Source: s3://data.kl3m.ai/documents/govinfo/USCOURTS/USCOURTS-ca13-15-01470/USCOURTS-ca13-15-01470-0/pdf.json

Nature of Suit Code: 830
Nature of Suit: Patent
Cause of Action: 

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United States Court of Appeals 

for the Federal Circuit ______________________ 

MENTOR GRAPHICS CORPORATION, 

AN OREGON CORPORATION,

Plaintiff-Cross-Appellant

v.

EVE-USA, INC., A DELAWARE CORPORATION, 

SYNOPSYS EMULATION AND VERIFICATION 

S.A.S., FORMED UNDER THE LAWS OF FRANCE, 

SYNOPSYS, INC., A DELAWARE CORPORATION,

Defendants-Appellants

______________________ 

2015-1470, 2015-1554, 2015-1556

______________________ 

Appeals from the United States District Court for the 

District of Oregon in Nos. 3:10-cv-00954-MO, 3:12-cv01500-MO, 3:13-cv-00579-MO, Judge Michael W. 

Mosman.

______________________ 

Decided: March 16, 2017 

______________________ 

MARK E. MILLER, O’Melveny & Myers LLP, San Francisco, CA, argued for plaintiff-cross-appellant. Also represented by ANNE E. HUFFSMITH, LUANN LORAINE SIMMONS. 

E. JOSHUA ROSENKRANZ, Orrick, Herrington & Sutcliffe LLP, New York, NY, argued for defendantsappellants. Also represented by DANIEL A. RUBENS,

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2 MENTOR GRAPHICS CORPORATION v. EVE-USA, INC. 

ANDREW D. SILVERMAN; ROBERT M. LOEB, ERIC SHUMSKY, 

Washington, DC; INDRA NEEL CHATTERJEE, VICKI L.

FEEMAN, TRAVIS JENSEN, SCOTT T. LONARDO, Menlo Park, 

CA; WILLIAM H. WRIGHT, Los Angeles, CA.

SEAN C. CUNNINGHAM, DLA Piper LLP (US), San Diego, CA, for amici curiae Hewlett-Packard Company, 

Aruba Networks, Inc., NETGEAR, Inc., Newegg Inc., 

Oracle America, Inc., Ruckus Wireless, Inc., Safeway Inc., 

SAS Institute Inc., Varian Medical Systems, Inc., VeriFone, Inc., VIZIO, Inc. 

______________________ 

Before LOURIE, MOORE, and CHEN, Circuit Judges.

MOORE, Circuit Judge. 

The present appeal arises from litigation in the District of Oregon between Mentor Graphics Corp. (“Mentor”) 

and Synopsys, Inc., Synopsys Emulation and Verification 

S.A.S., and EVE-USA, Inc. (“EVE”) (collectively, “Synopsys”).1 Mentor asserted several patents against Synopsys, 

including U.S. Patent Nos. 6,240,376 (“the ’376 patent”), 

6,947,882 (“the ’882 patent”), 6,009,531 (“the ’531 patent”), and 5,649,176 (“the ’176 patent”). Synopsys asserted two patents against Mentor—U.S. Patent Nos. 

6,132,109 (“the ’109 patent”) and 7,069,526 (“the ’526 

patent”). 

The ’376 patent was the only patent tried to the jury. 

Prior to trial, the district court granted summary judgment barring Synopsys from challenging the ’376 patent’s 

validity because of assignor estoppel. It also granted 

Synopsys’ motion in limine precluding Mentor from 

 

1 EVE is a subsidiary of Synopsys. References to 

Synopsys refer to all the Synopsys and EVE entities 

unless otherwise noted.

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MENTOR GRAPHICS CORPORATION v. EVE-USA, INC. 3

introducing evidence of willful infringement. The jury 

found in favor of Mentor and found damages of approximately $36,000,000. Synopsys appeals the infringement 

verdict, the damages award, and the summary judgment 

of assignor estoppel. Mentor cross-appeals the motion in 

limine regarding willfulness.

The district court granted summary judgment on the 

remaining patents prior to trial. It held that Synopsys’ 

’109 patent was indefinite and Synopsys’ ’526 patent 

lacked patent-eligible subject matter. Synopsys appeals 

both decisions. The district court also held that the 

claims of Mentor’s ’882 patent lacked written description 

support and its infringement allegations relating to the 

’531 and ’176 patents were barred by claim preclusion. 

Mentor cross-appeals both decisions.

We hold there was substantial evidence to support the 

jury’s infringement verdict regarding the ’376 patent and 

affirm the district court’s denial of judgment as a matter 

of law. We affirm the damages award. We affirm the 

summary judgment that assignor estoppel bars Synopsys 

from challenging the validity of the ’376 patent. We 

reverse the summary judgment that Synopsys’ ’109 patent 

is indefinite. We affirm the summary judgment that 

Synopsys’ ’526 patent lacks patent-eligible subject matter. 

We vacate the motion in limine precluding Mentor from 

presenting evidence of willful infringement. We reverse 

the summary judgment that Mentor’s ’882 patent lacks 

written description support. Finally, we reverse the 

summary judgment that Mentor’s infringement allegations regarding the ’531 and ’176 patents are barred by 

claim preclusion. 

I. BACKGROUND

Every patent in this case involves simulation/emulation technology. The parties have a complicated litigation history, and only the relevant portions 

thereof are addressed here. In 1998, Mentor filed the 

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4 MENTOR GRAPHICS CORPORATION v. EVE-USA, INC. 

application that would become the ’376 patent. The two 

inventors, Dr. Alain Raynaud and Dr. Luc Burgun, were 

Mentor employees and assigned the invention to Mentor. 

Dr. Raynaud and Dr. Burgun subsequently left Mentor 

and founded EVE, with Dr. Burgun serving as president 

and CEO and Dr. Raynaud serving as a Technology 

Center Director. In 2006, Mentor sued EVE for infringement of the ’376, ’531, and ’176 patents, alleging EVE’s 

“ZeBu” emulation and verification system infringed the 

patents. Mentor and EVE settled prior to trial, and EVE 

obtained a license to the three patents. The license 

contained a provision terminating the license if EVE were 

acquired by another company in the emulation industry. 

In 2012, Mentor learned Synopsys was in discussions 

to acquire EVE. Mentor’s CEO contacted his counterpart 

at Synopsys and offered to waive the confidentiality 

provision of the Mentor-EVE license to inform Synopsys 

that the license would terminate if Synopsys acquired 

EVE. Synopsys and EVE subsequently filed a declaratory 

judgment action, seeking a declaration that the ’531, ’176, 

and ’376 patents were invalid and not infringed. One 

week later, Synopsys acquired EVE. Mentor answered 

the declaratory judgment complaint, adding counterclaims of willful infringement of the ’531, ’176, and ’376 

patents. Synopsys then amended its complaint to assert 

claims of infringement of the ’526 and ’109 patents

against Mentor. The district court consolidated the suit 

with another involving Mentor’s ’882 patent.

The parties appeal the various summary judgment 

and post-trial rulings. We have jurisdiction pursuant to

28 U.S.C. § 1295(a)(1). 

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II. ANALYSIS

A. Synopsys’ Appeal

1. Infringement of Mentor’s ’376 Patent

The jury found Synopsys infringed claims 1, 24, and 

26–28 of the ’376 patent and awarded damages. Synopsys 

moved for JMOL that its products did not infringe. The 

district court denied the motion, and Synopsys appeals. 

We affirm the denial of JMOL.

We apply the law of the regional circuit when reviewing a denial of JMOL after a jury verdict. In the Ninth 

Circuit, JMOL is appropriate only “if the evidence, construed in the light most favorable to the nonmoving party, 

permits only one reasonable conclusion, and that conclusion is contrary to the jury’s verdict.” Pavao v. Pagay, 307 

F.3d 915, 918 (9th Cir. 2002).

The ’376 patent relates to debugging source code after 

synthesis. Synthesis is the process of transforming 

Hardware Description Language (“HDL”) into gate-level 

“netlists.” ’376 patent at 1:26–27. Much of the patent’s 

disclosure addresses Register Transfer Level (“RTL”) 

source code, which is a subset of HDL. See id. at 1:27–31. 

The patent teaches that prior art HDL simulators were 

limited because a developer could only view the input and 

ultimate output of a netlist; there was no way to “step 

through” the intermediate gates. Id. at 2:1–17. Without 

the ability to measure intermediate values, “the ability to 

debug the design at the gate level [was] severely limited.” 

Id. at 2:20–23. Additionally, to the extent intermediate 

signals could be measured, there was no way to map a 

value within a netlist to its corresponding RTL logic 

within the source code. Id. at 2:13–17.

The ’376 patent seeks to solve these problems by allowing developers to insert test probes at various stages of a 

netlist to monitor intermediate values. Id. at 2:30–39; 

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Figs. 1, 2. The probe results are referred to as “instrumentation signals.” Id. at 6:32–34. The system correlates 

instrumentation signals with corresponding portions of 

the RTL code and displays the results to a user. Id. at 

2:30–34. Asserted claim 1 is representative:

1. A method comprising the steps of:

a) identifying at least one statement within a 

register transfer level (RTL) synthesizable 

source code; and

b) synthesizing the source code into a gate-level 

netlist including at least one instrumentation 

signal, wherein the instrumentation signal is 

indicative of an execution status of the at least 

one statement. 

