10. Commitments and Contingencies

Collaborative Agreements, Royalties and Milestone Payments

The Company has committed to make potential future milestone payments to third parties as part of licensing and development programs. Payments under these agreements become due and payable only upon the achievement of certain developmental, regulatory and commercial milestones by the Company’s licensees. Because it is uncertain if and when these milestones will be achieved, such contingencies, aggregating up to $15.5 million (assuming one product per contract meets all milestones events) have not been recorded on the accompanying consolidated balance sheets. The Company is unable to determine precisely when and if payment obligations under the agreements will become due as these obligations are based on milestone events, the achievement of which is subject to a significant number of risks and uncertainties.

Lease Agreements

The Company leases facilities and office equipment under operating leases expiring on various dates through April 2023. These leases require the Company to pay taxes, insurance, maintenance and minimum lease payments. For each facility lease, the Company has two successive renewal options to extend the lease for five years upon the expiration of the initial lease term.

On November 21, 2017, the Company entered into a non-cancellable sublease agreement for a portion of one of its three leased facilities. The term of the sublease agreement commenced on December 26, 2017. Under the term of the sublease agreement, the Company will receive $5.1 million over the term of the sublease, which ends at the same time as the original lease in April 2023. Under the sublease agreement, the Company’s future sublease income will be equal to the amount required to be paid to the Company’s landlord. In addition, the sublease provides for a tenant improvement allowance of $0.8 million to the subtenant, which was funded by the Company in January 2018. Upon execution of the sublease agreement, the Company recognized a loss on the sublease equal to the tenant improvement allowance. Under the sublease agreement, the sub-lessee executed a standby letter of credit naming the Company as the beneficiary amounting to $1.0 million as security under the sublease in the event of uncured default by the sub-lessee. As of March 31, 2018, the Company has not drawn any funds from the letter of credit as there was no default by the sub-lessee. During the three months ended March 31, 2018, the Company recognized $0.4 million of sublease income under this agreement.