Subsequent Events	12 Months Ended
Dec. 31, 2012
Subsequent Events [Abstract]
Subsequent Events	23. Subsequent Events Asset Contribution Agreement On January 4, 2013, BioTime and BAC entered into an Asset Contribution Agreement with Geron Corporation ("Geron") pursuant to which BioTime and Geron will concurrently contribute certain assets to BAC in exchange for shares of BAC common stock. Closing of the asset contribution transaction is expected to occur no later than September 30, 2013. Pursuant to the Asset Contribution Agreement, Geron has agreed to contribute certain assets related to its discontinued stem cell research and development programs, including certain patents and know-how related to human embryonic stem cells; certain biological materials and reagents; certain laboratory equipment; certain contracts; and certain product clinical trials, in exchange for shares of BAC common stock, and BioTime has agreed to contribute 8,902,077 common shares; warrants to subscribe for and purchase 8,000,000 additional common shares; $5,000,000 in cash; 10% of the shares of common stock of OrthoCyte Corporationissued and outstanding on the date of the Asset Contribution Agreement; 6% of the ordinary shares of our subsidiary Cell Cure Neurosciencesissued and outstanding on the date of the Asset Contribution Agreement; and a quantity of certain human hES cell lines produced under cGMP, and a non-exclusive, world-wide, royalty-free license to use those hES cell lines and certain patents pertaining to stem cell differentiation technology, in exchange for BAC common stock and warrants to purchase BAC common stock. A private investor has agreed to contribute $5 million in cash to BAC for 2,136,000 shares of BAC Series B common stock, and warrants to purchase 350,000 additional shares of BAC Series B common stock. That investment will be made in conjunction with the closing under the Asset Contribution Agreement.If for any reason the private investor fails to make the $5 million contribution, BioTime will contribute cash, BioTime common shares, or a combination of cash and BioTime common shares to BAC in an amount equal to the cash not contributed by the private investor. The same private investor also agreed to invest $5 million in BioTime by purchasing, in two tranches, an aggregate of 1,350,000 BioTime common shares and warrants to purchase approximately 650,000 additional BioTime common shares. The first tranche of $2,000,000 was funded during January 2013, and BioTime issued to the investor 540,000 common shares and 259,999 warrants.The second tranche of $3,000,000 was originally intended to close later this year concurrent with the closing of the Asset Contribution Agreement. However, on March 7, 2013 the investor and BioTime entered into an amendment to accelerate the closing date to April 10, 2013. Upon closing of the second tranche, we will issue to the investor 810,000 common shares, and warrants to purchase an additional 389,998 common shares at an exercise price of $5.00 per share. BAC will assume all obligations and liabilities in connection with the assets contributed by Geron, to the extent such obligations and liabilities arise after the closing date of the Asset Contribution Agreement, including certain obligations and liabilities to provide follow-up procedures with patients who participated in Geron's clinical trials. Upon the closing under the Asset Contribution Agreement, BioTime will own 21,773,340 shares of BAC Series B common stock and Geron will own 6,537,779 shares of BAC Series A common stock. Upon the sale of BAC shares to the private investor, the private investor will own 2,136,000 shares of BAC Series B common stock. Geron has agreed to distribute to its stockholders on a pro rata basis the shares of BAC Series A common stock that Geron receives in the asset contribution transaction following the closing under the Asset Contribution Agreement. Following that distribution by Geron, BAC will distribute to the holders of its Series A common stock on a pro rata basis the 8,000,000 BioTime warrants that it receives under the Asset Contribution Agreement. Following the distributions of the BAC Series A common stock by Geron to its stockholders, BioTime will own, including the shares of BAC Series B common stock that BioTime presently owns, approximately 71.6% of the outstanding BAC common stock, the Geron stockholders will own approximately 21.4% of the outstanding BAC common stock and the private investor will own approximately 7.0%, of the outstanding BAC common stock. BioTime will also receive warrants to purchase 3,150,000 shares of BAC Series B common stock and the private investor will receive warrants to purchase 350,000 shares of BAC Series B common stock (the "BAC Warrants"). The BAC Warrants will have an exercise price of $5.00 per share and a term of three years. The exercise price per share and number of shares that may be purchased upon the exercise of the BAC Warrants will be subject to adjustment in the event of any BAC stock split, reverse stock split, stock dividend, reclassification of shares and certain other transactions. The BAC Series A and Series B common stock will be identical in most respects, however, BAC will be entitled to make certain distributions or pay dividends, other than stock dividends, on its Series A common stock, without making a distribution or paying a dividend on its Series B common stock. The BAC Series B common stock may be converted into BAC Series A common stock, on a share for share basis, at BAC's election, only after Geron distributes to its stockholders the BAC Series A common stock issued under the Asset Contribution Agreement and BAC subsequently distributes to the BAC Series