What happened

Shares of streaming-TV company Roku (ROKU -2.67%) surged on Thursday, rising 19% as of 10:00 a.m. EDT.

The stock's gain follows the release of Roku's strong first-quarter results, which boasted better-than-expected revenue and a narrower-than-anticipated loss per share.

A chalkboard sketch of a bar chart highlighting a growth trend

Image source: Getty Images.

So what

The company's first-quarter revenue rose 51% year over year to $206.7 million. This easily beat management's guidance for first-quarter revenue of $185 million to $190 million. The figure also crushed a consensus analyst estimate for revenue of $192 million.

Roku's loss per share widened from $0.07 in the year-ago quarter to $0.09. But the figure was narrower than analysts' average forecast for a loss per share of $0.24.

"The strength of our brand, the scale of our active account base, the advantages of our purpose-built streaming OS, and the engagement of our users make Roku an increasingly important partner for content publishers, advertisers and TV manufacturers," said Roku management in the company's first-quarter shareholder letter.

Now what

Also likely fueling the Street's positive response to the first-quarter results is management's decision to boost its outlook for the full year. Management now expects 2019 revenue between $1.03 billion and $1.05 billion, up from previous guidance for revenue between $1.0 billion and $1.025 billion. In addition, Roku now expects adjusted EBITDA in 2019 to be between $10 million and $20 million, up from a previous forecast of between negative $5 million and positive $5 million.