diff --git a/src/Form/MigrationExecuteForm.php b/src/Form/MigrationExecuteForm.php
index 623d639b4..77a01376b 100644
--- a/src/Form/MigrationExecuteForm.php
+++ b/src/Form/MigrationExecuteForm.php
@@ -160,9 +160,9 @@ protected function buildFormOptions(array $form, FormStateInterface $form_state)
     $form['options']['idlist'] = [
       '#type' => 'textfield',
       '#title' => $this->t('ID List'),
-      '#maxlength' => 255,
+      '#maxlength' => 1024,
       '#size' => 60,
-      '#pattern' => '^[0-9]+(' . MigrateTools::DEFAULT_ID_LIST_DELIMITER . '[0-9]+)?(,?[0-9]+(' . MigrateTools::DEFAULT_ID_LIST_DELIMITER . '[0-9]+)?)*$',
+      '#pattern' => '^[0-9A-Za-z]+(' . MigrateTools::DEFAULT_ID_LIST_DELIMITER . '[0-9A-Za-z]+)?(,?[0-9A-Za-z]+(' . MigrateTools::DEFAULT_ID_LIST_DELIMITER . '[0-9A-Za-z]+)?)*$',
       '#description' => $this->t('Comma-separated list of IDs to process.'),
       '#states' => [
         'enabled' => [