Smartsheet continues to increase revenue but shares were down slightly in after-hours trading following its first quarter earnings report Wednesday.

The Bellevue, Wash.-based work collaboration software maker posted $56.2 million in revenue for the first quarter, up 55 percent year-over-year, and a non-GAAP net loss of $0.12 per share, the same as the year-ago quarter. Analysts expected $54 million in revenue and a loss of $0.18.

Smartsheet stock, which has nearly doubled in price this year, was down more than 4 percent, trading at around $40 per share. The company’s offering price was $15 per share when it went public one year ago. Its market value is more than $4 billion.

Smartsheet’s subscription revenue came in at $50.3 million for the quarter, up 57 percent. It ended the quarter with 80,280 domain-based customers, up from 78,959 three months ago.

Smartsheet continues to see growth with its largest customers — 518 companies now spend more than $50,000 annually with Smartsheet. That’s up from 444 in the fourth quarter of 2018 and 360 in the third quarter, and up 117 percent year-over-year.

The company also today revealed the purchase price for its acquisition last month of Seattle startup 10,000ft: $27.5 million.

10,000ft was created as an internal project planning tool at Seattle-based product and industrial design firm Artefact, and then spun out on its own in 2012. It was led by Martijn van Tilburg, a designer from Microsoft who got his start working on products like Office and Windows and then spent six years as director of design for Artefact.

10,000ft had 27 employees and more than 1,000 customers, including Accenture, PwC and Stanford University.

The acquisition was Smartsheet’s second this year. In January, it scooped up Slope, another small Seattle startup founded in 2014 that helps companies manage the creative project production process.