Just over a year ago, cloud storage company Dropbox (NASDAQ:DBX) went public. Since then, the company has posted a full year of financial results, featuring strong double-digit growth, robust cash flow, and even a major acquisition.

Here's a look at Dropbox's performance since its March 23 IPO last year.

A diagram of three laptops connected to a cloud

Image source: Getty Images.

Revenue rose 26% year over year

In 2018, Dropbox's revenue rose 26% year over year to $1.4 billion. While this is notable growth, it's down from 31% and 40% year-over-year revenue growth rates in 2017 and 2016, respectively. 

Dropbox's revenue growth was driven by a combination of growth in paying users, improved paying user conversion, and average revenue per paying user (ARPU) expansion.

ARPU hit a record high

In the years leading up to Dropbox's IPO, ARPU seemed to be leveling off. ARPU of $110.54 and $111.91 in 2016 and 2017, respectively, failed to exceed 2015 ARPU of $113.54. But Dropbox saw a substantial increase in its ARPU since it has gone public. The important metric rose to $117.64 in 2018.

12.7 million paying users

Dropbox's paying users saw robust growth, rising from 11 million at the end of 2017 to 12.7 million in 2018.

Gross margin improved

Highlighting the scalability of Dropbox's business, the company's GAAP and non-GAAP gross margin improved year over year. Non-GAAP gross margin in 2018 was 75.1%, up from 67.8% in 2017.

Non-GAAP earnings jumped

Thanks to higher revenue and an improved non-GAAP gross margin, Dropbox's non-GAAP net income soared, rising from $59.5 million in 2017 to $166.2 million in 2018. Non-GAAP earnings per share were $0.41 2018, up from $0.17 in 2017.

Free cash flow was substantial

Capturing Dropbox's strong business model, free cash flow in 2018 was $362 million, up from $305 million in 2017 and $137 million in 2016.

Dropbox buys HelloSign

Topping off an eventful first year as a publicly trading company, Dropbox acquired HelloSign, an eSignature, workflow, and online fax company, earlier this year. Dropbox paid $230 million in cash to buy the company.

HelloSign software on a laptop, tablet, and smartphone

Image source: HelloSign.

"[W]e see a lot of opportunity with HelloSign both in their existing business and products and where this can go in the future," said HelloSign CEO Drew Houston about the acquisition in the company's fourth-quarter earnings call.

Shares have underperformed

Though Dropbox stock soared 36% on its first day of trading, shares have since pulled back sharply. In fact, the stock -- at $22.26 as of Wednesday's market close -- now trades only 6% higher than its IPO price of $21. That compares to an 11% gain for the S&P 500 over the same timeframe.

Though Dropbox's stock may have delivered an underwhelming performance since the company's IPO, Dropbox's growth in ARPU, paying users, and free cash flow highlights a healthy business. Management is certainly pleased with the cloud storage specialist's progress, noting in its fourth-quarter and full-year earnings release that it was an "incredible first year as a public company with a great Q4."