Summary of Significant Accounting Policies (Policies)	6 Months Ended
Sep. 30, 2018
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 2019 refers to the fiscal year ending March 31, 2019).
Use of Estimates	The accompanying interim 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, 2018, with the exception of new revenue recognition guidance discussed in the recently adopted accounting principles section below. Certain information and note disclosures normally included in the financial statements prepared in accordance with GAAP have been condensed or omitted pursuant to the rules and regulations of the Securities and Exchange Commission (SEC), regarding interim financial reporting.
Basis of Presentation	The March 31, 2018 year-end 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 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, 2018 and notes thereto included in the Company's fiscal 2018 Annual Report on Form 10-K. The results of operations and cash flows for the interim periods included in these 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 consolidated financial statements are disclosed in our Annual Report on Form 10-K for the fiscal year ended March 31, 2018 filed with the SEC on May 30, 2018, and there have been no changes to the Company's significant accounting policies during the three months ended September 30, 2018 except for the accounting policies described below that were updated as a result of adopting Accounting Standards Update (ASU) 2014-9, Revenue from Contracts with Customers: Topic 606 (ASU 2014-9 or ASC 606). ASU 2014-9 also included Subtopic 340-40, Other Assets and Deferred Costs - Contracts with Customers, which sets forth the requirement of deferring incremental costs of obtaining a contract with a customer. All amounts and disclosures set forth herein are in compliance with these standards.
Acquisition	*ACQUISITION* In April 2018, the Company entered into an asset purchase agreement with MarianaIQ, Inc. The total aggregate purchase price consisted of cash paid at closing and cash deposited into escrow to be held for fifteen months as security against indemnity claims made by the Company after the closing date. See Note 11 for additional information.
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 May 2014, the Financial Accounting Standards Board (FASB) issued ASU 2014-9, which replaces numerous requirements in U.S. GAAP and provide companies with a single revenue recognition model for recognizing revenue from contracts with customers. ASC 606 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 in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. It defines a five-step process to achieve this core principle and, in doing so, more judgment and estimates are required with the revenue recognition process than were required under the previous guidance (ASC 605). The new standard permits the use of either the full retrospective or modified retrospective transition method. The Company adopted the new standard effective April 1, 2018 using the modified retrospective method. Under the modified retrospective method, the comparative periods' information is not restated and continues to be reported under the accounting standards in effect in those prior periods. Instead, on April 1, 2018, the Company recognized the cumulative effect of initially applying ASC 606 as an adjustment to the opening balance of accumulated deficit and the corresponding balance sheet accounts, which resulted in a net decrease to accumulated deficit of $39.9 million. The impact on the Company's opening balances primarily relates to the capitalization of additional commission costs under ASC 606 in the amount of $38.2 million. Under ASC 605, the Company expensed all commission costs as incurred. Under ASC 606, the Company defers all incremental commission costs to obtain the contract and amortizes these costs over a benefit period of five years. The remaining $1.7 million impact of adopting the standard relates to revenue being recognized earlier under ASC 606 than it would have been under ASC 605, which resulted in a contract asset as of the adoption date. See Note 2 for additional disclosure on the impact of adopting this standard.
Recent Accounting Pronouncements	*RECENT ACCOUNTING PRONOUNCEMENTS* In February 2016, the FASB issued ASU 2016-2, Leases (Topic 842), along with amendments issued in 2018, which requires companies to generally recognize on the balance sheet operating and financing lease liabilities and corresponding right-of-use assets. The update also requires qualitative and quantitative disclosures designed to assess the amount, timing, and uncertainty of cash flows arising from leases. The update requires the use of a modified retrospective transition approach, which includes a number of optional practical expedients that entities may elect to apply. This amendment is effective for fiscal years beginning after December 15, 2018, including 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 June 2018, the FASB issued ASU 2018-7, Compensation-Stock Compensation (Topic 718), which now provides guidance for share-based payments to non-employees, resulting in alignment in accounting for employees and non-employees. The amendment is effective for public companies with fiscal years beginning after December 15, 2018. Early adoption is permitted. The Company is currently assessing the impact of this pronouncement to its consolidated financial statements. In August 2018, the FASB issued ASU 2018-13, Fair Value Measurement (Topic 820), which makes modifications to disclosure requirements on fair value measurements. The amendment is effective for public companies with 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. In August 2018, the FASB issued 2018-15, Intangibles-Goodwill and Other-Internal Use Software (Subtopic 350-40), which reduces complexity for the accounting for the accounting for costs of implementing a cloud computing service arrangement. The amendment is effective for public companies with 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.
Revenue recognition	*Revenue Recognition under ASC 606* The Company recognizes service revenue, mainly from subscription services to its cloud-based voice, call center, video and collaboration solutions using the five-step model as prescribed by ASC 606: • Identification of the contract, or contracts, with a customer; • Identification of the performance obligations in the contract; • Determination of the transaction price; • Allocation of the transaction price to the performance obligations in the contract; and • Recognition of revenue when or as, the Company satisfies a performance obligation. The Company identifies performance obligations in contracts with customers, which may include subscription services and related usage, product revenue and professional services. The transaction price is determined based on the amount the Company expects to be entitled to in exchange for transferring the promised services or products to the customer. The transaction price in the contract is allocated to each distinct performance obligation in an amount that represents the relative amount of consideration expected to be received in exchange for satisfying each performance obligation. Revenue is recognized when performance