Id. at 15:1–8 (emphasis added). 

Mentor accused Synopsys’ ZeBu emulators of infringing. The ZeBu emulators allow developers to insert 

“flexible probes” and “value-change probes” into a netlist. 

These probes measure values at various intermediate 

stages of a netlist. The ZeBu emulators output the test 

results to a waveform viewer. Mentor’s expert Dr. Sarrafzadeh testified that each probe signal shown in the 

waveform viewer identifies a portion of RTL by name, and 

the RTL name can be used to locate the corresponding 

source code. 

Synopsys argues it does not infringe because its ZeBu 

emulators do not “indicate” an RTL statement but rather 

merely provide the name of a block of RTL that a developer can use to locate corresponding code. It argues “you 

don’t ‘indicate’ information by providing other data that 

might help you indirectly figure out the needed information.” Synopsys Br. 32. We note at the outset that 

neither party asked the district court to construe “indicaCase: 15-1470 Document: 108-2 Page: 6 Filed: 03/16/2017
MENTOR GRAPHICS CORPORATION v. EVE-USA, INC. 7

tive,” and the parties agreed the plain and ordinary 

meaning of the term governs.2 The question presented on 

appeal is whether there is substantial evidence for the 

jury verdict that the ZeBu infringed. 

We hold there was substantial evidence to support the 

jury’s infringement verdict. A developer using the ZeBu 

emulator can create a test file called a “Tcl” file and input 

test probes into a netlist using the “probe signals” command. J.A. 43212. Dr. Sarrafzadeh testified that the 

probe signal command creates instrumentation signals 

when the simulation is run. J.A. 41127:12–41129:14. He

then explained how a developer could use the simulation 

results to locate a particular line of RTL code corresponding to an instrumentation signal. He explained that the 

Tcl file identifies a particular line of RTL code by identifying the name of a block of code, and then a developer can 

use that name to locate the specific lines of corresponding 

RTL code. J.A. 41130:7–21. He testified that “you look at 

the name of the signal, on flexible probes, for example, 

and you associate that back to the RTL source.” J.A. 

42417:3–5; see J.A. 42423:10–18 (“Q: How do you know if 

you have tens of thousands of instrumentation signals, 

which signal corresponds to the RTL that you are looking 

at? A: Fantastic question. I look at the name of the 

signal. If the name is S, I go and look for it. If the name 

is S5, I will go and look for it. So based on the name of 

the signal, I will know, among millions of lines of code,

which ones I’m talking about.”); J.A. 42426:7–10 (“Q: How 

would you find a particular process? A: Same thing, by 

looking at, for example, the sensitivity list and using its 

name identifier, you know which process you are talking 

about.”). This is substantial evidence to support the jury’s 

 

2 We have considered Synopsys’ arguments regarding plain meaning and disclaimer and find them to be 

without merit.

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finding that the instrumentation signal indicates at least 

one RTL statement. 

We affirm the district court’s denial of JMOL. 

2. Assignor Estoppel of Mentor’s ’376 Patent

Synopsys briefly challenges the district court’s grant of 

summary judgment that it was barred from challenging 

the validity of the ’376 patent because of assignor estoppel. Synopsys does not dispute that assignor estoppel 

applies to the facts of this case, but it argues the Supreme 

Court “demolished the doctrinal underpinnings of assignor estoppel in the decision that abolished the comparable 

licensee estoppel in Lear, Inc. v. Adkins, 395 U.S. 653 

(1969).” Synopsys Br. 42. We disagree. In Diamond 

Scientific, we emphasized the continued vitality of the 

doctrine of assignor estoppel after Lear. Diamond Sci. Co. 

v. Ambico, Inc., 848 F.2d 1220, 1222–26 (Fed. Cir. 1988); 

see also MAG Aerospace Indus., Inc. v. B/E Aerospace, 

Inc., 816 F.3d 1374, 1380–81 (Fed. Cir. 2016). The district 

court’s grant of summary judgment that assignor estoppel 

applies is affirmed. 

3. Damages for Synopsys’ Infringement of Mentor’s 

’376 Patent

At trial, Mentor argued it was entitled to obtain lost 

profit damages for lost sales of its Veloce emulators 

resulting from Synopsys’ infringing sales of its ZeBu 

emulators because Mentor would have made additional 

Veloce sales but for Synopsys’ infringing ZeBu sales. The 

district court gave detailed instructions to the jury about 

the standard for awarding lost profits, including extensive 

discussion of each of the four Panduit factors. J.A. 164–

75. The jury ultimately awarded Mentor $36,417,661 in 

lost profits and another $242,110.45 in reasonable royalties. J.A. 187. Synopsys appeals arguing that the damage award should be vacated because the district court 

failed to apportion the lost profits. We do not agree. 

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The Patent Act provides: “the court shall award [the 

patent owner] 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.” 35 U.S.C. § 284. Under the statute, “damages adequate to compensate” means “full compensation for any 

‘any damages’ [the patent owner] suffered as a result of 

the infringement.” Gen. Motors Corp. v. Devex Corp., 461 

U.S. 648, 654–55 (1983). As the Supreme Court explained 

in Aro Mfg. Co. v. Convertible Top Replacement Co., 377 

U.S 476, 507 (1964) (plurality opinion), the statutory 

measure of damages is “the difference between [the patent owner’s] pecuniary condition after the infringement, 

and what his condition would have been if the infringement had not occurred.” The Court went on to distinguish 

between disgorgement of defendant’s profits, which had 

been allowed prior to the 1946 statutory amendment, and 

the compensatory damages of § 284, which are defined as 

“compensation for pecuniary loss he (the patentee) has 

suffered from the infringement, without regard to the 

question whether the defendant has gained or lost by his 

unlawful acts.” Id. (quoting Coupe v. Royer, 155 U.S. 565, 

582 (1895)).3 Section 284 damages “have been said to 

 

3 Synopsys cites a number of pre-1946 Supreme 

Court cases discussing apportionment in the context of 

the pre-1946 state of the law which reference disgorgement of the defendant’s profits and patentee’s damages to 

argue that lost profits must be further apportioned after 

applying the Panduit factors. See Garretson v. Clark, 111 

U.S. 120, 121 (1884); Dowagiac Mfg. Co. v. Minn. Moline 

Plow Co., 235 U.S. 641, 646 (1915); Seymour v. McCormick, 57 U.S. 480, 487 (1853). While these pre-§ 284 

cases apply to a different damages regime, nonetheless, 

we find the basic principle of apportionment which they 

espouse applies in all of patent damages. We do not 

depart from this principle today. Rather we hold that in 

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constitute ‘the difference between his pecuniary condition 

after the infringement, and what his condition would have 

been if the infringement had not occurred.’” Id. (quoting

Yale Lock Mfg. Co. v. Sargent, 117 U.S. 536, 552 (1886)). 

Put simply, “[t]he question to be asked in determining 

damages is ‘how much had the Patent Holder and Licensee suffered by the infringement. And that question (is) 

primarily: had the Infringer not infringed, what would 

Patent Holder-Licensee have made?’” Id. 

Compensatory damages are a staple across most every 

area of law. And compensatory damages under the patent 

statute, which calls for damages adequate to compensate 

the plaintiff for its loss due to the defendant’s infringement, should be treated no differently than the compensatory damages in other fields of law. See Livesay Window 

Co. v. Livesay Indus., Inc., 251 F.2d 469, 471 (5th Cir. 

1958) (“To allow a patent owner to recover lost profits 

from an infringer is no unique treatment of this one type 

of wrongdoing, and [it] is essentially the same problem 

which inheres in other instances of an interference with a 

valuable business right.”). Their form is fairly standard; 

“but for” some harmful act by a defendant, a plaintiff 

would be in a certain position. When a plaintiff proves it 

would have been in a certain position but for a defendant’s harmful act, it is entitled to damages to put it in the 

same position it would have occupied had the harmful act 

never occurred. In breach of contract disputes, injured 

parties are awarded expectancy damages designed to 

replicate full performance of the contract. The goal of 

expectancy damages is to put the non-breaching party in 

the position it would have occupied but for the breach. 

See, e.g., Fifth Third Bank v. United States, 518 F.3d 

1368, 1374 (Fed. Cir. 2008); California Fed. Bank v. 

 

this case, on these facts, apportionment is achieved 

though the court’s use of the Panduit factors. 

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United States, 395 F.3d 1263, 1267 (Fed. Cir. 2005); 

Glendale Fed. Bank, FSB v. United States, 239 F.3d 1374, 

1380 (Fed. Cir. 2001). Similarly, under tort law, injured 

parties receive damages sufficient to put them in the 

same position they would have occupied had the injury 

never occurred. See, e.g., Cooper Indus., Inc. v. Leatherman Tool Grp., Inc., 532 U.S. 424, 432 (2001) (“[Compensatory damages] are intended to redress the concrete loss 

that the plaintiff has suffered by reason of the defendant’s 

wrongful conduct.”); Kansas v. Colorado, 533 U.S. 1, 13 

(2001) (state against state tort); New York, L.E. & W.R. 

