Share-based compensation

6 Months Ended

Jun. 30, 2019

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

14. Share-based compensation

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 June 30,				Six Months Ended June 30,
(U.S. Dollars, in thousands)	2019		2018		2019		2018
Cost of sales	$	180	$	132	$	367	$	257
Sales and marketing		692		473		1,302		922
General and administrative		4,564		4,249		9,128		7,294
Research and development		413		361		737		658
Total	$	5,849	$	5,215	$	11,534	$	9,131

	Three Months Ended June 30,				Six Months Ended June 30,
(U.S. Dollars, in thousands)	2019		2018		2019		2018
Stock options	$	926	$	1,241	$	3,038	$	1,863
Time-based restricted stock awards and units		2,951		1,789		4,657		3,236
Performance-based restricted stock awards and units		—		270		—		759
Market-based restricted stock units		1,576		1,604		2,923		2,557
Stock purchase plan		396		311		916		716
Total	$	5,849	$	5,215	$	11,534	$	9,131

During the three months ended June 30, 2019 and 2018, the Company issued 40,812 and 80,444 shares, respectively, of common stock related to stock purchase plan issuances, stock option exercises and the vesting of restricted stock awards and units. During the six months ended June 30, 2019 and 2018, the Company issued 251,893 and 206,955 shares, respectively, of common stock related to stock purchase plan issuances, stock option exercises and the vesting of restricted stock awards and units.

On August 5, the Company entered into an employment agreement with its new President of Global Spine and awarded restricted stock units and stock options valued at approximately $1.5 million as inducement grants.

Share-Based Compensation Modifications

During the first quarter of 2019, the Company entered into a Transition and Retirement Agreement (the “Retirement Agreement”) with the Company’s President and Chief Executive Officer. As part of the Retirement Agreement, certain time-based stock options and restricted stock awards were modified to accelerate the vesting to the retirement date. In addition, stock options were modified to extend the post-termination exercise period from 18 months under a standard qualified retirement to up to four years, dependent upon the remaining contractual term of the options. The Company recognized approximately $1.5 million and $3.7 million in share-based compensation expense during the three and six months ended June 30, 2019, related to the Retirement Agreement, which was charged to general and administrative expense in the condensed consolidated statements of operations and comprehensive income (loss).