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.