Revere Transducers, Inc. v. Deere & Co.

Several questions are presented in this appeal and cross appeal concerning plaintiff Revere Transducers, Inc.’s action against defendant Deere & Company for tortious interference with contractual relations, misappropriation of trade secrets and civil conspiracy. The basis of Revere’s claims is that Deere allegedly induced two former Revere employees, Greg Eckart and Francis Delfino, to violate an employment agreement with Revere, start a company, and develop and manufacture a draft sensor device to sell to Deere, which would replace a similar device that Revere was manufacturing and selling to Deere.

A jury returned verdicts in favor of Revere on its claims for tortious interference with contractual relations and civil conspiracy and in favor of Deere concerning Revere’s claim for misappropriation of trade secrets.

On Deere’s appeal and Revere’s cross appeal, we affirm in part, reverse in part and remand.

I. Background facts and proceedings.

A. Establishment of relationship between Revere and Deere. Plaintiff, Revere Transducers, Inc., is a Delaware corporation with its principal place of business in California, and operates a facility in Connecticut. Revere is engaged in the manufacture, marketing and sale of devices called resistive strain gauge force transducers. A force transducer is a device which measures force. A strain gauge is an electrical conductor which measures strain and is a component part of a force transducer.

Defendant Deere & Company is a Delaware corporation with its principal place of business in Illinois. Deere is engaged in the manufacture of tractors and has a facility in Waterloo, Iowa.

In the mid-1980s Deere became interested in locating a company to develop and manufacture a draft sensor device which, when installed on its tractors, would regulate the depth of an attached plow in the ground and monitor the forces on the plow as the tractor was plowing.

In 1986, Deere contacted a number of different manufacturers of strain gauge sensing devices, including plaintiff Revere. Revere and Deere discussed the possibility of using a “Gozinta.” A Gozinta is a strain gauge force sensor device developed and manufactured by Revere under the registered trademark “Gozinta.”

The Gozinta is a metal capsule or cylinder-shaped device, approximately two inches long. One end of the Gozinta has a ridged or “knurled” surface, similar to the edge of a coin. The Gozinta is pressed into a hole in a member or metal strap and the knurled surface accomplishes an interference fit between the Gozinta and the receiving member. In oversimplified terms, the Gozinta measures the strain produced in the member in which it is inserted.

Inside the metal capsule is a disc with four evenly spaced holes which channel the stress toward four strain gauges mounted on the disc. The holes have a minimum diameter of one-eighth of an inch. Wire pins extend through the holes to the strain gauges'and connect the strain gauges to an electric circuit board, or amplifier. The wire pins transfer the strain gauge signal or changes in resistance back through the printed circuit board or amplifier. The signal would eventually be transmitted to the tractor’s computer. By drilling a hole in a hitch that attaches a plow to a tractor, and placing a Gozinta in the hole, the force on the plow can be calculated.

*756 The concept of using Revere’s Gozinta as a draft sensor in a Deere product was unique. Deere had experience using strain gauges in testing application, but had never used strain gauges in a product.

To formalize their business relationship, Revere and Deere signed an agreement entitled “Non-Disclosure Agreement for Proprietary Information” in June 1986 to protect the proprietary information of the parties.

The initial plan was that Revere would manufacture the Gozinta at its plant in Connecticut. The Gozinta would then be inserted into a Deere designed strap made of forged steel. The Deere metal strap was to be manufactured by a third party. The decision was later made that Revere would be responsible for assembling the completed device, that is, inserting the Gozinta into Deere’s metal strap.

Deere was to provide the funding for the unique tooling which would be necessary for the manufacture, assembling and testing of the Gozinta. Deere agreed to purchase a fixed total quantity of Gozintas from Revere, pursuant to a blanket purchase order. The purchase order included language stating that Deere, at its discretion, could terminate the purchase order with 120 days notice. The parties estimated that production quantities of the Gozin-ta would increase from 5000 in 1989 to 30,000 in 1991. The original price of the Gozinta to Deere was estimated at $129.50 per part but later increased to $138.22.

Revere and Deere worked jointly on the project, and development of the Gozinta draft sensor device consumed the efforts of Deere and Revere over a three to four-year period. Each party had a team of engineers working on the project.

