Why can't I cite this patent using biblatex?

Question

I'm trying to cite the following patent:

@patent{sakuma2016,
 author = {Noritsugu Sakuma, Hidefumi Kishimoto, Akira Kato, Tetsuya Shoji, Dominique Givord, Nora Dempsey, Thomas George Woodcock, Oliver Gutfleisch, Gino Hrkac, Thomas Schrefl},
 title = {Production method of rare earth magnet},
 number = {US9520230B2},
 year = {2016}
}

However, when I use \cite{sakuma2016}, I get the standard bold text which indicates the citation does not exist.

Does anyone know why this is occurring? I am using biblatex, which I have imported with the following command:

\usepackage[sorting=none]{biblatex}