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</LabelSeparator><Level>1</Level><ElementName>us-gaap_CommitmentsAndContingenciesDisclosureAbstract</ElementName><ElementPrefix>us-gaap_</ElementPrefix><IsBaseElement>true</IsBaseElement><BalanceType>na</BalanceType><PeriodType>duration</PeriodType><IsReportTitle>false</IsReportTitle><IsSegmentTitle>false</IsSegmentTitle><IsCalendarTitle>false</IsCalendarTitle><IsEquityPrevioslyReportedAsRow>false</IsEquityPrevioslyReportedAsRow><IsEquityAdjustmentRow>false</IsEquityAdjustmentRow><IsBeginningBalance>false</IsBeginningBalance><IsEndingBalance>false</IsEndingBalance><IsReverseSign>false</IsReverseSign><FootnoteIndexer /><Cells><Cell FlagID="0" ContextID="" UnitID=""><Id>1</Id><IsNumeric>false</IsNumeric><IsRatio>false</IsRatio><DisplayZeroAsNone>false</DisplayZeroAsNone><NumericAmount>0</NumericAmount><RoundedNumericAmount>0</RoundedNumericAmount><NonNumbericText /><FootnoteIndexer /><CurrencyCode /><CurrencySymbol /><IsIndependantCurrency>false</IsIndependantCurrency><ShowCurrencySymbol>false</ShowCurrencySymbol><DisplayDateInUSFormat>false</DisplayDateInUSFormat></Cell></Cells><ElementDataType>xbrli:stringItemType</ElementDataType><SimpleDataType>string</SimpleDataType><IsTotalLabel>false</IsTotalLabel><UnitID>0</UnitID><Label>Commitments and Contingencies Disclosure [Abstract]</Label></Row><Row FlagID="0"><Id>2</Id><IsAbstractGroupTitle>false</IsAbstractGroupTitle><LabelSeparator>

</LabelSeparator><Level>2</Level><ElementName>us-gaap_LegalMattersAndContingenciesTextBlock</ElementName><ElementPrefix>us-gaap_</ElementPrefix><IsBaseElement>true</IsBaseElement><BalanceType>na</BalanceType><PeriodType>duration</PeriodType><IsReportTitle>false</IsReportTitle><IsSegmentTitle>false</IsSegmentTitle><IsCalendarTitle>false</IsCalendarTitle><IsEquityPrevioslyReportedAsRow>false</IsEquityPrevioslyReportedAsRow><IsEquityAdjustmentRow>false</IsEquityAdjustmentRow><IsBeginningBalance>false</IsBeginningBalance><IsEndingBalance>false</IsEndingBalance><IsReverseSign>false</IsReverseSign><PreferredLabelRole>verboseLabel</PreferredLabelRole><FootnoteIndexer /><Cells><Cell FlagID="0" ContextID="D2013Q2YTD" UnitID=""><Id>1</Id><IsNumeric>false</IsNumeric><IsRatio>false</IsRatio><DisplayZeroAsNone>false</DisplayZeroAsNone><NumericAmount>0</NumericAmount><RoundedNumericAmount>0</RoundedNumericAmount><NonNumbericText>&lt;div style="font-family:Times New Roman;font-size:10pt;"&gt;&lt;div style="line-height:120%;text-align:left;font-size:10pt;"&gt;&lt;font style="font-family:inherit;font-size:10pt;font-weight:bold;"&gt;LEGAL PROCEEDINGS&lt;/font&gt;&lt;/div&gt;&lt;div style="line-height:120%;text-align:left;text-indent:48px;font-size:10pt;"&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;&lt;br clear="none"/&gt;&lt;/font&gt;&lt;/div&gt;&lt;div style="line-height:120%;text-align:left;text-indent:48px;font-size:10pt;"&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;The Company has been in the past, and continues to be, a party to litigation which has consumed, and may continue to consume, substantial financial and managerial resources. The Company could incur substantial costs and divert attention of management and technical personnel in defending against litigation, and any adverse ruling or perception of an adverse ruling could have a material adverse impact on the Company&amp;#8217;s stock price. In addition, any adverse ruling could have a material adverse impact on the Company&amp;#8217;s cash flow and financial condition. The results of any litigation or any other legal proceedings are uncertain and as of the date of this report, the Company has not accrued any liability with respect to any of the litigation matters listed below:&lt;/font&gt;&lt;/div&gt;&lt;div style="line-height:120%;text-align:left;text-indent:48px;font-size:10pt;"&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;&lt;br clear="none"/&gt;&lt;/font&gt;&lt;/div&gt;&lt;div style="line-height:120%;text-align:left;text-indent:48px;font-size:10pt;"&gt;&lt;font style="font-family:inherit;font-size:10pt;font-style:italic;"&gt;E8 Pharmaceuticals LLC&lt;/font&gt;&lt;/div&gt;&lt;div