Event Income Summary - Jscript error related to date search widget

Jscript error when this report instance loads (and the accordion is non-functional due to error):
http://drupal.demo.civicrm.org/civicrm/report/instance/23?reset=1

Error is "Missing number at position 0"

We tracked it down to the event_start_date / event_end_date fields. There's an extra space being dumped in the value=' ' parameter on these input fields which is causing the date widget to throw this error.