Regular expression appears only once

Regular expression appears only once

If I have three strings like this:
-16.60
.......((((...(((..((((((.(((.....((((((.((..........)).))))))..)))...))))))))).))))
[]
-16.60
........(((((........(((......)))..((((.((......))))))...)))))..((((.........))))...
[[][]][]
-28.60
...........((((.((((.(((.((.((.(((((((((((........))))).)))))))).)).))).)))).)))).......(((......)))
[][]
and I want a regular expression that consider the first case only in which
[] appears only once at the end I used this regular expression
-\d+.\d+.*\[]\s but it considered the three cases any suggestions???