Stock-Based Compensation (Tables)

9 Months Ended

Sep. 30, 2018

Stock-Based Compensation Expense

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

	Three Months Ended September 30,				Nine Months Ended September 30,
	2018		2017		2018		2017
Cost of product revenue	$	277	$	197	$	777	$	491
Research and development		253		127		650		338
Selling, general and administrative		2,249		1,493		6,245		4,016
Total	$	2,779	$	1,817	$	7,672	$	4,845

Summary of Option Activity

Information regarding option activity for the nine-month period ended September 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		439,678			34.79
Exercised		(131,718	)		18.02
Forfeited/cancelled		(9,588	)		29.71
Options outstanding at September 30, 2018		1,033,312		$	26.99		7.38	$	29,421
Options exercisable at September 30, 2018		444,446		$	18.73		5.29	$	16,325
Vested and expected to vest at September 30, 2018 (1)		986,509		$	26.64		7.29	$	28,429

(1) Represents the number of vested options as of September 30, 2018 plus the number of unvested options expected to vest as of September 30, 2018 based on the unvested outstanding options at September 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.

RSU and Performance Stock Units

Summary of RSU and Performance Stock Unit Activity

Information regarding RSU and performance stock unit activity for the nine-month period ended September 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		385,461
Vested		(134,590	)
Forfeited/cancelled		(48,390	)
Restricted stock units outstanding at September 30, 2018		707,716			3.94	$	39,250
Vested and expected to vest at September 30, 2018 (1)		649,985			3.43	$	36,048

(1) Represents the number of unvested RSUs expected to vest as of September 30, 2018 based on the unvested outstanding RSUs at September 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.