Long Term Restricted Investments

Restricted investments relate to reimbursement obligations under letters of credit issued for the benefit of lessors of certain of our office space.  As of December 31, 2015 and 2014, our Long-term restricted investments were $9,888 and $5,922, respectively.  During the year ended December 31, 2015, we increased our letters of credit by $3,966 associated with leased office space.