A common stock holders the 8,000,000 BioTime warrants that BAC will recieve from BioTime under the Asset Contribution Agreement. Closing of the asset contribution transaction is subject to certain negotiated conditions, including: the effectiveness of registration statements under the Securities Act to be filed by BioTime and BAC, and the approval by BioTime shareholders of the issuance of BioTime shares and warrants in the transaction, and an amendment of BioTime's Articles of Incorporation to increase its authorized capital stock (the "Shareholder Proposals"). Closing of the cash contribution by the private investor is also subject to certain negotiated closing conditions, including the closing of the asset contribution transaction. BioTime will be required to pay Geron a termination fee of $1.8 million in certain circumstances if the Asset Contribution Agreement is terminated if (a) the BioTime board of directors withdraws its recommendation to BioTime shareholders to approve the Shareholder Proposals, (b) certain BioTime directors materially breach the Support Agreements under which they and certain of their affiliates have agreed to vote their BioTime shares in favor of the Shareholder Proposals, or (c) BioTime's shareholders do not vote to approve the Shareholder Proposals. On March 14, 2013, ReCyte and one of its shareholders entered into a Stock Purchase Agreement under which the shareholder agreed to purchase 81,169 additional ReCyte common shares for approximately $250,000, reflecting a purchase price of $3.08 pershare. In March 2013, ReCyte received $125,000 for which 40,584 ReCyte common shares were issued. ReCyte expects to receive the remaining $125,000 and to issue the remaining 40,585 common shares by the end of the second quarter. Lease On January 8, 2013, BioTime entered into a lease for an office and research facility located at 230 Constitution Drive, Menlo Park, California that BioTime plans to make available for use by BAC. The building on the leased premises contains approximately 24,080 square feet of space. The lease is for a term of three years commencing January 7, 2013. BioTime will pay base rent of $31,786 per month, plus real estate taxes and certain costs of maintaining the leased premises. As additional consideration for the lease, BioTime issued to the landlord BioTime common shares having a market value of $242,726, determined based upon the average closing price of our common shares on the NYSE MKT for a designated period of time prior to the signing of the lease. BioTime agreed to register those shares under the Securities Actand if it fails to file a registration statement for such purpose within 120 days the landlord will have a right to return the shares to BioTime, in which case the base rent will increase to $38,528 per month, retroactive to the commencement date of the lease. Cell Cure Neurosciences Investment On January 29, 2013, in accordance with the November 1, 2012 Share Purchase Agreement between BioTime and Cell Cure Neurosciences, BioTime purchased 87,456 Cell Cure Neurosciences ordinary shares in exchange for 906,735 of BioTime common shares. As a result of the share purchase, BioTime ownership directly and through ESI increased to approximately 62.6% of the outstanding ordinary shares of Cell Cure Neurosciences. The number of common shares that BioTime issued to acquire the Cell Cure Neurosciences shares was based upon an average market price of $3.86 per BioTime common share determined on the basis of the ten actual trading days prior to November 1, 2012. Under the Share Purchase Agreement, BioTime may be required to issue additional common shares to Cell Cure Neurosciences, or Cell Cure Neurosciences may be required to issue additional Cell Cure Neurosciences ordinary shares to BioTime, depending upon whether the market value of BioTime common shares increases or decreases by more than 15%, based upon the average closing price for the ten trading days commencing on May 1, 2013. If the market value of BioTime common shares declines by more than 15% then BioTime will issue an additional number of shares required to make the value of the total number of common shares BioTime issued equal to $3.5 million, less the initial $3.86 market price multiplied by any BioTime common shares sold by Cell Cure Neurosciences prior to that date, and subject to a maximum 33% increase in the number of BioTime shares issued. Conversely, if the value of BioTime shares increases by more than 15% as of such date, Cell Cure Neurosciences will be required to issue to BioTime a number of additional Cell Cure Neurosciences ordinary shares sufficient to bring the value of the Cell Cure shares Neurosciences issued to BioTime under the Share Purchase Agreement to the value of the BioTime common shares we issued, also determined on the basis of a ten day trading period commencing on May 1, 2013, but subject to a 33% maximum increase in the number of Cell Cure Neurosciences shares issued. In 2013, BioTime raised gross proceeds of $11,306,430 from the sale of 2,537,051 common shares at a weighted average price of $4.46 per share in the open market. The 2,537,051 shares were sold through BioTime's $25 million Controlled Equity Offering facility with Cantor Fitzgerald & Co., as sales agent, and through the sale of BioTime common shares held by its majority owned subsidiaries, LifeMap Sciences and Cell Cure Neurosciences. The proceeds of Biotime common shares sold by LifeMap Sciences and Cell Cure Neurosciences belong to those subsidiaries These consolidated financial statements were approved by management and the Board of Directors, and were issued on March 14, 2013. Subsequent events have been evaluated through that date.

