Stock Option Plans - Schedule of Share-based Compensation, Employee Stock Purchase Plan, Activity (Details) - $ / shares		12 Months Ended
		Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Stock Option 2002 Plan and 2012 Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares Available for Grant, Beginning balance		2,894,000	5,257,000	668,000
Shares Available for Grant, Increase to option pool		6,000,000		6,000,000
Shares Available for Grant, RSUs			(200,000)
Common stock issued to consultant in lieu of cash			(28,000)
Common stock issued to employee for bonuses in lieu of cash			(135,000)
Shares Available for Grant, Exercised
Shares Available for Grant, Temporary restriction by Board on available pool	[1]	(5,000,000)
Shares Available for Grant Restricted stock units vested
Shares Available for Grant End of the period		2,485,000	2,894,000	5,257,000
Number of Options Outstanding, Beginning balance		6,958,000	5,194,000	3,974,000
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 exercised		(9,000)		(156,000)
Number of Options Outstanding, Common stock issued to consultant in lieu of cash
Number of Options Outstanding, Common stock issued to employee for bonuses in lieu of cash
Number of Options Outstanding, RSUs
Number of Options Outstanding, End balance		8,043,000	6,958,000	5,194,000
Number of RSUs Outstanding, Beginning balance		100,000
Number of RSUs Outstanding, Restricted stock units vested		(38,000)	100,000
Number of RSUs Outstanding, End balance		62,000	100,000
Weighted Average Exercise Price of Options Outstanding, beginning balance		$ 3.60	$ 3.93	$ 4.04
Weighted Average Exercise Price of Options, Increase in option pool
Weighted Average Exercise Price of Options, RSUs
Weighted Average Exercise Price of Options, Common stock issued to consultant in lieu of cash
Weighted Average Exercise Price of Options, Common stock issued to employee for bonuses in lieu of cash
Weighted Average Exercise Price of Options, Options exercised		2.66		4.00
Weighted Average Exercise Price of Options, Outstanding end balance		$ 3.38	$ 3.60	$ 3.93
Stock Option Plan Of 2002 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares Available for Grant Options Forfeited/cancelled/expired
Number of Options Outstanding, Options forfeited/cancelled/expired			(236,000)	(35,000)
Weighted Average Exercise Price of Options, Options forfeited/cancelled			$ 5.17	$ 6.72
Stock Option Plan Of 2012 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares Available for Grant, Options Granted		(1,954,000)	(2,315,000)	(1,650,000)
Shares Available for Grant Options Forfeited/cancelled/expired		545,000	315,000	239,000
Number of Options Outstanding, Increase in option pool			2,315,000
Number of Options Outstanding, Options granted		1,954,000		1,650,000
Number of Options Outstanding, Options forfeited/cancelled/expired		(860,000)	(315,000)	(239,000)
Weighted Average Exercise Price of Options, Options granted		$ 3.04	$ 3.03	$ 3.72
Weighted Average Exercise Price of Options, Options forfeited/cancelled		$ 4.43	$ 3.77	$ 3.82

[1] On October 13, 2017, BioTime's Board of Directors determined to temporarily set a limit on shares available for grants of share-based awards pursuant to the 2012 Plan. While that limit remains in place, BioTime will not grant share-based awards for more than a total of approximately 2.5 million of the common shares remaining available for awards under the 2012 Plan.