Share-based compensation (Tables)

3 Months Ended

Mar. 31, 2020

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Schedule of Components of Share-Based Compensation Expense

Components of share-based compensation expense are as follows:

	Three Months Ended March 31,
(U.S. Dollars, in thousands)	2020		2019
Cost of sales	$	181	$	187
Sales and marketing		696		610
General and administrative		2,530		4,564
Research and development		452		324
Total	$	3,859	$	5,685

	Three Months Ended March 31,
(U.S. Dollars, in thousands)	2020		2019
Stock options	$	304	$	2,112
Time-based restricted stock awards and units		2,421		1,706
Market-based restricted stock units		670		1,347
Stock purchase plan		464		520
Total	$	3,859	$	5,685