Stock-Based Compensation (Tables)

3 Months Ended

Mar. 31, 2013

Stock-Based Compensation Expense

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

	Three Months Ended March 31,
	2013		2012
Cost of product revenue	$	12,000	$	10,000
Research and development		8,000		52,000
Selling, general and administrative		230,000		179,000
Total	$	250,000	$	241,000

Summary of Option Activity

Information regarding option activity for the three months ended March 31, 2013 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, 2013		2,315,090		$	4.20
Granted		325,000			6.23
Exercised		(310,300	)		4.86
Forfeited/Cancelled		(98,200	)		4.32
Options outstanding at March 31, 2013		2,231,590		$	4.40		6.70	$	5,618,691
Options exercisable at March 31, 2013		1,223,100		$	4.28		5.01	$	3,241,959
Vested and expected to vest at March 31, 2013 (1)		2,121,159		$	4.37		6.63	$	5,417,308

(1) This represents the number of vested options as of March 31, 2013 plus the number of unvested options expected to vest as of March 31, 2013 based on the unvested outstanding options at March 31, 2013 adjusted for estimated forfeiture rates of 8% for awards granted to non-executive level employees and 3% for awards granted to executive level employees.