Shareholders' Equity - Schedule of Reconciliation of Changes in Shareholders' Equity (Details) - USD ($) $ in Thousands		3 Months Ended				6 Months Ended
	Jan. 02, 2019	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2018	Mar. 31, 2018	Jun. 30, 2019	Jun. 30, 2018
Beginning balance	$ 92,246	$ 161,236	$ 92,246	$ 102,455	$ 164,263	$ 92,246	$ 164,263
Shares issued in connection with the Asterias Merger			32,353
Shares retired in connection with the Asterias Merger			(3,435)
Shares issued upon vesting of restricted stock units, net of shares retired to pay employees' taxes		(2)	(75)	(6)	(7)
Stock-based compensation		762	1,361	825	809
Stock-based compensation for shares issued upon vesting of Asterias restricted stock units attributable to post combination services			79
Cumulative-effect adjustment for adoption of Accounting Standard Codification	100		143	1	101
Foreign currency translation adjustments/loss		(487)	(732)	884	75	(1,219)	959
Shares issued for settlement of BioTime warrants		302
Stock-based compensation in subsidiaries				278	175
Sale of subsidiary warrants in AgeX					737
Sale of subsidiary shares in AgeX				5,000
Subsidiary financing transactions with noncontrolling interests - AgeX
Subsidiary financing and other transactions with noncontrolling interests - Cell Cure				(40)
NET INCOME/(LOSS)		(30,052)	39,296	(4,646)	(63,698)	9,244	(68,344)
Ending balance		131,759	161,236	104,751	102,455	131,759	104,751
Preferred Shares [Member]
Beginning balance
Beginning balance, shares
Shares issued in connection with the Asterias Merger
Shares issued in connection with the Asterias Merger, shares
Shares retired in connection with the Asterias Merger
Shares issued upon vesting of restricted stock units, net of shares retired to pay employees' taxes
Stock-based compensation
Stock-based compensation, shares
Stock-based compensation for shares issued upon vesting of Asterias restricted stock units attributable to post combination services
Stock-based compensation for shares issued upon vesting of Asterias restricted stock units attributable to post combination services, shares
Cumulative-effect adjustment for adoption of Accounting Standard Codification
Foreign currency translation adjustments/loss
Stock-based compensation in subsidiaries
Sale of subsidiary warrants in AgeX
Subsidiary financing transactions with noncontrolling interests - AgeX
NET INCOME/(LOSS)
Ending balance
Ending balance, shares
Common Shares [Member]
Beginning balance	$ 354,270	$ 384,553	$ 354,270	$ 379,186	$ 378,487	$ 354,270	$ 378,487
Beginning balance, shares	127,136,000	149,388,000	127,136,000	126,869,000	126,866,000	127,136,000	126,866,000
Shares issued in connection with the Asterias Merger			$ 32,353
Shares issued in connection with the Asterias Merger, shares			24,696,000
Shares retired in connection with the Asterias Merger			$ (3,435)
Shares retired in connection with the Asterias Merger, shares			(2,622,000)
Shares issued upon vesting of restricted stock units, net of shares retired to pay employees' taxes		$ (2)	$ (75)	$ (6)	$ (7)
Shares issued upon vesting of restricted stock units, net of shares retired to pay employees' taxes, shares		3,000	118,000	5,000	3,000
Stock-based compensation		$ 762	$ 1,361	$ 825	$ 809
Stock-based compensation, shares
Stock-based compensation for shares issued upon vesting of Asterias restricted stock units attributable to post combination services			$ 79
Stock-based compensation for shares issued upon vesting of Asterias restricted stock units attributable to post combination services, shares			60,000
Cumulative-effect adjustment for adoption of Accounting Standard Codification
Foreign currency translation adjustments/loss
Shares issued for settlement of BioTime warrants		$ 302
Shares issued for settlement of BioTime warrants, shares		252,000
Stock-based compensation in subsidiaries
Sale of subsidiary warrants in AgeX
