I don't have insider knowledge of their financials, but my impression is if they stayed lean and focused on their core product they'd have been a sustainable small company. Instead, they grew too big in typical VC-backed fashion and it wasn't sustainable.

They spent a lot on R&D and bet the company on kickstarters. Their direction also constrained them to Garmin-like products rather than heading off Android Wear or Apple watch (even fitbit can't compete after buying their guts)

Probably a lack of good marketing.

I would imagine that not enough people enjoyed it for the price they asked for.