CUSIP NO.  300614500 Page 1 0 of 12 Pages

EXHIBIT A

JOINT FILING AGREEMENT

The undersigned hereby agree that the Schedule 13G with respect to the Common Stock, $0.001 par value, of Exa Corporation, dated as of September 13, 2017, is, and any amendments thereto (including amendments on Schedule 13D) signed by each of the undersigned shall be, filed on behalf of each of us pursuant to and in accordance with the provisions of Rule 13d-1(k) under the Securities Exchange Act of 1934.

Date: September 13, 2017	SOROS FUND MANAGEMENT LLC
	By:	/s/ Regan O’Neill
		Regan O’Neill
		Assistant General Counsel
Date: September 13, 2017	GEORGE SOROS
	By:	/s/ Regan O’Neill
		Regan O’Neill
		Attorney-in-Fact
Date: September 13, 2017	ROBERT SOROS
	By:	/s/ Regan O’Neill
		Regan O’Neill
		Attorney-in-Fact