Derivative instruments (Tables)

12 Months Ended

Dec. 31, 2016

Derivative Instruments And Hedging Activities Disclosure [Abstract]

Schedule of Fair Values of Derivative Instruments

The tables below disclose the types of derivative instruments the Company owns, the classifications and fair values of these instruments within the balance sheet, and the amount of gain (loss) recognized in other comprehensive income (loss) (“OCI”) or net income (loss).

	December 31,
(U.S. Dollars, in thousands)	2016		2015		Balance sheet location
Cross-currency swap	$	—	$	2,485	Prepaid expenses and other current assets
Warrants (Note 6)		321		321	Other long-term assets

Schedule of Gain (Loss) Recognized in Other Comprehensive Income (Loss)

	For the year ended December 31,
(U.S. Dollars, in thousands)	2016			2015		2014
Cross-currency swap unrealized gain (loss), net of taxes	$	(228	)	$	128	$	251
Warrants unrealized loss, net of taxes	$	—		$	—	$	(3	)