style="line-height:120%;text-align:left;text-indent:48px;font-size:10pt;"&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;&lt;br clear="none"/&gt;&lt;/font&gt;&lt;/div&gt;&lt;div style="line-height:120%;text-align:left;text-indent:48px;font-size:10pt;"&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;On July 1, 2008, the Company was named as a defendant in a complaint filed by plaintiffs E8 Pharmaceuticals LLC and Massachusetts Institute of Technology ("MIT") in the United States District Court of Massachusetts. In the complaint, the plaintiffs allege that the Company is infringing &lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;"&gt;one&lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt; patent owned by MIT and licensed to E8 Pharmaceuticals by making and selling the Company&amp;#8217;s GeneChip&amp;#174; products to customers and teaching its customers how to use the products. The plaintiffs seek a permanent injunction enjoining the Company from further infringement, unspecified monetary damages, enhanced damages pursuant to 35 U.S.C. &amp;#167;284, costs, attorneys&amp;#8217; fees and other relief as the court deems just and proper. On September 4, 2012, the District Court issued its ruling construing key claims of the patent at issue. The parties thereafter stipulated to the dismissal of plaintiff&amp;#8217;s claims and in September, the District Court dismissed the lawsuit in its entirety. On September 26, 2012, the plaintiffs filed an appeal with the United States Court of Appeals for the Federal Circuit appealing the District Court&amp;#8217;s dismissal of the lawsuit. The Company will continue to vigorously defend against the plaintiffs&amp;#8217; claims. &lt;/font&gt;&lt;/div&gt;&lt;div style="line-height:120%;text-align:left;text-indent:48px;font-size:10pt;"&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;&lt;br clear="none"/&gt;&lt;/font&gt;&lt;/div&gt;&lt;div style="line-height:120%;text-align:left;text-indent:48px;font-size:10pt;"&gt;&lt;font style="font-family:inherit;font-size:10pt;font-style:italic;"&gt;Enzo Litigation&lt;/font&gt;&lt;/div&gt;&lt;div style="line-height:120%;text-align:left;text-indent:48px;font-size:10pt;"&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;&lt;br clear="none"/&gt;&lt;/font&gt;&lt;/div&gt;&lt;div style="line-height:120%;text-align:left;text-indent:48px;font-size:10pt;"&gt;&lt;font style="font-family:inherit;font-size:10pt;font-style:italic;"&gt;Southern District of New York Case&lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;: On October 28, 2003, Enzo Life Sciences, Inc., a wholly-owned subsidiary of Enzo Biochem, Inc. (collectively &amp;#8220;Enzo&amp;#8221;), filed a complaint against the Company that is pending in the United States District Court for the Southern District of New York for breach of contract, injunctive relief and declaratory judgment. The Enzo complaint relates to a 1998 distributorship agreement with Enzo under which the Company served as a non-exclusive distributor of certain reagent labeling kits supplied by Enzo. In its complaint, Enzo seeks monetary damages and an injunction against the Company from using, manufacturing or selling Enzo products and from inducing collaborators and customers to use Enzo products in violation of the 1998 agreement. Enzo also seeks the transfer of certain Affymetrix patents to Enzo. &lt;/font&gt;&lt;/div&gt;&lt;div style="line-height:120%;text-align:left;text-indent:48px;font-size:10pt;"&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;&lt;br clear="none"/&gt;&lt;/font&gt;&lt;/div&gt;&lt;div style="line-height:120%;text-align:left;text-indent:48px;font-size:10pt;"&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;On November 10, 2003, the Company filed a complaint against Enzo in the United States District Court for the Southern District of New York for declaratory judgment, breach of contract and injunctive relief relating to the 1998 agreement. In its complaint, the Company alleges that Enzo has engaged in a pattern of wrongful conduct against it and other Enzo labeling reagent customers by, among other things, asserting improperly broad rights in its patent portfolio, improperly using the 1998 agreement and distributorship agreements with others in order to corner the market for non-radioactive labeling reagents, and improperly using the 1998 agreement to claim ownership rights to the Company&amp;#8217;s proprietary technology. The court has not set a trial date for these actions, but has advised the parties to clear time for trials at the end of 2013 or the beginning of 2014, to potentially try these actions as well as other related actions between Enzo and other third parties.