Co. v. Estill, 147 U.S. 591, 616–17 (1893) (business tort). 

The “but for” damages the patentee must establish in 

patent law, as the Supreme Court explained, are an 

answer to a simply stated question: “[H]ad the Infringer 

not infringed, what would the Patent Holder-Licensee 

have made?” Aro Mfg. Co., 377 U.S. at 507. 

There is no particular required method to prove but for 

causation. One “useful, but non-exclusive” method to 

establish the patentee’s entitlement to lost profits is the 

Panduit test first articulated by the Sixth Circuit. RiteHite Corp. v. Kelley Co., 56 F.3d 1538, 1545 (Fed. Cir. 

1995) (en banc) (citing Panduit Corp. v. Stahlin Bros. 

Fibre Works, Inc., 575 F.2d 1152 (6th Cir. 1978)). When a 

patentee proves it would have made additional sales but 

for a defendant’s infringement, the patentee is entitled to 

be made whole for the profits it proves it lost. See, e.g.,

Asetek Danmark A/S v. CMI USA Inc., 842 F.3d 1350, 

1361 (Fed. Cir. 2016); Versata Software, Inc. v. SAP Am., 

Inc., 717 F.3d 1255, 1263–64 (Fed. Cir. 2013); Grain 

Processing Corp. v. Am. Maize-Prods. Co., 185 F.3d 1341, 

1352–53 (Fed. Cir. 1999); Photo Elecs. Corp. v. England, 

581 F.2d 772, 784 (9th Cir. 1978); Livesay Window, 251 

F.2d at 471. The goal of lost profit damages is to place the 

patentee in the same position it would have occupied had 

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there been no infringement.4 In this regard, lost profit 

patent damages are no different than breach of contract 

or general tort damages. Thus, the fact finder’s job is to 

determine what would the patent holder have made (what 

would his profits have been) if the infringer had not 

infringed. 

Under the Panduit test, a patentee is entitled to lost 

profit damages if it can establish four things: 

(1) demand for the patented product; 

(2) absence of acceptable non-infringing alternatives; 

(3) manufacturing and marketing capability to exploit 

the demand; and 

(4) the amount of profit it would have made. 

Panduit, 575 F.2d at 1156. Damages under Panduit are 

not easy to prove. See, e.g., Ian Ayres & Paul Klemperer, 

Limiting Patentees’ Market Power Without Reducing 

Innovation Incentives: The Perverse Benefits of Uncertainty and Non-Injunctive Remedies, 97 MICH. L. REV. 985, 

1030 (1999) (“The difficulties that patentees frequently 

have in proving the four Panduit prerequisites often mean 

that instead of being awarded lost profits (what amounts 

to make-whole damages), patentees must settle for the 

smaller reasonable royalty measure.”); Christopher Seaman, Reconsidering the Georgia-Pacific Standard for 

Reasonable Royalty Patent Damages, 2010 B.Y.U. L. REV. 

1661, 1675 (2010) (“[S]uccessful claims for lost profits are 

becoming less common as courts have insisted on strict 

standards of proof for entitlement to lost profits.” (quota-

 

4 As we explained in Rite Hite, lost profit damages 

are limited to those that are “reasonably foreseeable by an 

infringing competitor in the relevant market.” Rite-Hite, 

56 F.3d at 1546. Synopsys does not argue that Mentor’s 

lost emulator sales were not reasonably foreseeable. 

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tions omitted)); Mark Lemley, Distinguishing Lost Profits 

from Reasonable Royalties, 51 WM. & MARY L. REV. 655, 

657 (2009) (“Proving lost profits has not been easy, however.”); see also Grain Processing, 185 F.3d at 1349–53 

(patentee could not obtain damages under Panduit because a product that was not even sold on the market was 

considered an acceptable non-infringing alternative); BIC 

Leisure Prods., Inc. v. Windsurfing Int’l, Inc., 1 F.3d 1214, 

1218–19 (Fed. Cir. 1993) (patentee could not obtain 

damages under Panduit because it sold its products in a 

different price segment in the market than the infringing 

products); SmithKline Diagnostics, Inc. v. Helena Labs. 

Corp., 926 F.2d 1161, 1165–66 (Fed. Cir. 1991). 

We have explained the relationship between the first 

two Panduit factors. The first factor—demand for the 

patented product—considers demand for the product as a 

whole. DePuy Spine, Inc. v. Medtronic Sofamor Danek, 

Inc., 567 F.3d 1314, 1330–31 (Fed. Cir. 2009). The second 

factor—the absence of non-infringing alternatives—

considers demand for particular limitations or features of 

the claimed invention. Id. at 1331. Together, requiring 

patentees to prove demand for the product as a whole and 

the absence of non-infringing alternatives ties lost profit 

damages to specific claim limitations and ensures that 

damages are commensurate with the value of the patented features. See Presidio Components, Inc. v. Am. Tech. 

Ceramics Corp., 702 F.3d 1351, 1361 (Fed. Cir. 2012) 

(“[P]roducts lacking the advantages of the patented 

invention can hardly be termed a substitute acceptable to 

the customer who wants those advantages.” (quotations 

omitted)); Grain Processing, 185 F.3d at 1354 (holding 

that customers would have found a particular claim 

limitation “irrelevant,” so the patentee could not rely on 

that limitation for the second Panduit factor); Standard 

Haven Prods., Inc. v. Gencor Indus., Inc., 953 F.2d 1360, 

1373 (Fed. Cir. 1991) (“If purchasers are motivated to 

purchase because of particular features available only 

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from the patented product, products without such features–even if otherwise competing in the marketplace–

would not be acceptable noninfringing substitutes.”); 

SmithKline Diagnostics, 926 F.2d at 1166 (“If purchasers 

are motivated to purchase because of particular features 

of a product available only from the patent owner and 

infringers, products without such features would obviously not be acceptable noninfringing substitutes.”).

The second factor, absence of acceptable non-infringing 

alternatives, often proves the most difficult obstacle for 

patent holders. Under this factor, if there is a noninfringing alternative which any given purchaser would 

have found acceptable and bought, then the patentee 

cannot obtain lost profits for that particular sale.5 For 

example, if the customer would have bought the infringing product without the patented feature or with a different, non-infringing alternative to the patented feature, 

then the patentee cannot establish entitlement to lost 

profits for that particular sale. And this determination is 

made on a customer-by-customer basis. For this reason, 

it is quite common to see damage awards where, as in this 

case, the patentee proves entitlement to lost profits for 

some of its sales, but not others. See BIC Leisure, 1 F.3d 

at 1219–20; DePuy Spine, 567 at 1333–34. For sales in 

which the patentee cannot prove the elements necessary 

to establish entitlement to lost profits, the statute guar-

 

5 In a complex market with numerous competitors, 

a patentee may be awarded lost profit damages calculated 

using its market share among its competitors. See State 

Indus., Inc. v. Mor-Flo Indus., Inc., 883 F.3d 1573, 1577–

78 (Fed. Cir. 1989). The market share theory is irrelevant 

in this case because the jury made a factual finding, 

which Synopsys does not challenge on appeal, that the 

relevant emulator market for sales to Intel was a twosupplier market. See J.A. 164. 

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antees the patentee a reasonable royalty for those sales. 

In those circumstances, the patentee obtains its lost 

profits on the sales where it can prove all the Panduit

factors and a reasonable royalty on the other infringing 

sales. 

The facts of this case are remarkably simple for a patent damages appeal and Synopsys does not dispute any 

of them. The relevant market (suppliers of emulators to 

Intel) contained two parties, Synopsys and Mentor. 

Mentor sold its own Veloce emulators to Intel and Synopsys sold its ZeBu emulators to Intel which were found to 

infringe Mentor’s ’376 patent claims. Synopsys does not 

dispute that but for its infringement, Mentor would have 

made each of the infringing emulator sales to Intel. Nor 

does it dispute how much Mentor would have earned, the 

precise numbers of sales Mentor would have made, 

whether there were any alternatives that Intel may have 

preferred over the purchase of Mentor’s product, or 

whether Intel would have chosen to purchase fewer 

emulators. In short, Synopsys does not dispute on appeal 

that for each infringing sale it made to Intel, Mentor lost 

that exact sale. 

This is important as it makes this case quite narrow 

and unlike the complicated fact patterns that impact so 

many damages models in patent cases. The jury found, 

and Synopsys does not dispute on appeal, that Mentor 

satisfied all of the Panduit factors with regard to the sales 

to Intel for which the jury awarded lost profits: 

(1) there was a demand by Intel for the patented product;6 

 

6 The jury was expressly instructed that it could not 

award lost profits unless it found that “there were only 

two acceptable, available alternatives in the Intel market 

during the damages period: Mentor-Graphics’ emulation 

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(2) there were no non-infringing alternative emulator

systems acceptable to Intel; 

(3) Mentor had the manufacturing and marketing capability to satisfy Intel’s demand; and, 

(4) Mentor established the amount of profit it would 

have made if Synopsys had not infringed. 

