Shares in electric carmaker Tesla (NSADAQ:TSLA) rose over 8 percent in after-hours trading, after the company’s revenue almost doubled in the second quarter.

The company reported revenue of almost $2.8 billion, up from $1.3 billion during the same period last year. About $2.3 billion of the revenue during the quarter came from the firm’s automotive unit, the company’s best known business, a 93 percent increase on the same period in 2016.

However, the company’s costs, including for research and development and sales, rose 15 percent over the quarter causing overall losses to rise. Losses increased to $336 million, compared with $293 million last year.

Despite the mixed results, Tesla told shareholders it expects revenue to grow “significantly” in the second half of the year.

The firm have become increasingly well-known for their electric cars, delivering more than 47,000 of its earlier high-end Model S and Model X cars in the first half of 2017.

Shares in Tesla are currently up 1.98 percent at 325.89 (1111GMT).