diff --git a/src/parseSpecEntry.ts b/src/parseSpecEntry.ts
index 2806925..03160ff 100644
--- a/src/parseSpecEntry.ts
+++ b/src/parseSpecEntry.ts
@@ -5,7 +5,7 @@ export default function parseSpecEntry({ outputArgs, requiredOptions, shortToLon
   if (longOption === '') {
     throw new Error(`The long option may not be an empty string. This is a bug in the source code of the script that you tried to call.`);
   }
-  if (!longOption.match(/^[a-z0-9]+(-[a-z0-9]+)*$/)) {
+  if (longOption.match(/^[a-z0-9]+(?:-[a-z0-9]+)*$/) === null) {
     throw new Error(`The long option "${longOption}" must only contain alpha-numeric characters, optionally separated by hyphens. This is a bug in the source code of the script that you tried to call.`);
   }