Share-based compensation

3 Months Ended

Mar. 31, 2018

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Share-based compensation

9. Share-based compensation

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 March 31,
(U.S. Dollars, in thousands)	2018		2017
Cost of sales	$	125	$	149
Sales and marketing		449		360
General and administrative		3,045		2,102
Research and development		297		205
	$	3,916	$	2,816

	Three Months Ended March 31,
(U.S. Dollars, in thousands)	2018		2017
Stock options	$	622	$	595
Time-based restricted stock awards		1,447		1,292
Performance-based restricted stock awards		489		112
Performance-based and market-based restricted stock units		953		466
Stock purchase plan		405		351
	$	3,916	$	2,816

During the three months ended March 31, 2018 and 2017, the Company issued 126,511 and 214,679 shares, respectively, of common stock related to stock purchase plan issuances, stock option exercises and the vesting of restricted stock awards.