  Using the Kuznetsov formula, we prove several density theorems for
exceptional Hecke and Laplacian eigenvalues of Maass cusp forms of weight 0 or
1 for the congruence subgroups $\Gamma_0(q)$, $\Gamma_1(q)$, and $\Gamma(q)$.
These improve and extend upon results of Sarnak and Huxley, who prove similar
but slightly weaker results via the Selberg trace formula.
