Restructuring (Details) (USD $)	3 Months Ended								12 Months Ended			1 Months Ended	25 Months Ended	3 Months Ended	12 Months Ended			18 Months Ended	12 Months Ended						25 Months Ended	12 Months Ended				49 Months Ended	18 Months Ended	12 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Jul. 31, 2012 2008 Plan	Dec. 31, 2010 2008 Plan employee	Jun. 30, 2010 2010 Plan	Dec. 31, 2012 2010 Plan	Dec. 31, 2011 2010 Plan	Dec. 31, 2010 2010 Plan employee	Sep. 30, 2011 2010 Plan employee	Dec. 31, 2012 2012 Plan	Dec. 31, 2012 Contract Termination and Other Associated Costs 2008 Plan	Dec. 31, 2011 Contract Termination and Other Associated Costs 2008 Plan	Dec. 31, 2012 Contract Termination and Other Associated Costs 2010 Plan	Dec. 31, 2011 Contract Termination and Other Associated Costs 2010 Plan	Dec. 31, 2012 Contract Termination and Other Associated Costs 2012 Plan	Dec. 31, 2010 Severance and Related Costs 2008 Plan	Dec. 31, 2012 Severance and Related Costs 2010 Plan	Dec. 31, 2011 Severance and Related Costs 2010 Plan	Dec. 31, 2010 Severance and Related Costs 2010 Plan	Dec. 31, 2012 Severance and Related Costs 2012 Plan	Dec. 31, 2012 Contract Termination 2008 Plan	Sep. 30, 2011 Contract Termination 2010 Plan	Dec. 31, 2012 Contract Termination 2012 Plan
Restructuring Cost and Reserve [Line Items]
Positions terminated													70					25
Severance-related costs																									$ 1,500,000			$ 400,000	$ 400,000
Contract termination costs																														3,600,000	300,000	400,000
Abatement of rent and other operating expenses												200,000
Percentage reduction in workforce														10.00%
Number of positions intended to terminate																	26
Contractual commitments expected to remain obligations through December 2013																			200,000
Restructuring Reserve [Roll Forward]
Accrued restructuring balance, beginning of period															116,000	164,000				1,212,000	1,500,000	116,000	144,000			0	20,000
Restructuring plan expense	0	0	0	0	0	700,000	0	0	(205,000)	668,000	2,089,000				6,000	62,000			772,000	57,000	621,000	6,000	62,000	332,000		0	0		440,000
Adjustments to restructuring plan															(21,000)				206,000	(247,000)		(21,000)		206,000		0			0
Cash payments															(87,000)	(110,000)			(772,000)	(877,000)	(909,000)	(87,000)	(90,000)	(332,000)		0	(20,000)		(440,000)
Accrued restructuring balance, end of period															$ 14,000	$ 116,000	$ 164,000		$ 206,000	$ 145,000	$ 1,212,000	$ 14,000	$ 116,000	$ 206,000		$ 0	$ 0	$ 20,000	$ 0