Equity Method of Accounting for Common Stock of Asterias, at Fair Value - Schedule of Condensed Results of Operations and Balance Sheet Information (Details) - Asterias Biotherapeutics [Member] - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2018	Dec. 31, 2017
Total revenue		$ 812	$ 4,042
Gross profit		588	3,877
Loss from operations		(21,605)	(33,251)
Net loss		(21,820)	(28,372)
Current assets	[1]	8,793	22,716
Noncurrent assets	[1]	13,481	20,376
Total assets	[1]	22,274	43,092
Current liabilities	[1]	2,982	3,521
Noncurrent liabilities	[1]	2,241	6,028
Stockholders' equity	[1]	17,051	33,543
Total liabilities and stockholders' equity	[1]	$ 22,274	$ 43,092

[1] The condensed balance sheet information of Asterias as of December 31, 2018 and 2017, is provided for informational and comparative purposes only and was not included in BioTime's consolidated balance sheet as of December 31, 2018 and 2017 due to the Asterias Deconsolidation on May 13, 2016.