Stock-Based Compensation

6 Months Ended

Jun. 30, 2013

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

Stock-Based Compensation

Stock-Based Compensation

The Company recorded approximately $5.8 million and $10.5 million of stock-based compensation expense for the three and six months ended June 30, 2013, respectively. The Company recorded approximately $4.2 million and $7.3 million of stock-based compensation expense for the three and six months ended June 30, 2012, respectively. As of June 30, 2013, there was approximately $24.8 million of total unrecognized compensation costs related to non-vested stock-based employee compensation arrangements granted under the Company's equity compensation plans. The Company expects to recognize those costs over a weighted average period of 1.38 years.

During the six months ended June 30, 2013, the Company issued a total of 2,644,622 shares of its common stock upon the exercise of stock options, pursuant to restricted stock grants and pursuant to purchases under the 2010 ESPP. During the six months ended June 30, 2012, the Company issued a total of 973,056 shares of its common stock upon the exercise of stock options, pursuant to restricted stock grants and pursuant to purchases under the 2010 ESPP. Cash received from the exercise of stock options and purchases through the 2010 ESPP during the six months ended June 30, 2013 and June 30, 2012 was approximately $49.6 million and $4.7 million, respectively, and is included within the financing activities section of the consolidated statements of cash flows.

At June 30, 2013, there were an aggregate of 4,793,759 shares of common stock reserved for future issuance under the 2010 ESPP and for future grants under the Company's 2013 stock incentive plan.