The bear case was three-pronged, explicitly stated several times earlier and tracked/predicted with hard data a month before it reflected in the stock price. Was very robust and highly rational and data/market awareness model driven.
1. Market isn't large enough for $50K+ cars to sell the volume they claimed they'd build
2. They lose lots of money in the lower pricing tiers given the cost of batteries, on which they have no advantage
3. They generally suck at building the top of the car and at logistics.
One of my favorite things about this stock is how the dumbest retail baggies have crushed it, at least until the end of the 2018. They were buying low, selling high with great skill. I suspect they're becoming the baggies now though as that pattern breaks down. Record retail highs on RobinHood.