EXHIBIT 1

JOINT FILING AGREEMENT

The undersigned hereby agree to the joint filing of the Schedule 13G to which this Agreement is attached.

Dated:  February 6, 2007

DISCOVERY GROUP I LLC
By:	/s/ Michael R. Murphy
	Michael R. Murphy
	Managing Member
	/s/ Daniel J. Donoghue
	Daniel J. Donoghue
	/s/ Michael R. Murphy
	Michael R. Murphy