Francis Delfino, a manufacturing engineer, was a member of the Revere team. Delfino was responsible for designing the processes and equipment to manufacture the Gozinta and played an important role in its development. Delfino was hired by Revere on September 15,1986.

Greg Eckart was another member of the Revere team. Eckart was not an engineer but was a product manager and was the primary contact between Revere and Deere for the Gozinta/Deere project. Ec-kart was hired by Revere on August 26, 1986.

At the time they were hired, Delfino and Eckart signed agreements whereby they agreed to disclose any inventions or discoveries they made during their employment to Revere and also agreed not to disclose any such inventions or discoveries to others without Revere’s consent. The agreement further stated that Delfino and Eckart agreed not to disclose any inventions or discoveries relating to Revere’s methods, processes, or apparatus or production of goods or materials for a period of one year following termination from Revere’s employment. Delfino and Eckart also agreed to assignment of their rights to Revere in any invention or discovery made by them during their employment by Revere and agreed not to disclose to others at any time during their employment any confidential information, knowledge or data belonging to Revere without first obtaining Revere’s written consent. Delfino and Eckart were not bound by any other employment agreement or noncompete agreement and thus were considered at-will employees.

B. Production problems arose. According to Revere, Deere was late in supplying the funding for the tooling which prevented Revere from proceeding with development of the Gozinta. The strap forging company chosen by Deere also was late in providing the forged steel straps to Revere. Due to these delays, Revere was forced to begin actual production of the Gozinta without an opportunity to perform preproduction testing or a pilot run.

Revere began actual production of the Gozinta in December 1988. Production was not immediately successful. Problems developed in that the Gozinta produced an excessive output signal and produced an *757 unpredictable output of the sensor when no load was applied. Initial yields during the first few months of production were in the 17-20% range. (Yield is defined as the percentage of parts produced that passed post-production tests and were actually shipped to Deere.) Because of the low yields, Deere was forced to ship tractors to customers with a temporary part that would have to be replaced later.

Both Deere and Revere worked to solve the problems encountered in manufacturing the Gozinta. After testing and analysis, it was determined that problems with the product were related to the physical dimensions of the Deere metal strap. Deere, however, believed that some of the problems were due to the poor quality of the knurls on the Gozinta that Revere was receiving from its vendor. Deere later learned that Revere had changed suppliers for the knurl, but had not informed Deere.

While Revere and Deere were working to solve the problems associated with the Gozinta/Deere project, Revere was experiencing significant downsizing in its personnel following its purchase in 1988 by Dobson-Park, an English corporation. Several Revere employees who worked on the Gozinta/Deere project either left or were laid off.

Eckart and Delfino were concerned about their positions at Revere. Eckart was informed by his supervisor that Revere’s Connecticut plant would be closed in July 1989 and that he should start looking for another job. Delfino was initially assured by his supervisor that his job was secure and that he had nothing to worry about. That particular supervisor was laid off two weeks later. In early 1989, Delfino and Eckart told David Ramsey of Deere that they were scheduled to be let go from Revere.

C. Deere’s search for another sensor supplier. Although yields of the Gozinta had improved to 95% in the summer of 1989, the Revere Gozinta never completely met Deere’s engineering qualification tests. Deere was also concerned about whether Revere would be a long-term viable supplier. Based on these concerns, in addition to the turnover in Revere personnel, Deere, unknown to Revere, started looking for an alternative part for the Goz-inta.

To address some of the problems associated with the project, Deere and Revere held a meeting in Waterloo in February 1989. Eckart was not present at the meeting. During the meeting, Ramsey, a Deere engineer, suggested that perhaps the sensor could be welded rather than pressed into place. According to Deere employees, John Elengo, Revere’s vice president of engineering, said that he did not think that welding the device would work because it would put too much stress on the sensor and cause it to fail.

