Court Opinion

ID: 2742021
Source: CourtListenerOpinion
Date Created: 2014-10-14 16:00:59.341406+00
Date Added: 2024-06-11T09:55:12.280486
License: Public Domain

United States Court of Appeals
      for the Federal Circuit
                ______________________

                SSL SERVICES, LLC,
                  Plaintiff-Appellant,

                           v.

CITRIX SYSTEMS, INC. AND CITRIX ONLINE, LLC,
          Defendants-Cross-Appellants.
            ______________________

                   2013-1419, -1420
                ______________________

   Appeals from the United States District Court for the
Eastern District of Texas in No. 08-CV-0158, Judge J.
Rodney Gilstrap.
                 ______________________

               Decided: October 14, 2014
                ______________________

   GREGORY G. GARRE, Latham & Watkins LLP, of
Washington, DC, argued for plaintiff-appellant. With him
on the brief were ADAM M. GREENFIELD and KATYA S.
CRONIN.    Of counsel on the brief were MEGAN S.
WOODWORTH and THOMAS D. ANDERSON, Dickstein
Shapiro LLP, of Washington, DC.

    J. ANTHONY DOWNS, Goodwin Procter LLP, of Boston,
Massachusetts, argued for defendants-cross-appellants.
With him on the brief were LANA S. SHIFERMAN; and
WILLIAM M. JAY, of Washington, DC. Of counsel on the
brief were ERICA D. WILSON, Davis Wright Tremaine LLP,
2                    SSL SERVICES, LLC   v. CITRIX SYSTEMS, INC.

of San Francisco, California; and BLAIR MARTIN JACOBS,
McDermott Will & Emery LLP, of Washington, DC, and
LEIGH JOHN MARTINSON, of Boston, Massachusetts.
                ______________________

    Before LOURIE, LINN, and O’MALLEY, Circuit Judges.
O’MALLEY, Circuit Judge.
    This patent case involves multi-tier virtual private
networks. SSL Services, LLC (“SSL”) asserted that Citrix
Systems, Inc. and Citrix Online, LLC (collectively, “Cit-
rix”) infringed claims contained in U.S. Patent Nos.
6,061,796 (“the ’796 Patent”) and 6,158,011 (“the ’011
Patent”). The district court held a Markman hearing and
construed several terms raised on appeal. After a jury
trial, the jury found that Citrix willfully infringed claims
2, 4, and 7 of the ’011 Patent, and that those claims were
not shown to be invalid. The jury also found that Citrix
did not infringe claim 27 of the ’796 Patent. The district
court subsequently denied motions for judgment as a
matter of law (“JMOL”) and a new trial regarding non-
infringement of claim 27 of the ’796 Patent, willful in-
fringement of the asserted claims of the ’011 Patent, and
invalidity with respect to those same claims. The district
court also denied SSL prevailing party status, awarded
prejudgment interest, and precluded the jury from hear-
ing certain testimony.
    SSL appeals the district court’s denial of a new trial
on non-infringement of claim 27 of the ’796 Patent, argu-
ing that the district court erred in its claim construction
of the terms “intercepting” and “destination address,” and
in imposing a set step order requirement for the claim.
SSL also appeals the district court’s finding that it was
not the prevailing party in the litigation overall. Citrix
cross-appeals the district court’s denial of JMOL of no
willful infringement and invalidity of claims 2, 4, and 7 of
the ’011 Patent. Citrix further contests the district court’s
SSL SERVICES, LLC   v. CITRIX SYSTEMS, INC.                3

award of prejudgment interest and asserts that certain of
its evidentiary rulings justify a new trial on willful in-
fringement and damages.
     Based on the “destination address” limitation, we af-
firm the denial of a new trial on non-infringement of claim
27 of the ’796 Patent. Furthermore, we affirm the district
court’s denial of JMOL requesting a finding of no willful
infringement and invalidity of the asserted claims of
the ’011 Patent. We also affirm the denial of a new trial
based on the district court’s evidentiary rulings, and
affirm the award of prejudgment interest. Finally, we
vacate the district court’s denial of prevailing party status
to SSL because we find that SSL is the prevailing party,
and remand for an assessment of costs and fees.
                        I. BACKGROUND
                      A. The SSL Patents
    SSL acquired the ’796 Patent and ’011 Patent from V-
One, Inc. (“V-One”) in June 2005. Both patents are titled
“Multi-Access Virtual Private Network.” ’796 Patent, at
[54] (filed August 26, 1997); ’011 Patent, at [54] (filed
February 26, 1999). The ’011 Patent is a continuation of
the ’796 Patent. The patents contain virtually identical
specifications. The key difference is that the claims of
the ’011 Patent are directed to allowing users to establish
encrypted connections with a server, whereas the claims
of the ’796 Patent are directed to allowing users to estab-
lish encrypted communications with another client com-
puter.
    According to the ’796 Patent, a Virtual Private Net-
work (“VPN”) is “a system for securing communications
between computers over an open network such as the
Internet.” ’796 Patent col. 1 ll. 14–16. The asserted
patents have the same abstract, which states:
    A virtual private network for communicating be-
    tween a server and clients over an open network
4                    SSL SERVICES, LLC   v. CITRIX SYSTEMS, INC.

    uses an applications level encryption and mutual
    authentication program and at least one shim po-
    sitioned above either the socket, transport driver
    interface, or network interface layers of a client
    computer to intercept function calls, requests for
    service, or data packets in order to communicate
    with the server and authenticate the parties to a
    communication and enable the parties to the
    communication to establish a common session
    key. Where the parties to the communication are
    peer-to-peer applications, the intercepted function
    calls, requests for service, or data packets include
    the destination address of the peer application,
    which is supplied to the server so that the server
    can authenticate the peer and enable the peer to
    decrypt further direct peer-to-peer communica-
    tions.
’011 Patent, at [57]; ’796 Patent, at [57].
     The claimed methods and system require an authenti-
cation and encryption program that encrypts computer
files using a “session key” 1 before transmitting data over
the Internet. Once the other client computer has received
the encrypted files, it can decrypt those files using the
same session key. This approach allows the transfer of
encrypted data directly from one client computer to an-
other client computer over the open network.
    For the ’796 Patent, only claim 27 is at issue.           It
states:
    A method of carrying out communications over a
    multi-tier virtual private network, said network

    1   The parties agreed that a “session key” is “a se-
quence of bits that is input into an encryption algorithm
to encrypt data for a session.” SSL Servs., LLC v. Citrix
Sys., Inc., 816 F. Supp. 2d 364, 372 (E.D. Tex. 2011).
SSL SERVICES, LLC   v. CITRIX SYSTEMS, INC.                5

    including a server and a plurality of client com-
    puters, the server and client computers each in-
    cluding means for transmitting data to and
    receiving data from an open network, comprising
    the steps of:
    intercepting function calls and requests for service
    sent by an applications program in one of said cli-
    ent computers to a lower level set of communica-
    tions drivers;
    causing an applications level authentication and
    encryption program said one of said client com-
    puters to communicate with the server, generate a
    session key, and use the session key generated by
    the applications level authentication and encryp-
    tion program to encrypt files sent by the applica-
    tions program before transmittal over said open
    network;
    intercepting a destination address during initiali-
    zation of communications between said one of said
    client computers and a second of said client com-
    puters on said virtual private network;
    causing said applications level authentication and
    encryption program to communicate with the
    server in order to enable the applications level au-
    thentication and encryption program to generate
    said session key;
    transmitting said destination address to said
    server;
    causing said server to communicate with the sec-
    ond of said two client computers;
    enabling said second of said two client computers
    to recreate the session key;
6                     SSL SERVICES, LLC   v. CITRIX SYSTEMS, INC.