Synopsys does not challenge the sufficiency of Mentor’s 

evidence with regard to the individual Panduit factors. In 

this case, the jury found, and Synopsys does not dispute, 

that Intel would not have purchased the Synopsys emulator system without the two patented features and that 

there were no other alternatives available. Despite 

hearing evidence that there were many valuable and 

important features in the emulator system, this jury 

found that if Synopsys could not have sold its emulator 

system with the two infringing features (Mentor’s patented features), Intel would have bought the emulators from 

Mentor. There were no other competitors, and the jury 

found there were no non-infringing alternative emulator 

systems which would have satisfied Intel. Thus, what did 

Mentor lose when Synopsys appropriated its two patented 

features? It lost the profits it would have made on the 

sale of its emulators to Intel. These are the simple, 

undisputed facts on appeal. 

Synopsys largely ignores these facts and seeks to have 

us depart from basic compensatory damages principles 

equally applied across many areas of law. Synopsys 

advocates for a two-step process for calculating lost profits. First, Synopsys argues a patentee must calculate the 

amount of profits it lost as a result of the infringement 

using the Panduit factors. Second, Synopsys argues a 

patentee must further apportion its lost profits to cover 

 

system and Synopsys’ allegedly infringing emulation 

system.” J.A. 164.

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only the patentee’s inventive contribution. See Synopsys 

Br. 51. Synopsys does not dispute that “but for” its infringement, Mentor would have made $36,417,661 in lost 

profits. Instead, Synopsys argues that the allegedly 

infringing features were just two features of emulators 

that comprise thousands of hardware and software features. Synopsys Br. 48. Thus, according to Synopsys, 

Mentor is not entitled to recover what it lost, the amount 

necessary to make it whole for the sales it lost, but rather 

the value attributable to its patented features. 

Synopsys argues that “[p]rinciples of apportionment 

play an especially vital role in this age of complex, multicomponent electronic devices.” Synopsys Br. 44. Synopsys argues that the patentee does not “deserve,” id. at 46, 

lost profits for the whole emulator when it only invented 

some of the features on the emulator. Thus, according to 

Synopsys the damages should not be the profits the 

patentee lost when it lost the emulator sale because of 

Synopsys’ infringement, but rather only the amount of 

profit properly attributable to its patented features. 

We agree with Synopsys that apportionment is an important component of damages law generally, and we 

believe it is necessary in both reasonable royalty and lost 

profits analysis. See Ericsson, Inc. v. D-Link Sys., Inc., 

773 F.3d 1201, 1226 (Fed. Cir. 2014) (“Apportionment is 

required even for non-royalty forms of damages.” (citing 

Garretson, 111 U.S. at 121)); VirnetX, Inc. v. Cisco Sys., 

Inc., 767 F.3d 1308, 1326 (Fed. Cir. 2014) (“No matter 

what the form of the royalty, a patentee must take care to 

seek only those damages attributable to the infringing 

features.” (citing Garretson, 111 U.S. at 120–21)). In this 

case, apportionment was properly incorporated into the 

lost profits analysis and in particular through the Panduit

factors. Panduit’s requirement that patentees prove 

demand for the product as a whole and the absence of 

non-infringing alternatives ties lost profit damages to 

specific claim limitations and ensures that damages are 

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commensurate with the value of the patented features. 

We leave for another day whether a different theory of 

“but for” damages adequately incorporates apportionment 

principles.7 We hold today that on the undisputed facts of 

this record, satisfaction of the Panduit factors satisfies 

principles of apportionment: Mentor’s damages are tied 

to the worth of its patented features. 

The jury found, and Synopsys does not dispute, there 

were only two acceptable alternatives to Intel: Mentor’s 

emulator and Synopsys’ infringing emulator. The jury 

was properly instructed that if there were any other 

acceptable, non-infringing emulation system or if there 

were prototypes that may have been acceptable or if there 

was any acceptable non-infringing alternative that could 

have been made available (even if they did not already 

exist), then Mentor could not receive lost profits on those 

 

7 Synopsys argues that we have held in other cases 

that lost profits must be apportioned. Synopsys Br. 51–

56. The cases cited by Synopsys, however, did not address 

whether lost profits were appropriate under the Panduit

factors (where the apportionment was subsumed within 

the Panduit analysis). Id. (citing Ferguson Beauregard/Logic Controls v. Mega Sys., LLC, 350 F.3d 1327, 

1345–46 (Fed. Cir. 2003); Kori Corp. v. Wilco Marsh 

Buggies & Draglines, Inc., 761 F.2d 649, 656 (Fed. Cir. 

1985)). Synopsys recognizes, however, that in other cases, 

we have declined to apportion when the four-part Panduit 

test establishing but for causation has been met. See, e.g., 

Synopsys Rep. Br. 24–25 (citing Paper Converting Mach. 

v. Magna-Graphics Corp., 745 F.2d 11, 22–23 (Fed. Cir. 

1984) (declining to further apportion a lost profits award 

because the patentee proved it would have made the sales 

in question but for the infringing sales)).

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particular sales. J.A. 164.8 The jury was also instructed 

that it could have found the patented features were not 

critical to Intel and that it would have purchased Synopsys’ emulators without the features. The instruction 

expressly stated that Mentor could not obtain lost profit 

damages if “Synopsys could have made available during 

the damages period an acceptable, non-infringing alternative to Mentor-Graphics’ emulation system and Synopsys’ 

infringing emulation system.” J.A. 164. Synopsys could 

have made its emulator system minus the two infringing 

features—that would have been an alternative to the 

“Synopsys infringing emulation system.” However, the 

jury concluded, and Synopsys does not dispute on appeal 

the jury’s Panduit fact findings, that there was no such 

non-infringing alternative that Intel would have purchased. 

On appeal, Synopsys argues that its emulators “outperform Mentor’s in price, size, speed, and capacity.” 

Synopsys Br. 49. If the evidentiary record is as Synopsys 

claims it is, then it had recourse—it could have appealed 

the jury’s Panduit fact findings as not supported by 

substantial evidence. But it did not. And thus on appeal, 

it is left with a jury fact finding that Intel would not have 

bought Synopsys’ emulation system without the two 

infringing features, and Mentor would have made every 

single sale to Intel that Synopsys otherwise made. This is 

a highly factual case, and Synopsys did not appeal any of 

the jury’s fact findings relating to damages. 

Synopsys and the amicus brief argue that complex 

multi-feature devices necessitate change in patent damages law. They argue that not requiring an additional 

 

8 The instruction also explained that if Intel would 

have bought fewer or no emulation systems in place of 

those it bought from Synopsys then lost profits cannot be 

awarded on those sales. J.A. 165.

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20 MENTOR GRAPHICS CORPORATION v. EVE-USA, INC. 

apportionment step after the Panduit test has been met 

would “allow multiple entities to obtain lost profits on the 

same product where each entity holds a patent on a 

different ‘but for’ feature of the same product.” Amicus 

Br. 11. This claimed threat of “serial infringement 

claims” is not correct. Again, we do not speak to all 

damages models. Under Panduit, however, there can only 

be one recovery of lost profits for any particular sale. 

This case, for example, involved lost profits for an 

emulator system with the two patented features based on

certain sales Synopsys made to Intel. To be entitled to 

lost profits damages, Mentor had to prove no other supplier could have made those specific sales to Intel. If 

there were any acceptable non-infringing alternative Intel 

would have purchased instead of Mentor’s emulator, then 

Mentor could not obtain lost profits. 

The jury found (and Synopsys does not challenge on 

appeal) that Intel would not have purchased emulators 

without the features claimed in Mentor’s ’376 patent. 

While there may have been other features of the emulator 

that were important to Intel, only Mentor could sell Intel

an emulator with all the features it required. Because 

Mentor had proprietary rights to the only means of satisfying this demand by Intel, because no other party could 

sell Intel an emulator with those two components, no one 

else had the right to sell emulators to Intel that satisfied 

all of Intel’s requirements. In short, for these particular 

sales, no other party could satisfy the Panduit factors, 

making it impossible for multiple patentees to obtain lost 

profit damages for the same sales. 

Applying this logic to Synopsys’ laptop example, Synopsys argues that “nearly every component is a but-for 

cause of most sales.” Synopsys Rep. Br. 20. Synopsys

argues that “the reality” is “that sales of a complex product may be driven by ‘a plethora of features,’” many of 

which are patented. Id. If true, however, then lost profits 

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on the laptop would not be available. In Synopsys’ example, the customer demands a laptop with a high resolution 

screen, responsive keyboard, a fast wireless network 

receiver, and an extended-life battery.9 Id. at 18. If each 

are patented by separate companies, and no manufacturer 

has the right to sell them all, then no manufacturer could 

obtain lost profits on such a laptop (none could satisfy the 

demand for everything). Thus, each patentee would get a 

reasonable royalty on their respective component. 

With such multi-component products, it may often be 

the case that no one patentee can obtain lost profits on 

the overall product—the Panduit test is a demanding one. 

A patentee cannot obtain lost profits unless it and only it 

could have made the sale—there are no non-infringing 

alternatives or, put differently, the customer would not 

have purchased the product without the infringing feature.

