Commitments And Contingencies (Narrative) (Details) (USD $)	12 Months Ended						1 Months Ended	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2011 201 Spear Street [Member]	Dec. 31, 2011 201 Spear Street [Member] Maximum [Member]	Dec. 31, 2011 201 Spear Street [Member] Minimum [Member]	Mar. 31, 2010 345 Spear Street [Member]	Dec. 31, 2011 345 Spear Street [Member]	Dec. 31, 2011 525 Market Street [Member]	Dec. 31, 2011 Letter Of Credit [Member]	Dec. 31, 2011 Collateralized Letter Of Credit [Member]	Dec. 31, 2010 Collateralized Letter Of Credit [Member]
Operating Leased Assets [Line Items]
Operating lease space	3,700			34,000				64,000	57,000
Lease expiry period					May 2013	July 2012
Rent expense, net of sublease income	$ 2,800,000	$ 2,200,000	$ 2,800,000
Lease termination fees							1,500,000
Outstanding letters of credit collateralized by restricted cash											6,000,000	800,000
Restricted cash, current										500,000
Restricted cash, long-term assets	5,489,000	843,000								5,500,000
Coverage under its relevant insurance policies	350,000
Accumulated deficit	$ (250,291,000)	$ (211,450,000)