obligations are satisfied. Revenues are recorded based on the transaction price excluding amounts collected on behalf of third parties such as sales and telecommunication taxes, which are collected on behalf of and remitted to governmental authorities. The Company usually bills its customers on a monthly basis. Contracts typically range from annual to multi-year agreements with payment terms of net 30 days or less. The Company occasionally allows a 30-day period to cancel a subscription and return products shipped for a full refund. *Judgments and Estimates* The estimation of variable consideration for each performance obligation requires the Company to make subjective judgments. The Company has service-level agreements with customers warranting defined levels of uptime reliability and performance. Customers may get credits or refunds if the Company fails to meet such levels. If the services do not meet certain criteria, fees are subject to adjustment or refund representing a form of variable consideration. The Company may impose minimum revenue commitments (MRC) on its customers at the inception of the contract. Thus, in estimating variable consideration for each of these performance obligations, the Company assesses both the probability of MRC occurring and the collectability of the MRC, of which both represent a form of variable consideration. The Company enters into contracts with customers that regularly include promises to transfer multiple services and products, such as subscriptions, products, and professional services. For arrangements with multiple services, the Company evaluates whether the individual services qualify as distinct performance obligations. In its assessment of whether a service is a distinct performance obligation, the Company determines whether the customer can benefit from the service on its own or with other readily available resources, and whether the service is separately identifiable from other services in the contract. This evaluation requires the Company to assess the nature of each individual service offering and how the services are provided in the context of the contract, including whether the services are significantly integrated, highly interrelated, or significantly modify each other, which may require judgment based on the facts and circumstances of the contract. When agreements involve multiple distinct performance obligations, the Company allocates arrangement consideration to all performance obligations at the inception of an arrangement based on the relative standalone selling prices (SSP) of each performance obligation. Usage fees deemed to be variable consideration meet the allocation exception for variable consideration. Where the Company has standalone sales data for its performance obligations which are indicative of the price at which the Company sells a promised good or service separately to a customer, such data is used to establish SSP. In instances where standalone sales data is not available for a particular performance obligation, the Company estimates SSP by the use of observable market and cost-based inputs. The Company continues to review the factors used to establish list price and will adjust standalone selling price methodologies as necessary on a prospective basis. *Service Revenue* Service revenue from subscriptions to the Company's cloud-based technology platform is recognized over time on a ratable basis over the contractual subscription term beginning on the date that the platform is made available to the customer. Payments received in advance of subscription services being rendered are recorded as a deferred revenue. Usage fees, either bundled or not bundled, are recognized when the Company has a right to invoice. Professional services for configuration, system integration, optimization, customer training and/or education are primarily billed on a fixed-fee basis and are performed by the Company directly or, alternatively, customers may also choose to perform these services themselves or engage their own third-party service providers. Professional services revenue is recognized over time, generally as customer sites go live. When a contract with a customer is signed, the Company assesses whether collection of the fees under the arrangement is probable. The Company estimates the amount to reserve for uncollectible amounts based on the aging of the contract balance, current and historical customer trends, and communications with its customers. These reserves are recorded as operating expenses against the contract asset (Accounts Receivable). In the normal course of business, the Company records revenue reductions for customer credits. *Product Revenue* The Company recognizes product revenue for telephony equipment at a point in time, when transfer of control has occurred, which is generally upon shipment. Sales returns are recorded as a reduction to revenue estimated based on historical experience. *Contract Assets* Contract assets are recorded for those parts of the contract consideration not yet invoiced but for which the performance obligations are completed. The revenue is recognized when the customer receives services or equipment for a reduced consideration at the onset of an arrangement, for example when the initial month's services or equipment are discounted. Contract assets are included in other current or non-current assets in the consolidated balance sheets, depending on if their reduction is recognized during the succeeding 12-month period or beyond. *Deferred Revenue* Deferred revenues represent billings or payments received in advance of revenue recognition and is recognized upon transfer of control. Balances consist primarily of annual plan subscription services and professional and training services not yet provided as of the balance sheet date. Deferred revenues that will be recognized during the succeeding 12-month period are recorded as current deferred revenues in the consolidated balance sheets, with the remainder recorded as other non-current liabilities in the consolidated balance sheets. *Costs to Obtain a Customer Contract* Sales commissions and related expenses are considered incremental and recoverable costs of acquiring customer contracts. These costs are capitalized as other current or non-current assets and amortized on a straight-line basis over the anticipated benefit period, which is five years. The benefit period was estimated by taking into consideration the length of customer contracts, technology lifecycle, and other factors. This amortization expense is recorded in sales and marketing expense within the Company's consolidated statement of operations. *Practical Expedients* The new guidance under ASC 340-40, Other Assets and Deferred Costs - Contracts with Customers, sets forth the requirement of deferring incremental costs of obtaining a contract, typically sales commissions, that were expensed as incurred under the previous guidance. The Company applies a practical expedient that permits to apply Subtopic 340-40 to a portfolio of contracts, instead of on a contract-by-contract basis, as they are similar in their characteristics, and the financial statement effects of applying Subtopic 340-40 to that portfolio would not differ materially from applying it to the individual contracts within that portfolio.

