What happened After an underwhelming 2019, shares of GW Pharmaceuticals (NASDAQ: GWPH) perked up nicely in January, with the drugmaker's stock jumping 10% for the month, according to data from S&P Global Market Intelligence. The gain last month came in response to the company's preliminary fourth-quarter and full-year results released on Jan. 12. The major headline is the rapidly growing sales of the company's cannabis-based epilepsy medicine Epidiolex. During its first full year of sales as a treatment for two rare but potentially deadly forms of childhood epilepsy, Epidiolex hauled in an astounding $296 million. Image source: Getty Images. So what Investors cheered these strong financial results for two reasons. First, there was some concern among Wall Street analysts about Epidiolex's commercial viability ahead of its official launch. The concern stemmed from its rather high price and the fact that there are far cheaper alternatives already on the market. GW proved the naysayers wrong by transforming this cannabis-based medicine into an absolute commercial powerhouse. Second, GW has been one of the only unmitigated successes in the closely watched cannabis space. While other cannabis stocks floundered on the commercial front last year, GW actually exceeded expectations for the full year. Now what Can GW's stock keep marching higher? Wall Street presently has an average price target on the shares of $201.53, implying a staggering upside potential of approximately 72% from current levels. To get to this next level, however, GW will have to continue to deliver in both the clinic and the marketplace. Luckily, the drugmaker has been able to score high marks on both of these key fronts over the past year. That doesn't mean that GW's winning streak is guaranteed to continue in 2020, but there's also no obvious reason to doubt the company at this point. As a result, investors may want to think about adding this top growth stock to their portfolio soon. 10 stocks we like better than GW PharmaceuticalsWhen investing geniuses David and Tom Gardner have a stock tip, it can pay to listen. After all, the newsletter they have run for over a decade, Motley Fool Stock Advisor, has tripled the market.* David and Tom just revealed what they believe are the ten best stocks for investors to buy right now... and GW Pharmaceuticals wasn't one of them! That's right -- they think these 10 stocks are even better buys. See the 10 stocks *Stock Advisor returns as of December 1, 2019 George Budwell has no position in any of the stocks mentioned. The Motley Fool has no position in any of the stocks mentioned. The Motley Fool has a disclosure policy.Source