| Stock Option Activity |
The following summarizes the activity under the Company’s stock option plans: | | | | | | | | | | | | | Number of Options (#) | | Weighted Average Exercise Price ($) | | Aggregate Intrinsic Value ($) | | | | | | (In thousands) | Balance, December 31, 2014 | 1,847,669 |
| | $ | 26.99 |
| | | Granted | 1,271,391 |
| | 33.98 |
| | | Exercised(1) | (319,079 | ) | | 15.35 |
| | $ | 6,958 |
| Canceled | (30,722 | ) | | 28.11 |
| | | Balance, March 31, 2015 | 2,769,259 |
| | $ | 31.53 |
| | $ | 12,063 |
| Vested, March 31, 2015(2) | 830,911 |
| | $ | 25.27 |
| | $ | 8,401 |
| Vested and expected to vest, March 31, 2015(2)(3) | 2,538,150 |
| |
| | $ | 11,696 |
|
| | (1) | The aggregate intrinsic value was calculated based on the positive difference between the estimated fair value of the Company’s common stock as of the date of exercise and the exercise price of the underlying options. |
| | (2) | The aggregate intrinsic value was calculated based on the positive difference between the estimated fair value of the Company’s common stock as of March 31, 2015, and the exercise price of the underlying options. |
| | (3) | Represents the number of vested options as of March 31, 2015, plus the number of unvested options expected to vest as of March 31, 2015, based on the unvested options outstanding at March 31, 2015, adjusted for the estimated forfeiture. |
|
| Summary of Restricted Stock Units |
The following table summarizes the status of the Company’s restricted stock units: | | | | | | | | | Number of Shares (#) | | Weighted Average Fair Value ($) | Balance, December 31, 2014 | 746,612 |
| | $ | 31.40 |
| Granted | 418,584 |
| | 33.81 |
| Vested | (132,476 | ) | | 29.68 |
| Forfeited | (70,773 | ) | | 35.72 |
| Balance, March 31, 2015 | 961,947 |
| | $ | 32.35 |
|
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