12. LEASES

The Company has obtained the right of use for office space assets under two operating lease agreements. The Company has evaluated its facility leases and determined that, effective upon the adoption of Topic 842, the leases evaluated are all operating leases. The Company has performed an evaluation of its other contracts with suppliers and collaborators in accordance with Topic 842 and has determined that, except for the facility leases described below, none of the Company’s contracts contain a lease.

The Company obtained the right of use of office space located in Fremont, California, under a lease agreement entered into in September 2008 that was amended in December 2012 to extend the lease agreement to September 2016. In September 2014, the Company signed the second amendment to its facility lease agreement to add space and to extend the lease term through September 2019. In May 2016, the Company signed a third amendment to its facility lease agreement in Fremont, California to add space and to extend the lease term through September 2021 (the “Third Amendment”). The office space consists of 72,500 square feet, that includes an additional 10,716 square feet added in September 2019, with the entire lease terminating on September 10, 2021. The Company has an option to extend the term by five years as to the entire premises at the higher of (i) a 3% annual escalation of the then-current base rent and (ii) the then-current fair market value for comparable premises, by giving written notice of its election to exercise such option at least 12 months but not more than 18 months prior to the end of the expiration of the lease term. This option to extend the lease term by five years has not been included in the calculation since currently the exercise of the option is uncertain and therefore deemed not probable. The Company also obtained the right of use of 3,520 square feet of office space located in Waltham, Massachusetts, in October 2018 that terminates on September 30, 2021.

All of the Company’s leases are operating leases. Certain of the leases have both lease and non-lease components. The Company has elected to account for each separate lease component and the non-lease components associated with that lease component as a single lease component for all classes of underlying assets. As of December 31, 2019, the weighted average discount rate used for the calculations was 12.99% and the weighted average remaining lease term was 1.8 years.

The following table provides additional details of the leases presented in the balance sheets (in thousands except remaining life and discount rate):


	December 31, 2019
Facilities
Right of use assets	$	3,970

Current portion of lease liabilities		2,608
Operating lease liability, net of current portion		2,076
Total liabilities	$	4,684

Weighted-average remaining life		1.8	years
Weighted-average discount rate		12.99	%

The lease costs, which are included in operating expenses in our statements of operations, were as follows (in thousands):


	Year Ended
	December 31, 2019
Facilities
Operating lease cost	$	2,592
Cash paid for operating lease	$	2,645

The following table summarizes the Company’s undiscounted cash payment obligations for its operating lease liabilities as of December 30, 2019 (in thousands):


Years Ending December 31,
2020	$	3,065
2021		2,183
Total undiscounted operating lease payments		5,248
Imputed interest expenses		(564)
Total operating lease liabilities		4,684
Less: Current portion of operating lease liability		2,608
Operating lease liability, net of current portion	$	2,076

Rent expense under operating leases was $2.6 million, $1.8 million and $1.7 million for the years ended December 31, 2019, 2018 and 2017, respectively.