In early 1989, Eckart, Revere’s product manager for the Gozinta project, was having frequent conversations with Carl Ku-nath concerning product shipments of the Gozinta and problems associated with it. Kunath was employed by Deere as a buyer/purchasing agent of electronic and mechanical parts for Deere tractors and was Deere’s primary contact with Revere on the Gozinta project. During a conversation in early March 1989, the subject of personnel changes at Revere came up. At some point during the conversation, Ec-kart told Kunath that he intended to leave Revere and develop a consulting engineering business and that he had ideas for installing Gozintas into new products, some of which may be applicable to Deere. Kunath testified he told Eckart that, if he had any ideas, to send Deere a proposal. Kunath testified that he did not invite or solicit Eckart to submit a proposal, but that Eckart mentioned he had an idea and wanted to know if Deere was interested. Kunath told Eckart that he would have to submit the proposal to Deere’s engineering department because he was not in the position to receive proposals on engineering ideas or concepts.

*758 After this conversation, Eckart approached Delfino, a lead Revere manufacturing engineer working on the Gozin-ta/Deere project, and inquired if he would be interested in developing a new draft sensor for Deere that would be welded, rather than pressed, into a hole. Delfino and Eckart agreed to meet one day after work to discuss their ideas. Delfino and Eckart eventually met with a lawyer at Delfino’s suggestion. The record contains a letter from an attorney dated March 10, 1989, addressed to Delfino and Eckart regarding their potential liability concerning the manufacture of a welded-in disc sensor. The letter stated that if Delfino and Eckart decided to develop the welded-in sensor, it was extremely important for them not to take any documents, models, or engineering drawings from Revere. The letter also indicated that Delfino and Eckart’s contractual obligation regarding disclosure of inventions and discoveries presented the most risk and that the possibility of liability hinged on the definition of inventions and discoveries, but that what Delfino and Eckart were considering was not an invention or discovery in the narrower sense.

Sometime thereafter, but before March 12, Delfino and Eckart formed a company called D E Sensor Manufacturing, Inc.

On March 12, 1989, Delfino and Eckart, through their company D E Sensor, wrote to Kunath at Deere. The letter contains a quotation of estimated cost for “the development and manufacturing of a functional equivalent to sensor assembly part number RE30962 rev H,” a replacement part for the Gozinta. The letter also discusses payment schedules for development of the sensor. Attached to the letter were a number of drawings for a new strap assembly and draft sensor components.

Sometime thereafter, Delfino, Eckart and Kunath of Deere met in a hotel in Connecticut to discuss D E’s proposal for a welded-in sensor. Neither Delfino nor Ec-kart informed Revere of the meeting.

On April 11, 1989, Kunath of Deere wrote to Eckart confirming its intention to provide a purchase order in the amount of $172,900 for design and development work by D E of a welded-in sensor, known as a “weldzinta,” to replace the Gozinta.

On April 19, Delfino notified Revere that he was terminating his employment effective May 5. On April 26, Eckart notified Revere that he was terminating his employment effective April 28.

Subsequently, in July 1990, Kunath wrote to Revere stating that Deere was canceling its contract for purchasing Goz-intas. The letter also stated that “we [Deere] have developed a new product that replaces RE30962 [the Gozinta],” that will begin production at Deere’s facility on October 29,1990.

D. The Connecticut and present litigation. Revere eventually discovered that Delfino and Eckart were making a sensor similar to the Gozinta and sued Delfino and Eckart in federal district court in Connecticut in December 1992 for patent and trademark infringement and breach of contract. A noncompete injunction was entered against D E on February 4, 1993.

Revere later filed a petition in the present action against defendant Deere in Iowa district court on August 24, 1993, seeking damages for tortious interference with contractual relations, misappropriation of trade secrets, and civil conspiracy.

On November 30, 1993, Revere dismissed its claims against Delfino and Ec-kart in the Connecticut federal court action pursuant to a settlement agreement. In return for settlement of all pending disputes against them, and subject to any rights which Revere might have against Deere, Delfino and Eckart executed a promissory note in the amount of $60,000 in favor of Revere. Upon consent of the parties, the district court entered a permanent injunction which permanently enjoined Delfino and Eckart, acting through D E, from manufacturing certain types of sensors.

*759 Revere’s claims against Deere in the present action were tried to a jury. The jury returned verdicts on January 14, 1997 for compensatory damages in plaintiff Revere’s favor concerning the tortious interference with a contract and the civil conspiracy claims, and awarded $350,000 and $200,000 in damages on those respective claims. The jury found in defendant Deere’s favor regarding Revere’s claim for misappropriation of trade secrets. The jury also awarded Revere punitive damages in the amount of $450,000, but also found that Deere’s acts were not directed against Revere.

