If you owned shares of Apple throughout the past decade, you are undoubtedly a happy investor now. Over the past 10 years, the tech giant's stock has soared by a little over 950% -- vastly outpacing the S&P 500's 196% gain in the same period. But all that growth means that Apple is now one of the largest companies in the world.

There's no doubt the iPhone maker can keep finding ways to grow, and in my view, its shares are still worth buying. But given its market cap of more than $2 trillion, investors seekiong stocks with explosive, long-term growth potential may want to look elsewhere. Here are two stocks that fit the bill: DexCom (NASDAQ:DXCM) and Teladoc (NYSE:TDOC). Find out why these healthcare companies have a bright future ahead. 

DXCM Chart

DXCM data by YCharts

1. DexCom: Helping diabetes patients live better lives

DexCom develops continuous glucose monitoring (CGM) systems, which help diabetes patients perform an essential task -- keeping track of their blood glucose levels. Whereas blood glucose meter (BGM) options can only measure a patient's glucose level at the specific moments they're taken, CGMs allow those with diabetes to track their blood glucose levels continuously, with alerts if the reading gets too low or too high. BGMs and their pesky fingersticks are also often painful to use, but CGMs aren't.

The convenience of CGMs continues to help DexCom deliver great financial results. During its second quarter, which ended June 30, the company's revenue grew by 34% to $451.8 million. DexCom attributed its top-line growth to increasing awareness of CGMs. The company's GAAP gross margin also increased to 62.9%, up from 61.4%; non-GAAP gross profit grew to 64.1%, up from 61.4%. The higher revenue and higher gross profit led to a higher bottom line for DexCom. The company's net income for the quarter was $46.3 million, after it recorded a $10.5 million net loss during last year's second quarter.

Doctor checking a patient's blood glucose with meter

Image source: Getty Images.

DexCom makes the bulk of its revenue in the U.S., where there's plenty of room to penetrate the CGM space. Management estimates that its core market -- people on intensive insulin therapy (ITT) -- numbers roughly 3.3 million U.S. patients. Add in several other countries (including Australia and Canada) where DexCom does business, and its core ITT market jumps to between 7 million and 8 million people.

And there is a significantly larger untapped opportunity beyond these places, in countries where DexCom's presence is currently either minimal or nonexistent, but where those on ITT could benefit from its products. 

With a long history of innovations and a growing presence abroad, DexCom is in a good position to grow for years to come. Its market cap is $38.3 billion, which is tiny compared to Apple, giving the healthcare company a long runway for growth. Buying shares of DexCom today and holding them for the long haul would be a great move. 

2. Teladoc: Leading the telemedicine revolution 

If you had reservations about going to see a doctor at the height of the coronavirus pandemic, you weren't alone. Most healthcare facilities put nonessential procedures on pause as they dealt with the worst of COVID-19. Thankfully, Teladoc was there to offer some basic medical care -- including consultations with qualified physicians -- from the comfort of one's home, all thanks to the magic of telemedicine.

The company's virtual care visits famously spiked earlier this year, both from those whose health insurance plans covered telehealth costs and from those who had to pay a fee per visit. Naturally, Teladoc's revenue also grew significantly as a result. During its second quarter ending June 30, the company's revenue jumped by 85% year over year to $241 million, while its total visits skyrocketed by 203% to 2.8 million.

This could be just the beginning. There are excellent reasons to think the telehealth craze will continue long after the outbreak is over. According to a Doctor.com poll of more than 1,800 adults, 83% of patients say they are likely to use telemedicine even after the pandemic ends. Meanwhile, Grand View Research has estimated that the telemedicine market will hit $155.1 billion by 2027, up from $41.4 billion in 2019.

Doctor talking on laptop

Image source: Getty Images.

Let's not forget that in August, Teladoc initiated a move to acquire Livongo Health (NASDAQ:LVGO) in a cash-and-stock transaction valued at $18.5 billion. Livongo focuses on providing tools to help those with chronic conditions, particularly diabetes, achieve better health outcomes.

The combined market opportunity for these two companies in the U.S. alone is $121 billion, which means they haven't even begun to scratch the surface of these segments -- Teladoc currently has a market cap of $18.4 billion, while Livongo's is $14.4 billion. The combined entity will be minuscule compared to Apple, and with a long runway for growth ahead, it will continue to reward shareholders for many years to come.