in `=~': invalid byte sequence in UTF-8 (ArgumentError)

[ghazel]

$ ruby --version
ruby 2.0.0p451 (2014-02-24 revision 45167) [universal.x86_64-darwin13]
$ ruby -rUniversalDetector -e 'p UniversalDetector::chardet("(\342\214\220\xe2\x96 _\xe2\x96 )")'
/Library/Ruby/Gems/2.0.0/gems/chardet2-1.0.1/lib/UniversalDetector.rb:134:in `=~': invalid byte sequence in UTF-8 (ArgumentError)
    from /Library/Ruby/Gems/2.0.0/gems/chardet2-1.0.1/lib/UniversalDetector.rb:134:in `feed'
    from /Library/Ruby/Gems/2.0.0/gems/chardet2-1.0.1/lib/UniversalDetector.rb:46:in `chardet'
    from -e:1:in `<main>'