If you are planning on riding your bike whenever it gets warm, storing outside isn't all that bad. Your bike will suffer some, but it won't die. You'll want to do some extra cleaning come spring, especially if it gets exposed to salt and/or sand. If it snows around your bike, you might want to dig it out so the underneath doesn't get soaked in water so long.
If you go for more than two weeks without riding, definitely take your battery out of the bike and put it on a tender inside. It will help your battery last longer. If a battery sits discharged for more than a couple of weeks, you run the risk that it will never take a decent charge again (personal experience). Fuel stabilizer is your friend. It is so cheap and easy to do.
My bike stayed outside for two winters and fared decently. Your biggest risk is theft. Bikes get lifted all the time, so the closer you park your bike to your building, the better off it will be. I used to bump my bike up on the curb and parked her in the walkway leading to the front door of my townhouse. You can also make it more difficult for a thief to get to by have the bike share a space with your cage.