Revenues are not cash flows. That $375M of revenues from car orders has real costs associated (i.e. materials, labor).
Ford and GM, established car makers, have gross margins of about 12-15%. Tesla's margins are much lower, at least today. But let's ignore working capital needs and pretend Tesla had the "great" margins of its competitors, then that's still only $50M of cash contribution. Tesla will need lots of cash this year.
