11. Employee Benefit Plan

        We have a 401(k) retirement plan for our employees based in the United States. Employees may contribute a portion of their earnings up to a yearly maximum (in 2012, $17,000 for employees under age 50, $22,500 for employees over age 49). Except for the period from April 2009 to March 2010, we match 25% of the amount contributed by employees, up to a maximum employee contribution of 6% of gross earnings. During 2012, 2011 and 2010, we made matching contributions of approximately $653,000, $570,000 and $358,000, respectively.