Judgment was promptly entered on the verdicts.

The district court later overruled Deere’s motions for judgment notwithstanding the verdict and for new trial and Revere’s motion for a new trial.

Deere appealed and Revere cross appealed concerning the verdicts and rulings that were adverse to them.

Other facts will be stated as we discuss the assignments of error raised by the parties.

II. Enforceability of employment agreement.

We first address Deere’s contention that the district court erred in overruling Deere’s motion for judgment notwithstanding the verdict concerning Deere’s position that Revere’s employment agreements with Delfino and Eckart were not enforceable and thus cannot be the basis for Revere’s claim for tortious interference with a contract.

When considering a motion for judgment notwithstanding the verdict on appeal, we view the evidence as the trial court did in ruling on the motion, that is, in the light most favorable to the party against whom the motion was directed. Faught v. Budlong, 540 N.W.2d 33, 35 (Iowa 1995).

Iowa Rule of Civil Procedure 243(b) provides:

If the movant was entitled to a directed verdict at the close of all the evidence, and moved therefor, and the jury did not return such verdict, the court may then either grant a new trial or enter judgment as though it had directed a verdict for the movant.

The purpose of rule 243(b) is to afford the trial court an opportunity to correct its error in failing to sustain a motion for directed verdict where the movant was entitled to a directed verdict at the close of all evidence. Meeker v. City of Clinton, 259 N.W.2d 822, 827 (Iowa 1977).

A motion for judgment notwithstanding the verdict should be denied if there is substantial evidence to support the claim. Faught, 540 N.W.2d at 35. Conversely, absent such evidence, judgment notwithstanding the verdict may be sustained. Id. “Evidence is substantial when a reasonable mind would accept it as adequate to reach a conclusion.” Johnson v. Dodgen, 451 N.W.2d 168, 171 (Iowa 1990).

A. Language of the agreement. At the time they were hired by Revere, Eckart and Delfino each signed an agreement concerning disclosure of confidential information and inventions and/or discoveries and assignment of such inventions and/or discoveries, hereinafter referred to as the Revere agreement or agreement. The Revere agreement included the following provisions:

(1) During the period of my employment I will disclose promptly and in writing to the head of the department or the division in which I am employed, or to such other person as the Company may designate, all inventions or discoveries which I may make, whether alone or with others, and whether during normal business hours or otherwise, and I will not disclose such inventions or discoveries to others, except as required by my employer, without prior written consent of the Company.

*760 (2) For a period of one year following the termination of my employment for any reason, I will not disclose as herein-before provided, all inventions and discoveries made by me which relate to: (1) methods, processes, or apparatus concerned with the production of any character of goods or materials used or sold by the Company, or (2) in respect to any character of goods or materials sold or used by the Company.

(3) I hereby assign all of my right, title, and interest in and to such inventions and discoveries to the Company, and agree that I will, when requested at any time during my employment or thereafter execute specific assignments of any such inventions or discoveries to the Company or its nominee....

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(5) I acknowledge that technical information other than that generally published and available to the public and other confidential information regarding the Company’s business of which I may obtain knowledge in the course of and by virtue of my employment by the Company constitute valuable and confidential assets of the Company’s business and that unauthorized disclosure thereof would be detrimental to the Company. I therefore agree that I will not disclose to others at any time during my employment or thereafter any confidential information, knowledge or data belonging to the Company, without first obtaining the Company’s written consent thereto, except as such disclosure may be required by my service to the Company or by law.

(Emphasis added.)

On appeal, Deere contends that the Revere agreement is not enforceable because the language is overly broad and so open-ended as to include inventions and discoveries that are totally unrelated to Revere’s business or its employees. Deere thus argues that because the Revere agreement is unenforceable, it cannot be the basis for a claim for tortious interference with a contract.

Before examining whether the Revere agreement is enforceable, we deem it helpful to clarify the applicable standards concerning the enforceability of employment agreements containing nondisclosure-confidentiality or assignment provisions.

