If you use the -bdg flag you get a bedgraph file, which is almost exactly the same as a wig file. The difference is that if there are a set of adjacent positions with the same value they will be represented as a range, e.g. chr1 1000 1200 2. Wig would have 200 coordinates if value 2. See here for a better explanation.

You can use your bed graph file with wigToBigWig.