Summary of Significant Accounting Policies (Policies)

6 Months Ended

Sep. 30, 2018

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 2019 refers to the fiscal year ending March 31, 2019).

Use of Estimates

The accompanying interim 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, 2018, with the exception of new revenue recognition guidance discussed in the recently adopted accounting principles section below. Certain information and note disclosures normally included in the financial statements prepared in accordance with GAAP have been condensed or omitted pursuant to the rules and regulations of the Securities and Exchange Commission (SEC), regarding interim financial reporting.

Basis of Presentation

The March 31, 2018 year-end 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 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, 2018 and notes thereto included in the Company's fiscal 2018 Annual Report on Form 10-K.

The results of operations and cash flows for the interim periods included in these 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 consolidated financial statements are disclosed in our Annual Report on Form 10-K for the fiscal year ended March 31, 2018 filed with the SEC on May 30, 2018, and there have been no changes to the Company's significant accounting policies during the three months ended September 30, 2018 except for the accounting policies described below that were updated as a result of adopting Accounting Standards Update (ASU) 2014-9, Revenue from Contracts with Customers: Topic 606 (ASU 2014-9 or ASC 606). ASU 2014-9 also included Subtopic 340-40, Other Assets and Deferred Costs - Contracts with Customers, which sets forth the requirement of deferring incremental costs of obtaining a contract with a customer. All amounts and disclosures set forth herein are in compliance with these standards.

Acquisition

ACQUISITION

In April 2018, the Company entered into an asset purchase agreement with MarianaIQ, Inc. The total aggregate purchase price consisted of cash paid at closing and cash deposited into escrow to be held for fifteen months as security against indemnity claims made by the Company after the closing date. See Note 11 for additional information.

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 May 2014, the Financial Accounting Standards Board (FASB) issued ASU 2014-9, which replaces numerous requirements in U.S. GAAP and provide companies with a single revenue recognition model for recognizing revenue from contracts with customers. ASC 606 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 in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. It defines a five-step process to achieve this core principle and, in doing so, more judgment and estimates are required with the revenue recognition process than were required under the previous guidance (ASC 605).

