Exhibit 24.2

POWER OF ATTORNEY

KNOW ALL MEN BY THESE PRESENTS, that the undersigned hereby constitutes and appoints Darin T. Olson and Jason A. Dubchak, and each of them, his true and lawful attorneys-in-fact and agents, with full power of substitution and resubstitution, for him or her and in his or her name, place and stead, in any and all capacities, to sign any and all amendments to this registration statement on Form S-3 (Registration No. 333-174988) (including post-effective amendments and registration statements filed pursuant to Rule 462 or otherwise) and to file the same, with all exhibits thereto, and the other documents in connection therewith, with the Securities and Exchange Commission, and hereby grants to such attorneys-in-fact and agents and each of them, full power and authority to do and perform each and every act and thing requisite and necessary to be done, as fully to all intents and purposes as he might or could do in person, hereby ratifying and confirming all that said attorneys-in-fact and agents or any of them, or his or their substitute or substitutes, may lawfully do or cause to be done by virtue hereof.

IN WITNESS WHEREOF, the undersigned has caused this Power of Attorney to be executed as of July 21, 2011.

/s/ Simon Dupéré

Name: Simon Dupéré