Share-based compensation plans (Tables)

12 Months Ended

Dec. 31, 2013

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Schedule of Share-Based Compensation by Line Item in Consolidated Statements of Operations

The following table shows the detail of share-based compensation by line item in the consolidated statements of operations for the years ended December 31, 2013, 2012 and 2011 and the assumptions for each of these years in which grants were awarded:


(U.S. Dollars in thousands, except assumptions)	Year Ended December 31, 2013		Year Ended December 31, 2012		Year Ended December 31, 2011
Cost of sales	$	104	$	592	$	153
Sales and marketing		1,444		1,550		2,031
General and administrative		4,483		4,023		4,322
Research and development		236		138		142

Total	$	6,267	$	6,303	$	6,648

Schedule of Share-based Payment Award, Valuation Assumptions

Assumptions:
Expected term		5.00 years			4.50 years			4.58 years
Expected volatility		32.1% – 50.8	%		50.9% – 51.8	%		49.6% – 49.9	%
Risk free interest rate		0.58% – 1.52	%		0.76% – 0.84	%		.90% – 2.26	%
Dividend rate		0			—			—
Weighted average fair value of options granted during the year	$	10.83		$	16.99		$	14.21

Schedule of Stock Option Activity

Summaries of the status of the Company’s stock option plans as of December 31, 2013 and 2012 and changes during the year ended December 31, 2013 are presented below:


	Options			Weighted Average Exercise Price		Weighted Average Remaining Contractual Term
Outstanding at December 31, 2012		1,945,955		$	34.50
Granted		466,250		$	28.51
Exercised		(79,949	)	$	23.25
Forfeited		(408,077	)	$	36.33

Outstanding at December 31, 2013		1,924,179		$	33.12		4.41

Vested and expected to vest at December 31, 2013		1,839,383		$	33.50		4.17

Options exercisable at December 31, 2013		1,367,269		$	34.35		2.89

Schedule of Stock Options Outstanding and Exercisable by Price Range

Outstanding and exercisable by price range as of December 31, 2013


	Options Outstanding						Options Exercisable
Range of Exercise Prices	Number Outstanding		Weighted Average Remaining Contractual Life		Weighted Average Exercise Price		Number Exercisable		Weighted Average Exercise Price
$10.42 – $21.78		232,250		9.31	$	20.79		16,000	$	13.31
$22.75 – $25.05		326,166		4.10	$	24.73		306,166	$	24.84
$26.79 – $28.95		230,000		4.79	$	28.45		170,000	$	28.65
$29.23 – $37.36		225,168		5.10	$	33.14		169,839	$	32.41
$37.76 – $38.11		230,975		1.69	$	37.99		230,975	$	37.99
$38.40 – $40.27		351,354		3.17	$	39.76		174,355	$	39.77
$41.33 – $43.04		178,633		2.84	$	41.66		150,301	$	41.72
$44.87 – $45.84		140,133		3.05	$	45.02		140,133	$	45.02
$50.50 – $50.50		2,000		3.01	$	50.50		2,000	$	50.50
$50.99 – $50.99		7,500		3.04	$	50.99		7,500	$	50.99

$10.42 – $50.99		1,924,179		4.41	$	33.12		1,367,269	$	34.35

Schedule of Changes in Restricted Stock

A summary of the status of our restricted stock as of December 31, 2013 and 2012 and changes during the year ended December 31, 2013 are presented below:


	Shares			Weighted Average Grant Date Fair Value
Non-vested as of December 31, 2012		160,831		$	38.34
Granted		269,791		$	27.09
Vested		(62,948	)	$	36.58
Cancelled		(80,970	)	$	38.80

Non-vested as of December 31, 2013		286,704		$	28.01