Stock-Based Compensation (Tables)

3 Months Ended

Mar. 31, 2014

Stock-Based Compensation Expense

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

	Three Months Ended March 31,
	2014		2013
Cost of product revenue	$	26,562	$	11,664
Research and development		31,603		7,640
Selling, general and administrative		249,260		230,767
Total	$	307,425	$	250,071

Summary of Option Activity

Information regarding option activity for the three months ended March 31, 2014 under the Plans is summarized below:

	Options Outstanding			Weighted- Average Exercise Price Per Share		Weighted- Average Remaining Contractual Term (in years)		Aggregate Intrinsic Value
Options outstanding at January 1, 2014		1,610,988		$	5.07
Granted		181,431			11.14
Exercised		(114,942	)		4.54
Forfeited/Cancelled		(2,400	)		5.12
Options outstanding at March 31, 2014		1,675,077		$	5.78		6.98	$	12,256,703
Options exercisable at March 31, 2014		834,186		$	4.29		5.13	$	7,146,702
Vested and expected to vest at March 31, 2014 (1)		1,577,600		$	5.67		6.88	$	11,700,596

(1) This represents the number of vested options as of March 31, 2014 plus the number of unvested options expected to vest as of March 31, 2014 based on the unvested outstanding options at March 31, 2014 adjusted for estimated forfeiture rates of 8% for awards granted to non-executive level employees and 3% for awards granted to executive level employees.