Share-based compensation (Tables)

9 Months Ended

Sep. 30, 2018

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Schedule of Share-Based Compensation by Line Item in Condensed Consolidated Statements of Operations and Comprehensive Income (Loss)

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

	Three Months Ended September 30,				Nine Months Ended September 30,
(U.S. Dollars, in thousands)	2018		2017		2018		2017
Cost of sales	$	151	$	151	$	408	$	437
Sales and marketing		514		394		1,436		1,073
General and administrative		4,194		2,828		11,488		6,935
Research and development		402		259		1,060		679
Total	$	5,261	$	3,632	$	14,392	$	9,124

	Three Months Ended September 30,				Nine Months Ended September 30,
(U.S. Dollars, in thousands)	2018		2017		2018		2017
Stock options	$	579	$	684	$	2,442	$	1,802
Time-based restricted stock awards and units		2,244		1,552		5,480		4,083
Performance-based restricted stock awards and units		734		115		1,493		340
Market-based restricted stock units		1,298		997		3,855		1,935
Stock purchase plan		406		284		1,122		964
Total	$	5,261	$	3,632	$	14,392	$	9,124