San Francisco-based Fitbit acquired fitness coaching app developer, FitStar, for at least $17.8 million, according to an SEC filing.

FitStar had previously raised $5 million from Advancit Capital, Google Ventures, Trinity Ventures, Floodgate, and Mesa Ventures, according to CrunchBase.

In the filing, Fitbit selected "yes", when asked "Is this offering being made in connection with a business combination transaction, such as a merger, acquisition or exchange offer?". VentureBeat later received confirmation from a Fitbit spokeswoman that this filing was related to the FitStar acquisition, but she did not confirm whether the amount listed was the entire price of the acquisition.

Previous reports suggested that the deal was between $25 million to $40 million and included a mix of cash and stock.

Fitbit, which sells a variety of activity tracking devices, confirmed that it had acquired FitStar earlier this month.

FitStar offers two apps, FitStar Personal Trainer and FitStar Yoga. Both applications are free to download and use but most of the features require an in-app paid subscription. The apps provide users with workout training videos. They also track the user’s progress and help them reach fitness milestones. FitStar’s apps already sync with Fitbit as well as other activity tracking apps and devices including Jawbone and MyFitnessPal.

At the time of the acquisition, FitStar said in a statement that with the addition of FitStar’s personalized streaming video workouts to Fitbit’s offering, “users will find even more motivation through individually customized workout sessions”.

Fitbit’s devices are available in more than 30,000 North American retail stores and 45,000 stores around the globe — the products are sold in 54 countries. Fitbit users are primarily based in the US, followed by UK, Canada, Australia, Brazil, and China. At the time of the acquisition, FitStar’s app had logged more than 3 million downloads.