Appears the sale was confirmed at 40 Million. That said, It's Eric Migicivosky's (CEO) fault. They (Pebble) failed to be revelant. They failed to innovate and move forward with being more than just a notification Watch. In the last year, Pebble was attempting to alter to the health related side, adding a heart rate monitor. To little to late.
Second, and in my opinion was a crucial fail, was they never marketed their product. I would be willing to bet to conduct a survey at a major mall in my area, asking ten random strangers if they have ever heard of Pebble. And I'm willing to say maybe one out of those ten strangers would have some acknowledgement of who they are. And then ask those same ten strangers if they have heard of the Apple Watch, which Likely 80% would concur they are aware of the Apple Watch.
Point is, how is Pebble expected to stay revelant in a category that is completely uncertain with wearable technology, without expanding in marketing their product? The answer is you can't.
Pebble has been around for while and I believe they claim they were the first smart watch on the market. Then they should have the wisdom to understand what it takes to survive (Aside from having the funds to do so).
Pebble had a small following, but I don't feel sorry for them. I'm not saying they made a bad product, I'm saying they became stagnant and failed to be dynamic.