Restructurings and Lease Terminations (Narrative) (Details) (USD $) In Thousands, unless otherwise specified	1 Months Ended		12 Months Ended				1 Months Ended						12 Months Ended
	Dec. 31, 2011	Nov. 30, 2008	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2011 One-time Termination Benefits [Member]	Nov. 30, 2008 One-time Termination Benefits [Member]	Dec. 31, 2011 Non-Cash Stock-Based Compensation [Member]	Nov. 30, 2008 Non-Cash Stock-Based Compensation [Member]	Dec. 31, 2011 Leases [Member]	Dec. 31, 2008 Leases [Member]	Dec. 31, 2012 Leases [Member]	Dec. 31, 2011 Leases [Member]	Dec. 31, 2010 Leases [Member]	Dec. 31, 2009 Leases [Member]
Restructuring Cost and Reserve [Line Items]
Accrued restructuring liability	$ 3,904		$ 641	$ 3,904	$ 307	$ 821					$ 593		$ 517	$ 593	$ 0	$ 149
Number of employees in workforce reduction	70	110
Restructuring charge			$ 406	$ 4,886	$ 0		$ 4,200	$ 2,000	$ 400	$ (800)	$ 700	$ 500	$ 33	$ 651	$ 0