Income Taxes (Details Narrative) - USD ($) $ in Thousands					12 Months Ended
	Nov. 28, 2018	Mar. 23, 2018	Feb. 17, 2017	May 13, 2016	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Jun. 06, 2017
Repatriation tax foreign earnings in federal income						$ 227
Net deferred tax assets					$ 8,900	$ 8,900
Federal income tax rate					21.00%	34.00%
Federal current income tax benefit					$ 300
Net operating loss carryforwards for federal tax purposes					93,800
Foreign net operating loss carryforwards					72,900
Net operating loss carryforwards for state tax purposes					43,100
Proceeds from issuance of common stock						48,875
Unrealized loss on deconsolidation of asterias					$ 48,000
Foreign currency translation adjustment, description					BioTime allocated income tax expense against the component of foreign currency translation adjustment in 2018 using a 21% tax rate.
Income tax benefit					$ (346)
Net operating loss carryforwards change in ownership control					50.00%
Accrued interest and penalties
AgeX Therapeutics [Member]
Proceeds from issuance of common stock		$ 3,200
Gain on sale of equity method investment		3,200
Taxable gain	$ 26,400	2,200
Juvenescence Limited [Member]
Taxable gain		$ 29,400
OncoCyte Deconsolidation [Member]
Gain on deconsolidation of asterias			$ 71,700
Unrealized loss on deconsolidation of asterias						2,900
Asterias Deconsolidation [Member]
Gain on deconsolidation of asterias				$ 49,000			$ 34,300
Unrealized loss on deconsolidation of asterias					$ 35,400	51,100
LifeMap Solutions, Inc [Member]
Taxable gain on asset transfer						3,700
Federal alternative minimum tax payable						$ 22,000
LifeMap Solutions, Inc [Member] | Debt Conversion Agreement [Member]
Intercompany indebtedness								$ 8,700
Net operating loss carryforwards								$ 3,300
Federal and State [Member]
Federal income tax rate					21.00%
Federal [Member]
Net operating losses expiration date					between 2019 and 2038	between 2028 and 2037
Tax credit carryforwards					$ 2,500
State Tax [Member]
Net operating losses expiration date						between 2030 and 2037
Tax credit carryforwards					$ 2,800
Maximum [Member]
Deferred tax assets and liabilities re-rated percentage						34.00%
Minimum [Member]
Deferred tax assets and liabilities re-rated percentage						21.00%