v2.4.0.6
Income Taxes (Details) (USD $)
 12 Months Ended
Dec. 31, 2011
Dec. 31, 2010
Dec. 31, 2009
Deferred tax assets:      
Net operating loss carryforwards $ 359,000,000 $ 311,000,000  
Deferred revenues 56,000,000 63,000,000  
Capitalized research and development expenditures 35,000,000 34,000,000  
Research and development tax credit carryforwards 37,000,000 34,000,000  
Other 31,000,000 26,000,000  
Valuation allowance (518,000,000) (468,000,000)  
Information related to valuation allowance      
Increase in valuation allowance 50,000,000 35,000,000 32,000,000
Gross unrecognized tax benefits      
Gross unrecognized tax benefits at the beginning of the period 42,600,000 39,600,000 36,200,000
Gross decrease for tax positions for prior years     (100,000)
Gross increase in tax positions for current year 4,300,000 3,000,000 3,500,000
Gross unrecognized tax benefits at the end of the period 46,900,000 42,600,000 39,600,000
Federal
      
Operating Loss and Tax Credit Carryforward [Line Items]      
Net operating loss carryfowards 1,068,200,000    
Federal | Research and Development
      
Operating Loss and Tax Credit Carryforward [Line Items]      
Tax credit carryforward amount 43,200,000    
State
      
Operating Loss and Tax Credit Carryforward [Line Items]      
Net operating loss carryfowards 425,000,000    
State | Research
      
Operating Loss and Tax Credit Carryforward [Line Items]      
Tax credit carryforward amount $ 46,900,000