Consolidated Statements of Changes in Shareholders’ Equity - USD ($)	Preferred Stock [Member]	Common Stock [Member]	Common Shares [Member] Asterias Biotherapeutics [Member]	Common Shares [Member] OncoCyte [Member]	Common Shares [Member] AgeX [Member]	Treasury Shares [Member] OncoCyte [Member]	Treasury Shares [Member]	Contributed Capital [Member]	Accumulated Deficit [Member]	Noncontrolling Interest [Member] Asterias Biotherapeutics [Member]	Noncontrolling Interest [Member] AgeX [Member]	Noncontrolling Interest [Member] OncoCyte Corporation [Member]	Noncontrolling Interest [Member]	Accumulated Other Comprehensive Income/(Loss) [Member]	Total
Balance at Dec. 31, 2014	$ 3,500,000	$ 234,843,000					$ (19,890,000)	$ 7,000	$ (182,190,000)				$ 26,267,000	$ 186,000	$ 62,723,000
Balance, shares at Dec. 31, 2014	70,000	83,122,000					(4,894,000)
Sale of common shares, net of fees paid and amortized		$ 33,897,000													33,897,000
Sale of common shares, net of fees paid and amortized, shares		10,738,000
Exercise of options		$ 621,000													621,000
Exercise of options, shares		155,000
Warrants exercised		$ 19,000													19,000
Warrants exercised, shares		4,000
Stock options granted for compensation		$ 2,003,000													2,003,000
Stock options granted for compensation in subsidiaries													8,223,000		8,223,000
Restricted stock granted for compensation													822,000		822,000
Dividend in kind									(712,000)				712,000
Subsidiary shares retired to pay for employee's taxes													(98,000)		(98,000)
Subsidiary warrants exercised													11,700,000		11,700,000
Contingently issuable subsidiary warrants													65,000		65,000
Sale of treasury stock		$ (496,000)					$ 1,857,000								1,361,000
Sale of treasury stock, shares							421,000
Conversion of preferred stock to common stock	$ (3,500,000)	$ 3,500,000
Conversion of preferred stock to common stock, shares	(70,000)	875,000
Dividends on preferred stock		$ (408,000)						(7,000)							(415,000)
Exercise of subsidiary options													33,000		33,000
Subsidiary shares issued in lieu of cash for services received													486,000		486,000
Outside investment in subsidiary with cash													3,918,000		3,918,000
Sale of subsidiary shares at- the- market, net of fees paid and amortized													9,646,000		9,646,000
Foreign currency translation adjustment														(424,000)	(424,000)
Unrealized loss on available-for-sale securities														1,000	1,000
Common shares issued to purchase Cell Cure ordinary shares and Cell Cure Notes from noncontrolling interests in Cell Cure
NET INCOME (LOSS)									(46,991,000)				(11,143,000)		(58,134,000)
Balance at Dec. 31, 2015		$ 273,979,000					$ (18,033,000)		(229,893,000)				50,631,000	(237,000)	76,447,000
Balance, shares at Dec. 31, 2015		94,894,000					(4,473,000)
Sale of common shares, net of fees paid and amortized		$ 18,606,000													18,606,000
Sale of common shares, net of fees paid and amortized, shares		8,420,000
Stock options granted for compensation		$ 2,731,000													2,731,000
Stock options granted for compensation in subsidiaries													5,220,000		5,220,000
Dividends on preferred stock
Exercise of subsidiary options													2,151,000		2,151,000
Foreign currency translation adjustment														(106,000)	(106,000)
Unrealized loss on available-for-sale securities														(395,000)	(395,000)
Common shares issued for executive bonus in lieu of cash		$ 200,000													200,000
Common shares issued for executive bonus in lieu of cash, shares		68,000
Common shares issued for consulting services in lieu of cash		$ 40,000													40,000
Common shares issued for consulting services in lieu of cash, shares		14,000
Deconsolidation							$ 15,142,000						(21,752,000)		(6,610,000)
Deconsolidation, shares							3,853,000
Subsidiary financing transactions with noncontrolling interests			18,310,000	4,012,000						(18,310,000)		(4,012,000)
Distribution of Asterias warrants to its shareholders other than BioTime													3,125,000		3,125,000
Sale of common shares and warrants by OncoCyte, net of financing fees													9,777,000		9,777,000
Beneficial conversion feature on convertible debt issued to Cell Cure's noncontrolling interests													701,000		701,000
Common shares issued to purchase Cell Cure ordinary shares and Cell Cure Notes from noncontrolling interests in Cell Cure
NET INCOME (LOSS)									33,572,000				(14,951,000)		18,621,000
Balance at Dec. 31, 2016		$ 317,878,000					$ (2,891,000)		(196,321,000)				12,580,000	(738,000)	130,508,000
Balance, shares at Dec. 31, 2016		103,396,000					(620,000)
Sale of common shares, net of fees paid and amortized		$ 45,068,000													45,068,000
Sale of common shares, net of fees paid and amortized, shares		18,511,000
Exercise of options		$ 25,000													25,000
Exercise of options, shares		9,000
Stock options granted for compensation		$ 3,019,000													3,019,000
Stock options granted for compensation in subsidiaries													913,000		913,000
Dividends on preferred stock
Exercise of subsidiary options													4,000		4,000
Foreign currency translation adjustment														668,000	668,000
Unrealized loss on available-for-sale securities														521,000	521,000
Common shares issued for consulting services in lieu of cash		$ 3,000													3,000
Common shares issued for consulting services in lieu of cash, shares		1,000
Deconsolidation				(3,253,000)		$ 2,891,000						$ (8,512,000)			(8,874,000)
Deconsolidation, shares						620,000
Subsidiary financing transactions with noncontrolling interests					$ 8,207,000						$ (8,207,000)
Beneficial conversion feature on convertible debt issued to Cell Cure's noncontrolling interests													304,000		304,000
Sale of common shares at the market, net of fees		$ 835,000													835,000
Sale of common shares at the market, net of fees, shares		300,000
Purchase of shares from a related party and retired		$ (843,000)													(843,000)
Purchase of shares from a related party and retired, shares		(300,000)
Shares issued upon vesting of restricted stock units, net of shares retired to pay employee's taxes		$ (46,000)													(46,000)
Shares issued upon vesting of restricted stock units, net of shares retired to pay employee's taxes, shares		24,000
Sale of subsidiary shares in AgeX					$ 100,000						$ 9,868,000				9,968,000
Subsidiary financing and other transactions with noncontrolling interests -LifeMap Sciences, LifeMap Solutions, OrthoCyte, and ReCyte, net		$ 5,495,000											(5,495,000)
Common shares issued to purchase Cell Cure ordinary shares and Cell Cure Notes from noncontrolling interests in Cell Cure		$ 15,217,000													15,217,000
Common shares issued to purchase Cell Cure ordinary shares and Cell Cure Notes from noncontrolling interests in Cell Cure, shares		4,925,000
Purchase of noncontrolling interests in Cell Cure		$ (10,117,000)											3,480,000		(6,637,000)
Purchase of beneficial conversion option at intrinsic value in Cell Cure Notes		(3,101,000)													(3,101,000)
NET INCOME (LOSS)									(19,976,000)				(3,313,000)		(23,289,000)
Balance at Dec. 31, 2017		$ 378,487,000							$ (216,297,000)				$ 1,622,000	$ 451,000	$ 164,263,000
Balance, shares at Dec. 31, 2017		126,866,000