Although we don't believe in timing the market or panicking over market movements, we do like to keep an eye on big changes -- just in case they're material to our investing thesis.

What: Shares of 3-D printer maker ExOne (NASDAQ:XONE) fell as much as 16% today after the company reported earnings.

So what: Revenue rose 240% from a year ago to $9.2 million, falling just short of estimates. But net loss was $1.12 million, or $0.08 per share, $0.02 below estimates. The company also said that revenue for the full fiscal year will be at the low end of its $48 million-$52 million guidance.  

Now what: The 3-D printing business is all about growth, especially for a company trading at about 20 times annual revenue. Even the slightest hint that growth won't reach expectations can send the stock crashing, and that's what we saw today. I think the stock is just too expensive and don't see it becoming a value unless years of massive growth or a big drop in the stock occur.

Fool contributor Travis Hoium has no position in any stocks mentioned. The Motley Fool recommends ExOne. The Motley Fool owns shares of ExOne. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.