Income Taxes	6 Months Ended
Jun. 30, 2019
Income Tax Disclosure [Abstract]
Income Taxes	13. Income Taxes The provision for income taxes for interim periods is generally determined using an estimated annual effective tax rate as prescribed by ASC 740-270, Income Taxes, Interim Reporting. The effective tax rate may be subject to fluctuations during the year as new information is obtained, which may affect the assumptions used to estimate the annual effective tax rate, including factors such as valuation allowances and changes in valuation allowances against deferred tax assets, the recognition or de-recognition of tax benefits related to uncertain tax positions, if any, and changes in or the interpretation of tax laws in jurisdictions where BioTime conducts business. ASC 740-270 also states that if an entity is unable to reliably estimate some or a part of its ordinary income or loss, the income tax provision or benefit applicable to the item that cannot be estimated shall be reported in the interim period in which the item is reported. For items that BioTime cannot reliably estimate on an annual basis (principally unrealized gains or losses generated by changes in the market prices of the OncoCyte, and AgeX shares of common stock BioTime holds, and prior to March 8, 2019, Asterias shares BioTime held), BioTime uses the actual year to date effective tax rate rather than an estimated annual effective tax rate to determine the tax effect of each item, including the use of all available net operating losses and other credits or deferred tax assets. Although the deconsolidation of OncoCyte was not a taxable transaction to BioTime and did not create a current income tax payment obligation to BioTime, the market value of the shares of OncoCyte common stock BioTime holds creates a deferred tax liability to BioTime based on the closing prices of the shares, less BioTime’s tax basis in the shares. The deferred tax liability generated by the OncoCyte shares that BioTime holds as of June 30, 2019, is a source of future taxable income to BioTime, as prescribed by ASC 740-10-30-17, that will more likely than not result in the realization of its deferred tax assets to the extent of the deferred tax liability. This deferred tax liability is determined based on the closing prices of the OncoCyte shares as of June 30, 2019. Due to the inherent unpredictability of future prices of those shares, BioTime cannot reliably estimate or project those deferred tax liabilities on an annual basis. Therefore, the deferred tax liability pertaining to OncoCyte shares, determined based on the actual closing prices on the last stock market trading day of the applicable accounting period, and the related impacts to the valuation allowance and deferred tax asset changes, are recorded in the accounting period in which they occur. Prior to the Asterias Merger discussed in Note 3, the Asterias shares of common stock BioTime held generated similar deferred tax liabilities to BioTime as the OncoCyte shares discussed above. As of the Asterias Merger date and due to Asterias becoming a wholly owned subsidiary of BioTime, the Asterias deferred tax liabilities were eliminated with a corresponding adjustment to BioTime’s valuation allowance, resulting in no tax provision or benefit from this adjustment. On March 23, 2018, Ascendance was acquired by a third party in a merger through which AgeX received approximately $3.2 million in cash for its shares of Ascendance common stock. For financial reporting purposes, AgeX recognized a $3.2 million gain as a sale of its equity method investment in Ascendance. The sale was a taxable transaction to AgeX generating a taxable gain of approximately $2.2 million. BioTime had sufficient losses from operations to offset the entire gain resulting in no income taxes due. The income tax consequences of the AgeX Deconsolidation are discussed below. The Juvenescence Transaction discussed in Note 5 was a taxable event for BioTime that resulted in a gross taxable gain of approximately $29.4 million, which BioTime fully offset with available net operating losses (“NOL”) and NOL carryforwards, resulting in no net income taxes due. Although the AgeX Deconsolidation on August 30, 2018 was not a taxable transaction to BioTime and did not result in a current tax payment obligation, the unrealized financial reporting gain (see Note 6) on the AgeX Deconsolidation generated a deferred tax liability in accordance with ASC 740, primarily representing BioTime’s difference between book and tax basis of AgeX common stock on the AgeX Deconsolidation date. This deferred tax liability was fully offset by a corresponding release of BioTime’s valuation allowance on deferred tax assets, resulting in no income tax provision or benefit from the AgeX Deconsolidation. The deferred tax liabilities on BioTime’s investments in OncoCyte, Asterias and AgeX are considered to be sources of taxable income as prescribed by ASC 740-10-30-17 that will more likely than not result in the realization of its deferred tax assets to the extent of those deferred tax liabilities, thereby reducing the need for a valuation allowance. The distribution of AgeX shares of common stock to BioTime shareholders (see Note 6) on November 28, 2018 was a taxable event for BioTime that resulted in a gross taxable gain of approximately $26.4 million, which was fully offset by NOL carryforwards, resulting in no income taxes due. In connection with the Asterias Merger, a deferred tax liability of $13.0 million was recorded as part of the acquisition accounting (see Note 3). The deferred tax liability (“DTL”) is related to fair value adjustments for the assets and liabilities acquired in the Asterias Merger, principally consisting of IPR&D. This estimate of deferred taxes was determined based on the excess of the estimated fair values of the acquired assets and liabilities over the tax basis of the assets and liabilities acquired. The statutory tax rate was applied, as appropriate, to the adjustment based on the jurisdiction in which the adjustment is expected to occur. This estimate of deferred income tax liabilities is preliminary and is subject to change based upon BioTime’s final determination of the fair value of assets acquired and liabilities assumed. Because the IPR&D (prior to completion or abandonment of the R&D) is considered an indefinite-lived asset for accounting purposes, the fair value of the IPR&D on the acquisition date creates a deferred income tax liability in accordance with ASC 740. This DTL is computed using the fair value of the IPR&D assets on the acquisition date multiplied by BioTime’s respective federal and state income tax rates. While this DTL would reverse on impairment or sale or commencement of amortization of the related intangible assets, those events are not anticipated under ASC 740 for purposes of predicting reversal of a temporary difference to support the realization of deferred tax assets, except for certain deferred tax assets and credit carryforwards that are also indefinite in nature as of the Asterias Merger date, which may be considered for reversal under ASC 740 as further discussed below. A valuation allowance is provided when it is more likely than not that some portion of the deferred tax assets will not be realized. For federal and state income tax purposes, as a result of the deconsolidation of AgeX, Asterias and OncoCyte and the deferred tax liabilities generated from the market values of AgeX, Asterias and OncoCyte shares from the respective deconsolidation dates, including the changes to those deferred tax liabilities due to changes in the AgeX, Asterias and OncoCyte stock prices, BioTime’s deferred tax assets exceeded its deferred tax liabilities as of December 31, 2018. As a result, BioTime established a full valuation allowance as of December 31, 2018 due to the uncertainty of realizing future tax benefits from its net operating loss carryforwards and other deferred tax assets. For the three and six months ended June 30, 2019, BioTime reversed a portion of its valuation allowance. The partial reversal of the historical valuation allowance is related to BioTime’s deferred tax assets and credit carryforwards and is due to the acquired taxable temporary differences, primarily consisting of the acquired IPR&D discussed above and in Notes 3 and 8. ASC 740 allows for deferred tax assets and credit carryforwards, that are both available and indefinite in nature, to be used against similar deferred tax liabilities as a source of income to support the realization of those deferred tax assets and credit carryforwards. Any benefit recognized from such a reversal of the valuation allowance is recorded outside of the acquisition accounting. Accordingly, the $1.2 million and $5.6 million valuation allowance release and the corresponding tax benefits were primarily related to state research and development credits, including current year federal net operating losses generated for the three and six months ended June 30, 2019, respectively, both of which are available and indefinite in nature. BioTime did not record any provision or benefit for income taxes for the three and six months ended June 30, 2018 as BioTime had a full valuation allowance for the periods presented.

