The Studio 192 ships with a 1.5M (5ft) USB 3.0 Cable. When dealing with high bandwidth multi-channel pro audio interfaces (from us, or any other company—whether it's USB 2.0, 3.0 or 1394) it's a good idea to keep the data cable as short as possible. This is to ensure best data integrity, as longer cables tend to be susceptible to crosstalk from other data and power types.
In addition to the cable that ships with the Studio 192, we tested 18" and 6' cables from MonoPrice, and 3', 6, 10' and 15' USB 3.0 cables from a company called E-Core Cable, and didn't find any issues.
The folks at E-Core were kind enough to let us know that if you're interested in getting the longer cables from them, you can contact them directly on their website.