Stock Option Plans

6 Months Ended

Jun. 30, 2016

Stock Option Plans [Abstract]

Stock Option Plans

11. Stock Option Plans

BioTime has adopted a 2012 Equity Incentive Plan (the “2012 Plan”) under which BioTime has reserved 10,000,000 common shares for the grant of stock options, restricted stock, restricted stock units (RSUs) and stock appreciation rights.

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

During the six months ended June 30, 2016, BioTime issued 3,812 immediately vested common shares from the 2012 Plan, which are not reflected in the RSUs granted.  However, reduced the total shares available in the 2012 Plan for future grants shown in the table above.  Common shares issued or RSUs granted from the 2012 Plan reduce the shares available for grant by 2-for-1.

Stock-Based Compensation Expense

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	%

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