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 the specialty drugmaker Supernus Pharmaceuticals (NASDAQ:SUPN) briefly broke higher by more than 12% this morning on unusually high volume. Today's price action appears to reflect investors' enthusiasm for the company's unexpectedly strong fourth-quarter earnings report, released after the bell yesterday.

Digging into the details, Supernus reported net income of $4.4 million for the three-month period and $19.9 million for the full year. Total revenue for the quarter came in at $30.8 million, beating the company's own guidance by $4 million and consensus by roughly $1 million. On a GAAP basis, the biopharma generated $0.10 per diluted share for the quarter, compared to a loss of $0.65 per share for the same period a year ago. 

What's key to understand is that Supernus trounced the Street's expectations for both earnings and revenue, driven by particularly strong sales of its epilepsy drugs Oxtellar XR and Trokendi XR. 

So what: Supernus invested heavily in the commercialization of Oxtellar XR and Trokendi XR in 2014, resulting in both higher operating expenses and revenues. Given that both drugs saw their script numbers shoot higher -- especially in the fourth-quarter -- this investment appears to be paying off. 

Now what: Management expects product sales to grow by a noteworthy 50% this year to approximately $140 million. Unfortunately, they didn't provide any guidance regarding diluted EPS for the year, presumably due to the uncertainly regarding the potential cost of a late-stage trial for SPN-810 -- a drug indicated for impulsive aggression in patients afflicted with ADHD. 

Although the company's clinical activites will probably cause expenses to rise even further, Supernus shares do appear to be trading at a rather reasonable valuation (3 times annual revenues on a forward-looking basis) based on this annual guidance, making it a stock to keep an eye on going forward.