9. Commitments

In November 2010, the Company entered into an operating lease for office and laboratory space, which has been amended multiple times. Based on the latest amendment, the lease agreement includes escalating rent payments and is effective through June 30, 2020. The Company is recognizing rent expense on a straight-line basis over the lease term.

Future minimum payments required under the non-cancelable operating lease as of December 31, 2017 are summarized as follows (in thousands):

Period Ending December 31,	Amount
2018		1,379
2019		1,421
2020		721

Total minimum lease payments	$	3,521

Rent expense for the years ended December 31, 2017, 2016 and 2015 was $1.3 million, $0.9 million and $0.8 million, respectively.