Debt? What debt? It's earnings season and that's really all that seems to matter to investors right now. A majority of S&P 500 companies have reported impressive growth and the indexes are continuing to respond bullishly. For optimists, these rallies may seem like a dream come true. For skeptics like me, they're opportunities to see whether companies trading near their 52-week highs have actually earned their current valuations.

Keep in mind that some companies deserve their lofty valuations. Shareholders of Yamana Gold (NYSE: AUY) and the SPDR Gold Trust (NYSE: GLD) are relishing in gold's recent ascent above $1,600 per ounce. With little relief in sight to worldwide debt issues, gold remains a viable alternative to wealth retention for both nations and individual investors.

Still, some other companies might deserve a kick in the pants. Here's a look at three companies that could be worth selling.

Poison pill
For the second straight week, I'm going to stick it to a biotech company engaged in researching solutions for hepatitis. This week, the stock is Idenix Pharmaceuticals (Nasdaq: IDIX). Idenix currently has a pipeline of five drug hopefuls to combat hepatitis B and C, but only two of the five have even made it past the discovery phase into clinical trials. Contrast this with a current market cap in excess of $600 million, and you'll see why I'm waving the caution flag.

In April, Idenix diluted shareholders with a 21 million share offering, fully utilizing its 2008 shelf registration statement with the SEC. This offering was priced at $2.80, yet investors bid up shares all the way to $7 recently, which doesn't make very much sense. Even with this extra cash and certain royalty payments from its partnership with Novartis (NYSE: NVS), the company says the cash could get used up as soon as the second quarter of next year. With an FDA review likely years off, it's far too early to begin betting the boat on Idenix, and I'd urge caution going forward.

In a reality far, far away ...
Not only can you vacation like royalty when using HomeAway's (Nasdaq: AWAY) vacation home rental service, but you can also take a vacation from reality by closely examining the company's balance sheet.

HomeAway has an intriguing business concept that should generally net a profit, largely because more affluent individuals who are less likely to be affected by economic swings are going to use its services. But its current valuation could have you doing a double-take. Currently trading with an enterprise value to EBITDA ratio of more than 100 and an earnings multiple of more than 125, it's clear something has got to give. Following news that rival Airbnb plans to raise money through venture capital funding, HomeAway's shareholders took this as another excuse to tack even more onto the company's already exorbitant valuation. This could be a dangerous situation for longs once the six-month lock-up period ends, because if I were an insider, I'd be looking to run for the exits.

Fool me once...
Three years after emerging from bankruptcy, Calpine (NYSE: CPN) is back to its old tricks of trying to fool investors that it has a viable business platform.

Not much has changed over the past few years. Calpine still boasts a back-breaking $10.6 billion in debt, while future growth prospects look dreary, as evidenced by the company's five-year expected growth rate of just 7%. Currently losing money on a trailing basis, Calpine investors can only look forward to stagnant year-over-year revenue and a forward P/E of 84. It pays to be leery of companies emerging from bankruptcy, because some haven't learned their lesson and fall back into their old ways.

Foolish roundup
Sometimes, it's just easier to sit back and wait for the results to appear rather than chasing a potential disaster higher. These companies above are either unprofitable or barely profitable and investors might be wise to wait for tangible results and reasonable valuations before taking the plunge into these stocks.

What's your take? Are these stocks sells or belles? Share your thoughts in the comments section below and consider adding Idenix Pharmaceuticals, HomeAway, and Calpine to your watchlist to keep up on the latest news from each stock's respective sector.