It's no secret why investors flock to the healthcare sector: It generates results. Between 2007 and 2017, healthcare was either the second- or third-best-performing sector in the S&P 500 six of those years. By comparison, it underperfomed on a sector-equal weighting only three times in a decade. It's a high-growth sector that can deliver massive returns -- if you happen to pick the right stock, or group of stocks.  

With this mind in mind, we asked three of our healthcare-savvy Foolish investors to name one healthcare stock they believe would be a good buy right now. Though dental device maker Align Technology (NASDAQ:ALGN) is a large-cap stock, the remaining two suggestions were off-the-radar small caps: medical device company LeMaitre Vascular (NASDAQ:LMAT) and companion-pet drug developer Aratana Therapeutics (NASDAQ:PETX)

A stethoscope lying atop a fanned pile of hundred dollar bills.

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The top stock from last year is still a great pick

Keith Speights (Align Technology): The dental medical device maker reigned at the top of the S&P 500 last year, its shares soaring more than 130%. But is Align a good stock to buy right now, after those big gains? I think so.

The reasons why Align performed so well in 2017 are still in place. Align reported record sales of its Invisalign clear aligners last year. Despite the tremendous growth, there are still plenty of opportunities. Align has only around a 10% market share of the available orthodontic case market -- and just 4% of the teen market. The key to capturing more of that market is to make patients aware of Invisalign and educate dental care providers about the benefits of the clear aligners. Align is continuing to do both.

But while Align should be in good position to build its market share, the company could also build the overall market size as well. Align's clear aligners are suitable for roughly 60% of current cases of malocclusion (misalignment of the teeth). The company is hard at work developing new technology to increase its addressable market to close to 85% of all cases of malocclusion. 

Align Technology stock certainly looks pricey: Its shares trade at nearly 56 times expected earnings. However, I think strong growth prospects give this stock plenty of room to run.

A surgeon holding a dollar bill with forceps.

Image source: Getty Images.

A great business for a good price

Brian Feroldi (LeMaitre Vascular): Healthcare stocks have been on a great run over the last year, so finding bargains is quite a challenge. In times like these, it is smart to focus on great companies that don't receive a lot of attention from Wall Street. That's why I think that LeMaitre Vascular is a great stock for investors to check out

LeMaitre is a small-cap medical device company that focuses on the needs of vascular surgeons. CEO and founder George LeMaitre was a vascular surgeon himself before he founded the company a few decades ago. His surgical experience provided him with a unique insight into the needs of his customers. As a result, he has a great track record for building or acquiring products that meet the unique needs of this niche market segment.

So what types of products does LeMaitre Vascular sell? Think patches, grafts, catheters, angioscopes, shunts, tapes, and more. In total, the company has 15 unique product lines. What's more, the vast majority of its products hold the No. 1 or No. 2 market share, which speaks volumes about this company's eye for quality. 

LeMaitre's growth strategy is quite simple. Each year the company adds a few new sales reps, pushes through price increases, expands geographically, and rolls out new products. This is combined with margin improvements and occasional share buybacks. Thanks to this approach, LaMaitre's profits have grown in excess of 46% annually over the last five years. 

While I don't expect that level of profit growth from here, I'm confident that this company can grow its bottom line by double digits for the foreseeable future. With shares trading at around 36 times forward earnings estimates, I think that this wonderful business sports a fair price today. 

Man, woman, two girls, and a dog seated at a couch.

Image sources: Getty Images.

Plenty of potential in this small-cap biotech stock

Sean Williams (Aratana Therapeutics): I believe the top healthcare stock to buy right now is a small-cap stock bordering on microcap territory: Aratana Therapeutics.

Most folks would look at a money-losing biotech company with a $225 million market with disdain. But I see dollar signs. That's because Aratana's primary focus is developing medicines to treat companion animals. More and more, companion pets like cats and dogs are considered members of the family. This means pet owners are more than willing to open up their wallets and ensure their pets get whatever treatment is necessary to live a long and healthy life.

Americans spent $69.4 billion on pets in the U.S. last year, according to estimates from the American Pet Products Association, with roughly $31.6 billion for vet care and supplies and over-the-counter medicine. If Aratana can deliver with even a portion of its product portfolio, it should be able to move swiftly into the black.

The company has three Food and Drug Administration-approved drugs and a pipeline with a handful of additional products for felines that could turn out to be winners. Of greatest interest is Galliprant, a first-in-class treatment for osteoarthritis that's approved in the United States. Aratana signed a licensing partnership with Eli Lilly (NYSE:LLY) for Galliprant, netting $45 million in much-needed up-front cash, and giving it the opportunity to earn $83 million more in milestone revenue, along with net-sale royalties. According to investment firm Jefferies, the drug could have peak annual sales of $76 million in the U.S. and $75 million in Europe. And best of all, Aratana is able to lean on the marketing expertise of Eli Lilly's animal-health division Elanco to grow sales. 

Given Aratana's relatively small size, and the fact that it already has three approved products, it won't take too much to push it into the black (probably around $65 million in annual sales). By 2020, Wall Street anticipates the company could be generating $0.27 in annual earnings per share. Considering that Aratana is operating in a niche industry with three approved products and a healthy pipeline, it could easily double in value, in my view, in the years to come.

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.