v2.4.0.6
Operating Leases and Subleases (Details) (USD $)
 12 Months Ended
Dec. 31, 2011
Y
sqft
count
building
Dec. 31, 2010
Dec. 31, 2009
Operating Leases and Subleases      
Number of lease terms 2    
Additional lease period (in years) 5    
Number of buildings 2    
Area of building one in South San Francisco, California (in square feet) 110,000    
Area of building two in South San Francisco, California (in square feet) 40,000    
Future minimum lease payments      
2012 $ 5,429,000    
2013 5,029,000    
2014 4,859,000    
2015 5,005,000    
2016 5,156,000    
Thereafter 18,806,000    
Total 44,284,000    
Expenses and income associated with operating leases      
Rent expense 6,702,000 6,779,000 6,559,000
Sublease income, net (637,000) (622,000) (580,000)
Future minimum rental receivable under non-cancelable sublease $ 200,000