Subsidiary financing transactions with noncontrolling interests - AgeX				$ 3,634	$ (103)
Subsidiary financing transactions with noncontrolling interests - AgeX, shares
Subsidiary financing and other transactions with noncontrolling interests - Cell Cure				(111)
NET INCOME/(LOSS)
Ending balance		$ 385,615	$ 384,553	$ 383,529	$ 379,186	$ 385,615	$ 383,529
Ending balance, shares		149,643,000	149,388,000	126,874,000	126,869,000	149,643,000	126,874,000
Accumulated Deficit [Member]
Beginning balance	$ (261,856)	$ (222,403)	$ (261,856)	$ (279,416)	$ (216,297)	$ (261,856)	$ (216,297)
Shares issued in connection with the Asterias Merger
Shares retired in connection with the Asterias Merger
Shares issued upon vesting of restricted stock units, net of shares retired to pay employees' taxes
Stock-based compensation
Stock-based compensation for shares issued upon vesting of Asterias restricted stock units attributable to post combination services
Cumulative-effect adjustment for adoption of Accounting Standard Codification
Foreign currency translation adjustments/loss
Stock-based compensation in subsidiaries
Sale of subsidiary warrants in AgeX
Subsidiary financing transactions with noncontrolling interests - AgeX
NET INCOME/(LOSS)		(30,032)	39,310	(4,215)	(63,548)
Ending balance		(252,435)	(222,403)	(283,630)	(279,416)	(252,435)	(283,630)
Accumulated Deficit [Member] | Adoption of Leasing Standard [Member]
Stock-based compensation for shares issued upon vesting of Asterias restricted stock units attributable to post combination services
Cumulative-effect adjustment for adoption of Accounting Standard Codification			143
Accumulated Deficit [Member] | ASU 2016-01 [Member]
Cumulative-effect adjustment for adoption of Accounting Standard Codification					328
Accumulated Deficit [Member] | ASU 2014-09 [Member]
Cumulative-effect adjustment for adoption of Accounting Standard Codification				1	101
Noncontrolling Interest/(Deficit) [Member]
Beginning balance	(1,594)	(1,608)	(1,594)	2,487	1,622	(1,594)	1,622
Shares issued in connection with the Asterias Merger
Shares retired in connection with the Asterias Merger
Shares issued upon vesting of restricted stock units, net of shares retired to pay employees' taxes
Stock-based compensation
Stock-based compensation for shares issued upon vesting of Asterias restricted stock units attributable to post combination services
Cumulative-effect adjustment for adoption of Accounting Standard Codification
Foreign currency translation adjustments/loss
Stock-based compensation in subsidiaries				278	175
Sale of subsidiary warrants in AgeX					737
Sale of subsidiary shares in AgeX				5,000
Subsidiary financing transactions with noncontrolling interests - AgeX				(3,634)	103
Subsidiary financing and other transactions with noncontrolling interests - Cell Cure				71
NET INCOME/(LOSS)		(20)	(14)	(431)	(150)
Ending balance		(1,628)	(1,608)	3,770	2,487	(1,628)	3,770
Accumulated Other Comprehensive Income/(Loss) [Member]
Beginning balance	$ 1,426	694	1,426	198	451	1,426	451
Shares issued in connection with the Asterias Merger
Shares retired in connection with the Asterias Merger
Shares issued upon vesting of restricted stock units, net of shares retired to pay employees' taxes
Stock-based compensation
Stock-based compensation for shares issued upon vesting of Asterias restricted stock units attributable to post combination services
Cumulative-effect adjustment for adoption of Accounting Standard Codification
Foreign currency translation adjustments/loss		(487)	(732)	884	75
Stock-based compensation in subsidiaries
Sale of subsidiary warrants in AgeX
Subsidiary financing transactions with noncontrolling interests - AgeX
NET INCOME/(LOSS)
Ending balance		$ 207	$ 694	$ 1,082	198	$ 207	$ 1,082
Accumulated Other Comprehensive Income/(Loss) [Member] | ASU 2016-01 [Member]
Cumulative-effect adjustment for adoption of Accounting Standard Codification					$ (328)