Income Taxes (Narrative) (Details) (USD $)	3 Months Ended					12 Months Ended
	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2010	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2008
Income Taxes [Line Items]
Deferred tax liability associated with the issuance of the convertible notes						$ 22,700,000
Income tax benefit	(7,733,000)	(6,245,000)	(5,400,000)	(7,410,000)	(9,000)	(26,788,000)	(9,000)	(2,071,000)
Net operating loss carryforwards	114,600,000					114,600,000
Deferred tax asset attributable to excess stock option deductions						7,200,000
Valuation allowance	181,521,000				152,952,000	181,521,000	152,952,000
Deferred tax assets, increase in valuation allowance						28,500,000
Unrecognized tax benefit liability	2,700,000				10,261,000	2,700,000	10,261,000	10,011,000	11,211,000
Unrecognized tax benefit that would impact the company's effective tax rate	0				4,100,000	0	4,100,000	4,100,000
Unrecognized tax benefit liability, accrued interest expense	1,400,000					1,400,000
Unrecognized tax benefit liability, accrued penalty expenses	600,000					600,000
Federal [Member]
Income Taxes [Line Items]
Net operating loss carryforwards	305,000,000					305,000,000
Tax credit carryforwards	52,300,000					52,300,000
State [Member]
Income Taxes [Line Items]
Net operating loss carryforwards	390,400,000					390,400,000
State Tax Audit [Member]
Income Taxes [Line Items]
Reduction in a liability for unrecognized tax benefit				3,600,000
State Matters [Member]
Income Taxes [Line Items]
Reduction in a liability for unrecognized tax benefit				$ 500,000
Maximum [Member]
Income Taxes [Line Items]
State income tax returns examination period, years						5
Minimum [Member]
Income Taxes [Line Items]
State income tax returns examination period, years						3