Note 6 — Leases

Capital Leases

We have purchased certain manufacturing and office equipment under capital leases. As of December 31, 2016 and 2015, the gross amount of assets recorded under capital leases was $8.2 million and $5.1 million, respectively, and the recorded value of these assets, net of depreciation, was $7.4 million and $3.2 million, respectively.

We previously leased office space at 201 Industrial Road in San Carlos, California under a capital lease arrangement. This lease and related subleases ended on October 5, 2016.

Future minimum payments for our capital leases at December 31, 2016 are as follows (in thousands):

Year ending December 31,
2017	$	3,270
2018		2,339
Total minimum payments required		5,609
Less: amount representing interest		(478	)
Present value of future minimum lease payments		5,131
Less: current portion		(2,908	)
Capital lease obligation, less current portion	$	2,223

Operating Leases

On September 30, 2009, we entered into an operating sublease (Sublease) with Pfizer, Inc. for a 126,285 square foot facility located in San Francisco, California (Mission Bay Facility). The Sublease term is 114 months, commencing in August 2010 and terminating on January 31, 2020 and we began making non-cancelable lease payments in 2014, after the expiration of our free rent period on August 1, 2014. Monthly base rent will escalate over the term of the sublease at various intervals. In addition, throughout the term of the Sublease, we are responsible for paying certain costs and expenses specified in the Sublease, including insurance costs and a pro rata share of operating expenses and applicable taxes for the Mission Bay Facility.

We recognize rent expense on a straight-line basis over the lease period. For the years ended December 31, 2016, 2015, and 2014, rent expense was approximately $3.2 million in each year. As of December 31, 2016 and 2015, we had total deferred rent balances of $6.6 million and $8.5 million, respectively, which are recorded in other current and other long-term liabilities in our Consolidated Balance Sheets.

Our future minimum lease payments for our operating leases at December 31, 2016 are as follows (in thousands):

Year ending December 31,
2017	$	5,037
2018		5,187
2019		5,344
2020		452
Total future minimum lease payments	$	16,020