EX-2 3 ex2.htm EXHIBIT 2 ex2.htm
EXHIBIT 2
 
JOINT FILING AGREEMENT

    The undersigned hereby agree to the joint filing of Amendment No. 4 to the Schedule 13D to which this Agreement is attached.
 
    April 20, 2012
 
 
DISCOVERY GROUP I, LLC,
for itself and as general partner of
DISCOVERY EQUITY PARTNERS, L.P.
  
       
       
 
By:
Michael R. Murphy  
    Michael R. Murphy  
    Managing Member  
       
       
    Daniel J. Donoghue*  
    Daniel J. Donoghue  
       
       
    Michael R. Murphy*  
    Michael R. Murphy  
 
 
By:
 /s/ Mark Buckley
  
    Mark Buckley  
    Attorney-in-Fact for Daniel J. Donoghue  
    Attorney-in-Fact for Michael R. Murphy