We point out that the Revere agreement only addresses Delfino and Eckart’s duties concerning disclosure or nondisclosure of confidential information and inventions and/or discoveries, and assignment of rights thereto, made by them during their employment with Revere; the agreement does not contain any noncompete provisions.

B. Applicable law. At this point in the analysis, we are only concerned with whether the terms of Revere’s agreement with Delfino and Eckart are reasonable. This inquiry is different from whether Del-fino and Eckart breached the agreement, which will be discussed later.

We have apparently never addressed the enforceability of an employment agreement containing a nondisclosure-confidentiality provision. We have, however, established certain rules concerning how to determine the enforceability of a noncom-pete agreement. See Lemmon v. Hendrickson, 559 N.W.2d 278, 282 (Iowa 1997) (employment agreement contained nondisclosure provision but validity of provision was not discussed); Lamp v. American Prosthetics, Inc., 379 N.W.2d 909, 910 (Iowa 1986); Iowa Glass Depot, Inc., v. Jindrich, 338 N.W.2d 376, 381 (Iowa 1983). We believe that the rules concerning the enforceability of noncompete agreements, as restrictive covenants, may be helpful concerning the enforceability of Revere’s agreement with Delfino and Eckart and we therefore briefly review those rules.

We have established the following three-pronged test to be applied in determining whether an employment contract containing a restrictive covenant is enforceable:

*761 (1) Is the restriction reasonably necessary for the protection of the employer’s business; (2) is it unreasonably restrictive of the employee’s rights; and (3) is it prejudicial to the public interest?

Lamp, 379 N.W.2d at 910. We have stated that “[cjovenants not to compete are unreasonably restrictive unless they are tightly limited as to both time and area.” Lemmon, 559 N.W.2d at 282.

Factors we consider in determining the enforceability of a noncompete agreement include the employee’s close proximity to customers, the nature of the business, accessibility to information peculiar to the employer’s business, and the nature of the occupation which is restrained. Jindrich, 338 N.W.2d at 382. “An employee cannot be precluded from exercising the skill and general knowledge [the employee] has acquired or increased through experience or even instruction while in the employment.” Id. at 383.

N ondisclosure-eonfidentiality agreements enjoy more favorable treatment in the law than do noncompete agreements. See Terry Morehead Dworkin & Elletta Sangrey Callahan, Buying Silence, 36 Am. Bus.L.J. 151, 156-57 n. 30 (1998) [hereinafter Dworkin & Callahan]. This is because noncompete agreements are viewed as restraints of trade which limit an employee’s freedom of movement among employment opportunities, while nondisclosure agreements seek to restrict disclosure of information, not employment opportunities. See id. The distinction is based on the idea that “[o]nce a secret is disclosed, knowledge of the information cannot normally be confined to a particular area.” Restatement (Third) of Unfair Competition § 41 cmt. d. (1995). Thus, imposition of geographic or durational limitations “would defeat the entire purpose of restricting disclosure, since confidentiality knows no temporal or geographical boundaries.” 2 Rudolf Callmann, The Law of Unfair Competition, Trademarks & Monopolies § 14.04, at 222-23 (Supp.1998) [hereinafter Callmann], Thus, nondisclosure agreements lacking in geographic or time limitations have been held to be enforceable. See Dworkin & Callahan, at 156-57 n. 30.

Some states, however, either because of statutory law or public policy, require some form of geographic or time limitations in order for a nondisclosure agreement to be enforceable. See Callmann, § 14.04, at 225-26 n. 19.52 (Supp.1998) (noting that even after Illinois and Georgia enacted statutes stating that contractual duties regarding secrecy of trade secrets shall not be deemed void or unenforceable solely for lack of durational or geographical requirements, courts in those states still held nondisclosure agreements invalid for lack of such restrictions).

