Stock-Based Awards - Schedule of Share-based Compensation, Employee Stock Purchase Plan, Activity (Details) - Stock Option Plan of 2012 [Member] - $ / shares		12 Months Ended
		Dec. 31, 2018	Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares Available for Grant, Beginning balance		2,485,000	2,894,000
Shares Available for Grant, Increase to option pool			6,000,000
Shares Available for Grant, Temporary restriction by Board on available pool	[1]		(5,000,000)
Shares Available for Grant, Options Granted		(1,559,000)	(1,954,000)
Shares Available for Grant, Exercised
Shares Available for Grant, Options Forfeited/cancelled/expired		731,000	545,000
Shares Available for Grant, RSU vesting
Shares Available for Grant, Board mandated restriction restored	[1]	5,000,000
Shares Available for Grant, Exchange of options with Cell Cure	[2]	(866,000)
Shares Available for Grant, Restricted stock units granted	[3]	(1,586,000)
Shares Available for Grant, Inducement option grant	[4]
Shares Available for Grant, Adjustment due to the AgeX Distribution	[5]	(2,294,000)
Shares Available for Grant, Adjustment to inducement options due to the AgeX Distribution	[5]
Shares Available for Grant, Adjustment to restricted stock units due to the AgeX Distribution	[5]	(272,000)
Shares Available for Grant, Restricted stock units expired unvested		246,000
Shares Available for Grant End of the period		1,885,000	2,485,000
Number of Options Outstanding, Beginning balance		8,043,000	6,958,000
Number of Options Outstanding, Increase in option pool
Number of Options Outstanding, Temporary restriction by Board on available pool	[1]
Number of Options Outstanding, Options granted		1,559,000	1,954,000
Number of Options Outstanding, Options exercised			(9,000)
Number of Options Outstanding, Options forfeited/cancelled/expired		(750,000)	(860,000)
Number of Options Outstanding, RSU vesting
Number of Options Outstanding, Board mandated restriction restored	[1]
Number of Options Outstanding, Exchange of options with Cell Cure	[2]	866,000
Number of Options Outstanding, Restricted stock units granted	[3]
Number of Options Outstanding, Inducement option grant	[4]	1,500,000
Number of Options Outstanding, Adjustment due to the AgeX Distribution	[5]	2,294,000
Number of Options Outstanding, Adjustment to inducement options due to the AgeX Distribution	[5]	355,000
Number of Options Outstanding, End balance		13,867,000	8,043,000
Number of RSUs Outstanding, Beginning balance		62,000	100,000
Number of RSUs Outstanding, Restricted stock units vested		(466,000)	(38,000)
Number of RSUs Outstanding, Restricted stock units granted	[3]	793,000
Number of RSUs Outstanding, Adjustment to restricted stock units due to the AgeX Distribution	[5]	136,000
Number of RSUs Outstanding, Restricted stock units expired unvested		(123,000)
Number of RSUs Outstanding, End balance		402,000	62,000
Weighted Average Exercise Price of Options Outstanding, beginning balance		$ 3.38	$ 3.60
Weighted Average Exercise Price of Options, Options granted		2.84	3.04
Weighted Average Exercise Price of Options, Options exercised			2.66
Weighted Average Exercise Price of Options, Options forfeited/cancelled		3.33	4.43
Weighted Average Exercise Price of Options, Exchange of options with Cell Cure	[2]	2.16
Weighted Average Exercise Price of Options, Restricted stock units granted	[3]	0.00
Weighted Average Exercise Price of Options, Inducement option grant	[4]	2.31
Weighted Average Exercise Price of Options, Adjustment due to the AgeX Distribution	[5]	0.00
Weighted Average Exercise Price of Options, Adjustment to restricted stock units due to the AgeX Distribution	[5]	0.00
Weighted Average Exercise Price of Options, RSU vesting		0.00
Weighted Average Exercise Price of Options, Restricted stock units expired unvested		0.00
Weighted Average Exercise Price of Options, Outstanding end balance		$ 2.44	$ 3.38

[1] On October 13, 2017, BioTimes Board of Directors determined to temporarily set a 5.0 million total share limit on shares available for the grant of share-based awards pursuant to the 2012 Plan. As of December 31, 2017, the total 2.5 million shares available for grant was net of this 5.0 million share restriction. On May 4, 2018, BioTimes Board of Directors removed this restriction, thereby increasing shares available for the grant of share-based awards pursuant to the 2012 Plan.

