RSU's are shares of stock that will be issued to the beneficiary upon attainment of certaing goals. Most frequently, they are contingent on continuous employment through a specified period of tiem (golden handcuffs). In this case, it appears it is contingent on FDA approval. Unlike options, the named execs will not have to purchase the shares, they will simply be given to them. Be prepared, they will likely sell a portion of the shares upon issuance to cover the taxes.

Even though these awards seem lofty, compared to software startups, it is chump change.