As late as 2016 the Republicans won the popular vote for the Colorado legislature, and they did so pretty comfortably in 2014, along with multiple statewide offices. (Only Governor and Senator were actually particularly closely contested that year). Under the 2012/2014-era trends, if anything it seemed to be trending back to the right.
Colorado, which is really rapidly becoming a more-educated state, has some kind of weird and unique dynamics; its state constitution, which includes TABOR, forces it to be significantly more 'fiscally conservative' than most state governments, and it has a pretty moderate set of leading Democrats for such a Democratic state. It's also very vulnerable to trends among college-educated voters, and has persistently high third-party totals.
TABOR and the Gallagher amendment was the bane of our existence when I was in a youth policy group back in high school. They seriously screw up basic funding. One down, hopefully the monstrosity that is TABOR falls soon.
