Share-based compensation

6 Months Ended

Jun. 30, 2018

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

10. Share-based compensation

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

	Three Months Ended June 30,				Six Months Ended June 30,
(U.S. Dollars, in thousands)	2018		2017		2018		2017
Cost of sales	$	132	$	137	$	257	$	286
Sales and marketing		473		319		922		679
General and administrative		4,249		2,005		7,294		4,107
Research and development		361		215		658		420
	$	5,215	$	2,676	$	9,131	$	5,492

	Three Months Ended June 30,				Six Months Ended June 30,
(U.S. Dollars, in thousands)	2018		2017		2018		2017
Stock options	$	1,241	$	523	$	1,863	$	1,118
Time-based restricted stock awards and units		1,789		1,239		3,236		2,531
Performance-based restricted stock awards		270		113		759		225
Performance-based and market-based restricted stock units		1,604		472		2,557		938
Stock purchase plan		311		329		716		680
	$	5,215	$	2,676	$	9,131	$	5,492

During the three months ended June 30, 2018 and 2017, the Company issued 80,444 and 76,596 shares, respectively, of common stock related to stock purchase plan issuances, stock option exercises and the vesting of restricted stock awards. During the six months ended June 30, 2018 and 2017, the Company issued 206,955 and 291,275 shares, respectively, of common stock related to stock purchase plan issuances, stock option exercises and the vesting of restricted stock awards.