Bonus damage always stacks, unless it specifically says otherwise. So yes, it works. However, as everyone has already said, it sucks.

Consider a Psychic Warrior or Psychic Rogue/Psychic Assassin instead. That will give you Skills, Death Attack, Mind Cripple, some Sneak Attack, and some psionic powers.

Alternatively, you could use my homebrew Jedi/Soulknife.