[2] On July 9, 2018, BioTime's Board of Directors terminated the Cell Cure Equity Incentive Plan (the "Cell Cure Plan"), under which Cell Cure employees and certain consultants ("Cell Cure Option Holders") held outstanding options to purchase shares of common stock in Cell Cure, and BioTime granted the Cell Cure Option Holders BioTime options of equivalent value under the 2012 Plan in exchange for their Cell Cure options (the "BioTime Exchange). The BioTime Exchange resulted in 866,000 grants of BioTime stock options under the 2012 Plan, all issued with an exercise price of $2.16 per share to the Cell Cure Option Holders, based on BioTime's closing stock price on July 9, 2018. Of the total options granted under the BioTime Exchange, 275,000 are subject to continued service-based vesting from the original terms under the Cell Cure Plan, and 591,000 were immediately vested on the exchange date to reflect the fact that the Cell Cure Options Holders held prior to the exchange were already vested. Equivalent value of the BioTime Exchange was determined using the Black-Scholes option pricing model. The BioTime Exchange was accounted for as a modification under ASC 718, and BioTime recorded a noncash stock-based compensation expense of $298,000 for the year ended December 31, 2018 included in consolidated stock-based compensation expense.

[3] On May 24, 2018 and August 10, 2018, BioTime granted 485,000 and 8,000 RSUs, respectively, to employees. The RSUs vest in increments upon the attainment of specified performance conditions, as determined by BioTimes Board of Directors, including the completion of the AgeX Distribution and certain clinical milestones in the development of OpRegen® and Renevia®. Stock-based compensation expense for these performance-based RSUs is recognized when it is probable that the respective milestone will be achieved, as determined by BioTimes Board of Directors. On October 4, 2018, BioTimes Board of Directors determined that BioTime had achieved the AgeX Distribution performance condition and as a result 25%, or 123,250, of the RSUs granted in May and August 2018 vested. On December 18, 2018, BioTimes Board of Directors determined that BioTime had achieved other milestones related to the RSUs and as a result an additional 50%, or 246,500, of the RSUs granted in May and August 2018 vested. The remaining 25%, or 123,250 RSUs, expired unvested on December 31, 2018. On September 17, 2018, BioTime granted BioTimes new President and Chief Executive Officer, Brian M. Culley, two RSU awards under the 2012 Plan: (1) an award of 200,000 restricted stock units (RSU Award No. 1) and (2) an award of 100,000 restricted stock units (RSU Award No. 2 and together with RSU Award No. 1, the RSU Awards). Subject to Mr. Culleys continued service with BioTime, 25% of the shares subject to RSU Award No. 1 will vest on the first anniversary of the date of grant, and the balance of the shares subject to RSU Award No. 1 will vest in 12 equal quarterly installments at the end of each quarter thereafter. RSU Award No. 2 vested in full on January 1, 2019.

[4] On September 17, 2018 (the Stard Date), Brian M. Culley became President and Chief Executive Officer of BioTime. In connection with Mr. Culleys employment, BioTime granted Mr. Culley an inducement option to purchase 1,500,000 of BioTimes common shares (the Culley Option). The exercise price of the Culley Option is $2.31 per share, which was the closing stock price on September 17, 2018. This grant was made outside of the 2012 Plan and was approved by the independent members of the Board of Directors. Subject to Mr. Culleys continued service with BioTime on the applicable vesting date, the Culley Option will vest and become exercisable with respect to 25% of the shares on the first anniversary of the Start Date, and the balance of the Culley Option will vest and become exercisable in 36 equal monthly installments thereafter.

[5] Reflects the equitable adjustment to the exercise prices and number of outstanding stock options, and to restricted stock units, necessary to maintain the intrinsic value of those awards immediately prior to and following the AgeX Distribution.