In short, the holding by SCOTUS is that the appointment of the "judges" was correct, but the legal provision shielding their decisions from review by the Direct

In short, the holding by SCOTUS is that the appointment of the "judges" was correct, but the legal provision shielding their decisions from review by the Director of the PTO (or any other Principal Officer confirmed by the Senate) is unconstitutional. The Constitutional issue is that the Patent Trial and Appeal Board was established without any oversight of their key task: invalidating patents. Their decisions are not subject to review, and they cannot be removed from their appointments as a consequence of any decision that they deliver. They are wielding the power of Principal Officers regarding the rights of the people, but they are appointed through a procedure for Inferior Officers, without confirmation by the Senate. If the IOs were answerable to a PO (i.e., PTO Director or Secretary of Commerce), who is answerable in turn to the President, this exercise would be fine, but they answer to nobody; there is no arrangement for anybody in the Executive Branch to review this Board's decisions. The Government and another concerned party had argued that the Director had the power to choose which judges sat on any panel, thereby effectively removing "wrong" judges from making decisions, thereby effectively exercising control over the Board. The Federal Circuit held that this arrangement was insufficient, but could be remedied by allowing the Director to formally and completely remove judges from the Board if he took issue with their decisions. The Supreme Court agreed with the Circuit that the arrangement, as specified by law, is unconstitutional, but disagreed with the proposed remedy, preferring instead to merely invalidate the one provision of the law that shields the Board's decisions from review by the Director. SCOTUS vacated the Federal Circuit's decision (the decision that had been appealed to them) and remanded the case (i.e., the actual patent dispute, not the Constitutional issue surrounding it, which they have just resolved) down to the Director of the PTO, whom they have just decided has the authority to review the dispute.