23. Subsequent Events

Asset Contribution Agreement

On January 4, 2013, BioTime and BAC entered into an Asset Contribution Agreement with Geron Corporation ("Geron") pursuant to which BioTime and Geron will concurrently contribute certain assets to BAC in exchange for shares of BAC common stock. Closing of the asset contribution transaction is expected to occur no later than September 30, 2013.

Pursuant to the Asset Contribution Agreement, Geron has agreed to contribute certain assets related to its discontinued stem cell research and development programs, including certain patents and know-how related to human embryonic stem cells; certain biological materials and reagents; certain laboratory equipment; certain contracts; and certain product clinical trials, in exchange for shares of BAC common stock, and BioTime has agreed to contribute 8,902,077 common shares; warrants to subscribe for and purchase 8,000,000 additional common shares; $5,000,000 in cash; 10% of the shares of common stock of OrthoCyte Corporationissued and outstanding on the date of the Asset Contribution Agreement; 6% of the ordinary shares of our subsidiary Cell Cure Neurosciencesissued and outstanding on the date of the Asset Contribution Agreement; and a quantity of certain human hES cell lines produced under cGMP, and a non-exclusive, world-wide, royalty-free license to use those hES cell lines and certain patents pertaining to stem cell differentiation technology, in exchange for BAC common stock and warrants to purchase BAC common stock.

A private investor has agreed to contribute $5 million in cash to BAC for 2,136,000 shares of BAC Series B common stock, and warrants to purchase 350,000 additional shares of BAC Series B common stock. That investment will be made in conjunction with the closing under the Asset Contribution Agreement.If for any reason the private investor fails to make the $5 million contribution, BioTime will contribute cash, BioTime common shares, or a combination of cash and BioTime common shares to BAC in an amount equal to the cash not contributed by the private investor.

The same private investor also agreed to invest $5 million in BioTime by purchasing, in two tranches, an aggregate of 1,350,000 BioTime common shares and warrants to purchase approximately 650,000 additional BioTime common shares. The first tranche of $2,000,000 was funded during January 2013, and BioTime issued to the investor 540,000 common shares and 259,999 warrants.The second tranche of $3,000,000 was originally intended to close later this year concurrent with the closing of the Asset Contribution Agreement. However, on March 7, 2013 the investor and BioTime entered into an amendment to accelerate the closing date to April 10, 2013. Upon closing of the second tranche, we will issue to the investor 810,000 common shares, and warrants to purchase an additional 389,998 common shares at an exercise price of $5.00 per share.

BAC will assume all obligations and liabilities in connection with the assets contributed by Geron, to the extent such obligations and liabilities arise after the closing date of the Asset Contribution Agreement, including certain obligations and liabilities to provide follow-up procedures with patients who participated in Geron's clinical trials.

Upon the closing under the Asset Contribution Agreement, BioTime will own 21,773,340 shares of BAC Series B common stock and Geron will own 6,537,779 shares of BAC Series A common stock. Upon the sale of BAC shares to the private investor, the private investor will own 2,136,000 shares of BAC Series B common stock.

Geron has agreed to distribute to its stockholders on a pro rata basis the shares of BAC Series A common stock that Geron receives in the asset contribution transaction following the closing under the Asset Contribution Agreement. Following that distribution by Geron, BAC will distribute to the holders of its Series A common stock on a pro rata basis the 8,000,000 BioTime warrants that it receives under the Asset Contribution Agreement.

Following the distributions of the BAC Series A common stock by Geron to its stockholders, BioTime will own, including the shares of BAC Series B common stock that BioTime presently owns, approximately 71.6% of the outstanding BAC common stock, the Geron stockholders will own approximately 21.4% of the outstanding BAC common stock and the private investor will own approximately 7.0%, of the outstanding BAC common stock.

BioTime will also receive warrants to purchase 3,150,000 shares of BAC Series B common stock and the private investor will receive warrants to purchase 350,000 shares of BAC Series B common stock (the "BAC Warrants"). The BAC Warrants will have an exercise price of $5.00 per share and a term of three years. The exercise price per share and number of shares that may be purchased upon the exercise of the BAC Warrants will be subject to adjustment in the event of any BAC stock split, reverse stock split, stock dividend, reclassification of shares and certain other transactions.

The BAC Series A and Series B common stock will be identical in most respects, however, BAC will be entitled to make certain distributions or pay dividends, other than stock dividends, on its Series A common stock, without making a distribution or paying a dividend on its Series B common stock. The BAC Series B common stock may be converted into BAC Series A common stock, on a share for share basis, at BAC's election, only after Geron distributes to its stockholders the BAC Series A common stock issued under the Asset Contribution Agreement and BAC subsequently distributes to the BAC Series A common stock holders the 8,000,000 BioTime warrants that BAC will recieve from BioTime under the Asset Contribution Agreement.