Additionally, some states consider nondisclosure-confidentiality agreements to be a restraint of trade and such agreements are therefore regulated by state statutes governing contracts in restraint of trade. 1

Employment agreements requiring an employee to assign to the employer rights to inventions designed or conceived during the period of employment have been upheld. See Ingersoll-Rand Co. v. Ciavatta, *762 110 N.J. 609, 542 A.2d 879, 886 (1988); Callmann, § 14.27, at 95 (1996) (agreements to assign all inventions and improvements in employer’s field, patentable or unpatentable, which are developed by employee during employment belong to employer and such agreements are not invalid or unenforceable as an unreasonable restraint of trade); 27 Am.Jur.2d Employment Relationship § 288, at 735 (1996). We have said that

In the absence of special agreement to the contrary, an invention and a patent secured for it belong to the inventor, even though the invention was made during the period of his employment, and the invention relates to the matter in which the inventor was employed.

Bandog, Inc. v. Morenings, 259 Iowa 998, 1002, 146 N.W.2d 916, 918 (1966) (emphasis added) (quoted source omitted) (concluding that plaintiff-employer was not entitled to right and title to patentable formulas developed by employee during employment where employer had no agreement requiring employees to assign inventive ideas to employer). The determining factor of whether assignment-of-rights-agreements are enforceable seems to be one of reasonableness. See Inger-sollr-Rand, 542 A.2d at 886 (“Courts ... will not enforce invention assignment contracts that unreasonably obligate an employee in each and every instance to transfer the ownership of the employee’s invention to the employer.”).

C. Application of law to facts. Upon consideration of the principles discussed above, we conclude that the following test should be applied in determining whether a nondisclosure-confidential or invention assignment agreement is enforceable:

(1) Is the restriction prohibiting disclosure reasonably necessary for the protection of the employer’s business;

(2) is the restriction unreasonably restrictive of the employee’s rights; and

(3) is the restriction prejudicial to the public interest?

This test is obviously the same as that used to determine the enforceability of a noncompete agreement. We further conclude, however, that the absence of restrictions concerning time or geographic location do not render a nondisclosure-confidentiality, agreement presumptively unenforceable. This is because the inquiry whether the nondisclosure agreement unreasonably restricts the employee’s rights would address the breadth of the restrictions regarding disclosure. Having articulated the proper standard, our next task is to apply it.

The Revere agreement imposed basically three types of restrictions on Delfi-no and Eckart concerning disclosure of Revere proprietary information. First, the agreement required Delfino and Ec-kart to disclose to Revere any inventions and/or discoveries made by them during the course of their employment and also required them to assign their rights to any such inventions or discoveries to Revere. Second, the agreement precluded Delfino and Eckart from disclosing inventions and/or discoveries related to “methods, processes or apparatus concerned with the production of any character of goods or materials used or sold by the Company.” Third, the agreement precluded Delfino and Eckart from disclosing “any confidential information, knowledge or data belonging to the Company.”

Upon our review, we conclude that the restrictions in the agreement concerning disclosure of, and assignment of rights to, inventions and/or discoveries and confidential information, knowledge or data are reasonably necessary to protect Revere’s business interests. We believe an employer has the right to preclude its employees from disclosing such information. The language in paragraph five of the agreement regarding “technical information other than that generally published and available to the public” contemplates that an employee is only precluded from disclosing information that would not generally be *763 known by the public. We thus conclude that the restrictions concerning disclosure are sufficiently narrow in scope such that they do not interfere with Delfino and Eckart’s ability to use skills and general knowledge they acquired through employment with Revere in future employment. We further conclude that the invention assignment provision is reasonable and enforceable. Nor do we find any evidence in the record showing that enforcement of the restrictions is prejudicial to the public interest. The question of what information would constitute an invention or discovery or may be classified as confidential information, knowledge or data is more related to the inquiry regarding whether Delfino and Eckart breached the agreement and will be discussed later.

We thus conclude that Revere’s agrees ment with Delfino and Eckart concerning disclosure of Revere’s business information and assignment of inventions and discoveries is enforceable. The district court therefore properly overruled Deere’s motion for judgment notwithstanding the verdict concerning this issue.

III. Evidence concerning Revere’s claim for tortious interference with contractual relations.

Having determined that Revere’s agreement with Delfino and Eckart is valid and enforceable, we next consider Deere’s contention that even if the agreement is enforceable, the evidence is not sufficient to support the jury’s verdict that Deere tor-tiously interfered with Revere’s nondisclosure agreement with Delfino and Eckart. This issue was raised by Deere’s motions for directed verdict and for judgment notwithstanding the verdict.

