What: Shares of newly-public Penumbra (NYSE:PEN), a medical device maker that produces products for neurological and vascular conditions, were up more than 23% in afternoon trading after the company reported its third quarter earnings.

So what: Revenue for the period landed at $50.4 million, which was up an impressive 55% when compared to $32.5 million it generated in the year ago quarter, and would have come in at above 60% had it not been for the currency markets.

Sales from the company's peripheral vascular products unit showed especially impressive growth, jumping 157% to $14.1 million year over year. Penumbra's neurological division also showed strong growth of 34% with sales coming in at $36.3 million. That strong growth allowed the company to show a profit during the period of $0.9 million, or $0.03 per diluted share.

Thanks to its recent IPO, completed on September 23, 2015, the company now boasts $159 million on its balance sheet. 4.6 million shares of common stock were sold at an offering price of $30.00 per share and raised approximately $124.8 million in net proceeds.

Now what: Penumbra is certainly off to a good start in its life as a public company. Shares are now up more than 20% since the IPO, and it's great to see the company show such strong growth in its first quarter right out of the gate.

However, investors in Penumbra have a large number of well-financed competitors to keep their eyes on, as the company counts industry stars like StrykerMedtronic, and even almighty Johnson & Johnson, as potential competitors. 

They don't appear to be harming the company just yet though -- here is what Adam Elsesser, Penumbra CEO, had to say about results from the company's neuro division during the quarter:

...while we anticipate competition as the market grows, we did not see its effect this period. We believe that competition is important for advancing this field. It has existed in the field for well over a decade, and it has pushed us to work harder and stay innovative.

It's certainly good to see that the Johnson & Johnson's of the world haven't slowed down Penumbra's growth so far, but that doesn't mean they won't in the future. After all, Penumbra currently estimates that the market for its products in the United States and Europe combined was approximately $1.3 billion in 2014, which is certainly a big enough market for competitors to considering pushing hard into.

All in all, Penumbra is certainly off to a good start as a public company, so this may be a company that is worth adding to a watch list. 

Brian Feroldi has no position in any stocks mentioned. The Motley Fool owns shares of Medtronic. The Motley Fool recommends Johnson & Johnson. Try any of our Foolish newsletter services free for 30 days. We Fools may not 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.