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 September 30,				Nine Months Ended September 30,
(U.S. Dollars, in thousands)	2019		2018		2019		2018
Cost of sales	$	169	$	151	$	536	$	408
Sales and marketing		583		514		1,885		1,436
General and administrative		4,760		4,194		13,888		11,488
Research and development		332		402		1,069		1,060
Total	$	5,844	$	5,261	$	17,378	$	14,392

	Three Months Ended September 30,				Nine Months Ended September 30,
(U.S. Dollars, in thousands)	2019		2018		2019		2018
Stock options	$	599	$	579	$	3,637	$	2,442
Time-based restricted stock awards and units		3,805		2,244		8,462		5,480
Performance-based restricted stock awards and units		—		734		—		1,493
Market-based restricted stock units		1,092		1,298		4,015		3,855
Stock purchase plan		348		406		1,264		1,122
Total	$	5,844	$	5,261	$	17,378	$	14,392

During the three months ended September 30, 2019 and 2018, the Company issued 43,603 and 50,928 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 nine months ended September 30, 2019 and 2018, the Company issued 295,496 and 257,833 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, 2019 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.

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 $2.2 million and $5.9

million in share-based compensation expense during the three and nine months ended September 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).