diff --git a/debugger/go/instances/instances.go b/debugger/go/instances/instances.go
index b6ddc34..ab44b34 100644
--- a/debugger/go/instances/instances.go
+++ b/debugger/go/instances/instances.go
@@ -50,7 +50,7 @@
 
 var (
 	// instancePrefixRe is used to strip out the instance uuid.
-	instancePrefixRe = regexp.MustCompile("^/([A-Fa-f0-9]+)(/.*)")
+	instancePrefixRe = regexp.MustCompile("^/([A-Fa-f0-9-]+)(/.*)")
 
 	runningInstances = metrics2.GetCounter("running_instances", nil)
 )