    causing said authentication software to encrypt
    files to be sent to the destination address using
    the session key; and
    transmitting the encrypted files directly to the
    destination address.
’796 Patent col. 20 l. 49–col. 22 l. 5.
     In the claimed method, a first client computer runs an
application that attempts to open a communication link
with a second client computer by making “function calls
and requests for service” 2 to a “lower level set of commu-
nication drivers.” The patents describe three basic layers:
(1) the applications level, (2) the transport driver interface
(“TDI”) layer, and (3) the network driver interface (“NDI”)
layer. The patents reference the TDI and NDI layers
together as the lower level set of communication drivers.
    Before the communication drivers can execute the
function call, a software module on the first client com-
puter intercepts the function call. The specification
explains that this separate software module is called a
“shim.” After the shim intercepts the function call, an
“authentication and encryption program” initiates com-
munication with the authentication server and generates
a session key that is used to encrypt data. For the two
client computers to communicate, the “shim” must also
intercept the “destination address” of the second client
computer and transmit it to the server. The server then
communicates with the second client computer, and
provides information that allows the second client com-
puter to recreate the previously generated session key.

    2   An example of a function call or request for ser-
vice is an instruction to “connect” to another client com-
puter. Appellee Br. 12.
SSL SERVICES, LLC   v. CITRIX SYSTEMS, INC.               7

    The first client computer uses the session key to en-
crypt files. The encrypted files are then transmitted
directly to the second client computer over the open
network without having to route the communications
through the authentication server. The second client
computer can decrypt the encrypted files using the recre-
ated session key.
     For the ’011 Patent, claims 2, 4, and 7 are at issue on
appeal. Claim 2 of the ’011 Patent is directed to a multi-
tier VPN. Claim 4 of the ’011 Patent is directed to com-
puter software for installation on a client computer of a
multi-tier VPN. Claim 7 of the ’011 Patent is directed to a
method of carrying out communications over a multi-tier
VPN. All three claims include a limitation of “encrypting
files,” which is the only limitation at issue on appeal for
the ’011 Patent.
    Before SSL acquired the asserted patents from V-One,
Citrix and V-One had entered into a joint development
and licensing agreement that lasted from 2000 to 2003
(“V-One Agreements”). During this time, Citrix also
considered V-One as a potential target for acquisition,
and V-One provided Citrix with access to its technology.
The purpose of the V-One Agreements was to rebrand and
distribute V-One’s SmartGate software. While the V-One
Agreements incorporated the asserted patents, the
SmartGate software did not use the ’011 Patent’s claimed
technology.
              B. The Citrix Accused Products
                     1. The GoTo Products
    SSL asserted that Citrix’s GoTo Products infringe
claim 27 of the ’796 Patent. In 2004, Citrix acquired
ExpertCity.com.    Citrix rebranded ExpertCity.com’s
8                   SSL SERVICES, LLC   v. CITRIX SYSTEMS, INC.

products as GoToAssist, GoToMyPC, and GoToMeeting 3
(collectively, “GoTo Products”). The GoTo Products allow
direct encrypted communication between two computers
while bypassing a broker server that cannot access the
encrypted data. All of the GoTo Products use a broker
server to initialize the communication and that server
carries out communications between the computers.
    GoToMyPC is a desktop virtualization product that
creates a VPN to allow a user to securely access a com-
puter from another remote computer. A user can access
the host computer from a remote computer by transmit-
ting to the broker a request to connect to a client comput-
er based on an internal identification number, e.g.,
MachineNameKey or QuickConnectID. The broker then
identifies the location of the host computer on the GoTo-
MyPC network based on the MachineNameKey or
QuickConnectID. Once the broker identifies the request-
ed host computer, the broker communicates with the host
and remote computer to allow the two computers to
establish a secure session to exchange encrypted data.
    GoToAssist is a remote assistance product that allows
an individual, such as a customer support agent, to access
a customer’s computer securely through a VPN. Although
the customer initially requests assistance, the broker
forwards that request along with an associated SessionID
to available customer support agents so that they may
assist the customer. Once a customer support agent
accepts the help session request, the broker uses the
SessionID to generate a session key and identify the
customer’s computer to allow communication through a
VPN.

    3   GoToMeeting is materially the same as Go-
ToWebinar and GoToTraining. Joint Appendix (“J.A.”)
4017. Therefore, we address all of these products together
as part of GoToMeeting.
SSL SERVICES, LLC   v. CITRIX SYSTEMS, INC.               9

    GoToMeeting is a virtual meeting product that allows
computers to participate in online meetings. When a
meeting is scheduled, the meeting organizer’s computer
communicates with a broker and obtains a MeetingID.
The MeetingID is a short number or link that allows other
participants to join the meeting. The broker uses this
MeetingID to identify participating computers and then
sends information securely to the participants’ computers
through a server.
        2. The Access Gateway and Netscaler Products
    Access Gateway and Netscaler are software products
that enable a computer to communicate securely with a
remote server. These products were developed inde-
pendently by third parties and acquired by Citrix in late
2004 and 2005. On appeal, Citrix does not dispute that
Access Gateway and Netscaler include all the limitations
of the asserted claims of the ’011 Patent, except for the
“encrypt files” limitation.
                 C. Procedural Background
     In April 2008, SSL filed suit in the United States Dis-
trict Court for the Eastern District of Texas alleging that
Citrix’s GoTo Products infringe claim 27 of the ’796 Pa-
tent. In May 2009, SSL amended its complaint to assert
infringement of claims 2, 4, and 7 of the ’011 Patent by
Citrix’s Access Gateway and Netscaler Products.
    On May 18, 2011, the district court held a Markman
hearing. SSL Servs., LLC v. Citrix Sys., Inc., 816 F. Supp.
2d 364, 366 (E.D. Tex. 2011). Relevant to this appeal, the
district court construed the term “destination address” as
used in claim 27 of the ’796 Patent as “the network ad-
dress of a computer or server.” Id. at 385. 4 The court also

    4   The parties also dispute the propriety of the trial
court’s construction of the term “intercepting” as used in
10                   SSL SERVICES, LLC   v. CITRIX SYSTEMS, INC.