The new standard permits the use of either the full retrospective or modified retrospective transition method. The Company adopted the new standard effective April 1, 2018 using the modified retrospective method. Under the modified retrospective method, the comparative periods' information is not restated and continues to be reported under the accounting standards in effect in those prior periods. Instead, on April 1, 2018, the Company recognized the cumulative effect of initially applying ASC 606 as an adjustment to the opening balance of accumulated deficit and the corresponding balance sheet accounts, which resulted in a net decrease to accumulated deficit of $39.9 million. The impact on the Company's opening balances primarily relates to the capitalization of additional commission costs under ASC 606 in the amount of $38.2 million. Under ASC 605, the Company expensed all commission costs as incurred. Under ASC 606, the Company defers all incremental commission costs to obtain the contract and amortizes these costs over a benefit period of five years. The remaining $1.7 million impact of adopting the standard relates to revenue being recognized earlier under ASC 606 than it would have been under ASC 605, which resulted in a contract asset as of the adoption date.

See Note 2 for additional disclosure on the impact of adopting this standard.

Recent Accounting Pronouncements

RECENT ACCOUNTING PRONOUNCEMENTS

In February 2016, the FASB issued ASU 2016-2, Leases (Topic 842), along with amendments issued in 2018, which requires companies to generally recognize on the balance sheet operating and financing lease liabilities and corresponding right-of-use assets. The update also requires qualitative and quantitative disclosures designed to assess the amount, timing, and uncertainty of cash flows arising from leases. The update requires the use of a modified retrospective transition approach, which includes a number of optional practical expedients that entities may elect to apply. This amendment is effective for fiscal years beginning after December 15, 2018, including 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 June 2018, the FASB issued ASU 2018-7, Compensation-Stock Compensation (Topic 718), which now provides guidance for share-based payments to non-employees, resulting in alignment in accounting for employees and non-employees. The amendment is effective for public companies with fiscal years beginning after December 15, 2018. Early adoption is permitted. The Company is currently assessing the impact of this pronouncement to its consolidated financial statements.

In August 2018, the FASB issued ASU 2018-13, Fair Value Measurement (Topic 820), which makes modifications to disclosure requirements on fair value measurements. The amendment is effective for public companies with 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.

In August 2018, the FASB issued 2018-15, Intangibles-Goodwill and Other-Internal Use Software (Subtopic 350-40), which reduces complexity for the accounting for the accounting for costs of implementing a cloud computing service arrangement. The amendment is effective for public companies with 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.

Revenue recognition

Revenue Recognition under ASC 606

The Company recognizes service revenue, mainly from subscription services to its cloud-based voice, call center, video and collaboration solutions using the five-step model as prescribed by ASC 606:

• Identification of the contract, or contracts, with a customer;
• Identification of the performance obligations in the contract;
• Determination of the transaction price;
• Allocation of the transaction price to the performance obligations in the contract; and
• Recognition of revenue when or as, the Company satisfies a performance obligation.

The Company identifies performance obligations in contracts with customers, which may include subscription services and related usage, product revenue and professional services. The transaction price is determined based on the amount the Company expects to be entitled to in exchange for transferring the promised services or products to the customer. The transaction price in the contract is allocated to each distinct performance obligation in an amount that represents the relative amount of consideration expected to be received in exchange for satisfying each performance obligation. Revenue is recognized when performance obligations are satisfied. Revenues are recorded based on the transaction price excluding amounts collected on behalf of third parties such as sales and telecommunication taxes, which are collected on behalf of and remitted to governmental authorities. The Company usually bills its customers on a monthly basis. Contracts typically range from annual to multi-year agreements with payment terms of net 30 days or less. The Company occasionally allows a 30-day period to cancel a subscription and return products shipped for a full refund.

Judgments and Estimates

The estimation of variable consideration for each performance obligation requires the Company to make subjective judgments. The Company has service-level agreements with customers warranting defined levels of uptime reliability and performance. Customers may get credits or refunds if the Company fails to meet such levels. If the services do not meet certain criteria, fees are subject to adjustment or refund representing a form of variable consideration. The Company may impose minimum revenue commitments (MRC) on its customers at the inception of the contract. Thus, in estimating variable consideration for each of these performance obligations, the Company assesses both the probability of MRC occurring and the collectability of the MRC, of which both represent a form of variable consideration.

