• Roku posted solid growth on the top and bottom lines, but investors were still unsatisfied with the report.

• After it surged through May and June, investors seemed to think the stock had run too high.

• Roku’s losses are improving, but investors typically demand faster growth from an unprofitable company.

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Shares of Roku (NASDAQ: ROKU) were tumbling today even though the leading streaming distribution platform topped headline estimates. Investors still seemed to find fault with key metrics in the quarter, as well as with its guidance and valuation.

As a result, the stock was down 15.5% at 2:14 p.m. ET.

Roku is still losing money on a generally accepted accounting principles (GAAP) basis, but the company is making strides toward profitability.

In the second quarter, Roku reported revenue of $1.11 billion, up 15% from the quarter a year ago, which was better than estimates at $1.07 billion.

Revenue from devices was down 6% to $135.6 million, which could be a bad sign, as device sales help grow its customer base. Platform revenue, its core business, which is driven by advertising and subscription revenue share, was up 18% to $975.5 million. Streaming hours watched rose 17% to 35.4 billion, a positive trend for consumption.

On the bottom line, the company showed improvement as adjusted earnings before interest, taxes, depreciation, and amortization (EBITDA) rose 79% to $78.2 million. GAAP operating loss, meanwhile, narrowed from $71.2 million to $23.3 million.

With the help of $28 million in other income from interest and strategic investments, Roku reported a GAAP per-share profit of $0.07, up from a loss in the quarter a year ago of $0.24 and better than estimates at a per-share loss of $0.16.

Management credited its solid growth to “strong performance in video advertising and the successful acquisition of Frndly,” as well as new ad tech integrations, including with Amazon.

Looking ahead, Roku expects $1.205 billion in revenue for the third quarter, or 13% growth, though that was ahead of the consensus at $1.17 billion. Its full-year revenue guidance of $4.65 billion was slightly below the average estimate at $4.66 billion.

The company also announced a $400 million share buyback program.

Overall, the results weren’t the kind that typically lead to a double-digit decline. However, investors seem frustrated with Roku’s operating losses and its valuation, considering it’s expected to grow only in the low teens to midteens for the rest of the year.