construed the term “encrypt files” as used in claims 2, 4,
and 7 of the ’011 Patent as “to render a set of data used by
a program unintelligible without decrypting.” Id. at 384.
    After a jury trial, the jury found that: (1) Citrix’s Go-
To Products did not infringe claim 27 of the ’796 Patent;
(2) Citrix’s Access Gateway and Netscaler products direct-
ly and indirectly infringed claims 2, 4, and 7 of the ’011
Patent; (3) Citrix willfully infringed the asserted claims of
the ’011 Patent; and (4) Citrix had not proved that the
asserted claims of the ’011 Patent were invalid. Conse-
quently, the jury awarded $10 million in damages.
    SSL then filed a motion for: (1) prejudgment interest,
(2) post-judgment interest, (3) enhanced damages, and (4)
entry of final judgment. Citrix filed a motion for entry of
final judgment and an award of prevailing party status.
The district court granted-in-part and denied-in-part
SSL’s motion by: (1) awarding prejudgment interest, (2)
awarding post-judgment interest as agreed by the parties,
(3) awarding an additional $5 million in enhanced dam-
ages for a total of $15 million in damages, and (4) denying
prevailing party status to SSL and refusing to impose
costs on that ground. Addressing Citrix’s motion, the
district court entered a Final Judgment on September 17,
2012, but denied Citrix’s request for prevailing party
status and costs.
    The parties subsequently filed post-trial motions. The
district court denied Citrix’s motions for judgment as a
matter of law (“JMOL”) and for a new trial on non-
infringement, invalidity, willful infringement, and dam-
ages relating to the claims of the ’011 Patent. SSL Servs.,

the ’796 Patent and whether there is a step order required
for practicing the method claimed. For reasons explained
below, we do not resolve the parties’ debate on those
terms.
SSL SERVICES, LLC   v. CITRIX SYSTEMS, INC.               11

LLC v. Citrix Sys., Inc., 940 F. Supp. 2d 480, 485 (E.D.
Tex. 2013). The court also denied SSL’s motion for JMOL
on its infringement claim relating to claim 27 of the ’796
Patent and/or for a new trial on that claim. Id.
    SSL and Citrix filed notices of appeal on May 17,
2013. This court has jurisdiction over both the appeal and
cross-appeal pursuant to 28 U.S.C. § 1295(a)(1) (2012).
                         II. DISCUSSION
                     A. Standard of Review
    The Federal Circuit reviews decisions on motions for
JMOL, motions for a new trial, and evidentiary rulings
under the law of the regional circuit. Verizon Servs. Corp.
v. Cox Fibernet Va., Inc., 602 F.3d 1325, 1331 (Fed. Cir.
2010). Here, the applicable regional circuit is the Fifth
Circuit. Under Fifth Circuit law, we review the denial of
a motion for JMOL de novo while applying the same
standards as the district court. Cambridge Toxicology
Grp., Inc. v. Exnicios, 495 F.3d 169, 179 (5th Cir. 2007).
“[JMOL] is appropriate only when a ‘reasonable jury
would not have a legally sufficient evidentiary basis to
find for the party on that issue.’” Id. (quoting Fed. R. Civ.
P. 50(a)(1)).
    The Fifth Circuit reviews the denial of a new trial for
an abuse of discretion. Industrias Magromer Cueros y
Pieles S.A. v. La. Bayou Furs Inc., 293 F.3d 912, 924 (5th
Cir. 2002). “‘There is no such abuse of discretion unless
there is a complete absence of evidence to support the
verdict.’” Id. (quoting Sam’s Style Shop v. Cosmos Broad.
Corp., 694 F.2d 998, 1006 (5th Cir. 1982)). The Fifth
Circuit also reviews evidentiary rulings for an abuse of
discretion. Huss v. Gayden, 571 F.3d 442, 452 (5th Cir.
2009); Paz v. Brush Engineered Materials, Inc., 555 F.3d
383, 387–88 (5th Cir. 2009).
   Claim construction is a question of law reviewed de
novo. Lighting Ballast Control LLC v. Philips Elecs. N.
12                  SSL SERVICES, LLC   v. CITRIX SYSTEMS, INC.

Am. Corp., 744 F.3d 1272, 1276–77 (Fed. Cir. 2014) (en
banc). Infringement is a question of fact reviewed for
substantial evidence. ACCO Brands, Inc. v. ABA Locks
Mfrs. Co., 501 F.3d 1307, 1311 (Fed. Cir. 2007). Obvi-
ousness is a question of law based on specific factual
findings. Graham v. John Deere Co., 383 U.S. 1, 17–18
(1966). We presume that the jury resolved the underlying
factual disputes in favor of the verdict and review those
factual findings for substantial evidence. Kinetic Con-
cepts, Inc. v. Smith & Nephew, Inc., 688 F.3d 1342, 1356–
57 (Fed. Cir. 2012).
                     B. SSL’s Appeal
     On appeal, SSL asserts that the district court erred in
failing: (1) to grant SSL’s motion for a new trial on in-
fringement of claim 27 of the ’796 Patent, and (2) to find
that SSL was the prevailing party.
                    1. The ’796 Patent
                  a) Destination Address
    The district court construed “destination address” as
“the network address of a computer or server.” SSL
Servs., 816 F. Supp. 2d at 385. In support, it pointed to
the claim language, finding that the phrase “destination
address” refers to the address on the network of the
claimed second client computer. Id. at 386. Turning to
the written description, the district court emphasized the
distinction between the terms “destination” and “destina-
tion address.” Id. The district court explained that to
construe “destination address” the same as “destination”
would write the term “address” out of the former term.
Id. It further clarified that the network address is not
limited to Internet Protocol (“IP”) based protocols, con-
cluding that the claimed invention may use non-IP based
protocols. Id.
SSL SERVICES, LLC   v. CITRIX SYSTEMS, INC.               13

                    (1) Claim Construction
    Although SSL agrees that “[t]he plain meaning of
‘destination address’ is the address of the destination—
here, the second client computer or server,” it asserts that
the district court erred in interpreting the term to require
a network address, and then further equating “network
address” with IP address. Appellant Br. 45–47. SSL
argues that the district court should adopt its construc-
tion: an “[i]dentifier for a desired location.” Appellant Br.
48; see also SSL Servs., 816 F. Supp. 2d at 385. Citrix
responds that the district court correctly construed the
claim language in the context of a claim covering trans-
missions between computers on an open network as a
network address of a computer.
     We agree with Citrix that the district court correctly
construed the term “destination address.” To determine
the scope and meaning of the asserted claims, we look to
the words of the claims, the specification, the prosecution
history, and any relevant extrinsic evidence. Phillips v.
AWH Corp., 415 F.3d 1303, 1315–17 (Fed. Cir. 2005) (en
banc). We find the claim language regarding the destina-
tion address informative. Claim 27 requires “means for
transmitting data to and receiving data from an open
network.” ’796 Patent col. 20 ll. 49–53. The claim further
states “intercepting a destination address during initiali-
zation of communications between said one of said client
computers and a second of said client computers on said
virtual private network,” and “transmitting the encrypted
files directly to the destination address.” Id. at col. 20
l. 66–col. 21 l. 2, col. 22 ll. 4–5. Consequently, the desti-
nation address is the address for a second client computer
on the network, which is the network address of that
specific computer. Furthermore, the language of trans-
mitting the files directly to the destination address that is
intercepted during the initialization of communications
suggests that the destination address allows transmission
to the target client computer without having to distin-
14                  SSL SERVICES, LLC   v. CITRIX SYSTEMS, INC.

