October 2010 Restructuring (Details) (USD $)	1 Months Ended	3 Months Ended		9 Months Ended
	Oct. 31, 2010 position	Sep. 30, 2011	Dec. 31, 2010	Sep. 30, 2011
October 2010 Restructuring
Expected number of reduction in workforce, greater than (in positions)	60
Restructuring related costs recognized			$ 2,200,000
Components of restructuring expenses and reserve
Accrued restructuring, beginning of period		224,000		1,324,000
Employee severance, benefits and related costs		11,000		188,000
Payments		(108,000)		(1,263,000)
Other adjustments		(10,000)		(132,000)
Accrued restructuring, end of period		$ 117,000	$ 1,324,000	$ 117,000