New York (CNN Business) Tesla on Wednesday reported a massive drop in auto sales for last quarter, though the company said it's confident it will still reach its annual sales goal.

About 63,000 vehicles were delivered to customers in the first three months of 2019 — a 31% drop compared to the prior quarter. The total sales figures included about 50,900 Model 3 sedans, Tesla's best-selling vehicle, and 12,100 luxury Model S sedans and Model X SUVs.

Tesla TSLA It was the first quarter-to-quarter drop in sales atin nearly two years and the single largest drop ever. The company posted its delivery results late Wednesday, and its stock closed down 8.2% Thursday. Investors are also watching a separate piece of Tesla news: A federal judge is scheduled to hear oral arguments in a case that securities regulators filed against CEO Elon Musk

Tesla's slowing sales are a concern because the company needs cash in order to pay down its sizable debts. Tesla counts a sale whenever a vehicle is delivered, not when a new order or reservation is placed, because customers only pay the full price whenever they actually receive their car. So, sales figures do not necessarily reflect demand.

The slowdown in deliveries does not come as a shock: Wall Street analysts expected Tesla to deliver about 50,000 Model 3s. And Tesla had already said it expected fewer Model S and Model X sales compared to a year earlier.