A. Standard of review.

This action was tried at law. In such cases, we review for correction of errors of law. Iowa R.App.P. 4. Our scope of review in such cases is quite limited and factual findings of the jury are binding upon us if supported by substantial evidence. Iowa R.App.P. 14(f)(1); Toney v. Casey’s General Stores, Inc., 460 N.W.2d 849, 851 (Iowa 1990). We examine the evidence in a light most favorable to the verdict. Toney, 460 N.W.2d at 861-52. We are, however, not bound by the district court’s application of legal principles or conclusions of law. Power Eng’g & Mfg., Ltd. v. Krug Int’l, 501 N.W.2d 490, 493 (Iowa 1993).

B. Analysis.

Instruction no. 11 informed the jury that in order to recover on its claim for intentional interference with a contract, Revere had to prove all of the following:

(1) The Plaintiff had written contracts with Gregory Eckart and Francis Delfi-no.

(2) The Defendant knew of those contracts.

(3) The Defendant intentionally and improperly interfered with those contracts.

(4)(A) The interference caused Gregory Eckart and Francis Delfino to breach their contracts.

OR

(B) The interference caused Plaintiffs performance of the contract to be more burdensome or expensive.

(5) The amount of damages caused.

This is a correct statement of the law. See Jones v. Lake Park Care Center, Inc., 569 N.W.2d 369, 377 (Iowa 1997) (quoting Nesler v. Fisher & Co., 452 N.W.2d 191, 198 (Iowa 1990)); Robert’s River Rides v. Steamboat Dev. Corp., 520 N.W.2d 294, 303 (Iowa 1994).

1. Existence of contract.

We concluded above that Revere had an enforceable agreement with Delfino and Eckart. Revere thus presented substantial evidence to satisfy the first element.

*764 2. Knowledge of the agreement.

Deere contends Revere presented no evidence to prove that it had knowledge of Revere’s agreement with Delfino and Ec-kart.

Jury instruction no. 13 stated:

In order for you to find for the Plaintiff, you must determine that the Defendant knew of the existence of a contract. It is not necessary that the Defendant had actual knowledge of the specific contract. It is sufficient that the Defendant had knowledge of facts which, if followed by reasonable inquiry, would have led to the disclosure of the contractual relationship between the Plaintiff and Francis Delfino and Gregory Eckart.

We believe that the jury instruction correctly states the law concerning the knowledge element of a claim for tortious interference with contract. See Kallok v. Medtronic, Inc., 573 N.W.2d 356, 362 (Minn.1998) (“Tortious interference is not justified when a plaintiff demonstrates that the ‘defendant had knowledge of facts which, if followed by reasonable inquiry, would have led to a complete disclosure of the contractual relations and rights of the parties.’ ”) (quoting Swaney v. Crawley, 154 Minn. 263, 265, 191 N.W. 583, 584 (1923)); Callmann, § 9.01.50, at 99 (1996) (“There must be knowledge by the defendant ... of the contract or relationship interfered with; or at least of sufficient facts which, if followed by reasonable inquiry, would have revealed it.”).

Eckart testified that Delfino told Baxter and Kunath of Deere about their employment agreements with Revere prior to the time they resigned. The record also shows that Delfino made statements to Deere employees about an employment agreement with Revere. The record also includes notes that Kunath of Deere wrote to himself concerning the formation of D E Sensor. The notes contain comments regarding “signed corp. papers as D E Sensor Mfg. Inc,” “their lawyer recommended talking to pat atty,” “lawyer recommended leave Revere within a short time.” These notes were obviously written before Delfi-no and Eckart left Revere. Additionally, the jury could infer from these notes that Delfino and Eckart told Kunath about their employment agreement with Revere and their lawyer’s comments on the subject. Baxter of Deere testified he signed an agreement whereby he agreed to assign any patent rights to Deere.

On the other hand, Deere employees Kunath, Baxter, Dewey and Ramsey testified on Deere’s behalf that they either did not know or did not inquire whether Delfi-no and Eckart had a nondisclosure-confidentiality agreement with Revere.

