executive Officer, the Chief Financial Officer, and the Chief Technology Officer or the Company's Chief Operating Decision Makers (CODMs), evaluate performance of the Company and make decisions regarding allocation of resources based on geographic results. The Company's reportable segments are the Americas and Europe. The Americas segment is primarily North America. The Europe segment is primarily the United Kingdom. Each operating segment provides similar products and services.

The Company's CODMs evaluate the performance of its operating segments based on revenues and net income. Revenues are attributed to each segment based on the ordering location of the customer or ship to location. The Company allocates corporate overhead costs such as research and development, sales and marketing, general and administrative, amortization expense, stock-based compensation expense, and commitment and contingencies to the Americas segment.