Patents and other intangible assets

3 Months Ended

Mar. 31, 2014

Goodwill And Intangible Assets Disclosure [Abstract]

Patents and other intangible assets

3. Patents and other intangible assets

(U.S. Dollars, in thousands)	March 31, 2014			December 31, 2013
Cost
Patents	$	36,496		$	36,320
Trademarks — definite lived		645			620
Licenses and other		6,248			6,248
		43,389			43,188
Accumulated amortization
Patents		(32,351	)		(31,739	)
Trademarks — definite lived		(484	)		(454	)
Licenses and other		(2,036	)		(1,949	)
		(34,871	)		(34,142	)
Patents and other intangible assets, net	$	8,518		$	9,046