--- a/account.go	Mon Apr 17 15:22:45 2017 +0200
+++ b/account.go	Mon Apr 17 16:22:56 2017 +0200
@@ -257,6 +257,9 @@
 
 	params := make(apiCallParams)
 	for i, id := range accountIDs {
+		if id < 1 {
+			return nil, ErrInvalidID
+		}
 		qID := fmt.Sprintf("id[%d]", i+1)
 		params[qID] = strconv.Itoa(id)
 	}