Over the fence and out of the park -- that's the baseball analogy for how Questcor Pharmaceuticals (NASDAQ: QCOR) hit with its third-quarter results.

Revenue? Up 135% over the third quarter last year. Earnings? Up 160% compared to 2011. Shipments of the company's drug, Acthar? Up 92% over the same period last year. Analyst estimates? Beat 'em by more than 21%. 

Tough pitches
Questcor managed to hit a home run for the quarter despite having several tough pitches thrown its way recently.

Major insurer Aetna (AET) threw a curveball in September when it decided to cover Acthar only for infantile spasms, a rare disease that doesn't generate a lot of revenue for Questcor. Humana (HUM 1.12%) pitched a change-up soon afterward. The insurance company announced a policy change to require pre-authorizations for Acthar.

Along with these reimbursement challenges came stock volatility, which only escalated with accusations about Questcor from Andrew Left's Citron Research. Citron's negative reports about the reimbursement issues were the equivalent of a high-speed sinker.

Sinking shares of companies is the name of the game for Citron. Just in the past few months, Andrew Left's organization has targeted Nu Skin (NUS 1.75%) and VIVUS (VVUS) Citron alleged that Nu Skin operates an illegal multi-level marketing network in China. It raised questions about VIVUS' intellectual property protection over its weight loss drug, Qsymia.

Despite all of these challenges, though, Questcor pulled off one terrific quarter. Net sales of $140 million and earnings of close to $56 million, with phenomenal growth in both areas, should provide some smiles to investors who stuck with the company through the roller-coaster ride of the past few months.

The company said that insurance coverage for Acthar continues to be good overall. However, it's still a little early to fully know how significant an impact the changes by Aetna and Humana will have.

Taking a swing
Questcor's focus on increasing its sales force appears to continue to pay off. If it can keep convincing doctors about the merits of Acthar and allay insurers' concerns about the medical need for the drug, the momentum from third quarter will grow.

I have advised caution with Questcor in past months because of all of the volatility. And I still think caution is warranted. Multiple price swings of 20% and more during the span of three months seem to dictate a cautious approach.

My hunch is that the crazy volatility isn't fully behind Questcor yet. However, I'll take a swing and say this stock is a buy -- with all the caveats in full force about having a diversified portfolio and not risking more than you can afford to lose.

Home runs inspire those who watch them happen. And make no mistake about it, Questcor just hit a home run with its third-quarter results. The ball went out of the park. Probably over the left fielder's head.