EXHIBIT 2
JOINT FILING AGREEMENT
The undersigned hereby agree to the joint filing of the Amendment No. 5 to Schedule 13D to which this Agreement is attached.
Dated: May 18, 2011
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 |