Restructuring Charges (Details) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013 Severance	Dec. 31, 2012 Severance
Restructuring charges
Restructuring costs accrued and unpaid					$ 100,000	$ 700,000
Changes in restructuring liability
Balance at the beginning of the period					659,000
Severance and related costs	(112,000)	(578,000)	(2,334,000)	(3,612,000)	2,333,000
Cash payments					(2,861,000)
Balance at the end of the period					$ 131,000