guish or differentiate through various internal identifiers
or other methods to determine where those files need to
be delivered. This requires the destination address to be
the network address.
    The written description further supports the district
court’s construction. It states that the most commonly
used set of software routines for the transport or TDI
layer is the transport control protocol (“TCP”)/IP protocol,
where the TCP packages the data into datagrams and
provides addressing functions, and the IP “further pack-
ages those datagrams into packets by adding additional
headers used in routing the packets to a destination
address.” ’796 Patent col. 3 ll. 16–24. The written de-
scription also describes other transport protocols that can
be used, including the user diagram protocol (“UDP”), the
internet control message protocol, and non-IP based
protocols such as Netbeui or IPX. Id. col. 3 ll. 24–28. It
further states that “the shim 55 intercepts IP packets
from applications . . . [and] checks the destination address
(which can be in TCP format, UDP format, and so forth).”
Id. col. 10 ll. 45–48. This language suggests that the
“destination address” is a part of the address portion of
data packets in a network address format. Therefore, we
conclude that the district court correctly construed the
term “destination address” to mean “network address.”
     While SSL alleges that the district court’s construc-
tion limited the format to an IP format, we disagree. As
discussed above, the district court clarified that “the
claimed invention is not limited to IP-based protocols and
may use non-IP based protocols.” SSL Servs., 816 F.
Supp. 2d at 386. Although the district court focused on
how the accused products use IP-based protocols during
its infringement analysis, the district court properly did
not limit the construction of the term “destination ad-
dress” to an IP address.
SSL SERVICES, LLC   v. CITRIX SYSTEMS, INC.               15

                (2) Request for a New Trial
    SSL argues that even if we agree that the district
court correctly construed the term “destination address,”
our analysis of the infringement verdict must continue.
SSL asserts that it is entitled to a new trial if we agree
that any one of the disputed claim constructions was
erroneous, arguing that we must assess the constructions
relating to all the disputed limitations before we can rest
assured that the jury’s non-infringement finding was not
infected by some error. Because the jury returned a
general verdict of non-infringement after hearing multiple
theories of non-infringement, SSL argues that “it would
be impossible for this Court to discern whether the jury
rested its verdict of non-infringement on the erroneous
claim construction.” Appellant Br. 52.
    We agree that the general verdict rule applies with
the same force in patent cases as it does in all other cases.
We also agree that Citrix misreads our decision in Verizon
Servs. Corp. v. Cox Fibernet Va., Inc., 602 F.3d 1325 (Fed.
Cir. 2010), which does not even address the general
verdict rule or reach any conclusions regarding how that
rule might have been implicated—or avoided—on the
facts presented. 5 We find, however, that there is no
evidence in the record from which a good faith argument
can be made that the Citrix GoTo Products’ identifiers are
“network addresses” as that term was construed by the

    5    We specifically conclude that Verizon does not, as
Citrix contends, stand for the proposition that a general
verdict of non-infringement may be affirmed upon a
decision that the district court’s challenged construction
of even one claim term relating to a single claim limita-
tion is correct. That is so only, where, as here, there is no
argument and no evidence that substantial evidence
might have supported a finding of non-infringement
under the first challenged construction which we consider.
16                   SSL SERVICES, LLC   v. CITRIX SYSTEMS, INC.

district court. Because we now affirm that construction,
we conclude that, even if the district court erred in its
construction of the other challenged limitations, the result
the jury reached—the finding of non-infringement—would
not change. In these circumstances, we soundly can base
our conclusion that the non-infringement verdict stands
on the fact that the single network address limitation is
not practiced by the accused products. See Teleflex, Inc. v.
Ficosa N. Am. Corp., 299 F.3d 1313, 1328 (Fed. Cir. 2002)
(“We may affirm the jury’s findings on infringement or
validity issues if substantial evidence appears in the
record supporting the jury’s verdict and if correction of the
errors in a jury instruction on claim construction would
not have changed the result, given the evidence present-
ed.”).
    SSL seems to concede that it must show prejudice in
the trial court’s instructions to the jury regarding the
meaning of a relevant claim term before an erroneous
instruction regarding any such term can justify disturbing
a jury verdict. See, e.g., Ecolab Inc. v. Paraclipse, Inc.,
285 F.3d 1362, 1373 (Fed. Cir. 2002) (“A party seeking to
alter a judgment based on erroneous jury instructions
must establish that ‘those instructions were legally erro-
neous,’ and that ‘the errors had prejudicial effect.’”) (quot-
ing Advanced Display Sys., Inc. v. Kent State Univ., 212
F.3d 1271, 1281 (Fed. Cir. 2000)). It implies, however,
that prejudice must be presumed whenever a general
verdict makes it impossible to discern on which specific
limitation the jury rested its verdict of non-infringement.
The cases upon which SSL relies do not give rise to such a
presumption, however, and we know of no case law that
creates one. The general verdict rule guards against the
threat of a tainted or improper verdict. See SEB S.A. v.
Montgomery Ward & Co., 594 F.3d 1360, 1374 (Fed. Cir.
2010) (“Under the general verdict rule, where one or more
of multiple claims is found legally invalid, a reviewing
court must reverse and order a new trial if [the reviewing
SSL SERVICES, LLC   v. CITRIX SYSTEMS, INC.               17

court is] unable to determine whether the invalid theory
tainted the verdict.”) (citation omitted), aff’d on other
grounds, 134 S. Ct. 2060 (2011). But, the burden to
establish that such a threat exists is on the party chal-
lenging the verdict. Ecolab, 285 F.3d at 1373. SSL has
not satisfied the burden of establishing that an error in
any other claim construction could have changed the
verdict here if we conclude, as we have, that the “destina-
tion address” in claim 27 of the ’796 Patent means the
“network address of a computer or server.”
     While SSL argued that the Citrix GoTo Products’
identifiers would infringe under SSL’s construction of
“destination address” because they are “identifier[s] for a
desired location,” SSL did not argue in its opening brief to
this court that the GoTo Products would still infringe
under the district court’s construction. See Appellant Br.
48–49. Not until its reply did SSL contend that the jury
might have found that the Citrix GoTo Products met the
destination address limitation as construed by the district
court. Appellant Reply Br. 32–33. And, even then, SSL
failed to point to testimony or evidence in the record upon
which such a finding could be predicated. 6 Accordingly,
we find that SSL waived the argument that the jury could
have found that the GoTo Products met the destination
address limitation under the district court’s construction.
See SmithKline Beecham Corp. v. Apotex Corp., 439 F.3d
1312, 1319 (Fed. Cir. 2006) (“Our law is well established
that arguments not raised in the opening brief are
waived.” (citation omitted)).
    Even if this argument was not waived, moreover, all
relevant evidence supports the finding that the Citrix

    6   While SSL cites to the trial court’s refusal to grant
summary judgment or otherwise take the question of
infringement from the jury, those orders are not the same
as record evidence.
18                  SSL SERVICES, LLC   v. CITRIX SYSTEMS, INC.

