11.	Commitments

Leases

The Company has entered into operating leases for facilities and equipment. These leases are non-cancellable and typically do not contain renewal options. Certain leases contain rent escalation clauses for which the Company recognizes the expense on a straight-line basis. Rent expense under the Company’s operating leases for the years ended December 31, 2016, 2015 and 2014 was approximately $3.0 million, $3.0 million and $3.4 million, respectively.

Future minimum lease payments under operating leases as of December 31, 2016 are as follows:

(U.S. Dollars, in thousands)
2017	$	3,009
2018		2,332
2019		1,608
2020		1,320
2021		108
Thereafter		—
Total	$	8,377

Inventory purchase commitments

The Company had inventory purchase commitments with third-party manufactures for $1.2 million, $2.1 million and $2.5 million as of December 31, 2016, 2015, and 2014, respectively.