v2.4.0.6
Long-Term Obligations (Details) (USD $)
 1 Months Ended 12 Months Ended 1 Months Ended 12 Months Ended
Dec. 31, 2011
Dec. 31, 2010
Jan. 31, 2008
Convertible Subordinated Notes
Dec. 31, 2011
Convertible Subordinated Notes
D
Dec. 31, 2010
Convertible Subordinated Notes
Dec. 31, 2009
Convertible Subordinated Notes
Jul. 31, 2002
Note Payable
Dec. 31, 2011
Note Payable
Dec. 31, 2011
Capital Lease
Dec. 31, 2010
Capital Lease
Information related to long-term obligations                    
Carrying value of convertible subordinated notes $ 172,500,000 $ 172,500,000                
Estimated fair value of convertible subordinated notes 189,588,000 202,391,000                
Carrying value of note payable to lessor   42,000                
Estimated fair value of note payable to lessor   42,000                
Debt disclosures                    
Loan amount     172,500,000       900,000      
Proceeds from issuance of debt, net of issuance costs     166,700,000              
Interest rate (as a percent)       3.00%            
Conversion rate, number of shares to be issued per $1000 of principal amount of notes       38.6548            
Principal amount used for debt instrument conversion ratio       1,000            
Initial conversion price of convertible notes into common stock (in dollars per share)       $ 25.87            
Unamortized debt issuance costs       2,500,000            
Amortization expense       800,000 800,000 800,000        
Percentage of principal amount at which the entity may redeem some or all notes       100.00%            
Percentage of closing sales price of the entity's common stock the conversion price must exceed in order for the notes to be convertible       130.00%            
Number of days within 30 consecutive trading days in which the closing price of the entity's common stock must exceed the conversion price for the notes to be redeemable       20            
Number of consecutive trading days during which the closing price of the entity's common stock must exceed the conversion price for at least 20 days in order for the notes to be redeemable       30            
Interest rate (as a percent)               14.50%    
Aggregate maturities of note payable               42,000    
Capital lease agreement                    
Obligation of lease arrangement                 79,000 130,000
Minimum lease payments less interest                 (52,000) (51,000)
Present value of future payments                 27,000 79,000
Less current portion                 (27,000) (52,000)
Long-term portion                   27,000
Cost of equipment financed under capital leases                 200,000  
Accumulated amortization                 $ 72,000 $ 41,000