GoTo Products’ identifiers 7 are not “network addresses”
that are intercepted during initialization of communica-
tions between the first and second client computer where
the encrypted files are transmitted directly. First, there
is no dispute that the Citrix GoTo Identifiers are not IP
addresses. The GoTo Products, however, use IP-based
protocols. Accordingly, the network addresses of the
client computers running the GoTo Products necessarily
are the respective IP addresses. Therefore, because the
GoTo Identifiers are not the IP addresses of the client
computers, the record commands the finding that the
Citrix GoTo Products do not contain the “destination
address” limitation. Second, the first client computer
never knows the IP address of the second client computer
based on the GoTo Identifiers. Only the intermediary,
such as a broker or communications server, knows the
second client computer’s IP address. Accordingly, the
GoTo Products could neither intercept nor provide the
network address to direct the encrypted files. Because
the GoTo Identifiers are not the IP address of the second
client computer, the “destination address” limitation is
simply not met. SSL proffers no facts or evidence to
support a contrary conclusion. Consequently, we affirm
the denial of SSL’s motion for a new trial on infringement
of the ’796 Patent, without considering the “intercepting”
and step order limitations. 8
                   2. Prevailing Party
   We review the district court’s determination of
whether a party is the “prevailing party” under Federal
Rule of Civil Procedure 54(d) and 35 U.S.C. § 285 de novo.

     7  MeetingID, SessionID, MachineNameKey, or
QuickConnectID (collectively, “GoTo Identifiers”).
    8   We do not imply that the trial court’s construction
of those terms was erroneous, we simply do not reach
those questions.
SSL SERVICES, LLC   v. CITRIX SYSTEMS, INC.                19

See Shum v. Intel Corp., 629 F.3d 1360, 1367 (Fed. Cir.
2010); Inland Steel Co. v. LTV Steel Co., 364 F.3d 1318,
1320 (Fed. Cir. 2004). In a patent case, Federal Circuit
law governs the determination of which party has pre-
vailed. 35 U.S.C. § 285 (“The court in exceptional cases
may award reasonable attorney fees to the prevailing
party.”); Fed. R. Civ. P. 54(d)(1) (“Unless a federal statute,
these rules, or a court order provides otherwise, costs—
other than attorney’s fees—should be allowed to the
prevailing party”); Manildra Milling Corp. v. Ogilvie
Mills, Inc., 76 F.3d 1178, 1182 (Fed. Cir. 1996). To be the
“prevailing party,” we require: (1) that the party “received
at least some relief on the merits,” and (2) “[t]hat relief
must materially alter the legal relationship between the
parties by modifying one party’s behavior in a way that
‘directly benefits’ the opposing party.” Shum, 629 F.3d at
1367 (citations omitted); see also Farrar v. Hobby, 506
U.S. 103, 111–12 (1992) (“[A] plaintiff ‘prevails’ when
actual relief on the merits of his claim materially alters
the legal relationship between the parties by modifying
the defendant’s behavior in a way that directly benefits
the plaintiff.”). A party does not need to prevail on all
claims to qualify as the prevailing party. See Kemin
Foods, L.C. v. Pigmentos Vegetales Del Centro S.A. de
C.V., 464 F.3d 1339, 1347–48 (Fed. Cir. 2006).
     The district court found that Citrix prevailed on non-
infringement of the ’796 Patent and SSL prevailed on
willful infringement of the ’011 Patent. Accordingly, the
district court concluded that neither party is the prevail-
ing party because “both parties achieved some success
and sustained some failure.” J.A. 62–63. It then held
that each side shall bear its own costs. SSL asserts that
it is the prevailing party as it obtained a judgment that
Citrix willfully infringed the asserted claims of the ’011
Patent. Citrix requests that we affirm the district court’s
conclusion that neither party prevailed and that the
district court did not abuse its discretion in denying costs
20                  SSL SERVICES, LLC   v. CITRIX SYSTEMS, INC.

because Citrix “received greater relief by winning on the
primary ‘796 patent.” Appellee Br. 57. 9
     We find that the district court erred in holding that
SSL was not the prevailing party. It is well-established
that there is a distinction between being eligible for fees
as the prevailing party and the discretionary decision to
award fees. See Farrar, 506 U.S. at 111–13; Manildra, 76
F.3d at 1182–83. A party “prevails” when “actual relief on
the merits of his claim materially alters the legal rela-
tionship between the parties . . . in a way that directly
benefits the [party].” Farrar, 506 U.S. at 111–12. For
example, the Supreme Court in Farrar found that a
plaintiff who won nominal damages was still the prevail-
ing party because a judgment for damages in any amount
modified the defendant’s behavior to the plaintiff’s bene-
fit. Id. The Court explained that the degree of the overall
success impacts only the reasonableness of the fee award.
Id. Therefore, a district court may award minimal or no
fees after considering the amount of success to the pre-
vailing party. Id. at 115–16.
    In this case, the district court found that SSL proved
willful infringement of the three asserted claims of
the ’011 Patent by Citrix’s Access Gateway and Netscaler
Products. In light of this infringement finding, the jury
awarded lump-sum damages of ten million dollars, which
the district court enhanced to a total of fifteen million
dollars. See SSL Servs., 940 F. Supp. 2d at 486; J.A. 60.
In contrast, while Citrix did obtain a finding of non-
infringement as to claim 27 of the ’796 Patent, it did not
prove the asserted claims of the ’011 Patent were invalid,
and it was found to have infringed the ’011 Patent.

     9  Citrix does not argue that the trial court erred in
denying it prevailing party status, only that it was correct
to find that neither party is a prevailing party in the
circumstances at issue here.
SSL SERVICES, LLC   v. CITRIX SYSTEMS, INC.               21

     Despite some success by Citrix in defending against
some of SSL’s claims, we agree with SSL that it is the
prevailing party. SSL has a judgment for damages
against Citrix. This judgment is a “relief on the merits
[that] materially alters the legal relationship” of the
parties. Farrar, 506 U.S. at 111; Manildra Milling Corp.,
76 F.3d at 1182 (“[A] judgment for damages in any
amount modifies the defendant’s behavior to the plain-
tiff’s benefit.”). Even though SSL did not succeed on all of
its infringement claims, this does not change the outcome.
See Kemin, 464 F.3d at 1347–48 (upholding a district
court’s finding that a patent holder is the prevailing party
when it “prevailed on one of its two infringement claims
(resulting in a damages award and a permanent injunc-
tion),” and the patent holder “prevailed on [the accused
infringer’s] invalidity and unenforceability claims.”). In
view of the parties’ respective successes, we find SSL is
the “prevailing party” for purposes of Federal Rule of Civil
Procedure 54(d) and 35 U.S.C. § 285.
    Finding SSL to be the prevailing party, however, does
not automatically entitle it to any particular level of fees.
See Shum, 629 F.3d at 1366 (“An award of costs thus
involves two separate inquir[i]es. First, who is the ‘pre-
vailing party’ within the meaning of Rule 54(d)(1). Sec-
ond, how much (if any) costs should be awarded to the
prevailing party.” (citation omitted)). Accordingly, we
vacate the district court’s finding of no prevailing party
and remand so that the district court may assess the
amount of fees or costs to award to SSL in connection with
the claims on which it prevailed.
                    C. Citrix’s Cross-Appeal
    On cross-appeal, Citrix argues that this court should
grant JMOL of non-infringement or remand for a new
trial on SSL’s claims under the ’011 Patent. Citrix raises
several issues in its cross-appeal: (1) non-infringement
based on the “encrypt files” limitation; (2) invalidity; (3)
22                   SSL SERVICES, LLC   v. CITRIX SYSTEMS, INC.

