diff --git a/src/ATrade/Types.hs b/src/ATrade/Types.hs
index 5648ede..daa93ee 100644
--- a/src/ATrade/Types.hs
+++ b/src/ATrade/Types.hs
@@ -199,6 +199,7 @@ instance FromJSON OrderPrice where
               else return $ StopMarket trprice
           (Number n) -> return $ Stop trprice (fromScientific n)
           _ -> fail "Should be either number or 'market'"
+      _ -> fail "Should be a number"
 
   parseJSON _ = fail "OrderPrice"