Source: Ambarella.

Shares of video-processing semiconductor developer Ambarella (NASDAQ:AMBA) rose in after-hours trading today after the company reported results for the first quarter of fiscal year 2015. Shares were up about 0.6% as of 5 p.m.

Sales increased 21% year-over-year, landing at $40.9 million. Adjusted earnings jumped 19% to stop at $0.25 per diluted share. Analysts had expected earnings of $0.21 per share on $40 million in sales. Ambarella more than met the Street's consensus targets.

Non-GAAP gross margins shrank 1.3 percentage points year-over-year. R&D expenses increased by 14%, somewhat slower than the 19% increase in total operating expenses.

With this quarter on the books, Ambarella has $155.6 million of cash equivalents and short-term investments on hand, up from $104.3 million a year ago. Inventories decreased about 4% to $10.0 million.

In a prepared statement, Ambarella CEO Fermi Wang explained that his company's growth rested on high demand for its high-definition security camera products.

"We are very pleased with the financial results of our first fiscal quarter of 2015," Wang said. "We believe the expanding markets for innovative, high definition professional and consumer cameras will continue to give us the opportunity to grow our revenues in the year ahead."

Editor's Note: A previous version of this article incorrectly stated that Ambarella's cash equivalents and short-term investments amounted to $143.4 million in Q1 2013. The Fool regrets the error.