willful infringement; (4) the propriety of the district
court’s evidentiary ruling regarding expert reliance on the
V-One Agreements; and (5) the award of prejudgment
interest. We address these issues below.
                     1. The ’011 Patent
                     a) “Encrypt Files”
     The asserted claims of the ’011 Patent include a limi-
tation to “encrypt files.” The district court construed the
term as “to render a set of data used by a program unin-
telligible without decrypting.” SSL Servs., 816 F. Supp.
2d at 384–85. Citrix did not challenge this claim con-
struction. In explaining its construction, the district court
stated that “the term cannot be construed so broadly that
it would include ‘packets,’ ‘datagrams’ or other types of
communications. However, this does not mean that an
accused device that encrypts packets automatically falls
outside of the scope of the claims, but instead requires
that at a minimum the encryption must occur at the file
level.” Id. Furthermore, the district court concluded
“that one of ordinary skill in the art would interpret ‘files’
as ‘a set of data used by a program.’” Id. at 385. The
district court later denied Citrix’s request for JMOL on
non-infringement of the ’011 Patent. SSL Servs., 940 F.
Supp. 2d at 485.
    In considering Citrix’s motion for JMOL of non-
infringement, the district court found that the jury’s
infringement verdict—that the Access Gateway and
Netscaler products “encrypt files” as construed by the
court—was supported by substantial evidence. Id. at
494–95. In support, the court pointed to the testimony of
SSL’s expert and demonstrative slides, which provided
evidence from which a jury could determine that the
products encrypted files. Id.
    Citrix argues that the jury’s infringement verdict is
not supported by substantial evidence that Citrix’s Access
SSL SERVICES, LLC   v. CITRIX SYSTEMS, INC.              23

Gateway and Netscaler products “encrypt files.” Citrix
focuses on the difference between encrypting files and
encrypting “packets.” It asserts that SSL’s expert provid-
ed no evidence on the “encrypt files” limitation. SSL
disagrees and states that the testimony of its expert
combined with the exhibits shown to the jury provide
substantial evidence to support finding that Citrix’s
products practice this limitation.
    We agree that substantial evidence supports the jury’s
verdict of infringement. Although the district court
distinguished between encrypting files and packets, it
construed the term “encrypt files” as “to render a set of
data used by a program unintelligible without decrypt-
ing.” SSL Servs., 816 F. Supp. 2d at 384. Citrix does not
dispute this construction. The testimony of SSL’s expert
on the encryption of files supports the conclusion that the
Access Gateway and Netscaler products do, in fact, “ren-
der a set of data used by a program unintelligible without
decrypting.”
    SSL’s expert, Dr. Kelly, testified that the Access
Gateway and Netscaler products used encrypted commu-
nications, and that the data it sends over the Internet to
the server is encrypted. Specifically, he explained that
the data flows from an application through a shim to the
Net6VPN.exe program where it is encrypted. Dr. Kelly
also relied on demonstrative slides to show the flow of
data from an application to the encryption program
through a shim where that encrypted data is then sent to
the server. Based on this evidence, we affirm the district
court’s denial of Citrix’s motion for JMOL of non-
infringement because we find substantial evidence to
support the jury verdict of infringement of the claims of
the ’011 Patent.
             b) Invalidity of the SSL Patents
    On appeal, Citrix asserts that claims 2, 4, and 7 of the
’011 Patent would have been obvious under Takahashi et
24                  SSL SERVICES, LLC   v. CITRIX SYSTEMS, INC.

al., “Communication Method with Data Compression and
Encryption for Mobile Computing Environment”
(“Takahashi”) in view of Request for Comment on the
Generic Security Service Application Program Interface
(GSS-API) (“RFC1508”). The parties dispute whether: (1)
Takahashi discloses applications level authentication and
encryption software, and (2) RFC1508 discloses how to
perform mutual authentication. Claims 2, 4, and 7 all
require “applications level encryption and authentication
software.” 10 ’011 Patent col. 13 ll. 8–9, 52–53; col. 14
ll. 55–56.
    A patent claim is invalid as obvious if the claimed in-
vention as a whole would have been obvious to a person
having ordinary skill in the art at the time of the inven-
tion. 35 U.S.C. § 103. Obviousness is a question of law
based on specific factual findings, including: (1) the scope
and content of the prior art; (2) differences between the
claimed invention and the prior art; (3) the level of ordi-
nary skill in the art; and (4) any relevant secondary
considerations, including commercial success, long-felt
but unsolved needs, and the failure of others. Graham,
383 U.S. at 17–18. We presume that the jury resolved the
underlying factual disputes in favor of the verdict and
review those factual findings for substantial evidence.
Kinetic Concepts, 688 F.3d at 1356–57. A party must
prove an invalidity defense by clear and convincing evi-
dence. Microsoft Corp. v. i4i Ltd. P’ship, 131 S. Ct. 2238,
2242 (2011). We review the ultimate legal conclusion of
obviousness de novo in light of the underlying factual
findings. Kinetic Concepts, 688 F.3d at 1356–57.
  Citrix argues that the district court erred in denying
JMOL on invalidity based on Takahashi in view of

     10 Claim 7 uses slightly different wording of an “ap-
plications level authentication and encryption program.”
’011 Patent col. 14 ll. 55–56.
SSL SERVICES, LLC   v. CITRIX SYSTEMS, INC.            25

RFC1508. While Citrix asserts that Takahashi discloses
the use of encryption software at the applications level,
SSL argues that the district court correctly denied JMOL
on invalidity of the ’011 Patent as Takahashi does not
disclose the use of authentication and encryption software
on the applications level. The district court agreed with
SSL and found that the object identified in Takahashi
was not on the applications level. SSL Servs., 940 F.
Supp. 2d at 499–500.
    We agree with SSL that substantial evidence supports
the finding that Takahashi does not disclose the authenti-
cation and encryption software at the applications level.
Takahashi discloses a “Communication Method with Data
Compression and Encryption for Mobile Computing
Environment.” J.A. 6865. This method uses a “secure
communication add-in program” to perform encryption.
J.A. 6866. This secure communication add-in program
“intercepts the send command of the application program
from WinSock API, compresses its data in the send com-
mand, encrypts the data, and then returns this command
to WinSock DLL, which is properly transferred.” J.A.
6866–67.
    Takahashi Figure 8 (reproduced below) discloses the
program structure for the compression and encryption
methods.
26                  SSL SERVICES, LLC   v. CITRIX SYSTEMS, INC.

