Asset Contribution Agreement (Details) (USD $)	9 Months Ended				0 Months Ended	9 Months Ended				9 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Dec. 31, 2013	Oct. 01, 2013 Common [Member]	Oct. 01, 2013 Warrants [Member]	Sep. 30, 2014 Asterias Biotherapeutics [Member]	Sep. 30, 2014 Asterias Biotherapeutics [Member] Asterias Series B Common Stock [Member]	Sep. 30, 2014 OrthoCyte Corporation [Member]	Sep. 30, 2014 Cell Cure Neurosciences, Ltd. [Member]	Sep. 30, 2014 Geron [Member]	Dec. 31, 2013 Geron [Member]	Sep. 30, 2014 Geron [Member] Common Class A [Member]	Sep. 30, 2014 Romulus Films, Ltd. [Member] Asterias Series B Common Stock [Member]
Asset Contribution Agreement [Line Items]
Stock issued during period (in shares)						8,902,077	21,773,340					6,537,779	2,136,000
Common shares, par value (in dollars per share)	$ 0		$ 0				$ 0.0001					$ 0.0001
Number of warrants issued (in shares)						8,000,000	3,150,000						350,000
Number of warrants to be issued by Asterias to Series A common shareholders (in shares)												8,000,000
Exercise price of warrant (in dollars per share)					$ 5.00	$ 5.00	$ 5.00
Warrant expiration term						5 years	3 years
Amount of contribution from investor						$ 5,000,000
Percentage of subsidiary stock contributed (in hundredths)								10.00%	6.00%
Proceeds from issuance of common shares	0	23,810,421											5,000,000
Transaction costs allocated to issuance of equity										541,800
Stock price (in dollars per share)					$ 2.40		$ 2.40
Market value of BioTime common stock (in dollars per share)				$ 3.93
Intangible assets, useful life	10 years
Royalty rate on net sales of products (in hundredths)												4.00%
Weighted-average assumptions [Abstract]
Expected term					5 years		3 years
Risk-free interest rate (in hundredths)					1.42%		0.63%
Dividend yield (in hundredths)					0.00%		0.00%
Expected volatility (in hundredths)					77.63%		69.62%
Asterias Series B shares						52,164,568
Warrants to purchase Asterias Series B shares						2,012,481
Excess of contributed asset's value over consideration						4,800,063
Total consideration issued						58,977,112				34,917,532
BioTime common shares, at fair value						34,985,163
BioTime Warrants, at fair value						18,276,406
Cancellation of outstanding obligation to BioTime						5,000,000
Investment in affiliates, at cost						415,543
Geron asset acquisition related transaction costs paid by BioTime						300,000
Total assets transferred						58,977,112
Asterias Series A shares, net of issuance cost of $541,800										15,121,222
Obligation to distribute BioTIme Warrants										18,276,406
Transaction and other costs										1,519,904
Patents and other intellectual property rights related to hES cells										29,017,009
Deferred tax liability arising from difference in book versus tax basis on Geron intangible assets acquired										(11,558,243)
IPR&D expensed upon acquisition										17,458,766	17,458,766
Total assets and in-process research and development acquired										$ 34,917,532