Closing of the asset contribution transaction is subject to certain negotiated conditions, including: the effectiveness of registration statements under the Securities Act to be filed by BioTime and BAC, and the approval by BioTime shareholders of the issuance of BioTime shares and warrants in the transaction, and an amendment of BioTime's Articles of Incorporation to increase its authorized capital stock (the "Shareholder Proposals").

Closing of the cash contribution by the private investor is also subject to certain negotiated closing conditions, including the closing of the asset contribution transaction.

BioTime will be required to pay Geron a termination fee of $1.8 million in certain circumstances if the Asset Contribution Agreement is terminated if (a) the BioTime board of directors withdraws its recommendation to BioTime shareholders to approve the Shareholder Proposals, (b) certain BioTime directors materially breach the Support Agreements under which they and certain of their affiliates have agreed to vote their BioTime shares in favor of the Shareholder Proposals, or (c) BioTime's shareholders do not vote to approve the Shareholder Proposals.

On March 14, 2013, ReCyte and one of its shareholders entered into a Stock Purchase Agreement under which the shareholder agreed to purchase 81,169 additional ReCyte common shares for approximately $250,000, reflecting a purchase price of $3.08 pershare. In March 2013, ReCyte received $125,000 for which 40,584 ReCyte common shares were issued. ReCyte expects to receive the remaining $125,000 and to issue the remaining 40,585 common shares by the end of the second quarter.

Lease

On January 8, 2013, BioTime entered into a lease for an office and research facility located at 230 Constitution Drive, Menlo Park, California that BioTime plans to make available for use by BAC. The building on the leased premises contains approximately 24,080 square feet of space. The lease is for a term of three years commencing January 7, 2013. BioTime will pay base rent of $31,786 per month, plus real estate taxes and certain costs of maintaining the leased premises. As additional consideration for the lease, BioTime issued to the landlord BioTime common shares having a market value of $242,726, determined based upon the average closing price of our common shares on the NYSE MKT for a designated period of time prior to the signing of the lease. BioTime agreed to register those shares under the Securities Actand if it fails to file a registration statement for such purpose within 120 days the landlord will have a right to return the shares to BioTime, in which case the base rent will increase to $38,528 per month, retroactive to the commencement date of the lease.

Cell Cure Neurosciences Investment

On January 29, 2013, in accordance with the November 1, 2012 Share Purchase Agreement between BioTime and Cell Cure Neurosciences, BioTime purchased 87,456 Cell Cure Neurosciences ordinary shares in exchange for 906,735 of BioTime common shares. As a result of the share purchase, BioTime ownership directly and through ESI increased to approximately 62.6% of the outstanding ordinary shares of Cell Cure Neurosciences.

The number of common shares that BioTime issued to acquire the Cell Cure Neurosciences shares was based upon an average market price of $3.86 per BioTime common share determined on the basis of the ten actual trading days prior to November 1, 2012. Under the Share Purchase Agreement, BioTime may be required to issue additional common shares to Cell Cure Neurosciences, or Cell Cure Neurosciences may be required to issue additional Cell Cure Neurosciences ordinary shares to BioTime, depending upon whether the market value of BioTime common shares increases or decreases by more than 15%, based upon the average closing price for the ten trading days commencing on May 1, 2013. If the market value of BioTime common shares declines by more than 15% then BioTime will issue an additional number of shares required to make the value of the total number of common shares BioTime issued equal to $3.5 million, less the initial $3.86 market price multiplied by any BioTime common shares sold by Cell Cure Neurosciences prior to that date, and subject to a maximum 33% increase in the number of BioTime shares issued. Conversely, if the value of BioTime shares increases by more than 15% as of such date, Cell Cure Neurosciences will be required to issue to BioTime a number of additional Cell Cure Neurosciences ordinary shares sufficient to bring the value of the Cell Cure shares Neurosciences issued to BioTime under the Share Purchase Agreement to the value of the BioTime common shares we issued, also determined on the basis of a ten day trading period commencing on May 1, 2013, but subject to a 33% maximum increase in the number of Cell Cure Neurosciences shares issued.

In 2013, BioTime raised gross proceeds of $11,306,430 from the sale of 2,537,051 common shares at a weighted average price of $4.46 per share in the open market. The 2,537,051 shares were sold through BioTime's $25 million Controlled Equity Offering facility with Cantor Fitzgerald & Co., as sales agent, and through the sale of BioTime common shares held by its majority owned subsidiaries, LifeMap Sciences and Cell Cure Neurosciences. The proceeds of Biotime common shares sold by LifeMap Sciences and Cell Cure Neurosciences belong to those subsidiaries

These consolidated financial statements were approved by management and the Board of Directors, and were issued on March 14, 2013. Subsequent events have been evaluated through that date.