J.A. 6870. Looking at this figure, SSL’s expert testified
that the encryption software is not located at the applica-
tions level. J.A. 2368–70. The figure shows the applica-
tions (AP) separate from the “Compress and Encryption
process.” J.A. 6870.
    Citrix argues that the software in Takahashi is on the
applications level because it is above the TDI layer.
Appellee Br. 63. We disagree. That software is located
above the TDI level does not make it part of the applica-
tions level. For example, the ’011 Patent explains that
the Winsock element is located above the TDI level, but
the Winsock is not deemed part of the applications level.
See J.A. 110 (col. 3 ll. 60–64). SSL’s expert also testified
that the Winsock software, which appears above the TDI
level, is not in the applications level. J.A. 1261–63.
Therefore, Citrix’s argument that, if Takahashi discloses
software above the TDI layer, it is automatically a part of
the applications level is unpersuasive. Furthermore, as
seen in Figure 8, Takahashi separates the applications
SSL SERVICES, LLC   v. CITRIX SYSTEMS, INC.               27

from the encryption software at issue. Because we find
substantial evidence exists that Takahashi does not
disclose an applications level authentication and encryp-
tion software, we do not address whether RFC1508 dis-
closes mutual authentication. Therefore, we affirm the
district court’s denial of JMOL for invalidity because
Citrix did not show by clear and convincing evidence that
claims 2, 4, and 7 were invalid as obvious by Takahashi in
view of RFC1508.
                    c) Willful Infringement
    To establish willful infringement, the patent holder
must show clear and convincing evidence that: (1) “the
infringer acted despite an objectively high likelihood that
its actions constituted infringement” and (2) “that this
objectively-defined risk . . . was either known or so obvi-
ous that it should have been known to the accused in-
fringer.” In re Seagate Tech., LLC, 497 F.3d 1360, 1371
(Fed. Cir. 2007) (en banc). We review the first objective
prong de novo and the second subjective prong for sub-
stantial evidence. See Bard Peripheral Vascular, Inc. v.
W.L. Gore & Assocs., 682 F.3d 1003, 1005–08 (Fed. Cir.
2012), cert. denied, 133 S. Ct. 932 (2013).
     The district court first found that Citrix acted despite
an objectively high likelihood that its actions constituted
infringement of a valid patent. The jury then addressed
the subjective prong—whether Citrix actually knew or
should have known that its actions constituted an unjusti-
fiably high risk of infringement of a valid and enforceable
patent. The jury found that Citrix willfully infringed the
’011 Patent. For the following reasons, Citrix has failed
to show that the district court erred in denying its motion
for JMOL regarding willful infringement. Accordingly, we
affirm the district court’s willful infringement determina-
tion.
28                   SSL SERVICES, LLC   v. CITRIX SYSTEMS, INC.

                    (1) Objective Prong
    In concluding that Citrix acted despite an objectively
high likelihood that its actions constituted infringement
of a valid patent, the district court found that Citrix’s
alleged defenses of invalidity and non-infringement were
not reasonable.
     Citrix argues that, because its non-infringement and
invalidity defenses were reasonable, the district court
erred in denying JMOL of no willful infringement. In
support, Citrix relies on the fact that the district court did
not grant summary judgment and that the United States
Patent and Trademark Office (“USPTO”) rejected the
relevant claims of the ’011 Patent multiple times over the
same prior art references presented at trial during the
initial phases of an ex parte reexamination. SSL re-
sponds that it satisfied its burden of proving that Citrix’s
defenses of non-infringement and invalidity were objec-
tively unreasonable. SSL contends that there was ample
evidence presented at trial, including expert testimony,
which shows Citrix’s non-infringement defense based on
the “encrypt files” limitation and its invalidity defenses
involving Takahashi were meritless. SSL further argues
that the ex parte reexamination supports its own position
that Citrix acted unreasonably because the USPTO
ultimately rejected Citrix’s invalidity arguments under
the lower preponderance of the evidence standard. SSL
asserts that if Citrix was unable to prove the ’011 Patent
was invalid under the lower preponderance of the evi-
dence standard employed by the USPTO, it is unreasona-
ble for Citrix to re-raise such arguments under the clear
and convincing standard at the district court.
    The district court’s finding that SSL met the thresh-
old objective prong is supported by the record. The jury
soundly rejected Citrix’s invalidity argument and non-
infringement arguments. As noted above, the Takahashi
reference does not disclose an applications level encryp-
SSL SERVICES, LLC   v. CITRIX SYSTEMS, INC.               29

tion program. Although not dispositive, the USPTO
similarly found Citrix’s invalidity arguments unfruitful,
despite the lower preponderance of the evidence standard.
Further, we recognize that most of the limitations for the
asserted claims of the ’011 Patent were uncontested. And
we find that infringement of the only limitation raised on
appeal of “encrypt files” was clearly supported by sub-
stantial evidence. Accordingly, we agree with the district
court that SSL satisfied the objective prong.
                     (2) Subjective Prong
    After the district court found the objective prong satis-
fied, it submitted the issue of willful infringement to the
jury. The jury returned a verdict finding that Citrix
willfully infringed the relevant claims of the ’011 Patent.
SSL and the district court pointed to several items to
support the jury’s finding of willfulness, including the V-
One Agreements, V-One executives’ confirmation of
Citrix’s knowledge of the ’011 Patent, Citrix’s full access
to the V-One technology, and a Citrix executive’s admis-
sion of knowledge of the ’011 Patent based on the V-One
Agreements.
    Citrix disagrees, claiming that substantial evidence
does not support the subjective prong of willfulness. It
asserts that there is no evidence that anyone at Citrix had
read the ’011 Patent nor that Citrix should have investi-
gated that patent regarding Access Gateway and Netscal-
er. Further, it states that the V-One Agreements were
only distribution agreements for the SmartGate product,
which did not embody the ’011 Patent.
    We agree that SSL presented substantial evidence
that Citrix knew of the objectively high risk that its
products infringed the asserted claims of the ’011 Patent.
SSL presented evidence that Citrix first became aware of
the ’011 Patent in 2000 based on the V-One Agreements.
SSL Servs., 940 F. Supp. 2d at 504. Citrix negotiated and
executed the agreements with V-One. Id. The V-One
30                   SSL SERVICES, LLC   v. CITRIX SYSTEMS, INC.

Agreements specifically identified and incorporated
the ’011 Patent. Id. Furthermore, a former Citrix execu-
tive, Bill Mangum, testified that he knew of the ’011
Patent as a result of Citrix’s relationship with V-One. Id.
A V-One executive also testified that Citrix knew of
the ’011 Patent and that V-One had provided Citrix with
access to its technology relating to the ’011 Patent. Id.
Based on this evidence, we do not find that the district
court erred in denying Citrix’s motion for JMOL on the
subjective prong of SSL’s claim of willful infringement.
     Citrix argues that it should receive a new trial on
willfulness because the court prevented the jury from
hearing fact testimony from its Chief Engineer, Marco
Murgia, that: (1) Citrix believed in good faith that its
products were non-infringing; and (2) that reexamination
proceedings had been initiated at the PTO. The district
court held that Murgia could not opine on whether the
accused products infringed claims of the ’011 Patent to
support Citrix’s good faith belief of non-infringement.
SSL Servs., 940 F. Supp. 2d at 500–01. Specifically, the
district court found that “it would be significantly prejudi-
cial to allow a fact witness[ ] to testify as to his opinions
on the issues of infringement and validity, particularly
when the testimony expressing such an opinion would be
rendered without regard for how this Court has construed
the claims.” Id. at 500. The district court also precluded
testimony on the then ongoing reexaminations, stating
that its limited probative value (as the proceedings were
still ongoing at that time) was substantially outweighed
by its prejudicial effect. Id. at 501. We find that the
district court did not abuse its discretion in precluding
Murgia’s testimony on these items.
    As mentioned above, we review a district court’s ex-
clusion of evidence under the law of the regional circuit.
Where evidence is excluded because its probative value is
outweighed by its potential prejudice under Rule 403 of
the Federal Rules of Evidence, the Fifth Circuit reviews
SSL SERVICES, LLC   v. CITRIX SYSTEMS, INC.                  31