The Company enters into contracts with customers that regularly include promises to transfer multiple services and products, such as subscriptions, products, and professional services. For arrangements with multiple services, the Company evaluates whether the individual services qualify as distinct performance obligations. In its assessment of whether a service is a distinct performance obligation, the Company determines whether the customer can benefit from the service on its own or with other readily available resources, and whether the service is separately identifiable from other services in the contract. This evaluation requires the Company to assess the nature of each individual service offering and how the services are provided in the context of the contract, including whether the services are significantly integrated, highly interrelated, or significantly modify each other, which may require judgment based on the facts and circumstances of the contract.

When agreements involve multiple distinct performance obligations, the Company allocates arrangement consideration to all performance obligations at the inception of an arrangement based on the relative standalone selling prices (SSP) of each performance obligation. Usage fees deemed to be variable consideration meet the allocation exception for variable consideration. Where the Company has standalone sales data for its performance obligations which are indicative of the price at which the Company sells a promised good or service separately to a customer, such data is used to establish SSP. In instances where standalone sales data is not available for a particular performance obligation, the Company estimates SSP by the use of observable market and cost-based inputs. The Company continues to review the factors used to establish list price and will adjust standalone selling price methodologies as necessary on a prospective basis.

Service Revenue

Service revenue from subscriptions to the Company's cloud-based technology platform is recognized over time on a ratable basis over the contractual subscription term beginning on the date that the platform is made available to the customer. Payments received in advance of subscription services being rendered are recorded as a deferred revenue. Usage fees, either bundled or not bundled, are recognized when the Company has a right to invoice. Professional services for configuration, system integration, optimization, customer training and/or education are primarily billed on a fixed-fee basis and are performed by the Company directly or, alternatively, customers may also choose to perform these services themselves or engage their own third-party service providers. Professional services revenue is recognized over time, generally as customer sites go live.

When a contract with a customer is signed, the Company assesses whether collection of the fees under the arrangement is probable. The Company estimates the amount to reserve for uncollectible amounts based on the aging of the contract balance, current and historical customer trends, and communications with its customers. These reserves are recorded as operating expenses against the contract asset (Accounts Receivable). In the normal course of business, the Company records revenue reductions for customer credits.

Product Revenue

The Company recognizes product revenue for telephony equipment at a point in time, when transfer of control has occurred, which is generally upon shipment. Sales returns are recorded as a reduction to revenue estimated based on historical experience.

Contract Assets

Contract assets are recorded for those parts of the contract consideration not yet invoiced but for which the performance obligations are completed. The revenue is recognized when the customer receives services or equipment for a reduced consideration at the onset of an arrangement, for example when the initial month's services or equipment are discounted. Contract assets are included in other current or non-current assets in the consolidated balance sheets, depending on if their reduction is recognized during the succeeding 12-month period or beyond.

Deferred Revenue

Deferred revenues represent billings or payments received in advance of revenue recognition and is recognized upon transfer of control. Balances consist primarily of annual plan subscription services and professional and training services not yet provided as of the balance sheet date. Deferred revenues that will be recognized during the succeeding 12-month period are recorded as current deferred revenues in the consolidated balance sheets, with the remainder recorded as other non-current liabilities in the consolidated balance sheets.

Costs to Obtain a Customer Contract

Sales commissions and related expenses are considered incremental and recoverable costs of acquiring customer contracts. These costs are capitalized as other current or non-current assets and amortized on a straight-line basis over the anticipated benefit period, which is five years. The benefit period was estimated by taking into consideration the length of customer contracts, technology lifecycle, and other factors. This amortization expense is recorded in sales and marketing expense within the Company's consolidated statement of operations.

Practical Expedients

The new guidance under ASC 340-40, Other Assets and Deferred Costs - Contracts with Customers, sets forth the requirement of deferring incremental costs of obtaining a contract, typically sales commissions, that were expensed as incurred under the previous guidance. The Company applies a practical expedient that permits to apply Subtopic 340-40 to a portfolio of contracts, instead of on a contract-by-contract basis, as they are similar in their characteristics, and the financial statement effects of applying Subtopic 340-40 to that portfolio would not differ materially from applying it to the individual contracts within that portfolio.