Stock Option Plans (Tables)

6 Months Ended

Jun. 30, 2016

Stock Option Plans [Abstract]

Summary of stock option activity

A summary of BioTime’s 2012 Plan activity and related information follows (in thousands, except per share amounts):

	Shares Available for Grant			Number of Options and RSUs Outstanding			Weighted Average Exercise Price
December 31, 2015		5,257			5,194		$	3.93
Options granted		(1,541	)		1,541			2.87
RSUs granted		(208	)		100			-
Options exercised		-			-			-
Options forfeited/cancelled		207			(420	)		4.52
June 30, 2016		3,715			6,415		$	3.63

Schedule of weighted average assumptions to calculate fair value of stock options

The fair value of each option award is estimated on the date of grant using a Black-Scholes option valuation model applying the weighted-average assumptions noted in the following table:

	June 30, (Unaudited)
	2016			2015
Expected life (in years)		6.07			6.04
Risk-free interest rates		1.45	%		1.76	%
Volatility		61.78	%		67.02	%
Dividend yield		0	%		0	%

Schedule of share-based compensation, employee stock purchase plan, activity

Operating expenses include stock-based compensation expense as follows (in thousands):

	Six Months Ended June 30, (Unaudited)
	2016		2015
Research and development	$	1,785	$	978
General and administrative		3,808		2,722
Total stock-based compensation expense	$	5,593	$	3,700