diff --git a/utils.py b/utils.py
index aa809f4a085f97838ec8372c3e1e5d3a4c18e555..7248425a1b8260fbc29d6b8e986368ee19ed4ec2 100644
--- a/utils.py
+++ b/utils.py
@@ -41,7 +41,7 @@ def get_id_prefix_from_string(s):
     first_illegal_char_index = 0
     for i, c in enumerate(s.replace(' ', '')):
         first_illegal_char_index = i
-        if c not in 'QWERTYUIOPASDFGHJKLZXCVBNM1234567890qwertyuiopasdfghjklzxcvbnm':
+        if c not in 'QWERTYUIOPASDFGHJKLZXCVBNM1234567890qwertyuiopasdfghjklzxcvbnm.-':
             break
     return s[:first_illegal_char_index]