Image source: Renewable Energy Group.

What: Shares of biofuels company Renewable Energy Group Inc. (NASDAQ:REGI) rose 29% in March after reporting better-than-expected earnings.

So what: Revenue rose 15% from a year ago to $387.8 million on the back of a 33% increase in volume. But the company reported a net loss of $95.6 million, or $2.18 per share. That figure included a $175.0 million non-cash charge related to goodwill, and if you pulled that out, it earned $1.81 per share. That's the figure that investors got excited about in the quarter.  

Now what: The bottom-line adjusted net income number may have beaten expectations, but the business is still struggling fundamentally. Adjusted EBITDA, which is a proxy for cash flow before financing costs, fell 37% from a year ago to $21.6 million and selling prices are dropping as well.

I think this looks like a short-term reprieve for Renewable Energy Group, and until we see selling prices rise and the company start reporting a profit, I'll stay out of this stock.