S-1/A Options exercisable at December 31, 2014 86,431,063 $ 4.46 8.36 $ 490,227 A summary of stock option activity for the nine months ended September 30, 2015 is as follows (unaudited, in thousands, except share and per share data): Number of stock options outstanding Weighted average exercise price Weighted average remaining contractual term (in years) Aggregate intrinsic value Balance at December 31, 2014 87,471,413 $ 4.46 8.36 S 490,227 Granted 32,585,935 12.88 Exercised (5,197,234) 3.04 Forfeited (8,726.938) 6.46 Balance at September 30, 2015 106,133,176 $ 6.95 8.21 $ 896,164 Options vested and expected to vest at September 30, 2015 89,108,401 $ 6.25 7.90 $ 814,499 Options exercisable at September 30, 2015 106,133,176 $ 6.95 8.21 $ 896,164 Aggregate intrinsic value represents the difference between the Company's estimated fair value of its common stock and the exercise price of outstanding, "in-the-money" options. Aggregate intrinsic value for stock options exercised through December 31, 2012, 2013, and 2014 was $2.9 million, $10.9 million, and $47.8 million, respectively. Aggregate intrinsic value for stock options exercised through September 30, 2015 was $46.2 million. F-39 Tahk of Content% The total weighted average grant-date fair value of options granted was $1.05, $1.61, $3.84. $3.62. and $6.04 per share for the years ended December 31. 2012, 2013. 2014. and the nine months ended September 30, 2014 and September 30, 2015, respectively. Restricted Stock Activity The Company issued restricted stock awards (RSAs) to certain employees in fiscal year 2011 and prior. These awards typically vest over a term of two to four years. No restricted stock awards have been issued under the Plan since 2011. Activity related to RSAs for the year ended December 31, 2014 is set forth below: Weighted Number of average grant RSAs date fair value Unvested at December 31, 2013 152.580 0.12 Vested