To be patentable, an invention must be novel and non-obvious when compared with prior art patents, publications, and devices. An issued patent is infringed if the accused device or method has all of the elements of a single patent claim, or their equivalents. Proprietary rights also exist in trade secrets and confidential information, even if the trade secrets and confidential information are unpatentable. Rights in trade secrets are retained by keeping the information secret, by confidentiality agreements, or in some cases, by disclosing the confidential information to another in a confidential relationship. Rights in trade secrets and confidential information are typically lost when the information becomes generally known or publicly available, although in some cases the rights exist even after the information becomes publicly available. A company receives technological information from its employees and the law provides for determination of the respective rights of an employee and the employer in inventions made by the employee. Engineers and technical employees may be treated differently than non-technical employee-inventors and the rights of all employees may be varied by agreement with the employer. Employment agreements may also restrict the activities of an employee after termination. Companies obtain patents to protect the results of their research and development from their competitors. In a patent infringement or trade secret theft lawsuit brought to enforce intellectual property rights, the protectability of the invention or trade secret is typically in issue. The engineer's role in the lawsuit is to assist the attorney in understanding the technology and in presenting the technical information in a way that a non-technical judge or jury may understand.