That block explorer is open source and ( i believe ), free to use. See their github
https://github.com/iquidus/explorer, anyone with a little bit of technical/coding skills should be able to install this correctly.
I guess you could also use this open source software, although i'm not too sure if this can be used for commercial goals/projects...
https://insight.is/ //
https://github.com/bitpay/insight/