Consider the laptop example. If the only patented 

component is the extended life battery and a customer 

will only buy a laptop with this battery (meaning a laptop 

with a lower quality battery is not an acceptable noninfringing alternative to the customer), then when an 

infringer who appropriates the patented extended life 

battery sells a laptop, the infringer has deprived the 

patentee of the lost profits on the laptop sale which only it 

could have made. If a laptop with a lower-quality battery 

would be an acceptable non-infringing alternative to 

certain customers, the patentee would not be entitled to 

lost profits for these laptop sales. For those customers, 

 

9 Synopsys cites LaserDynamics for this example. 

LaserDynamics, however, does not analyze but for causation using the Panduit factors and is not even a lost 

profits case. The LaserDynamics analysis was limited to 

reasonable royalties. LaserDynamics, Inc. v. Quanta 

Comp., Inc., 694 F.3d 51, 66 (Fed. Cir. 2012).

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22 MENTOR GRAPHICS CORPORATION v. EVE-USA, INC. 

the patented battery was not a factor in their purchasing 

decision; it was not necessary for the sale. The only sales 

for which the patentee can obtain lost profits are the 

customers who would refuse to purchase laptops without 

the patented extended-life battery. For these lost customers, the extended-life battery drives their purchasing 

decisions. 

When a patentee proves it is entitled to recover lost 

profit damages, as Synopsys concedes Mentor has done 

here, it is entitled to be made whole for the injuries it 

suffered as a result of the infringement. See, e.g., State 

Indus., 883 F.2d at 1577 (“The measure of damages is an 

amount which will compensate the patent owner for the 

pecuniary loss sustained because of the infringement.”). 

In this case, the jury answered the question: “Had the 

Infringer not infringed, what would the Patent Holder/licensee have made?” Mentor has proven it would have 

earned certain profits but for Synopsys’ infringement. It 

is entitled to be made whole for the profits it proves it lost 

because Synopsys infringed. The jury found that if Synopsys had not infringed the Mentor patent by incorporating the two patented features into its emulators, Intel 

would not have purchased these products from Synopsys

and would instead have purchased the emulators from 

Mentor—there were no non-infringing alternative emulators which would have satisfied Intel. Panduit limits lost 

profits to sales where there are no acceptable noninfringing alternatives that the customer would have 

purchased. We hold that the district court did not err in 

refusing to further apportion lost profits after the jury 

returned its verdict applying the Panduit factors. We 

conclude that, when the Panduit factors are met, they

incorporate into their very analysis the value properly 

attributed to the patented feature. We affirm the district 

court’s denial of judgment as a matter of law and/or 

motion for new trial with regard to damages.

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4. Indefiniteness of Synopsys’ ’109 Patent

The district court granted summary judgment that 

claim 1 of Synopsys’ ’109 patent is indefinite. J.A. 121. A 

claim is indefinite if the claim, “read in light of the specification delineating the patent, and the prosecution 

history, fail[s] to inform, with reasonable certainty, those 

skilled in the art about the scope of the invention.” Nautilus, Inc. v. Biosig Instruments, Inc., 134 S. Ct. 2120, 2124 

(2014). Definiteness requires clarity, though “absolute 

precision is unattainable.” Id. at 2129. Claims reciting 

terms of degree “ha[ve] long been found definite” if they 

provide reasonable certainty to a skilled artisan when 

read in the context of the patent. Biosig Instruments, Inc. 

v. Nautilus, Inc., 783 F.3d 1374, 1378 (Fed. Cir. 2015) 

(quoting Interval Licensing LLC v. AOL, Inc., 766 F.3d 

1364, 1370 (Fed. Cir. 2014)). This requires a patent to 

provide “some standard for measuring that [term of] 

degree.” Id. For example, in Nautilus we found the 

phrase “spaced relationship” definite because a “skilled 

artisan would understand the inherent parameters of the 

invention as provided in the intrinsic evidence.” Id. at 

1384. In Sonix Technology, we found the phrase “visually 

negligible” definite based on examples from the specification and prosecution history. Sonix Tech. Co. v. Publ’ns

Int’l, Ltd., 844 F.3d 1370, 1379–80 (Fed. Cir. 2017). And 

in DDR Holdings, LLC v. Hotels.com, L.P., we found the 

phrase “look and feel” definite because it had “an established meaning in the art by the relevant timeframe” 

consistent with how the phrase was used in the specification. 773 F.3d 1245, 1261 (Fed. Cir. 2014). 

The ’109 patent discloses “a method for displaying the 

results of synthesized circuit analysis visually near the 

HDL source specification that generated the circuit.” ’109 

patent at 7:57–59 (emphasis added). It explains that the 

method “uses information developed during translation to 

relate the results of the analysis to the HDL source . . . .” 

Id. at 11:29–32. It teaches that by displaying the circuit 

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24 MENTOR GRAPHICS CORPORATION v. EVE-USA, INC. 

analysis results “near” the corresponding HDL code, “the 

present invention allows a designer to make more effective use of logic synthesis and reduce the complexity of 

the circuit debugging process.” Id. at 8:59–63.

Claim 1 requires “displaying said characteristics associated with those said final circuit’s nets and parts that 

correspond directly with said initial circuit’s nets and 

parts near said portions of said synthesis source text file 

that created said corresponding initial circuit parts and 

nets.” Id. at 22:52–56 (emphasis added). Mentor moved 

for summary judgment that the word “near” was indefinite. The district court granted the motion, holding “[t]he

patent’s claims and specification do not permit a person of 

ordinary skill in the art to define the claim term ‘near’ 

with reasonable certainty.” J.A. 121. We conclude that 

the court erred as a matter of law. 

We hold the term “near” informs a person of ordinary 

skill in the art about the scope of the invention with 

reasonable certainty. A goal of the ’109 patent is to aid 

developers when debugging HDL. ’109 patent at 8:59–63. 

To accomplish this, the patent “relates” circuit analysis 

results with the HDL corresponding to a particular result, 

and then places the two pieces of information “near” each 

other on the display screen. Id. at 7:57–64. This allows a 

developer to identify and fix problems with specific lines 

of HDL when debugging. Id. at 11:29–35. In order for the 

patent’s stated objective to occur, the system must display 

the related HDL and analysis results “near” enough to 

each other such that a developer would “relate” the two. 

Thus, we hold a skilled artisan would understand “near” 

requires the HDL code and its corresponding circuit 

analysis to be displayed in a manner that physically 

associates the two.

The patent provides examples of HDL displayed near 

the corresponding circuit tracing results. Figure 11 

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discloses HDL code fragment 400 displayed next to timing 

result 500:

Id. at Fig. 11. The specification explains that the circuit 

analysis “can be displayed next to the appropriate line of 

the output.” Id. at 13:25–28. Similarly, Figure 19 displays “timing and area analysis” next to the corresponding HDL code: 

Case: 15-1470 Document: 108-2 Page: 25 Filed: 03/16/2017
26 MENTOR GRAPHICS CORPORATION v. EVE-USA, INC. 

Id. at Fig. 19, 14:32–34. A skilled artisan viewing Figures 

11 and 19 would readily understand which HDL code 

corresponds to which timing result, based on the way the 

information is displayed on the screen. These examples 

support the conclusion that skilled artisans would understand the meaning of “near” with reasonable certainty. 

See Sonix Tech., 844 F.3d at 1379–80 (relying on specific 

examples from the specification to find a term definite).

Mentor cites Figure 30, which it argues demonstrates 

“near” is ambiguous: 

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’109 patent at Fig. 30. Figure 30 discloses an embodiment 

where the circuit analysis 3030 is displayed in a separate 

window in the corner of the display screen. Id. at 21:2–3. 

Circuit analysis 3030 corresponds to the HDL code highlighted in text box 3020. Id. at 21:8–9. In this embodiment, the circuit analysis and corresponding HDL are not 

displayed necessarily “near” each other. 

We conclude that the Figure 30 embodiment is a different embodiment than the claimed embodiment. See 

Intamin Ltd. v. Magnetar Techs., Corp., 483 F.3d 1328, 

1336–37 (Fed. Cir. 2007) (claims may exclude embodiments if the specification discloses multiple embodiments); Baran v. Med. Device Techs., Inc., 616 F.3d 1309, 

1316 (Fed. Cir. 2010). The purpose of the claimed “near” 

requirement is to allow a developer to associate HDL with 

its corresponding tracing analysis. See ’109 patent at 

7:61–64 (“The present invention relates the analysis 

results of each portion of the synthesized circuit to the 

particular part of the HDL specification that generated 

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28 MENTOR GRAPHICS CORPORATION v. EVE-USA, INC. 

that circuit portion.”). This includes the embodiments 

shown in Figures 11 and 19. Figure 30 discloses an 

alternative scheme for associating HDL and circuit analysis. Rather than placing HDL code and tracing results

“near” one another, the HDL code is highlighted (3020 in 

Fig. 30) and the tracing results for the highlighted code 

are placed in a separate window (3030 in Fig. 30). Id. at 

21:2–9. Thus, there is no need to place the HDL code and 

circuit analysis near each other because they are already 

associated by alternative means. See id. at 21:15–16 

(“Here, cursor window 3030 could display other characteristics associated with the object under the cursor.”) (emphasis added). 