&lt;/font&gt;&lt;/div&gt;&lt;div style="line-height:120%;text-align:left;text-indent:48px;font-size:10pt;"&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;&lt;br clear="none"/&gt;&lt;/font&gt;&lt;/div&gt;&lt;div style="line-height:120%;text-align:left;text-indent:48px;font-size:10pt;"&gt;&lt;font style="font-family:inherit;font-size:10pt;font-style:italic;"&gt;Delaware Case&lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;: On April 6, 2012, Enzo filed a complaint against the Company in the United States District Court for the District of Delaware. In the complaint, plaintiff alleges that Affymetrix is infringing U.S. Patent No. 7064197 by making and selling certain GeneChip&amp;#174; products. The plaintiff seeks a preliminary and permanent injunction enjoining the Company from further infringement and unspecified monetary damages. The Company will vigorously defend against the plaintiff&amp;#8217;s case. No trial date is set for this action.&lt;/font&gt;&lt;/div&gt;&lt;div style="line-height:120%;text-align:left;text-indent:48px;font-size:10pt;"&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;&lt;br clear="none"/&gt;&lt;/font&gt;&lt;/div&gt;&lt;div style="line-height:120%;text-align:left;text-indent:48px;font-size:10pt;"&gt;&lt;font style="font-family:inherit;font-size:10pt;font-style:italic;"&gt;Administrative Proceedings&lt;/font&gt;&lt;/div&gt;&lt;div style="line-height:120%;text-align:left;text-indent:48px;font-size:10pt;"&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;&lt;br clear="none"/&gt;&lt;/font&gt;&lt;/div&gt;&lt;div style="line-height:120%;text-align:left;text-indent:48px;font-size:10pt;"&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;The Company&amp;#8217;s intellectual property is subject to a number of significant administrative actions. These proceedings could result in the Company&amp;#8217;s patent protection being significantly modified or reduced, and the incurrence of significant costs and the consumption of substantial managerial resources. For the &lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;"&gt;six months ended June 30, 2013&lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;, the Company did not incur significant costs in connection with administrative proceedings.&lt;/font&gt;&lt;/div&gt;&lt;/div&gt;</NonNumbericText><FootnoteIndexer /><CurrencyCode /><CurrencySymbol /><IsIndependantCurrency>false</IsIndependantCurrency><ShowCurrencySymbol>false</ShowCurrencySymbol><DisplayDateInUSFormat>false</DisplayDateInUSFormat></Cell></Cells><ElementDataType>nonnum:textBlockItemType</ElementDataType><SimpleDataType>na</SimpleDataType><ElementDefenition>The entire disclosure for legal proceedings, legal contingencies, litigation, regulatory and environmental matters and other contingencies.</ElementDefenition><ElementReferences>No definition available.</ElementReferences><IsTotalLabel>false</IsTotalLabel><UnitID>0</UnitID><Label>LEGAL PROCEEDINGS</Label></Row></Rows><Footnotes /><IsEquityReport>false</IsEquityReport><ReportName>LEGAL PROCEEDINGS</ReportName><MonetaryRoundingLevel>UnKnown</MonetaryRoundingLevel><SharesRoundingLevel>UnKnown</SharesRoundingLevel><PerShareRoundingLevel>UnKnown</PerShareRoundingLevel><ExchangeRateRoundingLevel>UnKnown</ExchangeRateRoundingLevel><HasCustomUnits>true</HasCustomUnits><IsEmbedReport>false</IsEmbedReport><IsMultiCurrency>false</IsMultiCurrency><ReportType>Sheet</ReportType><RoleURI>http://www.affymetrix.com/role/LegalProceedings</RoleURI><NumberOfCols>1</NumberOfCols><NumberOfRows>2</NumberOfRows></InstanceReport>
