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 laser manufacturer Rofin-Sinar Technologies (Nasdaq: RSTI) fell more than 11% after the company guided to Q1 revenue and earnings targets that were well below Wall Street's estimates.

So what: Management cited a "cautious sentiment" among industrial customers in projecting $137 to $142 million in revenue and $0.33 to $0.36 in earnings per share. Analysts had been calling for $0.50 a share of profit on $153.7 million in revenue, according to data compiled by Yahoo! Finance.

Now what: Rofin-Sinar's poor guidance overshadowed what was an otherwise good Q4. Earnings came in $0.05 ahead of estimates while revenue grew 36% year over year. Do you think the sell-off was premature? Would you buy shares at current prices? Please weigh in using the comments box below.

Interested in more information about Rofin-Sinar Technologies? Add it to your watchlist.