8. Commitments and Contingencies In December 2013, the Company entered into a three-year lease for 6,837 square feet of office space in Cambridge, Massachusetts. The lease has monthly lease payments of approximately $31,000 for the first twelve months, with annual rent escalation thereafter, and provides a rent abatement of approximately $31,000 for the first full calendar month of the lease term. The lease term commenced and rental payments began in January 2014. The Company recorded a deferred lease obligation in 2014 which represents the cumulative difference between actual facility lease payments and lease expense recognized ratably over the lease period, which is included in other liabilities. In accordance with the lease, the Company entered into a cash-collateralized irrevocable standby letter of credit in the amount of $125,345, naming the landlord as beneficiary. In December 2014, the Company entered into a First Amendment to Lease, or the Amendment, for additional office space contiguous to its current office space in Cambridge, Massachusetts. The Amendment includes leasing an additional 8,530 square feet of office space, or the Expansion Space, with an occupancy date of March 13, 2015. The Amendment provides for additional monthly lease payments of approximately $45,000 for the 8,530 square feet for the first twelve months and provides for annual rent escalations thereafter. The monthly rent on the existing 6,837 square feet will remain at approximately $32,000 through December 31, 2016, the expiration of the lease. The Amendment includes a Landlord s contribution for leasehold improvements in the amount of approximately $100,000 which will be accounted for as a deferred lease incentive and reduction in monthly rent expense over the term of the lease. The Company recorded an additional deferred lease obligation for the Expansion Space which represents the cumulative difference between actual facility lease payments and lease expense recognized ratably over the lease period. The Company has an existing