SUBSEQUENT EVENT	12 Months Ended
Dec. 31, 2012
SUBSEQUENT EVENT
SUBSEQUENT EVENT	16. SUBSEQUENT EVENT In January 2013, we entered into an Asset Contribution Agreement, or the Agreement, with BioTime, Inc., or BioTime, and BioTime's recently formed subsidiary, BioTime Acquisition Corporation, or BAC, providing for the divestiture of all of our human embryonic stem cell assets and our autologous cellular immunotherapy program to BAC upon the closing of the transaction. The transaction, which is expected to close no later than September 30, 2013, is subject to negotiated closing conditions, including certain approvals by BioTime's shareholders, the effectiveness of certain registration statements to be filed by BioTime and BAC with the United States Securities and Exchange Commission, or the SEC, with respect to the securities to be distributed as contemplated by the Agreement, and other customary closing conditions. Under the terms of the Agreement, upon closing of the transaction, we will contribute to BAC our intellectual property, cell lines and other assets related to our discontinued human embryonic stem cell programs, including our Phase 1 clinical trial of oligodendrocyte progenitor cells, or GRNOPC1, in patients with acute spinal cord injury, as well as our autologous cellular immunotherapy program, including data from the Phase 2 clinical trial of the autologous immunotherapy in patients with acute myelogenous leukemia. Upon the closing of the transaction, we will receive 6,537,779 shares of BAC Series A Common Stock and BioTime will contribute to BAC $5,000,000 in cash, 8,902,077 shares of BioTime common stock to be held by BAC, five-year warrants to purchase 8,000,000 shares of BioTime common stock at an exercise price of $5.00 per share, or the BioTime Warrants, rights to use certain human embryonic stem cell lines and minority stakes in two of BioTime's subsidiaries. Upon the closing of the transaction, BioTime will receive 21,773,340 shares of BAC Series B Common Stock and three-year warrants to purchase 3,150,000 shares of BAC Series B Common Stock at an exercise price of $5.00 per share, or the BAC Warrants. Under the Agreement, BAC will also pay royalties to us on the sale of products that are commercialized, if any, in reliance upon our patents acquired by BAC. Following the closing of the transaction, we will distribute the BAC Series A Common Stock received from BAC to our stockholders on a pro rata basis (other than with respect to fractional shares and stockholders in certain to-be-determined excluded jurisdictions, which will instead receive cash on a pro rata basis). Following the distribution by us to our stockholders of the BAC Series A Common Stock, BAC will then distribute the BioTime Warrants on a pro rata basis to the holders of BAC Series A Common Stock. Following these distributions, it is anticipated that Geron stockholders would own approximately 21% of BAC, BioTime would own approximately 72%, and a private investor would own approximately 7% after an additional $5,000,000 investment by them in BAC. The BAC Warrants will enable BioTime to increase its ownership in BAC by approximately 2%, which would dilute our stockholders' ownership in BAC to approximately 19%. Prior to the closing, we are subject to certain obligations, including the obligation to exercise reasonable best efforts to preserve intact and maintain the assets to be contributed by us to BAC upon the closing of the transaction, including our intellectual property rights and patents in-licensed from third parties. If we are unable to preserve intact and maintain the assets to be contributed by us to BAC, or if BioTime or BAC are unable to satisfy their obligations with respect to the transaction contemplated by the Agreement, including the obligation to obtain the effectiveness of certain registration statements to be filed by them with the SEC, we may be unable to fully complete the transaction with BioTime and BAC.

16. SUBSEQUENT EVENT

In January 2013, we entered into an Asset Contribution Agreement, or the Agreement, with BioTime, Inc., or BioTime, and BioTime's recently formed subsidiary, BioTime Acquisition Corporation, or BAC, providing for the divestiture of all of our human embryonic stem cell assets and our autologous cellular immunotherapy program to BAC upon the closing of the transaction. The transaction, which is expected to close no later than September 30, 2013, is subject to negotiated closing conditions, including certain approvals by BioTime's shareholders, the effectiveness of certain registration statements to be filed by BioTime and BAC with the United States Securities and Exchange Commission, or the SEC, with respect to the securities to be distributed as contemplated by the Agreement, and other customary closing conditions.

Under the terms of the Agreement, upon closing of the transaction, we will contribute to BAC our intellectual property, cell lines and other assets related to our discontinued human embryonic stem cell programs, including our Phase 1 clinical trial of oligodendrocyte progenitor cells, or GRNOPC1, in patients with acute spinal cord injury, as well as our autologous cellular immunotherapy program, including data from the Phase 2 clinical trial of the autologous immunotherapy in patients with acute myelogenous leukemia. Upon the closing of the transaction, we will receive 6,537,779 shares of BAC Series A Common Stock and BioTime will contribute to BAC $5,000,000 in cash, 8,902,077 shares of BioTime common stock to be held by BAC, five-year warrants to purchase 8,000,000 shares of BioTime common stock at an exercise price of $5.00 per share, or the BioTime Warrants, rights to use certain human embryonic stem cell lines and minority stakes in two of BioTime's subsidiaries. Upon the closing of the transaction, BioTime will receive 21,773,340 shares of BAC Series B Common Stock and three-year warrants to purchase 3,150,000 shares of BAC Series B Common Stock at an exercise price of $5.00 per share, or the BAC Warrants. Under the Agreement, BAC will also pay royalties to us on the sale of products that are commercialized, if any, in reliance upon our patents acquired by BAC.

Following the closing of the transaction, we will distribute the BAC Series A Common Stock received from BAC to our stockholders on a pro rata basis (other than with respect to fractional shares and stockholders in certain to-be-determined excluded jurisdictions, which will instead receive cash on a pro rata basis). Following the distribution by us to our stockholders of the BAC Series A Common Stock, BAC will then distribute the BioTime Warrants on a pro rata basis to the holders of BAC Series A Common Stock. Following these distributions, it is anticipated that Geron stockholders would own approximately 21% of BAC, BioTime would own approximately 72%, and a private investor would own approximately 7% after an additional $5,000,000 investment by them in BAC. The BAC Warrants will enable BioTime to increase its ownership in BAC by approximately 2%, which would dilute our stockholders' ownership in BAC to approximately 19%.

Prior to the closing, we are subject to certain obligations, including the obligation to exercise reasonable best efforts to preserve intact and maintain the assets to be contributed by us to BAC upon the closing of the transaction, including our intellectual property rights and patents in-licensed from third parties. If we are unable to preserve intact and maintain the assets to be contributed by us to BAC, or if BioTime or BAC are unable to satisfy their obligations with respect to the transaction contemplated by the Agreement, including the obligation to obtain the effectiveness of certain registration statements to be filed by them with the SEC, we may be unable to fully complete the transaction with BioTime and BAC.