8. Commitments and Contingencies Operating Leases The Company leases its headquarters and South San Francisco laboratory facilities under a non-cancelable lease agreement that expired March 31, 2013. The lease was amended in July 2012 to extend the term to March 31, 2016 and to provide tenant improvement allowances of up to $253,000. The Company provided security deposits in the form of irrevocable standby letters of credit secured with restricted cash deposits at the Company's primary bank. The Company deposited $118,000 in restricted cash accounts as collateral for the lease which is included in restricted cash in the Company's balance sheets as of December 31, 2013 and 2012. In November 2012, the Company entered into a non-cancelable lease agreement commencing February 1, 2013 to lease laboratory space in Austin, Texas. The lease expires on July 31, 2018. The Company paid a cash security deposit of $75,000, which is included in other assets in the Company's balance sheet as of December 31, 2013 and 2012. Future minimum lease payments under non-cancelable operating leases as of December 31, 2013 are as follows (in thousands): Year Ending December 31, Amounts 2014 $ 938 2015 989 2016 413 2017 222 2018 130 Thereafter   ? ? ? ? ? Total minimum lease payments $ 2,692 ? ? ? ? ? ? ? ? ? ? The Company recognizes rent expense on a straight-line basis over the non-cancelable lease period. Facilities rent expense was $840,000, $711,000 and $570,000 for the years ended December 31, 2013, 2012 and 2011, respectively. Volume Purchase Agreement The Company had non-cancelable purchase obligations to contract manufacturers and suppliers for approximately $250,000 at December 31, 2013, of which $125,000 and $125,000 are estimated to be payable in the years ended December 31, 2014 and 2015, respectively. Contingencies From time to time, the Company may be involved in legal proceedings arising in the ordinary course of business. The Company believes there is no litigation pending that could have, individually or in the aggregate,