No, Qxd4 was not good, the alternatives were not good, but "less bad", the lesser evils.
Since some people watch in here: this is hypothetical after 11..../cd4:
Now two options:
First, this: 12. Nd4:/Ne5: 13. Be2/Nd6 14. Na3 (must go to a3, c3 does not work because c4 must be guarded against my nights going for c4 and again putting your dark bishop under pressure, I want that one to be gone with my dark bishop surviving). The result is this:
Not good a position, but much better than what there is now.
Edited: better posiiton than I initially assumed. White has one pawn less, yes, but he has the pair of bishops, can castle short, and organise a defence - maybe even a counterattack later on. MUCH better than Qd4: and the doom that follows that move.
or:
Second, this: 12. Bd4:/Ne5: 13. Bb3/Bf5 14. Le5:/Qd1:+ 15. Bd1:/Be5: 16: Nbc3
Again, preferrable to what there is now. Black has the pair of bishops, open firing lines of both, the short-legged nights may find it difficult to defend the two pawn-fronts on the left and right side later one.
These variations are no magic to find, since much is pretty much enforced.