Stock Option Plans (Details) - 2012 Plan [Member] - $ / shares		9 Months Ended
		Sep. 30, 2017	Sep. 30, 2016	Oct. 13, 2017	Sep. 30, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares available for grants (in shares)		2,894,000			7,558,000	[1]
Shares Available for Grant [Roll Forward]
Beginning of the period (in shares)		2,894,000
Increase to the 2012 Plan option pool (in shares)		6,000,000
Options granted (in shares)		(1,762,000)
Options exercised (in shares)		0
Options forfeited/cancelled (in shares)		426,000
End of the period (in shares)	[1]	7,558,000
Number of Options Outstanding [Rollforward]
Outstanding, beginning of the period (in shares)		6,958,000
Increase to the 2012 Plan option pool (in shares)		0
Options granted (in shares)		1,762,000
Options exercised (in shares)		(9,000)
Options forfeited/cancelled (in shares)		(606,000)
Outstanding, end of the period (in shares)	[1]	8,105,000
Options exercisable, end of period (in shares)		4,072,000
Number of RSUs Outstanding [Roll Forward]
Outstanding, beginning of the period (in shares)		100,000
Restricted stock units vested (in shares)		(31,000)
Outstanding, end of the period (in shares)	[1]	69,000
Weighted Average Exercise Price of Options [Rollforward]
Outstanding, beginning of the period (in dollars per share)		$ 3.60
Increase to the 2012 Plan option pool (in dollars per share)		0
Options granted (in dollars per share)		3.11
Options exercised (in dollars per share)		2.66
Options forfeited/cancelled (in dollars per share)		3.99
Outstanding end of the period (in dollars per share)	[1]	3.47
Options exercisable, end of period (in dollars per share)		$ 3.71
Weighted-average assumptions [Abstract]
Expected life		5 years 5 months 19 days	4 years 11 months 19 days
Risk-free interest rates		1.78%	1.43%
Volatility		59.04%	60.77%
Dividend yield		0.00%	0.00%
Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common shares reserved for future issuance (in shares)					16,000,000
Maximum [Member] | Subsequent Event [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares available for grants (in shares)				2,500,000

[1] On October 13, 2017, BioTime's Board of Directors (the "Board") determined to temporarily set a limit on shares available for grants for 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.