As described in Note 1, we adopted ASC 842 as of January 1, 2019. We evaluated our contracts and have determined that, effective upon the adoption of ASC 842, our operating leases included laboratory, equipment and office/manufacturing facility leases.

We lease our facilities in Berkeley, California (“Berkeley Lease”), Emeryville, California and Düsseldorf, Germany.

On September 17, 2018, we entered into an Office/Laboratory Lease (“Lease”) for office and laboratory space located at 5959 Horton Street, Emeryville, California (“Premises”). Under the terms of the Lease, we will lease 75,662 square feet in the Premises (“Rented Area”) at the rate of $4.75 (“Base Rate”) multiplied by the Rented Area, paid on a monthly basis, starting on the earlier of our commencement of our business operations at the Premises or April 1, 2019 (“Commencement Date”). The Base Rate is subject to scheduled annual increases, and we are also responsible for certain operating expenses and taxes throughout the life of the Lease. In connection with the Lease, we are entitled to a tenant improvement allowance of up to $8.3 million. The Lease has an initial term of 12 years, following the Commencement Date with an option to extend the lease for two successive five-year terms. The optional periods were not included in the lease term used in determining the right-of-use asset or the lease liability as we did not consider it reasonably certain that we would exercise the options. The operating lease right-of-use assets and liabilities on our March 31, 2019 condensed consolidated balance sheets primarily relate to this Lease.

In connection with our execution of the Lease, on September 17, 2018, we entered into a Lease Termination Agreement to terminate the Berkeley Lease effective as of the date we vacate the Berkeley premises. The rent payable for the Berkeley Lease is subject to a “hold-over” increase should we not vacate prior to July 31, 2019.

	Three Months Ended March 31,
	2019		2018
Operating lease expense	$	1,738	$	696

Cash paid for amounts included in the measurement of lease liabilities for the three months ended March 31, 2019 was $0.7 million and was included in operating cash flows in our condensed consolidated statement of cash flows.

The balance sheet classification of our operating lease liabilities was as follows (in thousands):

	March 31, 2019		December 31, 2018
Operating lease liabilities:
Current portion of lease liabilities (included in other current liabilities)	$	1,884	$	-
Long-term portion of lease liabilities		35,076		-
Total operating lease liabilities	$	36,960	$	-

At March 31, 2019, the maturities of our operating lease liabilities were as follows (in thousands):

Years ending December 31,
2019 (remaining)	$	4,240
2020		5,353
2021		5,248
2022		5,290
2023		4,988
Thereafter		39,537
Total lease payments		64,656
Less:
Present value adjustment		(27,696	)
Total operating lease liabilities	$	36,960

As of March 31, 2019, the weighted average remaining lease term is 11.1 years and the weighted average discount rate used to determine the operating lease liability was 10.1%.

In February 2018, we entered into a $175.0 million term loan agreement. Borrowings under the term loan agreement in the amount of $177.3 million, which includes paid-in-kind interest, are payable at maturity on December 31, 2023, unless earlier prepaid. See Note 8.

In February 2018, we entered into a sublicense agreement with Merck Sharpe & Dohme Corp (“Merck”). Under the agreement, we are required to make a payment of $7.0 million in the first quarter of 2020. See Note 7.

We have entered into material purchase commitments with commercial manufacturers for the supply of HEPLISAV-B and SD-101. As of March 31, 2019, our non-cancelable purchase commitments totaled $11.9 million.

We have entered into contractual arrangements that obligate us to make payments to the contractual counterparties upon the occurrence of future events. In addition, in the normal course of operations, we have entered into license and other agreements and intend to continue to seek additional rights relating to compounds or technologies in connection with our discovery, manufacturing and development programs. Under the terms of the agreements, we may be required to pay future up-front fees, milestones and royalties on net sales of products originating from the licensed technologies, if any, or other payments contingent upon the occurrence of future events that cannot reasonably be estimated.

We rely on and have entered into agreements with research institutions, contract research organizations and clinical investigators. These agreements are terminable by us upon written notice. Generally, we are liable only for actual effort expended by the organizations at any point in time during the contract through the notice period.

From time to time, we may be involved in claims, suits, and proceedings arising from the ordinary course of our business, including actions with respect to intellectual property claims, commercial claims, and other matters. Such claims, suits, and proceedings are inherently uncertain and their results cannot be predicted with certainty. Regardless of the outcome, such legal proceedings can have an adverse impact on us because of legal costs, diversion of management resources, and other factors. In addition, it is possible that a resolution of one or more such proceedings could result in substantial damages, fines, penalties or orders requiring a change in our business practices, which could in the future materially and adversely affect our financial position, results of operations, or cash flows in a particular period.

In conjunction with a financing arrangement with Symphony Dynamo, Inc. and Symphony Dynamo Holdings LLC (“Holdings”) in November 2009, we agreed to make contingent cash payments to Holdings equal to 50% of the first $50 million from any upfront, pre-commercialization milestone or similar payments received by us from any agreement with any third party with respect to the development and/or commercialization of cancer and hepatitis C therapies originally licensed to Symphony Dynamo, Inc., including SD-101. We have made no payments and have not recorded a liability as of March 31, 2019.