Party asserting IPR estoppel bears the burden of proof because it is the party asserting and seeking benefit from the affirmative defense of IPR estoppel. Reasoning consistent with general principle that party asserting an affirmative defense bears the burden to prove it.
This case addresses the “skilled and diligent searcher” standard used for establishing Inter Partes Review (“IPR”) estoppel (or lack thereof). In particular, this case establishes: (1).