Consolidated Statements of Changes in Shareholders' Equity - USD ($) $ in Thousands	Preferred Stock [Member]	Common Stock [Member]	Common Shares [Member] OncoCyte [Member]	Common Shares [Member] AgeX [Member]	Treasury Shares [Member] OncoCyte [Member]	Treasury Shares [Member]	Accumulated Deficit [Member]	Noncontrolling Interest/(Deficit) [Member] AgeX [Member]	Noncontrolling Interest/(Deficit) [Member] OncoCyte Corporation [Member]	Noncontrolling Interest/(Deficit) [Member]	Accumulated Other Comprehensive Income/(Loss) [Member]	Total
Balance at Dec. 31, 2016		$ 317,878				$ (2,891)	$ (196,321)			$ 12,580	$ (738)	$ 130,508
Balance, shares at Dec. 31, 2016		103,396,000				(620,000)
Sale of common shares, net of financing fees		$ 45,068										45,068
Sale of common shares, net of financing fees, shares		18,511,000
Sale of common shares at the market, net of fees		$ 835										835
Sale of common shares at the market, net of fees, shares		300,000
Purchase of shares from a related party and retired		$ (843)										(843)
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)										(46)
Shares issued upon vesting of restricted stock units, net of shares retired to pay employee's taxes, shares		24,000
Common shares issued for consulting services in lieu of cash		$ 3										3
Common shares issued for consulting services in lieu of cash, shares		1,000
Stock-based compensation		$ 3,019										3,019
Stock-based compensation in subsidiaries										913		913
Exercise of options		$ 25										25
Exercise of options, shares		9,000
Exercise of subsidiary options										4		4
Deconsolidation			$ (3,253)		$ 2,891				$ (8,512)			(8,874)
Deconsolidation, shares					620,000
Sale of subsidiary shares in AgeX				$ 100				$ 9,868				9,968
Subsidiary financing transactions with noncontrolling interests - AgeX				8,207				(8,207)
Beneficial conversion feature on convertible debt issued to Cell Cure's noncontrolling interests										304		304
Foreign currency translation adjustment											668	668
Unrealized gain on available-for-sale securities											521	521
Subsidiary financing and other transactions with noncontrolling interests - LifeMap Sciences, LifeMap Solutions, OrthoCyte, and ReCyte, net		5,495								(5,495)
Common shares issued to purchase Cell Cure ordinary shares and Cell Cure Notes from noncontrolling interests in Cell Cure		$ 15,217										15,217
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)								3,480		(6,637)
Purchase of beneficial conversion option at intrinsic value in Cell Cure Notes		(3,101)										(3,101)
Distribution of AgeX shares to BioTime shareholders, on a pro rata basis, at fair value as a dividend-in-kind
NET LOSS							(19,976)			(3,313)		(23,289)
Balance at Dec. 31, 2017		$ 378,487					(216,297)			1,622	451	164,263
Balance, shares at Dec. 31, 2017		126,866,000
Shares issued upon vesting of restricted stock units, net of shares retired to pay employee's taxes		$ (203)										(203)
Shares issued upon vesting of restricted stock units, net of shares retired to pay employee's taxes, shares		270,000
Stock-based compensation		$ 4,912										4,912
Stock-based compensation in subsidiaries										490		490
Exercise of subsidiary options
Deconsolidation				$ (163)				(3,467)				(3,630)
Deconsolidation, shares
Sale of subsidiary shares in AgeX								5,239				5,239
Subsidiary financing transactions with noncontrolling interests - AgeX				$ 3,790				(3,790)
Foreign currency translation adjustment											1,303	1,303
Common shares issued to purchase Cell Cure ordinary shares and Cell Cure Notes from noncontrolling interests in Cell Cure
Purchase of noncontrolling interests in Cell Cure		(38)										(38)
Cumulative-effect adjustment for adoption of ASU 2016-01							328				(328)
Cumulative-effect adjustment for adoption of Accounting Standard Codification, Topic 606							103					103
Sale of subsidiary warrants in AgeX								$ 1,000				1,000
Distribution of AgeX shares to BioTime shareholders, on a pro rata basis, at fair value as a dividend-in-kind		(34,409)										(34,409)
Subsidiary financing and other transactions with noncontrolling interests - Cell Cure		1,894								(1,894)
NET LOSS							(45,990)			(794)		(46,784)
Balance at Dec. 31, 2018		$ 354,270					$ (261,856)			$ (1,594)	$ 1,426	$ 92,246
Balance, shares at Dec. 31, 2018		127,136,000