Summary of Stock Options (Detail) (USD $)
6 Months Ended
Jun. 30, 2012
Jul. 01, 2010
Number of Stock Options    
Beginning Balance 7,542,459  
Granted 753,400  
Expired (483,896)  
Forfeited (2,693)  
Exercised     
Ending Balance 7,809,270  
Exercisable - June 30, 2012 6,177,948  
Available for grant - June 30, 2012 1,641,979  
Weighted-Average Exercise Price    
Beginning Balance $ 0.41  
Granted $ 0.15  
Expired $ 0.33  
Forfeited $ 0.30  
Exercised     
Ending Balance $ 0.39  
Exercisable - June 30, 2012 $ 0.44 $ 0.27
Weighted Average Remaining Life (years)    
Outstanding - June 30, 2012 5 years 9 months 22 days  
Exercisable - June 30, 2012 5 years 7 days  
Aggregate Intrinsic Value    
Outstanding - December 31, 2011 $ 221,127  
Exercisable - June 30, 2012 $ 155,699  
Outstanding - December 31, 2011
   
Weighted-Average Exercise Price    
Price range, lower limit $ 0.07  
Price range, upper limit $ 1.33  
Granted
   
Weighted-Average Exercise Price    
Price range, lower limit $ 0.14  
Price range, upper limit $ 0.20  
Expired
   
Weighted-Average Exercise Price    
Price range, lower limit $ 0.30  
Price range, upper limit $ 1.06  
Forfeited
   
Weighted-Average Exercise Price    
Price range, lower limit $ 0.30  
Price range, upper limit $ 0.30  
Outstanding - June 30, 2012
   
Weighted-Average Exercise Price    
Price range, lower limit $ 0.07  
Price range, upper limit $ 1.33  
Exercisable - June 30, 2012
   
Weighted-Average Exercise Price    
Price range, lower limit $ 0.07  
Price range, upper limit $ 1.33