Income Taxes

6 Months Ended

Jun. 30, 2019

13. Income Taxes

The provision for income taxes for interim periods is generally determined using an estimated annual effective tax rate as prescribed by ASC 740-270, Income Taxes, Interim Reporting. The effective tax rate may be subject to fluctuations during the year as new information is obtained, which may affect the assumptions used to estimate the annual effective tax rate, including factors such as valuation allowances and changes in valuation allowances against deferred tax assets, the recognition or de-recognition of tax benefits related to uncertain tax positions, if any, and changes in or the interpretation of tax laws in jurisdictions where BioTime conducts business. ASC 740-270 also states that if an entity is unable to reliably estimate some or a part of its ordinary income or loss, the income tax provision or benefit applicable to the item that cannot be estimated shall be reported in the interim period in which the item is reported.

For items that BioTime cannot reliably estimate on an annual basis (principally unrealized gains or losses generated by changes in the market prices of the OncoCyte, and AgeX shares of common stock BioTime holds, and prior to March 8, 2019, Asterias shares BioTime held), BioTime uses the actual year to date effective tax rate rather than an estimated annual effective tax rate to determine the tax effect of each item, including the use of all available net operating losses and other credits or deferred tax assets.

Although the deconsolidation of OncoCyte was not a taxable transaction to BioTime and did not create a current income tax payment obligation to BioTime, the market value of the shares of OncoCyte common stock BioTime holds creates a deferred tax liability to BioTime based on the closing prices of the shares, less BioTime’s tax basis in the shares. The deferred tax liability generated by the OncoCyte shares that BioTime holds as of June 30, 2019, is a source of future taxable income to BioTime, as prescribed by ASC 740-10-30-17, that will more likely than not result in the realization of its deferred tax assets to the extent of the deferred tax liability. This deferred tax liability is determined based on the closing prices of the OncoCyte shares as of June 30, 2019. Due to the inherent unpredictability of future prices of those shares, BioTime cannot reliably estimate or project those deferred tax liabilities on an annual basis. Therefore, the deferred tax liability pertaining to OncoCyte shares, determined based on the actual closing prices on the last stock market trading day of the applicable accounting period, and the related impacts to the valuation allowance and deferred tax asset changes, are recorded in the accounting period in which they occur.

Prior to the Asterias Merger discussed in Note 3, the Asterias shares of common stock BioTime held generated similar deferred tax liabilities to BioTime as the OncoCyte shares discussed above. As of the Asterias Merger date and due to Asterias becoming a wholly owned subsidiary of BioTime, the Asterias deferred tax liabilities were eliminated with a corresponding adjustment to BioTime’s valuation allowance, resulting in no tax provision or benefit from this adjustment.

