EXHIBIT A
JOINT FILING AGREEMENT

SCHEDULE 13G
JOINT FILING AGREEMENT

     This Agreement is dated as of January 30, 2007 by and between Mercury Fund IV, Ltd. (“Mercury IV”), Mercury Fund V, Ltd. (“Mercury V”), Mercury Ventures, Ltd. (“Mercury Ventures”), Mercury Management, L.L.C. (“Mercury Management”) and Kevin C. Howe (“Mr. Howe”).

     WHEREAS, pursuant to paragraph (k)(1) of Rule 13d-1 promulgated under Section 13d(1) of the Securities Exchange Act of 1934, as amended (the “Act”), the parties hereto have decided to satisfy their filing obligations under the Act by a single joint filing.

     NOW, THEREFORE, the undersigned do hereby agree as follows:

     1. The Schedule 13G (the “Schedule 13G”) with respect to Document Sciences Corporation, a Delaware corporation, to which this Agreement is attached as Exhibit A is filed on behalf of Mercury IV, Mercury V, Mercury Ventures, Mercury Management and Mr. Howe. Mercury IV, Mercury V, Mercury Ventures and Mercury Management hereby authorize Mr. Howe to file the Schedule 13G on their behalf.

     2. Each of Mercury IV, Mercury V, Mercury Ventures, Mercury Management and Mr. Howe is responsible for the completeness and accuracy of the information concerning such person or entity contained therein; provided that each person or entity is not responsible for the completeness or accuracy of the information concerning any other person or entity making such filing.

[Remainder of Page Intentionally Left Blank]

     IN WITNESS WHEREOF, the undersigned hereunto set their hands as of the date first above written.

MERCURY FUND IV, LTD.
By:	MERCURY VENTURES, LTD.
	General Partner
	By:	MERCURY MANAGEMENT, L.L.C.
		General Partner
		By:	/s/ Kevin C. Howe
		Name:	Kevin C. Howe
		Title:	Manager
MERCURY FUND V, LTD.
By:	MERCURY VENTURES, LTD.
	General Partner
	By:	MERCURY MANAGEMENT, L.L.C.
		General Partner
		By:	/s/ Kevin C. Howe
		Name:	Kevin C. Howe
		Title:	Manager
MERCURY VENTURES, LTD.
By:	MERCURY MANAGEMENT, L.L.C.
	General Partner
	By:	/s/ Kevin C. Howe
	Name:	Kevin C. Howe
	Title:	Manager
MERCURY MANAGEMENT, L.L.C.
By:	/s/ Kevin C. Howe
Name:	Kevin C. Howe
Title:	Manager
/s/ Kevin C. Howe
Name:	Kevin C. Howe