| CUSIP No. 87184Q107 | Page 12 of 13 |
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 13, 2019
| POLARIS PARTNERS VII, L.P. | ||
| By: Polaris Management Co. VII, L.L.C., its general partner | ||
| By: | * | |
| Managing Member | ||
| POLARIS ENTREPRENEURS’ FUND V, L.P. | ||
| By: Polaris Management Co. VII, L.L.C., its general partner | ||
| By: | * | |
| Managing Member | ||
| POLARIS MANAGEMENT CO. VII, L.L.C. | ||
| By: | * | |
| Managing Member | ||
| DAVID BARRETT | ||
| By: | * | |
| David Barrett | ||
| BRIAN CHEE | ||
| By: | * | |
| Brian Chee | ||
| CUSIP No. 87184Q107 | Page 13 of 13 |
| AMIR NASHAT | ||
| By: | * | |
| Amir Nashat | ||
| BRYCE YOUNGREN | ||
| By: | * | |
| Bryce Youngren | ||
| *By: | /s/ Max Eisenberg | |
| Name: | Max Eisenberg | |
| Attorney-in-Fact |
[This Schedule 13D 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.]