Commitments and Contingencies Leases In August 2018, the Company entered into an operating lease agreement for new office and laboratory space which consists of approximately 68,000 square feet located in South San Francisco, California. The lease term is 127 months beginning August 2018 through February 2029 with an option to extend the term for another seven years which is not reasonably assured of exercise. The Company has made certain tenant improvements, including the addition of laboratory space, and has received $5.0 million of tenant improvement allowances up to September 30, 2020. The rent payments began on March 1, 2019 after an abatement period. In October 2018, the Company entered into an operating lease agreement for new office and laboratory space which consists of 14,943 square feet located in South San Francisco, California. The lease term is 124 months beginning November 2018 through February 2029, with an option to extend the term for another seven years which is not reasonably assured of exercise. The Company has made certain tenant improvements, including the upgrading of current office and laboratory space with a lease incentive allowance of $0.8 million. Rent payments began in November 2018. In February 2019, the Company entered into a lease agreement for approximately 118,000 square feet of space to develop a cell therapy manufacturing facility in Newark, California. The lease has a term of 188 months and is expected to commence in November 2020. Upon certain conditions, the Company has two ten-year options to extend the lease which are not reasonably assured of exercise. The Company is entitled to a tenant improvement allowance of $2.9 million for costs related to the design and construction of certain Company improvements. The Company maintained letters of credit for the benefit of landlords which is disclosed as restricted cash in the condensed consolidated balance sheet. Restricted cash related to letters of credit due to landlords was $5.2 million and $4.3 million as of September 30, 2020 and December 31, 2019, respectively. The balance sheet classification of our lease liabilities were as follows (in thousands): September 30, 2020 December 31, 2019 Operating lease liabilities Current portion included in accrued and other current liabilities $ 2,873 $ 1,679 Long-term portion of lease liabilities 50,846 51,349 Total operating lease liabilities $ 53,719 $ 53,028 The components of lease costs for operating leases, which were recognized in operating expenses, were as follows (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2020 2019 2020 2019 Operating lease cost $ 1,845 $ 1,374 $ 5,543 $ 4,076 Variable lease cost 353 277 961 702 Total lease costs $ 2,198 $ 1,651 $ 6,504 $ 4,778 Cash paid for amounts included in the measurement of lease liabilities for the nine months ended September 30, 2020 was $4.2 million and was included in net cash used in operating activities in our condensed consolidated statements of cash flows. The undiscounted future lease payments under the lease agreements as of September 30, 2020 were as follows (in thousands): Year ending December 31: 2020 (remaining 3 months) $ 1,426 2021 6,649 2022 7,922 2023 8,173 2024 8,435 2025 and thereafter 56,722 Total undiscounted lease payments 89,327 Less: Present value adjustment (33,496) Less: Tenant improvement allowance (2,112) Total $ 53,719 Operating lease liabilities are based on the net present value of the remaining lease payments over the remaining lease term. In determining the present value of lease payments, we use our estimated incremental borrowing rate. The weighted average discount rate used to determine the operating lease liability was 8.36%. As of September 30, 2020, the weighted average remaining lease term for our operating leases is 10.41 years. Other Commitments In July 2020, the Company entered into a Solar Power Purchase and Energy Services Agreement with Onyx Development Group LLC (Onyx) for the installation and operation of a solar photovoltaic generating system and battery energy storage system at the Company's cell therapy manufacturing facility in Newark, California. The agreement has a term of 20 years and is expected to commence in the first quarter of 2021. The Company is obligated to pay for electricity generated from the system at an agreed rate for the duration of the agreement term. Termination of the agreement by the Company will result in a termination payment due of approximately $4.3 million. In connection with the agreement, the Company maintains a letter of credit for the benefit of Onyx in the amount of $4.3 million which is disclosed as restricted cash in the condensed consolidated balance sheet as of September 30, 2020. The Company has entered into certain license agreements for intellectual property which is used as part of our development and manufacturing processes. Each of these respective agreements are generally cancellable by the Company. These agreements require payment of annual license fees and may include conditional milestone payments for achievement of specific research, clinical and commercial events, and royalty payments. The timing and likelihood of any significant conditional milestone payments or royalty payments becoming due was not probable as of September 30, 2020. The Company enters into contracts in the normal course of business that includes arrangements with clinical research organizations, vendors for preclinical research and vendors for manufacturing. These agreements generally allow for cancellation with notice. As of September 30, 2020, the Company had non-cancellable purchase commitments of $3.9 million.