Realize, that all of these gleaming reviews here with little context saying how great the company is and how it's experiencing growing pains are almost certainly being produced by the HR department. Before you get too involved with a role with interviewing for a role with the company, take a look at the very poor company performance over the past few years. It has only trended down, and while I hope this changes there is little to point that this will happen.
The truth is that your future is about as uncertain as the direction the company's own. Year after year, they have had massive layoffs, typically laying off hundreds of employees. There is not much you can do to protect yourself either, as they layoff every role from Kiosk workers to developers. Make sure you are keeping an eye out for new jobs around the end of February to mid-March each year, because as certain as there will be a new iPhone each year, Rosetta Stone will be laying off employees.
The direction that the company decides to pursue has changed countless times over the past few years. Every couple of quarters you will hear about a new "pivot" that the company is deciding to pursue because the previous one isn't working out. While this impact on your complacency with the role you're in would be minimal, it's rather annoying as you will certainly be shifted around from project to project before the products you're building can get to a point of maturity.
Please note that day-to-day life is not miserable as the people you're working with are a bunch of great people. You won't be unhappy here because of a poor work environment, I just don't believe you will ever get a strong sense of permanency due to the continuously shifting company direction and annual layoffs.
Also, the pay is not on par with the industry standard; it is much lower which is understandable when there is little profit being made.