How long was it in your basement for? Sometimes the yeast wake back up and eat a little more when you move the carboy or transfer the beer to a secondary container.
I'd say leave it where it is for a few more days until you are sure the yeast are done. The only precise way to tell this is by taking hydrometer readings.
Typically, give your beer 3 weeks in the primary fermentor and it'll be done 9 times out of 10.