the trial court’s determination for “clear abuse of discre-
tion” resulting in substantial prejudice. Wellogix Inc. v.
Accenture LLP, 716 F.3d 867, 882 (5th Cir. 2013). We
cannot say the district court abused its discretion in
excluding this evidence. As for Murgia’s personal beliefs
regarding non-infringement, the fact that they were
beliefs formed by a lay person without the benefit of the
court’s claim construction determinations rendered them
of little probative value and potentially prejudicial.
     The same is true with respect to the evidence of activ-
ity in an ongoing reexamination. As we noted recently,
“this court’s precedent has often warned of the limited
value of actions by the PTO” to establish a good faith
belief of invalidity. VirnetX, Inc. v. Cisco Sys., Inc., No.
13-1489, 2014 U.S. App. LEXIS 17748, at *32 (Fed. Cir.
Sept. 16, 2014) (citing Hoechst Celanese Corp. v. BP
Chems. Ltd., 78 F.3d 1575, 1584 (Fed. Cir. 1996) (“[G]rant
by the examiner of a request for reexamination is not
probative of unpatentability.”) and Acoustical Design, Inc.
v. Control Elecs. Co., 932 F.2d 939, 942 (Fed. Cir. 1991)
(“[I]nitial rejection by the [PTO] . . . hardly justifies a good
faith belief in the invalidity of the claims.”)). As we did in
VirnetX, we conclude that the district court did not abuse
its discretion in finding that the probative value of unfin-
ished agency proceedings was substantially outweighed
by the risk of unfair prejudice to the patentee and the
potential for misleading the jury, thereby justifying
exclusion under Federal Rule of Evidence 403. See, e.g.,
SynQor, 709 F.3d at 1380 (finding no abuse of discretion
for excluding non-final reexamination evidence as being
“confusing and more prejudicial than probative”); Calla-
way Golf Co. v. Acushnet Co., 576 F.3d 1331, 1342–43
(Fed. Cir. 2009) (finding the probative value of a co-
pending reexamination marginal and the effect likely to
be highly prejudicial). For these reasons, we affirm the
district court’s exclusion of this evidence.
32                  SSL SERVICES, LLC   v. CITRIX SYSTEMS, INC.

            d) Evidentiary Ruling on Damages
    Again applying Fifth Circuit law, we review eviden-
tiary rulings and the denial of a motion for a new trial for
an abuse of discretion. Huss, 571 F.3d at 452; Paz, 555
F.3d at 387–88. Citrix argues that the district court
abused its discretion by allowing SSL’s damages expert to
rely on the V-One Agreements, which were not patent
licenses, in his damages analysis. These 2000 and 2001
agreements were between V-One and Citrix, and refer-
enced the ’011 Patent as intellectual property that was
relevant to the technology underlying the agreements.
Though the agreements only supplied Citrix with distri-
bution rights to the Smartgate software product and
provided no patent license, the court found the agree-
ments “sufficiently ‘comparable’ to be probative of the
hypothetical negotiation” as they involve the actual
parties, relevant technology, and were close in time to the
date of the hypothetical negotiation. SSL Servs., 940 F.
Supp. 2d at 489–90. The district court also concluded that
the information in the licenses was relevant to other
Georgia Pacific factors, including V-One’s licensing poli-
cies and the parties’ respective competitive positions. Id.
at 490; Georgia-Pacific Corp. v. U.S. Plywood Corp., 318
F. Supp. 1116, 1120 (S.D.N.Y. 1970).
    Although both sides used the V-One Agreements in
their analyses, 11 Citrix now contends that SSL should not
have been allowed to rely on these agreements. But
Citrix’s own expert stated that these agreements were the
closest comparable information for a hypothetical negotia-
tion that he could find. SSL Servs., 940 F. Supp. 2d at
490. And, SSL’s expert expressly addressed the differ-

     11Citrix’s damages expert used a 1% royalty rate
based on the V-One Agreements, whereas SSL’s damages
expert used a 2.5 to 3% royalty rate based on those same
agreements.
SSL SERVICES, LLC   v. CITRIX SYSTEMS, INC.             33

ences between the license negotiations and any hypothet-
ical negotiations, thereby clarifying for the jury where
such differences might exist and the limited value of such
evidence.
    As the district court concluded, the V-One agreements
are sufficiently probative of the circumstances which
would surround a hypothetical negotiation to be admissi-
ble. We do not discount all agreements regarding the
technology at issue other than licenses addressing the
price terms and circumstances at issue in the case at bar.
The trial court carefully assessed the probative value of
the V-One agreements and properly concluded that any
issues regarding their fit to the precise facts presented
should be addressed by way of cross-examination. We
agree. In these circumstances, we find that the district
court did not abuse its discretion in allowing SSL’s expert
to rely on the V-One Agreements.
                    e) Prejudgment Interest
    “Upon finding for the claimant the court shall award
the claimant damages adequate to compensate for the
infringement, but in no event less than a reasonable
royalty for the use made of the invention by the infringer,
together with interest and costs as fixed by the court.” 35
U.S.C. § 284. “[P]rejudgment interest should be awarded
under § 284 absent some justification for withholding
such an award.” Gen. Motors Corp. v. Devex Corp., 461
U.S. 648, 657 (1983). The purpose of prejudgment inter-
est is to place the patentee in as good a position as he
would have been had the infringer paid a reasonable
royalty rather than infringe. Beatrice Foods v. New
England Printing, 923 F.2d 1576, 1580 (Fed. Cir. 1991).
We review the award of prejudgment interest for an abuse
of discretion. Gen. Motors Corp., 461 U.S. at 657.
    The district court awarded prejudgment interest in
the amount of $4.5 million calculated to 2004, when the
infringement began. Citrix alleges that awarding pre-
34                  SSL SERVICES, LLC   v. CITRIX SYSTEMS, INC.

judgment interest was an abuse of discretion because it
did not receive notice of potential infringement until the
filing of the complaint in May 2009. It asserts that SSL
delayed bringing the lawsuit, and should not be rewarded
for that delay. As part of the willful infringement finding
discussed above, however, the district court found that
Citrix knew of the ’011 Patent as early as 2000, when it
entered into the V-One Agreements. Consequently, we
find that the district court did not abuse its discretion in
awarding prejudgment interest back to 2004—the date
the infringement began. By awarding SSL prejudgment
interest to 2004, the district court placed SSL in the
position it would have been in had Citrix paid a reasona-
ble royalty upon notice of the ’011 Patent and its rele-
vance to the technology it chose to market.
                     III. CONCLUSION
     For the reasons stated above, we affirm the district
court’s judgment of non-infringement of the ’796 Patent,
willful infringement of the ’011 Patent, no invalidity of
the ’011 Patent, award of prejudgment interest, and find
no error in its evidentiary rulings. We also vacate the
district court’s finding of no prevailing party and remand
for further proceedings consistent with this opinion.
  AFFIRMED-IN-PART, VACATED-IN-PART, AND
                REMANDED