Lets think of the following hypothetical situation,
Bob works in a company named P-House. He submitted a patentable idea to P-House in a template document (in private official meeting). P-House rejects his idea but neither company nor Bob himself reveals the idea in public for next 2 years. Bob resigns and joins in another Company and suddenly finds the exact same idea that he proposed to P-House has been submitted to USPTO with different inventor and P-House as assignee. Bob has no evidence to prove he is the sole inventor because all the evidences are kept secret by P-House and they wont allow accessing those evidences.
In such situation, is there any legal action Bob can do to get his inventionship back? Or there is no hope?