Share-based compensation (Tables)

9 Months Ended

Sep. 30, 2017

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

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

The following tables present the detail of share-based compensation by line item in the condensed consolidated statements of operations as well as by award type:

	Three Months Ended September 30,				Nine Months Ended September 30,
(U.S. Dollars, in thousands)	2017		2016		2017		2016
Cost of sales	$	151	$	175	$	437	$	401
Sales and marketing		394		331		1,073		887
General and administrative		2,828		7,148		6,935		10,082
Research and development		259		488		679		784
	$	3,632	$	8,142	$	9,124	$	12,154

	Three Months Ended September 30,				Nine Months Ended September 30,
(U.S. Dollars, in thousands)	2017		2016		2017		2016
Stock options	$	684	$	425	$	1,802	$	1,367
Time-based restricted stock awards		1,552		1,840		4,083		4,278
Performance-based restricted stock awards		115		5,089		340		5,089
Performance-based and market-based restricted stock units		997		472		1,935		472
Stock purchase plan		284		316		964		948
	$	3,632	$	8,142	$	9,124	$	12,154