Quarterly report pursuant to Section 13 or 15(d)

Stock Option Information (Detail)

v2.4.0.6
Stock Option Information (Detail) (USD $)
 3 Months Ended
Mar. 31, 2013
Mar. 31, 2012
Shares    
Beginning Balance 1,927,099 2,225,947
Granted 735,750  
Exercised 47,041  
Forfeited or expired 35,775  
Ending Balance 2,580,033 2,225,947
Exercisable at end of period 781,592  
Expected to Vest 1,707,621  
Weighted Average Exercise Price    
Beginning Balance $ 4.37  
Granted $ 6.93  
Exercised $ 2.73  
Forfeited or expired $ 12.39  
Ending Balance $ 5.02  
Exercisable at end of period $ 6.11  
Expected to Vest $ 4.54  
Weighted Average Grant Date Fair value    
Beginning Balance $ 3.45  
Granted $ 4.90  
Exercised $ 8.17  
Forfeited or expired $ 7.62  
Ending Balance $ 3.72  
Exercisable at end of period $ 4.74  
Expected to Vest $ 3.28  
Weighted Average Remaining Contractual Term    
Outstanding at beginning of period 5 years 4 months 24 days  
Outstanding at end of period 5 years 10 months 24 days  
Exercisable at end of period 3 years 3 months 18 days  
Expected to Vest 7 years  
Aggregate Intrinsic Value    
Beginning Balance $ 3,899  
Granted     
Exercised     
Forfeited or expired     
Ending Balance 8,595  
Exercisable at end of period 2,503  
Expected to Vest $ 5,785