There's little question that one of the surest paths to wealth generation is investing in quality companies and holding them over the long term. If you have any doubts, consider this: Since its inception in the mid-1920s through 2019, the S&P 500 (originally just 90 stocks) has returned roughly 10% annually. Since expanding to 500 stocks in the mid-1950s, the index has returned roughly 8%. 

This means that time is on the side of investors, and the sooner you get started, the better your chances are of retiring with a seven-figure nest egg.

Another way investors can increase their chances of building a life-changing portfolio is by investing in smaller companies with a disruptive, game-changing product. Let's look at three companies that meet this criteria and see what else they have in common.

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1. Guardant Health: A game-changer in cancer detection

While cancer treatment has come a long way in recent years, one thing hasn't changed: early detection is a key to survival. Unfortunately, many of the existing methods for determining if a patient has cancer are both costly and invasive. That's where Guardant Health (GH 1.34%) comes in.

The company is a pioneer in the field of liquid biopsy, which can detect fragments of cancerous cells with a simple blood test. By identifying DNA and RNA fragments shed by cancerous tumors, Guardant is revolutionizing the future of cancer detection. That's not all. By helping to determine what type of cancer is present, doctors can tailor a treatment plan much quicker than was previously possible.

During 2019, Guardant Health's revenue soared by 137% year over year, though the company hadn't yet generated a profit. The trend continued into early 2020, with first-quarter revenue up 84%. The onset of the pandemic crimped the company's growth, however, as patients put off all but the most critical medical procedures and second-quarter revenue climbed just 23%. Management has since revealed that demand was returning levels it experienced pre-COVID, which should signal improvement for its upcoming quarter. 

Finally, the Food and Drug Administration approved the company's latest cancer screening tool, Guardant360 CDx, which will help accelerate wider adoption of this game-changing healthcare technology. 

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2. Okta: Identify verification takes center stage

More people are working from home than ever before, which took many employees out from under the umbrella of their corporate IT department and forced them to access systems remotely. This increased the already formidable threat of unauthorized access and intrusion. Okta (OKTA 0.62%) was there to answer the call.

The company's cloud-based identity management service was already the undisputed leader in identity and access management, handling the task of user authentication for employees, contractors, and customers, integrating with more than 6,500 business software applications to create a single, secure login. The company boasts more than 8,400 global organizations that rely on Okta to manage their access and authentication protocols. Okta was named the industry leader in access management for the third year running by research company Gartner, taking the top spot in its vaunted Magic Quadrant. Forrester Research awarded the company similar accolades, naming it the leading identity-as-a-service (IaaS) provider. 

The proof, as they say, is in the pudding. For the first half of 2020, Okta's revenue jumped 44% year over year. At the same time, its remaining performance obligation -- which consists of future revenue that is under contract but has not yet been recognized -- surged 56% year over year.

Management cited the adoption of cloud computing, the ongoing digital transformation, and the need for zero-trust security as significant tailwinds accelerating Okta's already heady growth prospects, with no signs of slowing on the horizon. 

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3. MongoDB: A new take on what a database can do

Let's face it: Today's data is messy. What once fit neatly into well-defined columns and rows is now made up of photos, video, audio, even entire documents. As a result of the changing nature of data analysis, the legacy database falls far short of requirements.

Enter MongoDB (MDB -3.12%). The company's cutting-edge, cloud-based platform does away with the strict structure required by its predecessors and can handle a wide variety of data types pulled from multiple sources. That makes it the top choice of developers, empowering them and the apps they design. It's MongoDB's free community offering that entices customers to try it out, but it's the company's cloud-centric, fully managed database-as-a-service (DBaaS) product -- Atlas -- that's the key to MongoDB's stellar growth.

In the second quarter, MongoDB reported revenue that grew 39% year over year, while subscription revenue climbed 41%. It was Atlas that stole the show, however, climbing 66% and now representing 44% of the company's total revenue. That's an impressive performance for a product that's less than four years old. 

It was impressive underlying customer acquisition that drove the company's strong growth. MongoDB's total customer count climbed to 20,200, up roughly 35% year over year. Those gravitating to Atlas grew at an even quicker pace, up 42% to 18,800. Customers contributing annual recurring revenue (ARR) of $100,000 or more grew to 819, an increase of 32%.

Messy data is here to stay, giving this database disruptor a large and growing opportunity.  

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You get what you pay for

Eagle-eyed investors will have detected several similarities between these future all-stars. First, they each have a relatively small market cap, with Guardant Health, MongoDB, and Okta coming in at $11 billion, $15 billion, and $32 billion, respectively. While a lower market cap typically results in higher volatility, it also provides each of these disruptors with a long runway for future growth.

Each company is also a high risk, high reward proposition, earning each a somewhat lofty sticker price and a valuation to match. MongoDB, Guardant Health, and Okta are currently selling at 28, 39, and 39 times forwards sales, respectively -- when a good price-to-sales ratio is generally between 1 and 2. It's also important to note that none of these companies is currently profitable, instead opting to spend their limited resources to secure future growth.

In each case, however, investors have thus far been willing to pay up for the impressive top-line growth and the potential for the explosive profits in the months and years to come.