Tesla shares have fallen more than 7% after the firm posted a record $710m loss and its founder, Elon Musk, dismissed Wall St analysts for asking “boring bonehead” and “dry” questions about the company’s financial health.

The California-based company burned through more than $745m in cash as it again missed production targets for its Model 3, which it has billed as its first affordable electric car.

Musk appeared to make light of the losses, tweeting “la la la” while linking to media reports of the results for the first three months of the year, and his behaviour during a bizarre results call with analysts prompted investors to turn away from Tesla.

The share price dropped 5% on Wednesday and slid further on Thursday, wiping more than $3.4bn off the value of the company.

During the call, the company’s chief financial officer said Tesla was “best in class”, only for Musk to correct him, saying the firm was simply the best. “The best in a class of one,” he said.

After half an hour of questioning on the company’s prospects for the rest of the year and efforts to increase production at Tesla’s Freemont factory, Musk appeared to lose patience.

“Next, next. Boring bonehead questions are not cool. Next,” he said, cutting off one questioner.

He was then asked what percentage of customers had chosen to personally configure their Model 3, an indicator of potential future revenues because the car’s $35,000 (£27,800) starting price can rise to $50,000 with options.

Instead of answering, Musk said: “We’re going to go to YouTube. Sorry, these questions are so dry, they’re killing me.”

He then answered numerous questions from the YouTube channel HyperChange, whose host said he was shocked to get on the call. Musk proceeded to take questions from the YouTuber on Tesla’s ride-sharing platform, self-driving cars and charging network.

Losses deepened from $675m for the final quarter of 2017 to $710m in the first quarter of this year, but the company brought in more revenue than expected. Revenue grew by 26% from a year ago to a record $3.4bn, up on analysts’ estimate of $3.28bn.

Tesla has, however, had production problems with the Model 3 and rlast month briefly shut its Freemont plant. It produced 9,766 vehicles during the quarter, missing its target of 10,000.

More than 2,000 were made each week in April, however, and the company insisted it was on track to hit its target of 5,000 a week by the end of June.

Musk said: “Our focus is on the Model 3. We need to get that to above 5,000 a week at a good margin. We need to become a profitable company.” Tesla said it was likely to be profitable in the third quarter of 2018 as the assembly lines increase production.