Computer-aided design veteran Autodesk (Nasdaq: ADSK) hit earnings estimates right on the button last night and knocked the cover off sales projections. The stock dropped more than 4% on the news. What gives?

The $477 million in sales and $0.32 of non-GAAP earnings per share both showed strong growth year over year and stable trends from one quarter to the next. Earnings also landed at the top end of management guidance while revenue went $2 million above the official range of expectations.

Perhaps investors wanted more because Autodesk is in the habit of beating expectations senseless rather than just meeting them. And if you're thinking that the forward guidance might have been to blame this time, you'd only be partly right -- fourth-quarter sales guidance is much stronger than analyst targets for the period, but the bottom line does look a little weak.

All of this paints a somewhat bleak picture of Autodesk's margin trends. Big revenue numbers are great, but should then translate into strong profits. Investors should keep a close eye on how those margins play out in coming quarters.

That said, Autodesk's stock set fresh two-year highs yesterday, just hours before the earnings report. Plain old profit-taking makes lots of sense here, particularly if the lack of outrageous results doesn't inspire a belief that the stock can go much higher. After a 45% year-to-date run, this stock has absolutely crushed chief rivals Dassault Systemes (OTC BB: DASTY.PK) and Adobe Systems (Nasdaq: ADBE), and stayed very close to another competitor and market darling known as Apple (Nasdaq: AAPL). Crying over a few percentage points of spilled gains at this point would be silly.

Add Autodesk to your Foolish watchlist if you want to follow this story from the sidelines, or make a call in your CAPS portfolio to get even closer.