3.       STOCK-BASED COMPENSATION

Stock options are granted under the Company’s long-term incentive plan and have an exercise price that may not be less than the fair market value of the underlying shares on the date of grant. In general, stock options granted to employees will become exercisable over a period determined by the Compensation Committee, which in the past has been a five year life. A portion of the stock options granted in the six months ended June 30, 2014 and 2013 vested immediately with the remainder vesting over a two year period. In addition, stock options will become exercisable upon a change in control, unless provided otherwise by the Compensation Committee of our Board of Directors. At June 30, 2014, there were 4,284,693 shares subject to options authorized but not granted.

For the three months and six months ended June 30, 2014, the Company recognized non-cash compensation expense of $0.6 million and $2.0 million, respectively, related to stock options and restricted stock grants. For the three months and six months ended June 30, 2013, the Company recognized non-cash compensation expense of $0.8 million and $2.2 million, respectively, related to stock options. These amounts were recorded as general and administrative expense. Because the Company does not pay significant United States federal income taxes, no amounts were recorded for tax benefits.

A summary of the stock option activity for the six months ended June 30, 2014 is provided below:

The intrinsic value of a stock option is the amount by which the current market value of the underlying stock exceeds the exercise price of the option.

Shares of restricted stock are granted under the Company’s long-term incentive plan using the fair market value of the underlying shares on the date of grant. In general, restricted stocks granted to employees will vest over a period determined by the Compensation Committee which is generally a three year period, with the initial one-third vesting on the first grant date anniversary.

No restricted stocks were granted in the three months ended June 30, 2014. A summary of the restricted stock activity for the six months ended June 30, 2014 is provided below:

As of June 30, 2014, unrecognized compensation costs totaled $4.2 million. The expense is expected to be recognized over a weighted average period of 2.7 years.