If you're having trouble with any encounter that you should be able to beat (read: class story bosses that should be solo-able), here are a few tips that have worked well for me so far.
1. Use medpacs and stims. If a fight is close, a medpac saves your life and you win. A stim to boost your health or damage is not insignificant.
2. Let your companion take a good chunk of damage before jumping in. Have your companion attack first and do as much damage as possible, then when they're a bit low on health, jump in, taunt and grab aggro. You'll basically have a head start on the fight. It also allows them to "suck up" the initial hit or two of the boss' specials such as knockbacks or stuns.
3. Use your defensive skills. Use Saber Ward, use Call on the Force, then use Saber Ward again. No reason not to blow cooldowns every time they're up when you're trying to beat a tough story boss.
4. Interrupt! Save your force kick, force stasis, force push, anything that stuns or stops casting (assuming the target is not immune to the particular skill). If the boss has a big skill with a cast time, watch for that cast bar and break it as much as possible.
5. Use different companions (if available). Honestly I've had the easiest time just using my highest DPS companions since I'm pure defense spec and I can take the hits / need the extra damage, but every spec is going to require some different help depending on the encounter.
6. If all else fails... level up. Seriously, even 1 more level can sometimes make the difference. I've gotten ahead of myself on class quests a few times now.
I beat this boss on my second attempt at level 24. I didn't use any of the "stand in front of the box" tricks or anything, just straight up fighting. When you get knocked back, leap immediately back in as soon as you can. I'm not saying this to imply that you suck if you can't do it, just to illustrate that it's doable.
I also realize that some of these are very obvious tips, but not everybody uses them. I hope it helps somebody.