An offer of employment from the prospective U.S. employer is required. Self-petitioning is not allowed. The employer may be a university or a private employer with at least 3 full-time researchers and documented accomplishments in the research field. For a researcher who is not offered a tenured or tenure-track position, the position must be "permanent." A permanent position is one that is for a term of indefinite or unlimited duration, and in which the employee will ordinarily have an expectation of continued employment unless there is good cause for termination.