12. Commitments and Contingences

Litigation

The Company is not a party to any litigation and does not have contingency reserves established for any litigation liabilities as of December 31, 2019.

Lease

In April 2019, the Company amended its multi-year lease agreement to relocate its office space in Boston, Massachusetts under an operating lease agreement. The amended lease term is for a period of seven years from the date of relocation on August 1, 2019. The initial annual base rent of the relocation premises is $0.6 million per year, increasing 2% annually. In connection with the lease amendment, the Company issued a new cash-collateralized letter of credit for the benefit of the landlord in the amount of $0.2 million. Rent expense was $0.5 million, $0.3 million and $0 the years ended December 31, 2019, 2018, and 2017, respectively. Obligations to make future minimum lease payments as of December 31, 2019, are as follows:


Year ending December 31,	Minimum Lease Payments
	(In thousands)
2020	$	594
2021		606
2022		618
2023		630
2024		643
Years thereafter		1,043

Total	$	4,134

Novartis License Agreement

The Company is required to pay up to an aggregate of $1.5 million upon the satisfaction of clinical milestones, up to an aggregate of $24 million upon the satisfaction of regulatory milestones for the first indication approved, and up to an aggregate of $18 million upon the satisfaction of regulatory milestones for the second indication approved. In addition, the Company is required to pay up to an aggregate of $125 million upon the satisfaction of commercial milestones, based on the amount of annual net sales. The Company is also required to pay tiered royalties ranging from a mid single-digit percentage to a low teen-digit percentage on annual net sales of products. These royalty obligations last on a product-by-product and country-by-country basis until the latest of (i) the expiration of the last valid claim of a Novartis patent covering a subject product, (ii) the expiration of any regulatory exclusivity for the subject product in a country, or (iii) the 10^th anniversary of the first commercial sale in the country, and are subject to a reduction after the expiration of the last valid claim of a Novartis patent or the introduction of a generic equivalent of a product in a country.

Silverstein Foundation

The Company is obligated to repay the Funding Amount in full to the Silverstein Foundation if it successfully conducts a positive Phase 3 clinical trial of the Product for PD (see Note 7).