Equity Method Accounting for Common Stock of Asterias, at fair value (Details) - Asterias Biotherapeutics, Inc. [Member] - USD ($) $ / shares in Units, $ in Thousands, shares in Millions		3 Months Ended		4 Months Ended	9 Months Ended
		Sep. 30, 2017	Sep. 30, 2016	May 12, 2016	Sep. 30, 2017	Sep. 30, 2016	Jun. 30, 2017	Dec. 31, 2016	May 13, 2016
Schedule of Equity Method Investments [Line Items]
Common stock, outstanding (in shares)									21.7
Fair value on investment		$ 73,900			$ 73,900			$ 100,000
Price per share on NYSE American (in dollars per share)		$ 3.40			$ 3.40		$ 3.55	$ 4.60
Unrealized (loss) on equity method investment		$ (3,300)			$ (26,100)
Condensed Statements of Operations (unaudited) [Abstract]
Total revenue	[1]	1,688	$ 2,076	$ 2,354	4,014	$ 5,202
Gross profit	[1]	1,607	2,017	2,301	3,863	5,084
Loss from operations	[1]	(7,063)	(7,425)	(13,944)	(24,703)	(25,591)
Net loss	[1]	$ (6,809)	$ (10,648)	$ (13,113)	$ (21,824)	$ (26,144)

[1] The condensed unaudited statement of operations information included in the table above reflects Asterias' results of operations for the three and nine months ended September 30, 2017 and 2016. The periods shown are provided for comparative purposes only, and the condensed results of operations of Asterias shown for the three and nine months ended September 30, 2017 were not included in BioTime's condensed consolidated statements of operations. The unaudited results of operations of Asterias for the period January 1, 2016 through May 12, 2016 only are included in the unaudited condensed consolidated results of BioTime for the nine months ended September 30, 2016 due to the Asterias Deconsolidation on May 13, 2016.