Stock-Based Compensation (Tables)

6 Months Ended

Jun. 30, 2018

The following table presents stock-based compensation expense included in the Company’s consolidated statements of comprehensive income (in thousands):


	Three months ended June 30,				Six months ended June 30,
	2018		2017		2018		2017
Cost of product revenue	$	234	$	153	$	500	$	294
Research and development		227		79		397		211
Selling, general and administrative		2,164		1,264		3,996		2,522

Total	$	2,625	$	1,496	$	4,893	$	3,027

Summary of Option Activity

Information regarding option activity for the six-month period ended June 30, 2018 under the Plans is summarized below:


	Options Outstanding			Weighted- Average Exercise Price Per Share		Weighted- Average Remaining Contractual Term (in years)		(in thousands) Aggregate Intrinsic Value
Options outstanding at December 31, 2017		734,940		$	20.80
Granted		429,678			34.48
Exercised		(96,196	)		15.49
Forfeited/cancelled		(9,588	)		29.71

Options outstanding at June 30, 2018		1,058,834		$	26.72		7.57	$	21,518

Options exercisable at June 30, 2018		448,068		$	19.14		5.60	$	12,502

Vested and expected to vest at June 30, 2018 ⁽¹⁾		1,008,777		$	26.37		7.48	$	20,854

⁽¹⁾

Represents the number of vested options as of June 30, 2018 plus the number of unvested options expected to vest as of June 30, 2018 based on the unvested outstanding options at June 30, 2018 adjusted for estimated forfeiture rates of 8% for awards granted to non-executive level employees and 3% for awards granted to executive level employees.

Restricted Stock Units and Performance Stock Units

Summary of Restricted Stock Unit and Performance Stock Unit Activity

Information regarding restricted stock unit and performance stock unit activity for the six-month period ended June 30, 2018 under the Plans is summarized below:


	Units Outstanding			Weighted- Average Remaining Contractual Term (in years)		(in thousands) Aggregate Intrinsic Value
Restricted and performance stock units outstanding at December 31, 2017		505,235
Granted		367,961
Vested		(115,295	)
Forfeited/cancelled		(40,905	)

Restricted stock units outstanding at June 30, 2018		716,996			3.97	$	33,727

Vested and expected to vest at June 30, 2018 ⁽¹⁾		654,423			3.60	$	30,784

⁽¹⁾

Represents the number of unvested restricted stock units expected to vest as of June 30, 2018 based on the unvested outstanding restricted stock units at June 30, 2018 adjusted for estimated forfeiture rates of 8% for awards granted to non-executive level employees and 3% for awards granted to executive level employees.