It's best not to go all in on high-risk stocks, but that doesn't mean you should avoid them entirely. If you can tolerate some risk, certain players could make a good addition to a diversified portfolio.

That's because, along with the risk, these companies also offer you the potential for a significant gain. If they meet their goals, the shares could skyrocket.

You can find many of these types of stocks trading for a few dollars or mere pennies, which makes them accessible for a broad range of investing budgets. Today, two healthcare stocks fit the bill. I'm talking about vaccine maker Novavax (NVAX 0.72%) and genetic testing company Invitae (NVTA). With just $10, or even less, you can invest in both of these stocks.

Let's take a closer look at these two high-risk players that could deliver big rewards down the road.

1. Novavax

Novavax's big problem is that it fell behind in the coronavirus vaccine race, launching its product a year after rivals Pfizer and Moderna. As a result, the company missed out on the biggest revenue opportunity -- and found itself with expenses that were too high, considering potential future sales. And earlier this year, Novavax even questioned its ability to continue.

The good news is the biotech has taken action to turn things around. Novavax announced it would eliminate 25% of its workforce and make other cost cuts to reduce overall expenses by as much as 50% by next year.

Meanwhile, Novavax still aims to get in on the fall vaccine market with its updated shot. And the company is working on a combined flu/coronavirus vaccine candidate that could be successful down the road. (Moderna also is developing combination vaccine candidates, so it will be important to watch both companies' timelines -- Novavax probably can't afford to fall behind again.)

Novavax's clinical trial results have been strong, meaning the company has what it takes to produce quality products. The biggest challenge today is the ability to bring products to market ahead of or around the same time as rivals -- and carve out market share.

Today, Novavax shares are trading for about $8, or 0.4 times sales. If Novavax is able to reach its cost-cutting goals and participate in the fall vaccination period, the stock could gain from here -- and if the vaccine maker progresses with the combined candidate, the shares may really take off.

2. Invitae

Invitae specializes in the area of genetic testing, with a wide range of tests, from neurology to obstetrics and gynecology. The idea is to take a simple test to determine your risks for certain diseases -- and possibly make lifestyle changes that may prevent illness.

The company has increased revenue over time, but it's burned through more and more cash to do so. That's why last year, it announced a plan to turn things around. Invitae exited certain geographies, cut jobs and offices, and focused on core activities most likely to accelerate the path to positive cash flow.

Results are starting to show. For example, in the most recent quarter, Invitae's revenue increased about 1% excluding exited businesses. The company's generally accepted accounting principles (non-GAAP) gross margin showed improvement for the eighth straight quarter. And Invitae lowered its forecast for ongoing cash burn this year to the range of $220 million to $245 million from earlier guidance of more than $250 million.

Of course, Invitae isn't out of the woods yet. The company still lowered its forecast for annual revenue, and though cash burn is improving, it still represents a significant headwind.

That said, demand exists for the company's tests. In fact, in the quarter, rare disease and women's health each posted double-digit revenue growth. So if Invitae can progressively move closer to profitability, the shares could climb -- especially considering their level today.

The stock trades for less than a dollar, with a price-to-sales ratio of 0.4.

Should you buy?

Now, the big question is whether you should buy these exciting but uncertain stocks.

As mentioned, it depends on your comfort with risk. If you're a cautious investor, steer clear. You're better off sticking with companies that already are profitable and deliver steady earnings and share price growth. They may not offer you the potential for multibagger gains, but you still have a great chance of seeing your returns increase over time.

If you don't mind a bit of risk, though, a small investment in both Novavax and Invitae, or just one of them, may be worth your while -- especially at the levels they're trading at today. If they meet their goals, they may triumph. And you could share in the victory.