Discovery Group I SC 13D/A Horizon Pharma, Inc.

EXHIBIT 2

JOINT FILING AGREEMENT

The undersigned hereby agree to the joint filing of the Amendment No. 8 to Schedule 13D to which this Agreement is attached.

Dated: March 19, 2014

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