diff --git a/tupak/core/likelihood.py b/tupak/core/likelihood.py
index 562b79898184d10a72a1394550cf49c3c1fcaa9b..01add79f19d89402b9968a7dcb570e618267795f 100644
--- a/tupak/core/likelihood.py
+++ b/tupak/core/likelihood.py
@@ -251,7 +251,7 @@ class ExponentialLikelihood(Analytical1DLikelihood):
 
     @y.setter
     def y(self, y):
-        if isinstance(y, int):
+        if not isinstance(y, np.ndarray):
             y = np.array([y])
         if np.any(y < 0):
             raise ValueError("Data must be non-negative")