So far, 2019 is turning out to be a very good year for many marijuana stocks. But not for all of them. Tilray (NASDAQ:TLRY), for example, is performing much worse than most of its peers, with its share price slipping nearly 16% year to date.

However, Tilray ranked as the top-performing Canadian marijuana stock of 2018. The company has tremendous opportunities for growth in the future. If you're looking to buy Tilray while it's down, though, here are five things you should know first.

Marijuana leaf in a shopping cart.

Image source: Getty Images.

1. Great partners

One area in which Tilray has arguably outshone its peers is in forging multiple partnerships with big players outside of the cannabis industry. Granted, Canopy Growth and Cronos Group have made deals that involved significant investments from their partners. Tilray, though, has teamed up with several large global companies.

Tilray's first major deal was with Novartis' Sandoz subsidiary. The relationship was initially limited to developing and marketing medical cannabis products in Canada. However, Tilray and Novartis later expanded the scope of their partnership to a global scale.

In December, Tilray announced a partnership with big beermaker Anheuser-Busch InBev to research cannabis-infused nonalcoholic beverages for potential introduction in the Canadian market once cannabis edibles are allowed. The company hopes this relationship leads to collaboration outside of Canada in the future.

Earlier this year, Tilray and Authentic Brands Group (ABG) teamed up to market and distribute consumer cannabis-infused products across the world. ABG's product lineup includes more than 50 beauty, lifestyle, and wellness brands.

2. Solid international medical cannabis operations

Although Tilray definitely should be able to grow revenue significantly in Canada, the company's opportunities in global medical cannabis markets are even greater. The good news is that Tilray already has solid international medical cannabis operations.

Tilray's medical cannabis products are currently available in 12 countries. The company was the first to secure approval to sell both cannabis flower and cannabis oils in Germany, the largest international medical cannabis market outside of North America. Tilray was also the first company to export legal medical cannabis products from North America to four continents.

The company's Portugal facility gives it a launching pad to distribute medical cannabis throughout Europe. Tilray's partnership with Novartis should also help in establishing solid relationships with physicians and pharmacists across the world.

3. Leadership position in the U.S. hemp market

One international marijuana market in which Tilray can't currently compete is the U.S. Tilray can't keep its listing on the Nasdaq stock exchange and establish U.S. marijuana operations as long as marijuana remains illegal at the federal level. But it's a different story for hemp, which became legal in the U.S. in December 2018.

Tilray has quickly become a leader in the U.S. hemp market thanks to its acquisition of Manitoba Harvest in February. Manitoba Harvest ranks as the world's largest hemp food maker. The company's products are sold in more than 16,000 stores in North America, with around 13,000 of those stores in the U.S.

In addition, Tilray and ABG will market consumer products that contain hemp-based cannabidiol (CBD) in the U.S. Tilray's Manitoba Harvest operations provide the company a strong supply chain for CBD to be used in ABG's products.

4. Relatively low capacity -- but expanding quickly

A major knock against Tilray is that its production capacity is significantly less than that of other top-tier Canadian marijuana producers. The company currently relies on third-party cannabis suppliers much more than it would like. This dependence contributed to Tilray's gross margin slipping in the fourth quarter of 2018.

However, Tilray is taking steps to expand its production capacity. CEO Brendan Kennedy stated in the company's Q4 conference call that a top priority is to boost capacity. Tilray expects to be able to produce around 90,000 kilograms of cannabis by the end of this year, excluding the impact of its acquisition of Natura Naturals earlier this year.

5. Lofty valuation

Another thing that investors should consider before buying Tilray is its valuation. With a market cap of around $5.8 billion and 2018 revenue of only $43.1 million, there's a whole lot of growth expectation baked into the share price.

Tilray certainly has plenty of avenues for growth. The Canadian adult-use recreational marijuana market is expected to grow to around $5 billion within the next few years. European medical cannabis and CBD markets could approach $10 billion by 2023. The U.S. hemp CBD market could be as large as $22 billion by 2022, according to a projection by Brightfield Group.

Keep in mind, though, that these figures are just estimates. They could be wrong. And there's no guarantee that Tilray will be able to capture sufficient market share to justify its current valuation even if the estimates do prove to be on target.

The bottom line is that Tilray has a lot going for it, but there's also a lot of uncertainty.