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 service assurance and network performance management specialist NetScout (Nasdaq: NTCT) were scouting out the stock market's peaks today, as investors boosted shares as much as 19% after the company announced its fiscal third-quarter results.

So what: What do investors want to know at earnings season? They want to know that their company performed at least as well as they -- and, maybe more importantly, Wall Street analysts -- had expected. In its third quarter -- which ended Dec. 31 -- NetScout managed to top estimates, logging $0.35 in adjusted per-share profit against the $0.33 that was expected.

Year over year, revenue grew 9%, led by a 12% increase in service sales. Product revenue was up 7%, but it showed an even more marked 21% jump from the company's fiscal second quarter.

Now what: Management narrowed the company's expectations for the full year now that it has only one quarter left to go. Revenue is seen clocking in between $305 million and $310 million, while non-GAAP earnings per share are expected to be between $1.07 and $1.11. On balance, the new ranges show management stepping back its expectations. However, current analyst expectations have the company earning $1.07 per share on $304 million in sales for the year, so management's new view is still above Wall Street's.

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