Share-based compensation (Tables)

6 Months Ended

Jun. 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 June 30,				Six Months Ended June 30,
(U.S. Dollars, in thousands)	2017		2016		2017		2016
Cost of sales	$	137	$	109	$	286	$	226
Sales and marketing		319		280		679		556
General and administrative		2,005		1,376		4,107		2,934
Research and development		215		148		420		296
	$	2,676	$	1,913	$	5,492	$	4,012

	Three Months Ended June 30,				Six Months Ended June 30,
(U.S. Dollars, in thousands)	2017		2016		2017		2016
Stock options	$	523	$	467	$	1,118	$	942
Time-based restricted stock awards		1,239		1,130		2,531		2,438
Performance-based restricted stock awards		113		—		225		—
Performance-based and market-based restricted stock units		472		—		938		—
Stock purchase plan		329		316		680		632
	$	2,676	$	1,913	$	5,492	$	4,012