Pro Forma Financial Information for Fiscal Years Ended December 31, 2013 and 2012 (UNAUDITED) (Details) (USD $)	3 Months Ended								12 Months Ended
	Dec. 31, 2013		Sep. 30, 2013		Jun. 30, 2013		Mar. 31, 2013		Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
Pro Forma Financial Information for Fiscal Years Ended December 31, 2013 and 2012 (UNAUDITED)
Revenues									$ 4,434,336		$ 4,206,973
(Loss) available to common shareholders									(26,424,069)	[1]	(38,781,953)	[1]
(Loss) per common share - basic (in dollars per share)									$ (0.49)		$ (0.78)
(Loss) per common share - diluted (in dollars per share)									$ (0.49)		$ (0.78)
Acquired in-process research and development	$ 17,458,766	[2]	$ 0	[2]	$ 0	[2]	$ 0	[2]	$ 17,458,766		$ 0		$ 0

[1] For 2012, includes $17,458,766 of IPR&D acquired under the Asset Contribution Agreement which was completed on October 1, 2013. See Note 15.

[2] Includes IPR&D expenses related to intangible assets acquired by Asterias from Geron under the Asset Contribution. IPR&D represents the value of incomplete research and development projects which Asterias intends to continue. See Notes 2 and 15.