(16) Commitments and Contingencies (a)Leases and Letters of Credit The Company leases office space and office equipment under operating leases, which expire at various times through February 2016. Excluding the lease liability activity described in Note 9, rent expense under these operating leases was $0.7 million and $0.2 million for each of the years ended December 31, 2011 and 2012, respectively. The following table summarizes future minimum lease payments as of December 31, 2012 (in thousands): 2013 $ 947 2014 1,055 2015 1,079 2016 278 Total minimum lease payments (1) $ 3,360 (1) The future minimum lease payments above do not include the impact of any potential sublease income discussed in Note 9 related to the Company's lease liability. Effective March 2011, the lease agreement for the Company's facility in East Norriton, Pennsylvania required the Company to provide security and restoration deposits totaling $2.2 million to the landlord, an increase from the prior amount of $1.7 million. Until January 2011, the Company obtained letters of credit from a bank in favor of the landlord to satisfy the obligations. In January 2011, the Company deposited $1.0 million with the landlord as a security deposit, which amount is recorded as a non-current other asset on the Company's balance sheet as of December 31, 2011. As of December 31, 2011, an outstanding letter of credit was satisfying the remaining restoration deposit obligation of $1.2 million. At the end of the lease term, the landlord has the right to require us to utilize the funds collateralizing this letter of credit to restore the facility to its original condition. The letter of credit was collateralized by an account held at the bank. The letter of credit expired on December 2, 2012. As a result, the Company has deposited an additional $1.2 million in an account held by the landlord to satisfy its deposit obligation. In May 2011, the Company exercised the first five-year renewal option under its lease for laboratory space in Winston-Salem, North Carolina.