Accounts Payable and Accrued Liabilities (Details Narrative) - USD ($) $ in Thousands		6 Months Ended
		Jun. 30, 2019	Dec. 31, 2018
Separation payments		$ 500
Accrued compensation	[1]	$ 1,970	$ 2,456
Description of termination plan		Termination dates for these individuals range from August 9, 2019 to September 30, 2019.
Accrued Seperation payments		$ 200
Asterias Biotherapeutics, Inc. [Member]
Separation payments		$ 500
Description of termination plan		Termination dates for these individuals ranged from May 31, 2019 to June 28, 2019.
Accrued Seperation payments		$ 300
Asterias Biotherapeutics, Inc. [Member] | General and Administrative [Member]
Accrued compensation		2,000
Asterias Biotherapeutics, Inc. [Member] | Three Employees Member [Member]
Separation payments		$ 2,000

[1] Includes $0.3 million of change of control and related transaction costs related to the Asterias Merger (see Note 3) recorded outside of the business combination.