Can All Prior Art Patent Applications Be Submitted in an Inter Parties Review (IPR)?

Inter Partes Review (IPR) proceedings have become a crucial aspect of the patent landscape, allowing parties to challenge the validity of granted patents in front of patent judges instead of laymen juries. However, it would seem logical that all forms of prior art would be usable to challenge a patent. Unfortunately, that is not the case.  

The IPR proceedings have always been limited to prior art patents or prior art printed publications. If you want to invalidate a patent using prior non-patent literature, offers for sale, or public disclosures, you either need to do it within the first nine months from when the patent issues using a Post Grant Review (PGR) or challenge the patent in court using the ineligible prior art.  

The Federal Circuit recently found that not all prior art printed publications are eligible for the IPR proceedings. Specifically, the court held that a prior art printed publication is ineligible for IPR proceedings when the printed publication was published after the challenged patent's filing date even though the prior art printed publication was filed before the challenged patent's filing date.