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, 2015, 2014 and 2013 was approximately $3.0 million, $3.4 million and $3.4 million, respectively.

Future minimum lease payments under operating leases as of December 31, 2015 are as follows:

(U.S. Dollars in thousands)
2016	$	3,531
2017		2,905
2018		2,629
2019		2,175
2020		1,732
Thereafter		1,729
	$	14,701

Inventory purchase commitments

The Company has inventory purchase commitments with third-party manufactures for $1.1 million, $2.5 million and $3.0 million as of December 31, 2015, 2014, and 2013, respectively.