I've overwintered some indoors that I received too late to risk planting. They may not go dormant indoors even if they are registered as "dormant" and may continue to grow to some extent, but they do fine in a sunny window. There's no advantage to cutting them back that I can think of, unless the leaves die back which they probably won't. The only problem I've had with wintering them indoors has occasionally been spider mites. Some have flowered indoors but others have not.