Angular js ng repeat with conditional ng class not applying css class

I have a ng repeat with a ng class that doesn't apply the css class in the case where my css class has a hyphen in the name:

<li
  ng-repeat="item in items"
  ng-class="{'i-someclass' : item.Id > 10}">
  {{item .name}}
</li>

Am I doing anything wrong? If I change the css class name to isomeclass it works. AngularJS v1.0.7