You should talk to a lawyer who specializes in IP. IANAL, but they don't own the IP -- they license it from you. Whether that means they owe you anything would

You should talk to a lawyer who specializes in IP. IANAL, but they don't own the IP -- they license it from you. Whether that means they owe you anything would depend on the specifics of the case, and that's something you'll need an attorney to figure out.