LinkedIn (NASDAQ:LNKD) had a boffo IPO Thursday that values its shares at a price-to-earnings ratio of 584 — about 37 times that of the average stock.

But that’s nothing compared to Tesla Motors (NASDAQ:TSLA), a company that sports a $2.7 billion market capitalization — up 18% from its July 2010 IPO price — despite losing $154 million on $117 million in sales in 2010.

Tesla Motors makes cool-looking electric cars. Its Tesla Roadster can go 236 miles on a single charge. As of March 2011, Tesla had sold 1,650 Roadsters – at a starting price $109,000 — in 30 countries and it currently has 17 dealers. It also sells battery packs to Daimler — “up to 1,000 battery packs and chargers to support a trial of the Smart for two electric,” according to its most recent 10Q.  And it has received “more than 4,600 reservations” for another vehicle, the Model S.

Tesla’s financial results, however, are not as cool. For example, in the first quarter of 2011, Tesla reported a loss of $49 million that was two-thirds wider than its loss of $29.5 million a year earlier..

But the good news is that Tesla’s sales rose 136% to $49 million and it beat analysts’ expectations for both losses and revenue. If you are an investor in this stock, you are likely to seize on this good news as a reason to keep holding on.

Needless to say, a new car company has big cash needs. And it could not meet those needs without help — it gets $465 million worth from the U.S. government in the form of a so-called loan facility from the Federal Financing Bank that is guaranteed by the Department of Energy Loan Facility.

This facility is helping to pay for Tesla to develop that Model S. And its business prospects could dim Tesla if that model does not meet the development milestones required to get more of that cash.

Meanwhile, Tesla has about $101 million worth of cash on its balance sheet and is required to come up with $17.5 million in 2011. Curiously, despite $102 million in long-term debt, Tesla does not record any interest expense on its income statement for the first quarter. Its 10Q suggests that Tesla is “capitalizing the interest expense to construction in process” — meaning it is adding the expense to the value of the asset rather than actually paying it.

Is this just a tiny, obscure accounting matter or cause for investor concern?  You could look on the bright side — on May 4, Tesla Motors raised its guidance for 2011 sales by 6% from between to between $170 million and $185 million.

But I wonder how long a company can survive posting losses that are more than its total sales. Its market capitalization depends on its ability to convince investors to keep using their hearts and not their brains when it comes to deciding whether to fork over their hard-earned cash.

I’d avoid this equity.

Peter Cohan has no financial interest in the securities mentioned.