Although Bonsai are frequently displayed and sold in indoor areas, with very few exceptions, bonsai are outdoor plants!
Bonsai need sunshine and air circulation just like their outdoor cousins, and they exposure to seasonal changes are required in order to maintain health. More bonsai are killed by being brought indoors and neglected than any other single cause. Certain species of tropical bonsai (such as ficus) can be enjoyed indoors year round. But these are the exceptions.
Check the
BCI Species Index to learn more about your plant and discover if it should be kept indoors or out!