Right now they are building the Signature series cars. These are the first 1000 cars. The reservations for these cars involved a $40k payment up front, in some cases up to 3 years ago. General production cars only required a $5k payment up front. As a result, they are only capturing ~$50k per car, versus ~$85k once GP cars start rolling off the line.

In addition, they've been ramping up production (they're roughly halfway to their target 400/wk goal), and that involves overhead like training new staff and building out an operations team. They should get to full production capacity at the end of the month, but they've already hired those extra workers and they're going to burn through cash while they get up to speed.