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            <identifier scheme="http://www.sec.gov/CIK">0000886744</identifier>
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            <startDate>2025-08-06</startDate>
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            <startDate>2025-08-06</startDate>
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        <measure>shares</measure>
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    <unit id="usd">
        <measure>iso4217:USD</measure>
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        <measure>pure</measure>
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    <dei:EntityCentralIndexKey contextRef="c-1" id="f-19">0000886744</dei:EntityCentralIndexKey>
    <ffd:FeeExhibitTp contextRef="c-1" id="f-20">EX-FILING FEES</ffd:FeeExhibitTp>
    <ffd:OffsetTableNa contextRef="c-1" id="f-21">N/A</ffd:OffsetTableNa>
    <ffd:FormTp contextRef="c-1" id="f-1">S-8</ffd:FormTp>
    <ffd:SubmissnTp contextRef="c-1" id="f-2">S-8</ffd:SubmissnTp>
    <dei:EntityRegistrantName contextRef="c-1" id="f-3">Geron Corporation</dei:EntityRegistrantName>
    <ffd:OfferingSctyTp contextRef="c-2" id="f-4">Equity</ffd:OfferingSctyTp>
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    <ffd:OfferingSctyTitl contextRef="c-2" id="f-6">2018 Inducement Award PlanCommon Stock, $0.001 par value per share,  reserved for future grants under the Geron Corporation 2018 Inducement Award Plan</ffd:OfferingSctyTitl>
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    <ffd:OfferingNote contextRef="c-2" id="f-18">&lt;div style="margin-bottom:6pt;padding-right:-1.13pt"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',serif;font-size:10pt;font-weight:400;line-height:104%"&gt;This Registration Statement registers the offer and sale of an aggregate of 11,000,000 shares of common stock of Geron Corporation (the &#x201c;Registrant&#x201d;), par value $0.001, (the &#x201c;Common Stock&#x201d;) issuable under the Registrant&#x2019;s 2018 Inducement Award Plan (the &#x201c;2018 Inducement Plan&#x201d;).&lt;/span&gt;&lt;/div&gt;&lt;div style="margin-bottom:6pt;padding-right:-1.13pt"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',serif;font-size:10pt;font-weight:400;line-height:104%"&gt;Pursuant to Rule 416 promulgated under the Securities Act of 1933, as amended (the &#x201c;Securities Act&#x201d;), this Registration Statement shall also cover any additional shares of Common Stock which become issuable under the 2018 Inducement Plan by reason of any stock dividend, stock split, recapitalization or other similar transaction effected without receipt of consideration that increases the number of outstanding shares of Common Stock.&lt;/span&gt;&lt;/div&gt;&lt;span style="color:#000000;font-family:'Times New Roman',serif;font-size:10pt;font-weight:400;line-height:100%"&gt;Estimated solely for the purposes of calculating the registration fee pursuant to Rule 457(c) and Rule 457(h) under the Securities Act. The offering price per share and the aggregate offering price are based on (a) the average of the high and low prices of the Common Stock as reported on the Nasdaq Global Select Market on August 4, 2025.&lt;/span&gt;</ffd:OfferingNote>
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