How can I adjust the size of the outer braces to make the following equation neater?
\documentclass[a4paper]{scrreprt}
\usepackage{amsmath}
\begin{document}
\[
M = \left\{ x \in X :
\begin{cases} p(x) > 0 \\ q(x) > 0 \end{cases}
\right\}
\]
\end{document}

