I don't know how well the Sphero BB-8 did, so I can't speak to that but people I know who have one rave about it.
Nobody could keep this in stock from Force Friday through early December. It seemed that this was a hot, hot toy that took months for production to catch up with.
Not sure what Sphero's expectations were, but it seems like demand was higher than supply for several months.
Have they provided a demo video of this yet, showing how the app works? If the app is cool that should also help bolster sales. If its just a remote control without fun add-ons then its a missed opportunity.