Holding that our written description requirement requires that a specification “reasonably convey to those skilled in the art” that the inventor “actually invented” and “had possession of the claimed subject matter as of the filing date [of the invention]”
Holding that whether undue experimentation is required is a "conclusion reached by weighing many factual considerations. . . . includ[ing] the quantity of experimentation necessary, the amount of direction or guidance presented, the presence or absence of working examples, the nature of the invention, the state of the prior art, the relative skill of those in the art, the predictability or unpredictability of the art, and the breadth of the claims."
Reversing the district court's finding of invalidity for lack of enablement because defendant failed to provide evidence that established the person of ordinary skill would need to engage in “undue experimentation” in order to practice the asserted claims