Stock-Based Compensation

3 Months Ended

Mar. 31, 2012

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

Disclosure of Compensation Related Costs, Share-based Payments [Text Block]

3. Stock-Based Compensation

Compensation expense for all stock-based awards is measured at the grant date based on the fair value of the award and is recognized as an expense, on a straight-line basis, over the employee's requisite service period (generally the vesting period of the equity award). The fair value of each option award is estimated on the date of grant using a Black-Scholes option valuation model. Stock-based compensation expense is recognized only for those awards that are expected to vest using an estimated forfeiture rate. We estimate pre-vesting option forfeitures at the time of grant and reflect the impact of estimated pre-vesting option forfeitures in compensation expense recognized. For options and warrants issued to non-employees, the Company recognizes stock compensation costs utilizing the fair value methodology over the related period of benefit.

Stock-based compensation expense was as follows for the three months ended March 31 (in thousands):

	2011		2012
Research and development	$	164	$	158
General and administrative		329		884
Total stock- based compensation expense	$	493	$	1,042

There were no options to purchase common stock granted during the three month periods ended March 31, 2011 and 2012. At March 31, 2012, the unrecognized compensation expense related to stock options was $3.6 million which is to be recognized over a weighted average period of approximately 3 years.