11. Commitments and Contingencies Lease Commitments In September 2012, the Company entered into an operating lease for office space in Norcross, GA for a term of twenty-six months, beginning on October 1, 2012 and ending November 30, 2014 at a rate of approximately $3,000 per month. The lease provides for free rent for the first two months of the lease and required a security deposit of $6,000. In addition to base rental payments included in the contractual obligations table above, we are responsible for our pro-rata share of the operating expenses for the building. In October 2012, the Company entered into an operating lease for office space collocated with lab space for research and development activities. The lease is for a period of one year, beginning on October 1, 2012, for a rate of $15,000 for the term, payable in equal monthly increments. This lease was continued on a month to month basis from October 1, 2013. In July 2011, the Company entered into an agreement to amend its lease for offices in Newton, MA to extend the term for a period of one year, which expired on September 30, 2012, at a base rent of $235,000 for the period. In addition to base rental payments, the Company was responsible for its pro-rata share of increases in the operating expenses for the building. In connection with this lease, a commercial bank issued a letter of credit collateralized by cash, which the Company had on deposit with the bank of $59,000 at December 31, 2011 and which was released during 2012 after the lease term ended. In July 2011, the Company entered into an operating lease for an apartment for Company executive use for a one-year term, which ended in August 2012, at a rate of $44,000 for the term. Rent expense under the above operating leases was $36,000 and $216,000 for the years ended December 31, 2013 and 2012, respectively. Future minimum payments under this lease as of December 31, 2013 are as follows (in thousands): Year ended December 31, 2014 $ 36 Separation Agreement   Former Chief Executive Officer and C