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 Guidance Software (NASDAQ: GUID) got crushed today -- down by 25% at the low -- after the company reported first-quarter results.

So what: Non-GAAP revenue in the first quarter came in at $27.2 million, which translated into a non-GAAP net loss of $0.15 per share. Both results were well below expectations, especially on the bottom line. Consensus estimates were calling for $30.2 million in sales and an adjusted net loss of just $0.03 per share.

Now what: CEO Victor Limongelli blamed the tough macroeconomic environment for the weakness in the first half of the year, but said the company was investing in research and development along with expanding sales and marketing. Guidance Software also revised guidance for 2013, with sales expected in the range of $133 million to $138 million, which should translate into an adjusted bottom line of a $0.20-per-share loss to breakeven. Benchmark downgraded the stock from "buy" to "hold" while assigning a $9 price target.

Interested in more info on Guidance Software? Add it to your watchlist by clicking here.