Boise passed a law in 2012 preventing businesses to discriminate based on sexual orientation. The law took effect January 1, 2013.  

http://www.hrc.org/m/blog/boise-passes-non-discrimination-ordinance

Proposition 1 proposed in 1992 was set out to limit rights of the gay community, but was defeated. 

In May 2014 gay marriage became legal in Idaho.