--- a/toolkit/components/telemetry/docs/collection/events.rst
+++ b/toolkit/components/telemetry/docs/collection/events.rst
@@ -41,17 +41,17 @@ Where the individual fields are:
 - ``value``: ``String``, optional, may be ``null``. This is a user defined value, providing context for the event.
 - ``extra``: ``Object``, optional, may be ``null``. This is an object of the form ``{"key": "value", ...}``, used for events where additional context is needed.
 
 .. _eventlimits:
 
 Limits
 ------
 
-Each ``String`` marked as an identifier is restricted to the following regex pattern: ``^[:alpha:][:alnum:_.]+[:alnum:]$``.
+Each ``String`` marked as an identifier is restricted to the following regex pattern: ``^[:alpha:][:alnum:_.]*[:alnum:]$``.
 
 For the Firefox Telemetry implementation, several fields are subject to limits:
 
 - ``category``: Max. byte length is ``30``.
 - ``method``: Max. byte length is ``20``.
 - ``object``: Max. byte length is ``20``.
 - ``value``: Max. byte length is ``80``.
 - ``extra``: Max. number of keys is ``10``.

--- a/toolkit/components/telemetry/parse_events.py
+++ b/toolkit/components/telemetry/parse_events.py
@@ -10,17 +10,17 @@ import string
 import shared_telemetry_utils as utils
 
 MAX_CATEGORY_NAME_LENGTH = 30
 MAX_METHOD_NAME_LENGTH = 20
 MAX_OBJECT_NAME_LENGTH = 20
 MAX_EXTRA_KEYS_COUNT = 10
 MAX_EXTRA_KEY_NAME_LENGTH = 15
 
-IDENTIFIER_PATTERN = r'^[a-zA-Z][a-zA-Z0-9_.]+[a-zA-Z0-9]$'
+IDENTIFIER_PATTERN = r'^[a-zA-Z][a-zA-Z0-9_.]*[a-zA-Z0-9]$'
 DATE_PATTERN = r'^[0-9]{4}-[0-9]{2}-[0-9]{2}$'
 
 
 def nice_type_name(t):
     if isinstance(t, basestring):
         return "string"
     return t.__name__