We reverse the grant of summary judgment of indefiniteness of claim 1 of the ’109 patent. We hold that the 

term “near” informs those of skill in the art about the 

scope of the invention with reasonable certainty. 

5. Patent-eligibility of Synopsys’ ’526 Patent

The district court granted summary judgment that 

claims 19, 24, 28, 30, and 33 of the ’526 patent lack patentable subject matter, holding the “claims embrace 

unpatentable electromagnetic carrier waves.” J.A. 121. 

We affirm. 

Mentor argues the term “machine-readable medium,” 

present in every challenged claim, renders the claimed 

subject matter invalid under 35 U.S.C. § 101. A patentee 

is free to be his own lexicographer. Phillips v. AWH 

Corp., 415 F.3d 1303, 1316 (Fed. Cir. 2005) (en banc). 

Here, the specification expressly defines the term: “The 

computer readable medium is any data storage device 

that can store data which can be thereafter be [sic] read 

by a computer system. Examples of the computer readable medium include read-only memory, random-access 

memory, CD-ROMs, magnetic tape, optical data storage 

devices, carrier waves.” ’526 patent at 52:31–36 (emphasis added). Mentor argues that because the ’526 patent 

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defines a “machine-readable medium” as including “carrier waves,” the claims are invalid under In re Nuijten, 500 

F.3d 1346 (Fed. Cir. 2007). 

In Nuijten, we addressed whether a claim covering a 

signal was eligible for patenting under 35 U.S.C. § 101. 

The claimed signal in Nuijten was not limited to a particular medium or carrier but rather covered “any tangible 

means of information carriage.” Id. at 1353. We held 

that a “transitory, propagating signal” did not fall within 

any statutory category of subject matter: process, machine, manufacture, or composition of matter. Id. Therefore, because the claims covered “the signal itself,” they 

were not eligible subject matter. Id. at 1357. 

Because the challenged ’526 claims are expressly defined by the specification to cover carrier waves, they are 

similar to the ineligible Nuijten claims. Here, the specification defined the claimed machine-readable medium as 

including read-only memory, random-access memory, CDROMs, magnetic tape, optical data storage devices, and 

carrier waves. Even though carrier waves differ greatly 

from the other disclosed mediums (such as CD-ROMs or 

magnetic tape), we are bound by the patentee’s lexicography. See Thorner v. Sony Comput. Entm’t Am. LLC, 669 

F.3d 1362, 1365 (Fed. Cir. 2012). Thus, the claims cover 

carrier signals themselves. The “presence of [other] acts 

recited in the claim[s] does not transform a claim covering 

a thing—the signal itself—into one covering the process 

by which that thing was made.” Nuijten, 500 F.3d at 

1355. 

The challenged ’526 claims present a scenario where 

there are multiple covered embodiments, and not all 

covered embodiments are patent-eligible. For example, if 

the machine-readable medium used was a “random-access 

memory” or “optical data storage device,” the claims 

would not run afoul of Nuijten. Synopsys contends a 

“nonexclusive example, from an alternate embodiment” 

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30 MENTOR GRAPHICS CORPORATION v. EVE-USA, INC. 

does not render the entire claim ineligible. Synopsys Br. 

69. While not binding on our court, the Manual of Patent 

Examining Procedure (“MPEP”) is instructive on this 

point. The MPEP instructs that when a claim covers 

“both statutory and non-statutory embodiments,” it is not 

eligible for patenting. MPEP § 2106 (9th ed. Mar. 2014). 

As an example, it states that “a claim to a computer 

readable medium that can be a compact disc or a carrier 

wave covers a non-statutory embodiment and therefore 

should be rejected under 35 U.S.C. § 101 as being directed 

to non-statutory subject matter.”10 Id. 

We affirm the district court’s grant of summary judgment that claims 19, 24, 28, 30, and 33 of the ’526 patent 

lack patentable subject matter. 

B. Mentor’s Cross-Appeal

1. Mentor’s Allegations of Willful Infringement of the 

’376 Patent

The district court granted a motion in limine precluding Mentor from presenting evidence of willful infringement of the ’376 patent. J.A. 40,545–47. We reverse.

We review evidentiary rulings under Ninth Circuit 

law, which reviews for abuse of discretion. Advance 

Cardiovascular Sys. v. Medtronic, Inc., 265 F.3d 1294, 

1308 (Fed. Cir. 2001). After Synopsys filed an action 

seeking declaratory judgment that the ’376 patent was 

invalid and not infringed, Mentor answered and counterclaimed that Synopsys willfully infringed. The district 

court granted Synopsys’ motion in limine to preclude 

 

10 We note that Synopsys was later granted a second 

patent based on the ’526 patent’s disclosure (U.S. Patent 

No. 8,099,271) in which Synopsys drafted its claims to 

cover a “non-transitory machine-readable medium,” 

thereby excluding the carrier waves embodiment.

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MENTOR GRAPHICS CORPORATION v. EVE-USA, INC. 31

Mentor from presenting evidence of willfulness. The court

held that Mentor was precluded from presenting evidence 

of willfulness because it relied exclusively on post-suit 

willfulness conduct, and it had not first sought a preliminary injunction. It stated, “I think Synopsys is right 

about what we will call the Seagate rule, which is if you 

don’t seek an injunction, you can’t seek willful infringement for post-filing conduct.” J.A. 40,547; see In re 

Seagate Tech., LLC, 497 F.3d 1360, 1374 (Fed. Cir. 2007) 

(“[W]hen an accused infringer’s post-filing conduct is 

reckless, a patentee can move for a preliminary injunction, which generally provides an adequate remedy for 

combating post-filing willful infringement.” (citations 

omitted)). On route to this conclusion, the district court 

made two errors. First, it erred in determining that the 

alleged conduct was post-suit conduct because it erred in 

determining the filing date of the relevant suit. Second, it 

erred in concluding that Synopsys could not present 

evidence of post-filing willful infringement because Synopsys did not seek a preliminary injunction. 

The relevant date for determining which conduct is 

pre-suit is the date of the patentee’s affirmative allegation 

of infringement, in this case the date of Mentor’s counterclaim. See Seagate, 497 F.3d at 1374 (explaining that “in 

ordinary circumstances, willfulness will depend on an 

infringer’s prelitigation conduct” because “a patentee 

must have a good faith basis for alleging willful infringement”). Mentor relies on Synopsys’ acquisition of EVE, 

which terminated the license and rendered all subsequent 

sales infringing. These events occurred after the declaratory judgment was filed but prior to Mentor’s counterclaim for infringement. The alleged acts of infringement 

are thus pre-suit acts, and there is accordingly no basis 

for excluding Mentor’s evidence of willfulness. 

We also disagree with the district court’s second decision—that Mentor could not assert willful infringement 

because it did not seek a preliminary injunction. As we 

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32 MENTOR GRAPHICS CORPORATION v. EVE-USA, INC. 

noted in Aqua Shield, there is “no rigid rule” that a patentee must seek a preliminary injunction in order to seek 

enhanced damages. Aqua Shield v. Inter Pool Cover 

Team, 774 F.3d 766, 773–74 (Fed. Cir. 2014); see Halo

Elecs., Inc. v. Pulse Elecs., Inc., 136 S. Ct. 1923, 1934 

(2016) (“[W]e eschew any rigid formula for awarding 

enhanced damages under § 284 . . . .”). 

We hold that the district court abused its discretion in 

precluding Mentor from presenting evidence of willful 

infringement. Because the district court determined 

Mentor’s willfulness allegations were improper, there are 

no findings on willfulness for appellate review. We vacate 

the district court’s grant of the motion in limine and 

remand for further proceedings consistent with Halo. 

2. Written Description of Mentor’s ’882 Patent

The district court granted summary judgment that 

claims 7, 9, and 13 of the ’882 patent are invalid for lack 

of written description. We reverse.

The ’882 patent discloses an emulator comprised of a 

series of field programmable gate arrays (FPGAs, also 

referred to as “reconfigurable logic devices” in the patent). 

’882 patent at 2:10–13. Each FPGA is comprised of a 

collection of smaller logic elements (called “reconfigurable 

logic elements”). Id. Some simulations require more than 

one FPGA to model. Id. at 2:13–21. When that occurs, 

the emulator connects multiple FPGAs to create larger 

circuits. Id. This can lead to timing errors if signals 

progress through individual FPGAs at different lengths of 

time. Id. at 1:21–32. To address this problem, the ’882 

patent discloses using at least two different clocks: a user 

clock for the logic elements within a FPGA, and a signal 

routing clock for the timing between FPGAs. Id. at 4:13–

16. 

Each asserted claim requires that “the signal routing 

clock is independent of the first clock signal and the 

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MENTOR GRAPHICS CORPORATION v. EVE-USA, INC. 33

second clock signal.” The district court construed “independent” as “wherein there is no required timing relationship between clock edges.” J.A. 10,848. Synopsys moved 

for summary judgment that the ’882 patent’s specification 

failed to disclose written description support for an “independent” signal routing clock. The district court granted 

the motion:

The motion is GRANTED with respect to invalidity of claims 7, 9, and 13 of U.S. Patent No. 