On March 23, 2018, Ascendance was acquired by a third party in a merger through which AgeX received approximately $3.2 million in cash for its shares of Ascendance common stock. For financial reporting purposes, AgeX recognized a $3.2 million gain as a sale of its equity method investment in Ascendance. The sale was a taxable transaction to AgeX generating a taxable gain of approximately $2.2 million. BioTime had sufficient losses from operations to offset the entire gain resulting in no income taxes due.

The income tax consequences of the AgeX Deconsolidation are discussed below.

The Juvenescence Transaction discussed in Note 5 was a taxable event for BioTime that resulted in a gross taxable gain of approximately $29.4 million, which BioTime fully offset with available net operating losses (“NOL”) and NOL carryforwards, resulting in no net income taxes due. Although the AgeX Deconsolidation on August 30, 2018 was not a taxable transaction to BioTime and did not result in a current tax payment obligation, the unrealized financial reporting gain (see Note 6) on the AgeX Deconsolidation generated a deferred tax liability in accordance with ASC 740, primarily representing BioTime’s difference between book and tax basis of AgeX common stock on the AgeX Deconsolidation date. This deferred tax liability was fully offset by a corresponding release of BioTime’s valuation allowance on deferred tax assets, resulting in no income tax provision or benefit from the AgeX Deconsolidation. The deferred tax liabilities on BioTime’s investments in OncoCyte, Asterias and AgeX are considered to be sources of taxable income as prescribed by ASC 740-10-30-17 that will more likely than not result in the realization of its deferred tax assets to the extent of those deferred tax liabilities, thereby reducing the need for a valuation allowance.

The distribution of AgeX shares of common stock to BioTime shareholders (see Note 6) on November 28, 2018 was a taxable event for BioTime that resulted in a gross taxable gain of approximately $26.4 million, which was fully offset by NOL carryforwards, resulting in no income taxes due.

In connection with the Asterias Merger, a deferred tax liability of $13.0 million was recorded as part of the acquisition accounting (see Note 3). The deferred tax liability (“DTL”) is related to fair value adjustments for the assets and liabilities acquired in the Asterias Merger, principally consisting of IPR&D. This estimate of deferred taxes was determined based on the excess of the estimated fair values of the acquired assets and liabilities over the tax basis of the assets and liabilities acquired. The statutory tax rate was applied, as appropriate, to the adjustment based on the jurisdiction in which the adjustment is expected to occur. This estimate of deferred income tax liabilities is preliminary and is subject to change based upon BioTime’s final determination of the fair value of assets acquired and liabilities assumed. Because the IPR&D (prior to completion or abandonment of the R&D) is considered an indefinite-lived asset for accounting purposes, the fair value of the IPR&D on the acquisition date creates a deferred income tax liability in accordance with ASC 740. This DTL is computed using the fair value of the IPR&D assets on the acquisition date multiplied by BioTime’s respective federal and state income tax rates. While this DTL would reverse on impairment or sale or commencement of amortization of the related intangible assets, those events are not anticipated under ASC 740 for purposes of predicting reversal of a temporary difference to support the realization of deferred tax assets, except for certain deferred tax assets and credit carryforwards that are also indefinite in nature as of the Asterias Merger date, which may be considered for reversal under ASC 740 as further discussed below.

A valuation allowance is provided when it is more likely than not that some portion of the deferred tax assets will not be realized. For federal and state income tax purposes, as a result of the deconsolidation of AgeX, Asterias and OncoCyte and the deferred tax liabilities generated from the market values of AgeX, Asterias and OncoCyte shares from the respective deconsolidation dates, including the changes to those deferred tax liabilities due to changes in the AgeX, Asterias and OncoCyte stock prices, BioTime’s deferred tax assets exceeded its deferred tax liabilities as of December 31, 2018. As a result, BioTime established a full valuation allowance as of December 31, 2018 due to the uncertainty of realizing future tax benefits from its net operating loss carryforwards and other deferred tax assets.

For the three and six months ended June 30, 2019, BioTime reversed a portion of its valuation allowance. The partial reversal of the historical valuation allowance is related to BioTime’s deferred tax assets and credit carryforwards and is due to the acquired taxable temporary differences, primarily consisting of the acquired IPR&D discussed above and in Notes 3 and 8. ASC 740 allows for deferred tax assets and credit carryforwards, that are both available and indefinite in nature, to be used against similar deferred tax liabilities as a source of income to support the realization of those deferred tax assets and credit carryforwards. Any benefit recognized from such a reversal of the valuation allowance is recorded outside of the acquisition accounting. Accordingly, the $1.2 million and $5.6 million valuation allowance release and the corresponding tax benefits were primarily related to state research and development credits, including current year federal net operating losses generated for the three and six months ended June 30, 2019, respectively, both of which are available and indefinite in nature.

BioTime did not record any provision or benefit for income taxes for the three and six months ended June 30, 2018 as BioTime had a full valuation allowance for the periods presented.