Selected Quarterly Financial Information (Unaudited) - Schedule of Selected Quarterly Financial Information (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017
Quarterly Financial Information Disclosure [Abstract]
Revenues, net	$ 758	$ 982	$ 2,547	$ 701	$ 945	$ 1,636	$ 376	$ 333	$ 4,988	$ 3,458	[1]
Operating expenses	10,813	11,304	11,585	12,779	10,508	11,149	10,694	11,595	46,481	43,946
Loss from operations	(10,107)	(10,357)	(9,144)	(12,187)	(9,563)	(9,513)	(8,564)	(11,262)	(41,795)	(38,902)
Net income (loss) attributable to BioTime	$ (44,952)	$ 66,725	$ (4,215)	$ (63,548)	$ (71,934)	$ 14,321	$ (11,651)	$ 49,288	$ (45,990)	$ (19,976)
Basic net income (loss) per share	$ (0.36)	$ 0.53	$ (0.03)	$ (0.50)	$ (0.58)	$ 0.12	$ (0.11)	$ 0.46

[1] Amounts recognized prior to adoption of Topic 606 have not been adjusted under the Topic 606 modified retrospective transition method.