We conclude that substantial evidence exists in the record to support the jury’s verdict that Deere had knowledge of sufficient facts to put it on notice regarding Revere’s agreement with Delfino and Eckart. concerning disclosure of confidential information and/or discoveries and inventions and assignment of rights thereto. While the evidence presented was conflicting, it was the jury’s duty to evaluate the evidence qjid make a decision concerning whether Deere had knowledge of Revere’s agreement with Delfino and Eckart.

3. Evidence regarding breach.

In order to find in favor of Revere concerning its claim of tortious interference with business relations, the jury had to find that Delfino and Eckart violated their agreement with Revere concerning disclosure of Revere’s proprietary information and assignment of rights to inventions. See Iowa-Illinois Gas & Elec. Co. v. Black & Veatch, 497 N.W.2d 821, 825 (Iowa 1993) (“questions of performance or breach are for the jury”).

Deere argued to the jury that the March 12 proposal did not contain confidential information or trade secrets belonging to Revere, but rather that the drawings were in fact based on prior art of a welded-in sensor. Deere also presented evidence that drawings of the Gozinta that Revere *765 submitted to Deere did not contain proprietary stamps, which were required if the information was to be considered confidential between the parties. Deere thus contends that Revere cannot argue that information Delfino, and Eckart disclosed in the March 12 proposal was confidential when in fact Revere disclosed essentially the same information to Deere.

Upon our review, we conclude that substantial evidence supports the jury’s verdict that Delfino and Eckart breached their agreement with Revere either based on the conclusion that they made a discovery or invention which they failed to disclose or assign to Revere, or wrongfully disclosed confidential information, knowledge or data.

First, the agreement required Delfino and Eckart to disclose or assign any inventions and/or discoveries to Revere made during the course of their employment and likewise precluded them from disclosing confidential information, knowledge or data belonging to Revere. Trade secrets would clearly fall within the definition of confidential information. Revere thus did not have to prove that the confidential information disclosed amounted to a trade secret, but rather only had to convince the jury that information depicted in the March 12 proposal amounted to a discovery or invention or that the proposal contained confidential information, knowledge or data belonging to Revere. 2 This fact is consistent with the jury’s finding that Deere tortiously interfered with Revere’s agreement with Delfino and Eckart, but did not misappropriate Revere’s trade, secrets.

Second, Revere presented evidence from which the jury could conclude that Delfino and Eckart’s March 12 proposal to Deere contained confidential information, knowledge or data, belonging to Revere that was not generally published or made available to the public, including to Deere. By comparing the drawings depicted in D E’s March 12 proposal to Deere with Revere’s original drawings of the Gozinta, Elengo of Revere testified that in his opinion the diameter of the holes depicted in the March 12 proposal were identical to those depicted in the drawings of Revere’s Goz- *766 inta. Elengo also testified that the diameter of holes depicted in a document entitled Draft Sensor Development Program, D E Sensor Manufacturing, were Revere trade secrets, that this information was not publicly available and that this information was not disclosed in the Gozinta patent. Additionally, Elengo testified that Delfino and Eckart had access to Revere’s drawings of the Gozinta during the course of their employment with Revere and further testified that the device described in the March 12 proposal could not have been designed in four or five days without using Revere’s trade secrets.

A proprietary stamp appears on Revere’s drawings of the Gozinta stating, “[t]his drawing contains proprietary information which shall not be reproduced or transferred to other drawings or disclosed to others or used for manufacturing or any other purpose without written permission of Revere Corporation of America.” Delfi-no and Eckart were thus put on notice that Revere considered any information that appeared in the Gozinta drawings to be confidential. Delfino and Eckart likewise affixed a proprietary stamp with language similar to Revere’s stamp on the drawings they submitted with the March 12 proposal, which the jury could find incorporated Revere confidential proprietary information.

Deere presented evidence through its witness, Walt Jacobson, the inventor of the Gozinta, that size and placement of the strain gauges, and all the other features of the product are allegedly common knowledge. Jacobson also testified that what he invented, or the strong part of the invention, was the knurl feature of the device. Deere also presented evidence that the idea of welding a sensor had been the subject of prior patents.

Despite this testimony, and even if true, the jury could still conclude that the Gozin-ta drawin