Stock-Based Compensation Expense

6 Months Ended

Jun. 30, 2011

Stock-Based Compensation Expense

Stock-Based Compensation Expense

7. Stock-Based Compensation Expense

Stock-based compensation is measured at the grant date based on the fair value of the award, and recognized as an expense over the requisite service period, net of an estimated forfeiture rate. We have four types of stock-based compensation programs: stock options, restricted common stock, restricted stock units, and performance stock units. For further information see Notes 2 and 11 included in our Annual Report on Form 10-K for the year ended December 31, 2010 filed with the SEC on February 18, 2011.

The following summarizes stock-based compensation expense recognized for the three and six months ended June 30, 2011 and 2010 (in thousands):

	Three Months Ended June 30,				Six Months Ended June 30,
	2011		2010		2011		2010
Stock options	$	1,207	$	1,552	$	2,500	$	3,025
Restricted common stock		70		548		288		1,114
Restricted stock units		1,427		808		2,654		1,473
Performance stock units		322		179		526		217
Total stock-based compensation expense	$	3,026	$	3,087	$	5,968	$	5,829