Look at it from a supply and demand perspective.
The two factors here are the domain (supply), and the company's desire for the name (demand).
The "supply" is unchanging. You own the domain. And you will continue to own the name until such time that it is transferred out of your possession; notwithstanding any hacking of your domain registrar's account, or nonpayment of renewal fees.
The "demand" on the other hand, is what stands to change in this circumstance. Right now, the domain would help, since they are still in the middle of the project's development. It is a want, not a need.
As they become further invested in the project, and inherently, further invested into the word that your domain name contains, they are simply creating a greater demand for your domain... not just for them to use it, but also for domain investors with a similar vision to purchase it speculatively.
Just imagine... back in 1995, the word "Skype" meant nothing. If you owned "Skype.com", and heard that a couple of guys in the early 2000's were working on a project and thinking of calling it "Skype"... would you really want to sell it to them in the project's infancy at zero users? Or perhaps wait it out until they've built a bit of a userbase, and in turn, a dependency on the name?
To put it into clearer terms... if you were to approach them in development, they have the power to say "no". Or "here's $100". However, if THEY were to approach YOU, after they've created their own demand, they don't exactly have the power to say "no".
Selling it too early would be like selling your gold when it was $200 an ounce. After the value of currency dropped further, it went up to $500, then $1,000, then even as high as the $1,700's.
The "demand" for your name as it stands right now is pretty flat. But let it build up a little, and watch the profit create itself. You need not do anything but renew the name.