XML 39 R35.htm IDEA: XBRL DOCUMENT v2.4.0.6
Fair Value of Financial Instruments (Details) (USD $)
 12 Months Ended
Dec. 31, 2012
Item
Dec. 31, 2011
Dec. 31, 2010
Dec. 31, 2009
Fair Value of Financial Instruments        
Cash and cash equivalents, cost $ 2,529,000 $ 40,025,000 $ 14,340,000 $ 7,123,000
Cash and cash equivalents, fair value 2,529,000 40,025,000    
Estimated fair values of financial instruments        
Unrealized Gains 17,000 6,000    
Unrealized Losses (6,000) (5,000)    
Fair value of available-for-sale securities with unrealized losses 8,200,000      
Number of maturity groups 2      
Investments by fiscal year maturity, Cost        
Due within 1 year 30,790,000 9,412,000    
Due in 1-2 years 7,380,000 8,537,000    
Total 38,170,000 17,949,000    
Investments by fiscal year maturity, Unrealized Gains        
Due within 1 year 14,000 3,000    
Due in 1-2 years 3,000 3,000    
Total 17,000 6,000    
Investments by fiscal year maturity, Unrealized Losses        
Due within 1 year (6,000) (2,000)    
Due in 1-2 years   (3,000)    
Total (6,000) (5,000)    
Investments by fiscal year maturity, Fair Value        
Due within 1 year 30,798,000 9,413,000    
Due in 1-2 years 7,383,000 8,537,000    
Total 38,181,000 17,950,000    
Short-term investments
        
Estimated fair values of financial instruments        
Cost 30,790,000 9,412,000    
Unrealized Gains 14,000 3,000    
Unrealized Losses (6,000) (2,000)    
Fair Value 30,798,000 9,413,000    
Investments by fiscal year maturity, Unrealized Gains        
Total 14,000 3,000    
Investments by fiscal year maturity, Unrealized Losses        
Total (6,000) (2,000)    
Short-term investments | U.S. government debt securities
        
Estimated fair values of financial instruments        
Cost 15,852,000 4,834,000    
Unrealized Gains 6,000 2,000    
Unrealized Losses (2,000)      
Fair Value 15,856,000 4,836,000    
Investments by fiscal year maturity, Unrealized Gains        
Total 6,000 2,000    
Investments by fiscal year maturity, Unrealized Losses        
Total (2,000)      
Short-term investments | Corporate notes
        
Estimated fair values of financial instruments        
Cost 14,471,000 4,578,000    
Unrealized Gains 8,000 1,000    
Unrealized Losses (4,000) (2,000)    
Fair Value 14,475,000 4,577,000    
Investments by fiscal year maturity, Unrealized Gains        
Total 8,000 1,000    
Investments by fiscal year maturity, Unrealized Losses        
Total (4,000) (2,000)    
Short-term investments | Certificates of deposit
        
Estimated fair values of financial instruments        
Cost 467,000      
Fair Value 467,000      
Long-term investments
        
Estimated fair values of financial instruments        
Cost 7,380,000 8,537,000    
Unrealized Gains 3,000 3,000    
Unrealized Losses   (3,000)    
Fair Value 7,383,000 8,537,000    
Investments by fiscal year maturity, Unrealized Gains        
Total 3,000 3,000    
Investments by fiscal year maturity, Unrealized Losses        
Total   (3,000)    
Long-term investments | U.S. government debt securities
        
Estimated fair values of financial instruments        
Cost 6,330,000 5,721,000    
Unrealized Gains 2,000 1,000    
Unrealized Losses   (1,000)    
Fair Value 6,332,000 5,721,000    
Investments by fiscal year maturity, Unrealized Gains        
Total 2,000 1,000    
Investments by fiscal year maturity, Unrealized Losses        
Total   (1,000)    
Long-term investments | Corporate notes
        
Estimated fair values of financial instruments        
Cost 1,050,000 2,816,000    
Unrealized Gains 1,000 2,000    
Unrealized Losses   (2,000)    
Fair Value 1,051,000 2,816,000    
Investments by fiscal year maturity, Unrealized Gains        
Total 1,000 2,000    
Investments by fiscal year maturity, Unrealized Losses        
Total   $ (2,000)