Stock-Based Compensation (Tables)

3 Months Ended

Mar. 31, 2018

Stock-Based Compensation Expense

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

	Three Months Ended March 31,
	2018		2017
Cost of product revenue	$	266	$	141
Research and development		170		132
Selling, general and administrative		1,832		1,258
Total	$	2,268	$	1,531

Summary of Option Activity

Information regarding option activity for the three-month period ended March 31, 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		398,532			33.85
Exercised		(14,531	)		23.70
Forfeited/cancelled		(9,588	)		29.71
Options outstanding at March 31, 2018		1,109,353		$	25.34		7.51	$	12,176
Options exercisable at March 31, 2018		499,504		$	17.73		5.50	$	9,300
Vested and expected to vest at March 31, 2018 (1)		1,057,255		$	24.96		7.40	$	12,015

⁽¹⁾  Represents the number of vested options as of March 31, 2018 plus the number of unvested options expected to vest as of March 31, 2018 based on the unvested outstanding options at March 31, 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 three-month period ended March 31, 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		319,701
Exercised		(90,691	)
Forfeited/cancelled		(31,169	)
Restricted stock units outstanding at March 31, 2018		703,076			4.06	$	25,437
Vested and expected to vest at March 31, 2018 (1)		639,530			3.75	$	23,138

⁽¹⁾  Represents the number of vested restricted stock units as of March 31, 2018 plus the number of unvested restricted stock units expected to vest as of March 31, 2018 based on the unvested outstanding restricted stock units at March 31, 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.