ZoneDirector (ZD) 1200 is a physical appliance. So, for redundancy you need two ZD 1200s and enable redundancy between them. Up on enabling redundancy one ZD 1200 will act as Active ZD and the other as Standby ZD.
Jay FIles is right. You will be looking for a SmartZone virtual controller (vSZ) if you are set on being virtualized. Be sure to look at SmartZone documentation for limitations and compatibility with any current access points you may have. If you have older access points they might not be compatible with SmartZone and would also need to be upgraded.