| CUSIP No. 372427104 | Page 15 of 16 |
Exhibit A
AGREEMENT REGARDING THE JOINT FILING OF
SCHEDULE 13D
The undersigned, being duly authorized thereunto, hereby execute this agreement as an exhibit to this Schedule 13D to evidence the agreement of the below-named parties, in accordance with the rules promulgated pursuant to the Securities Exchange Act of 1934, to file this Schedule jointly on behalf of each such party.
Date: February 14, 2014
| POLARIS VENTURE PARTNERS V, L.P. | ||
| By: Polaris Venture Management Co. V, L.L.C. | ||
| By: | * | |
| Managing Member | ||
| POLARIS VENTURE PARTNERS ENTREPRENEURS’ FUND V, L.P. | ||
| By: Polaris Venture Management Co. V, L.L.C. | ||
| By: | * | |
| Managing Member | ||
POLARIS VENTURE PARTNERS FOUNDERS’ FUND V, L.P. | ||
| By: Polaris Venture Management Co. V, L.L.C. | ||
| By: | * | |
| Managing Member | ||
CUSIP No. 372427104 | Page 16 of 16 |
| POLARIS VENTURE PARTNERS SPECIAL FOUNDERS’ FUND V, L.P. | ||
| By: Polaris Venture Management Co. V, L.L.C. | ||
| By: | * | |
| Managing Member | ||
| POLARIS VENTURE MANAGEMENT CO. V, L.L.C. | ||
| By: | * | |
| Managing Member | ||
| JONATHAN A. FLINT | ||
| By: | * | |
| Jonathan A. Flint | ||
| TERRANCE G. MCGUIRE | ||
| By: | * | |
| Terrance G. McGuire | ||
| KEVIN BITTERMAN | ||
| By: | /s/ Kevin Bitterman | |
| Kevin Bitterman | ||
| *By: | /s/ John Gannon | |
| Name: | John Gannon | |
| Attorney-in-Fact | ||
[This Schedule 13G was executed pursuant to a Power of Attorney. Note that copies of the applicable Powers of Attorney are already on file with the appropriate agencies.]