EXHIBIT 1

JOINT FILING AGREEMENT

The undersigned hereby agree to the joint filing of Amendment No. 10 to the Schedule 13D to which this Agreement is attached.

Dated:  November 2, 2010

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