A recent Securities and Exchange Commission filing suggests that Boston-based indie studio Harmonix has raised just over $15 million in equity funding from investors it has chosen not to disclose.

The news was brought to Gamasutra's attention by a Boston Business Journal article, which notes that representatives of the Techstars accelerator and the Foundry Group investment firm (each have outposts in Boston) are listed on the SEC filing.

This investment is particularly notable because Harmonix has had a tricky time funding projects of late; the studio laid off a significant number of employees last year as it restructured its organization in the wake of an Amplitude Kickstarter that barely made its funding goal.

Now, however, the company is on track to debut a new Rock Band game next month and give crowdfunding another go by using new crowdfunding/investment platform Fig (which supports equity crowdfunding) to bankroll a new project later this year.