6,947,882. The 882 Patents [sic] specification describes the minimum frequency relationship between the signal routing clock signal and the first 

and second clock signals as an exception to independent clocking. As a result, the specification 

does not demonstrate possession of the unqualifiedly independent clocking that the asserted 

claims require, and the claims do not meet the 

written description requirement.

J.A. 23,749–50.

A patent satisfies the written description requirement 

when “the disclosure of the application relied upon reasonably conveys to those skilled in the art that the inventor had possession of the claimed subject matter as of the 

filing date.” Ariad Pharms., Inc. v. Eli Lilly & Co., 598 

F.3d 1336, 1351 (Fed. Cir. 2010). We review a grant of 

summary judgment of no written description de novo. 

Crown Packaging Tech. v. Ball Metal Beverage, 635 F.3d 

1373, 1380 (Fed. Cir. 2011).

Synopsys’ argument before the district court and on 

appeal is based on the following passage from the ’882 

patent’s specification:

As illustrated in FIG. 2, I/O circuitry 115 and 116 

are clocked by signal routing clocks 117 whereas 

the LEs are clocked by a different clock signal (or 

signals), user clock(s) 118. Except for the relationCase: 15-1470 Document: 108-2 Page: 33 Filed: 03/16/2017
34 MENTOR GRAPHICS CORPORATION v. EVE-USA, INC. 

ship that each of signal routing clock 117 having a 

higher frequency than an associated user clock 

118, signal routing clocks 117 are independent of 

user clocks 118. 

’882 patent at 4:13–19 (emphasis added). Synopsys 

argues this passage requires each signal routing clock to 

run faster than its associated user clock. It argues this 

means there is a relationship between the signal routing 

clock and the user clock, given that the signal routing 

clock must operate at a higher frequency than the user 

clock. Therefore, the specification does not disclose an 

“independent” signal routing clock. 

We do not agree. The very language of claim 1 which 

the court held was not supported by the specification was 

present in the originally-filed claims. Original claims are 

part of the original specification and in many cases will 

satisfy the written description requirement. Ariad, 598 

F.3d at 1349; see ScriptPro LLC v. Innovation Assocs., 

Inc., 833 F.3d 1336, 1341 (Fed. Cir. 2016); Crown Packaging, 635 F.3d at 1381. These claims raise none of the 

genus/species concerns that have caused us to question 

whether originally filed claims satisfy written description. 

See, e.g., Ariad, 598 F.3d at 1349–51. The claims at issue 

in this case are indistinguishable from other cases relying 

on originally-filed claims to satisfy the written description 

requirement. Like Crown Packaging, the “original claims 

clearly show that the applicants recognized and were 

claiming [the disputed limitation]. . . . These claims show, 

as Ariad recognized many original claims do, that the 

applicants had in mind the invention as claimed” and 

described it. 635 F.3d at 1381. Original claim 1 recites 

“one or more signal routing clock signals which are independent of the first and second clock signals.” J.A. 

19,441. This is the precise language the district court 

found missing from the ’882 specification. See J.A. 

23,749–50 (“[T]he specification does not demonstrate 

possession of the unqualifiedly independent clocking that 

Case: 15-1470 Document: 108-2 Page: 34 Filed: 03/16/2017
MENTOR GRAPHICS CORPORATION v. EVE-USA, INC. 35

the asserted claims require . . . .”) (JMOL order); compare 

ScriptPro, 833 F.3d at 1341 (finding written description 

support when the original claims and the challenged 

claims recited the same limitation). We conclude that this 

original claim language clearly demonstrates that the 

inventor possessed an invention including “one or more 

signal routing clock signals which are independent of the 

first and second clock signals” and described it.

We reverse the grant of summary judgment that 

claims 7, 9, and 13 of the ’882 patent are invalid for lack 

of written description and remand for further proceedings.11

3. Claim Preclusion Relating to Mentor’s ’531 and ’176

Patents 

The ’176 and ’531 patents are two of the three patents 

litigated in the 2006 lawsuit between Mentor and EVE. 

Mentor and EVE settled the litigation when EVE took a 

license to the asserted patents, and Mentor dismissed its 

claims with prejudice. Synopsys’ 2012 acquisition of EVE 

automatically terminated the Mentor/EVE license. Synopsys then filed a declaratory judgment action for noninfringement of the ’176 and ’531 patents, and Mentor 

counterclaimed for infringement. Mentor contends its 

infringement allegations were “based exclusively on acts 

 

11 Synopsys filed a motion to strike portions of Mentor’s reply brief. Docket No. 90. Synopsys argues Mentor 

raised five new arguments relating to the ’882 patent’s 

written description that it did not raise before the district 

court or in its opening brief to our court, and it contends 

those arguments should be struck. Because we decide the 

written description issue in Mentor’s favor on the argument it undisputedly properly raised, we need not consider the arguments arguably made for the first time in the 

reply brief. We deny the motion. 

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36 MENTOR GRAPHICS CORPORATION v. EVE-USA, INC. 

of infringement that occurred after October 4, 2012”—the 

date Synopsys acquired EVE. Mentor Br. 72. Synopsys 

moved for summary judgment that claim preclusion 

barred Mentor’s infringement allegations, and the district 

court granted the motion. 

Whether a cause of action is barred by claim preclusion is a question of law reviewed without deference. 

Brain Life, LLC v. Elekta Inc., 746 F.3d 1045, 1052 (Fed. 

Cir. 2014). We apply regional circuit law when determining whether claim preclusion applies. Id. In the Ninth 

Circuit, claim preclusion applies when the prior suit: (1) 

involved the same claim or cause of action as the later 

suit; (2) reached a final judgment on the merits; and (3) 

involved the same parties or privies. Id. (citing Mpoyo v. 

Litton Electro-Optical Sys., 430 F.3d 985, 987 (9th Cir. 

2005)). Whether two infringement allegations constitute 

the same claim or cause of action is an issue particular to 

patent law, and we apply our own law. Id. 

Mentor and Synopsys dispute the applicable law. Our 

recent decisions in Aspex Eyewear and Brain Life are 

squarely on point. In Aspex Eyewear, we addressed the 

third suit in a series of related actions involving the same 

patent and patentee. Aspex Eyewear, Inc. v. Marchon 

Eyewear, Inc., 672 F.3d 1335 (Fed. Cir. 2012). In the first 

action, the patentee asserted the patent against a first 

defendant. Id. at 1338. The district court found the 

patent infringed and not invalid. Id. at 1339. After a jury 

trial on damages, we affirmed. Id. In the second action,

the patentee asserted the patent against a second defendant. Id. The parties ultimately settled. Id. The settlement agreement contained a provision that the parties 

“stipulate to dismissal with prejudice of [the action], 

including all claims and counterclaims, and any claim 

which would have been had by and between the Parties 

arising from or connected with [the action].” Id. (alterations in original). Subsequently, the patentee filed a third 

action asserting the same patent against the same deCase: 15-1470 Document: 108-2 Page: 36 Filed: 03/16/2017
MENTOR GRAPHICS CORPORATION v. EVE-USA, INC. 37

fendants from the two prior actions, this time alleging 

infringement by newer models of the previously-accused 

products. Id. at 1340. The district court granted summary judgment that the patentee’s claims were barred by 

claim preclusion. Id. It held that the patentee’s infringement allegations “were the same as the claims that 

either were, or could have been, raised in the [previous 

actions]” and that the new accused products were “essentially the same” as the previously litigated ones. Id. 

We reversed. We explained that claim preclusion does

not bar later infringement allegations “with respect to 

accused products that were not in existence at the time of 

the [previous actions] for the simple reason that [claim 

preclusion] requires that in order for a particular claim to 

be barred, it is necessary that the claim either was asserted, or could have been asserted, in the prior action.” 

Id. at 1342. We explained that claim preclusion did not 

bar infringement allegations that “did not exist at the 

time of the earlier action.” Id. We held that “if the party 

could not have asserted particular claims [in a previous 

action]—because the tortious conduct in question had not 

occurred at that time—those claims could not have been 

asserted and therefore are not barred.” Id. (citing Lawlor 

v. Nat’l Screen Serv. Corp., 349 U.S. 322, 328 (1955)). 

And we explained that for products made or sold after the 

previous actions, it did not matter whether the new 

products were “essentially the same” as the previously 

accused products—claim preclusion did not bar the infringement allegations as to the new products. Id. 

