EXHIBIT 1

JOINT FILING AGREEMENT

The undersigned hereby agree to the joint filing of the Amendment No. 1 to Schedule 13D to which this Agreement is attached.

Dated:  November 7, 2007
	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/ Robert M. McLennan
			Robert M. McLennan
			Attorney-in-Fact for Daniel J. Donoghue
			Attorney-in-Fact for Michael R. Murphy