The financial results from the link don't show a $800 million loss for this year.

From that document in the FINANCIAL SUMMARY section there are these quarterly profit/loss number:

    Income (loss) from operations 
    Q1-2019  Q2-2019  Q3-2019   Q4-2019  
       -522     -167      261       359

So for the first half of the year Tesla did lose 689 million dollars.

But for the whole year that was only a loss of 69 million dollars.

I think what the market likes is the Tesla cash position.

If you look at those it would appear Tesla is no longer burning cash.

    Cash and cash equivalents 
    Q4-2018   Q1-2019  Q2-2019  Q3-2019   Q4-2019  QoQ   YoY
    3,686     2,198    4,955    5,338     6,268    17%   70%

The fact that the year on year cash position grew by 70% would be pretty comforting to shareholders.