CUSIP No. 37953N108 13G Page 31 of 34 Pages

Exhibit 1

JOINT FILING AGREEMENT PURSUANT TO RULE 13d-1(k)(1)

The undersigned acknowledge and agree that the foregoing statement on Schedule 13G is filed on behalf of each of the undersigned and that all subsequent amendments to this statement on Schedule 13G shall be filed on behalf of each of the undersigned without the necessity of filing additional joint filing statements. The undersigned acknowledge that each shall be responsible for the timely filing of such amendments, and for the completeness and accuracy of the information concerning him, her or it contained herein, but shall not be responsible for the completeness and accuracy of the information concerning the other entities or persons, except to the extent that he, she or it knows or has reason to believe that such information is inaccurate.

Date: February 17, 2015

HIGHVISTA STRATEGIES, LLC
By:	/s/ Brian H. Chu
	Name: Brian H. Chu
	Title: Manager
HIGHVISTA GP, LLC
By:	/s/ Brian H. Chu
	Name: Brian H. Chu
	Title: Manager
HIGHVISTA GP LIMITED PARTNERSHIP
By:	HighVista GP, LLC
By:	/s/ Brian H. Chu
	Name: Brian H. Chu
	Title: Manager
HIGHVISTA GP II LIMITED PARTNERSHIP
By:	HighVista GP, LLC
By:	/s/ Brian H. Chu
	Name: Brian H. Chu
	Title: Manager
HIGHVISTA GP III LIMITED PARTNERSHIP
By:	HighVista GP, LLC
By:	/s/ Brian H. Chu
	Name: Brian H. Chu
	Title: Manager
HIGHVISTA I LIMITED PARTNERSHIP
By:	HighVista GP Limited Partnership
By:	HighVista GP, LLC
By:	/s/ Brian H. Chu
	Name: Brian H. Chu
	Title: Manager

CUSIP No. 37953N108 13G Page 32 of 34 Pages

HIGHVISTA II LIMITED PARTNERSHIP
By:	HighVista GP Limited Partnership
By:	HighVista GP, LLC
By:	/s/ Brian H. Chu
	Name: Brian H. Chu
	Title: Manager
HIGHVISTA III, LTD.
By:	/s/ Brian H. Chu
	Name: Brian H. Chu
	Title: Director
HIGHVISTA V LIMITED PARTNERSHIP
By:	HighVista GP Limited Partnership
By:	HighVista GP, LLC
By:	/s/ Brian H. Chu
	Name: Brian H. Chu
	Title: Manager
HIGHVISTA VI LIMITED PARTNERSHIP
By:	HighVista GP II Limited Partnership
By:	HighVista GP, LLC
By:	/s/ Brian H. Chu
	Name: Brian H. Chu
	Title: Manager
HIGHVISTA LIQUID MULTI-ASSET FUND – MODERATE (CAYMAN), LTD.
By:	/s/ Brian H. Chu
	Name: Brian H. Chu
	Title: Director
HIGHVISTA 1.5 (OFFSHORE) LTD.
By:	/s/ Brian H. Chu
	Name: Brian H. Chu
	Title: Director
HIGHVISTA 1.5 (U.S.) LP
By:	HighVista GP III Limited Partnership
By:	HighVista GP, LLC
By:	/s/ Brian H. Chu
	Name: Brian H. Chu
	Title: Director

CUSIP No. 37953N108 13G Page 33 of 34 Pages

XL RE LTD
By:	/s/ Mark Twite
	Name: Mark Twite
	Title: Chief Financial Officer and Senior Vice President
	/s/ Brian H. Chu
	Brian H. Chu
	/s/ André F. Perold
	André F. Perold