We reemphasized that decision in Brain Life, where

we addressed a second action involving the same patent

as a prior litigation. Brain Life, 746 F.3d at 1050. In the 

first action, the jury found infringement and awarded 

damages. Id. We reversed on claim construction grounds, 

and the district court entered final judgment of no infringement. Id. After the final judgment, the patentee 

licensed the asserted patent to a new entity, and the new

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38 MENTOR GRAPHICS CORPORATION v. EVE-USA, INC. 

licensee filed suit against the same defendant from the 

first action. Id. at 1050–51. The licensee accused new 

products (that were not at issue in the prior litigation) of 

infringement, but it conceded “there was no material 

difference between the currently accused products and the 

previously adjudicated noninfringing products.” Id. at 

1051. The district court granted summary judgment that 

claim preclusion barred the licensee’s infringement allegations. Id. We reversed. We held that claim preclusion 

did not bar any infringement allegations that postdated 

the prior judgment. Id. at 1054 (“We find that [the patentee’s] second suit is not barred by claim preclusion—

regardless of whether the same transactional facts are 

present in both suits—to the extent [the patentee’s] 

current infringement allegations are temporally limited to 

acts occurring after the final judgment was entered in the 

first suit.”). We explained that claim preclusion did not 

bar allegations of infringement occurring after the prior 

final judgment because the patentee could not have 

brought those claims in the prior case. Id. 

Exactly like Aspex Eyewear and Brain Life, Mentor’s 

infringement allegations are based on alleged acts of 

infringement that occurred after the Mentor/EVE license 

terminated and were not part of the previous lawsuit. See

J.A. 1223–27 (Mentor’s 2013 counterclaims of infringement); Mentor Br. 72. Claim preclusion does not bar 

these allegations because Mentor could not have previously brought them. See Brain Life, 746 F.3d at 1054. The

present lawsuit is based on post-license conduct, so the 

alleged infringement did not exist during the previous 

action. See Lawlor, 349 U.S. at 328 (“[The prior judgment] cannot be given the effect of extinguishing claims 

which did not even then exist and which could not possibly have been sued upon in the previous case.”); Asetek 

Danmark, 842 F.3d at 1362 (“It is well established, however, that the difference in timing means that the two 

situations do not involve the same ‘claim’ for claimCase: 15-1470 Document: 108-2 Page: 38 Filed: 03/16/2017
MENTOR GRAPHICS CORPORATION v. EVE-USA, INC. 39

preclusion purposes, even if all the conduct is alleged to 

be unlawful for the same reason.”). Thus, Mentor’s allegations are not barred. See Aspex Eyewear, 672 F.3d at 

1342. Because the allegations could not have been 

brought in the first action, we need not determine whether the newly accused products are “essentially the same” 

as the products litigated in the first action. See id. 

Synopsys contends Aspex Eyewear and Brain Life are 

inconsistent with our decisions in the Foster cases, which 

it argues control because they were issued prior to Aspex 

Eyewear and Brain Life. See Foster v. Hallco Mfg. Co., 

947 F.2d 469 (Fed. Cir. 1991) (“Foster I”); Hallco Mfg. Co. 

v. Foster, 256 F.3d 1290 (Fed. Cir. 2001) (“Foster II”). 

Foster I addressed a second action after a previous action 

ended with a consent judgment. Foster I, 947 F.2d at 472. 

In the first action, the parties settled, and the defendant 

obtained a license to the asserted patents. Id. The consent judgment contained a provision saying the asserted 

patents were “valid and enforceable in all respects.” Id. 

The defendant subsequently began manufacturing new 

products and filed suit seeking a declaration that the 

asserted patents were invalid and the new products did 

not infringe. Id. at 473. We held that claim preclusion 

barred relitigation of the patents’ validity only if the 

patentee’s “claim” was identical to its previous claims. Id. 

at 478. We explained that “a ‘claim’ rests on a particular 

factual transaction or series thereof on which a suit is 

brought.” Id. at 479. We were “unpersuaded that an 

‘infringement claim,’ for purposes of claim preclusion, 

embraces more than the specific devices before the court 

in the first suit.” Id. In Foster II—an unrelated lawsuit 

involving the same parties—we addressed whether a 

defendant could challenge a patent’s validity in a second 

action after a first action involving the patent was dismissed with prejudice after a settlement. Foster II, 256 

F.3d at 1294. We held that claim preclusion bars relitigation of the patent’s validity only if the accused 

Case: 15-1470 Document: 108-2 Page: 39 Filed: 03/16/2017
40 MENTOR GRAPHICS CORPORATION v. EVE-USA, INC. 

devices “are essentially the same, or if any differences 

between them are merely colorable.” Id. at 1297. 

There is language in the Foster cases that could be 

read as inconsistent with Aspex Eyewear and Brain Life. 

However, the cases addressed different factual issues. 

Foster I and Foster II both addressed whether a defendant

could re-raise validity challenges in a subsequent action. 

In Foster II, we specifically characterized Foster I as 

addressing “under what circumstances, if any, claim 

preclusion would operate to prevent a subsequent challenge to patent validity when the device in the second 

action was not involved in the first action.” Foster II, 256 

F.3d at 1295. Neither case addressed whether a patentee

could bring new infringement allegations based on conduct occurring after a previous litigation ended. This is 

the precise issue addressed in Aspex Eyewear and Brain 

Life and the precise issue now before us.

Reading the Foster cases as Synopsys requests—that 

claim preclusion bars successive infringement suits when 

the accused products are essentially the same—would not 

only create an intra-circuit split, but also would be inconsistent with the Supreme Court’s decision in Lawlor. In 

Lawlor, the Supreme Court instructed that a prior judgment “cannot be given the effect of extinguishing claims 

which did not even then exist and which could not possibly have been sued upon in the previous case.” Lawlor, 

349 U.S. at 328. Aspex Eyewear and Brain Life are consistent with this holding. Conversely, interpreting the 

Foster cases as barring a patentee from asserting infringement allegations that did not exist at the time of a 

previous action would be at odds with Lawlor. 

The facts of the underlying case further weigh against 

Synopsys’ position. Synopsys consciously terminated the 

Mentor/EVE license by acquiring EVE. Similarly, EVE 

consciously terminated the Mentor/EVE license by allowing itself to be acquired by Synopsys. Synopsys/EVE

Case: 15-1470 Document: 108-2 Page: 40 Filed: 03/16/2017
MENTOR GRAPHICS CORPORATION v. EVE-USA, INC. 41

should not be able to use the fact that it voluntarily 

terminated the Mentor/EVE license as a shield from 

further infringement liability. If we adopted Synopsys’ 

position, any licensee holding a license obtained through 

litigation could breach that license, yet prevent the patentee from asserting infringement against new products

not covered by the license. A licensee should not be able 

to use the fact that it voluntarily terminated a license as a 

shield against future infringement liability.12 

Synopsys also argues Mentor’s infringement allegations are barred by the Kessler decision. See Kessler v. 

Eldred, 206 U.S. 285 (1907). The Kessler decision permits 

an adjudicated non-infringer “to continue the same activity in which it engaged prior to the infringement allegations once it ha[s] defeated those contentions in the first 

suit.” Brain Life, 746 F.3d at 1056. It allows “an adjudged non-infringer to avoid repeated harassment for 

continuing its business as usual post-final judgment in a 

patent action where circumstances justify that result.” 

Id. (emphasis in original). EVE is not an adjudicated noninfringer; it was a willing licensee that was granted a 

license to the ’176 and ’531 patents, which terminated 

when it was acquired by Synopsys. Without a valid 

license from Mentor, it could not “continue the same 

activity in which it engaged prior to the infringement 

allegations.” The Kessler decision does not apply. 

Consistent with the Supreme Court’s Lawlor decision 

and our decisions in Aspex Eyewear and Brain Life, we 

hold that claim preclusion does not bar a patentee from

 

12 Mentor filed its ’176 and ’531 infringement allegations as a counterclaim to Synopsys’ declaratory judgment 

of non-infringement. J.A. 1216–29. It would be strange 

to hold that claim preclusion barred a patentee from 

raising a counterclaim of infringement when it was sued 

for a declaration of non-infringement. 

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42 MENTOR GRAPHICS CORPORATION v. EVE-USA, INC. 

bringing infringement claims for acts of infringement 

occurring after the final judgment in a previous case. We 

reverse the grant of summary judgment that claim preclusion barred Mentor’s assertion of the ’531 and ’176 

patents and remand for further proceedings. 

III. CONCLUSION

We hold there was substantial evidence to support the 

jury’s infringement verdict regarding the ’376 patent and 

affirm the district court’s denial of judgment as a matter 

of law. We affirm the damages award. We affirm the 

summary judgment that assignor estoppel bars Synopsys 

from challenging the validity of the ’376 patent. We 

reverse the summary judgment that Synopsys’ ’109 patent 

is indefinite. We affirm the summary judgment that 

Synopsys’ ’526 patent lacks eligible subject matter. We 

vacate the order granting the motion in limine precluding 

Mentor from presenting evidence of willful infringement

and remand for a trial of that issue and assessment of 

Mentor’s claim for enhanced damages. We reverse the 

summary judgment that Mentor’s ’882 patent lacks 

written description support. Finally, we reverse the 

summary judgment that Mentor’s infringement allegations regarding the ’531 and ’176 patents are barred by 

claim preclusion.

We remand for further proceedings consistent with 

this opinion. 

AFFIRMED-IN-PART, REVERSED-IN-PART, 

VACATED-IN-PART, AND REMANDED

COSTS

Costs to Mentor. 

Case: 15-1470 Document: 108-2 Page: 42 Filed: 03/16/2017