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 Merit Medical Systems (NASDAQ:MMSI) -- a manufacturer of disposable medical devices in cardiology, radiology, and endoscopy -- plunged as much as 27% after reporting its fourth-quarter earnings results.

So what: For the quarter, Merit Medical reported a 12% increase in revenue to $102.2 million and $0.15 in EPS compared to $0.18 in the year-ago period. While surpassing the Street's expectation of just $100.9 million in revenue, it fell $0.04 short of the $0.19 in EPS that was forecast. It actually got even worse from an earnings perspective with the company's 2013 guidance. For the upcoming year, Merit anticipates revenue of $455 million to $465 million and adjusted EPS of $0.61-$0.67. Current estimates on the Street called for $446.9 million in revenue and $0.89 in EPS.

Now what: Say hello to higher research and development costs and the introduction of the medical device excise tax! Sales of Merit's products appear to be relatively healthy; unfortunately, the industry is highly competitive, and R&D expenses and taxes are rising. While I'm tempted to call Merit an intriguing value here, the scope of the miss is far too large for me to just consider it a one-time thing, and I'd suggest keeping your distance for at least the next quarter or two.

Craving more input? Start by adding Merit Medical Systems to your free and personalized watchlist so you can keep up on the latest news with the company.

Fool contributor Sean Williams has no material interest in any companies mentioned in this article. You can follow him on CAPS under the screen name TMFUltraLong, track every pick he makes under the screen name TrackUltraLong, and check him out on Twitter, where he goes by the handle @TMFUltraLong.

Try any of our Foolish newsletter services free for 30 days. We Fools don't all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.