Document and Entity Information - USD ($)	12 Months Ended
Mar. 31, 2016	May 27, 2016	Sep. 30, 2015
Document And Entity Information
Entity Registrant Name	8X8 INC /DE/
Entity Central Index Key	0001023731
Document Type	10-K/A
Document Period End Date	Mar. 31, 2016
Amendment Flag	true
Amendment Description	The sole purpose of this Amendment No. 1 to our Annual Report on Form 10-K for the fiscal year ended March 31, 2016, as filed with the Securities and Exchange Commission on May 31, 2016, is to furnish corrected interactive data files as Exhibit 101 to the Form 10-K. Exhibit 101. No other changes have been made to the Form 10-K other than those described above. This Amendment No. 1 does not reflect subsequent events occurring after the original filing date of the Form 10-K or modify or update in any way disclosures made in the Form 10-K.
Current Fiscal Year End Date	--03-31
Is Entity a Well-known Seasoned Issuer?	Yes
Is Entity a Voluntary Filer?	No
Is Entity's Reporting Status Current?	Yes
Entity Filer Category	Large Accelerated Filer
Entity Public Float			$ 715,364,941
Entity Common Stock, Shares Outstanding		89,370,746
Document Fiscal Period Focus	FY
Document Fiscal Year Focus	2016

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End date of current fiscal year in the format --MM-DD.

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This is focus fiscal period of the document report. For a first quarter 2006 quarterly report, which may also provide financial information from prior periods, the first fiscal quarter should be given as the fiscal period focus. Values: FY, Q1, Q2, Q3, Q4, H1, H2, M9, T1, T2, T3, M8, CY.

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This is focus fiscal year of the document report in CCYY format. For a 2006 annual report, which may also provide financial information from prior periods, fiscal 2006 should be given as the fiscal year focus. Example: 2006.

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The end date of the period reflected on the cover page if a periodic report. For all other reports and registration statements containing historical data, it is the date up through which that historical data is presented. If there is no historical data in the report, use the filing date. The format of the date is CCYY-MM-DD.

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Indicate number of shares or other units outstanding of each of registrant's classes of capital or common stock or other ownership interests, if and as stated on cover of related periodic report. Where multiple classes or units exist define each class/interest by adding class of stock items such as Common Class A [Member], Common Class B [Member] or Partnership Interest [Member] onto the Instrument [Domain] of the Entity Listings, Instrument.

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State aggregate market value of voting and non-voting common equity held by non-affiliates computed by reference to price at which the common equity was last sold, or average bid and asked price of such common equity, as of the last business day of registrant's most recently completed second fiscal quarter. The public float should be reported on the cover page of the registrants form 10K.

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