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 voxeljet AG (NYSE:VJET) jumped as much as 12% today after falling up to 45% for the week. Is this a sustainable bump or just a dead cat bounce?

So what: There was a lack of market moving news out today but the sharp decline in voxeljet's shares are enough to bring in some buyers. Remember that it was only a week ago that shares popped after a pretty decent earnings report.

Let's put all of these pops an plunges into some perspective. Voxeljet's management expects about 11 million euros, or about $14.9 million in revenue for all of 2013. In the fourth quarter, it expects to ship four -- yes FOUR -- 3-D printers and only has seven total in its backlog.  

This is what investors are getting for buying a company that currently has a market cap of $548 million.

Now what: Today looks like nothing more than a dead cat bounce to me, or a short-term jump in a stock that's headed south over the long term. Voxeljet has a lot to prove before it will be worth its current market cap and has a lot of competition along the way. I think investors got ahead of themselves buying into the 3-D printing craze and would be wise to wait for leaders to emerge before betting on a high risk stock like voxeljet.