DoorDash posted stronger-than-expected results in the first quarter as it expanded into new markets overseas and new delivery categories at home. The San Francisco company said its total orders rose 27% to 512 million in the January-March period. That was higher than the 493 million Wall Street forecast. DoorDash acquired the Finnish delivery service Wolt Enterprises last summer, allowing it to expand in 22 countries where it previously had no presence, including Germany. And in the U.S., the company said orders from convenience stores, groceries and other newer categories are growing faster than restaurant deliveries.