The fabrication of integrated circuits, particularly those made of gallium arsenide (“GaAs”), is a highly complex and precise process. Integrated circuits incorporating the POET platform are primarily manufactured on wafers made of GaAs. Compared to the manufacturing of silicon integrated circuits, GaAs technology is less mature and more difficult to design and manufacture within specifications in large volume. In addition, the more brittle nature of GaAs wafers can result in lower manufacturing yields than with silicon wafers. Further, during manufacturing, each wafer is processed to contain numerous integrated circuits or which may also result in lower manufacturing yields. As a result, our customers utilizing POET GaAs wafers may reject or be unable to sell a substantial percentage of wafers or the die on a given wafer because of, among other factors...

That is straight out of the 20F maybe you need to take a read