From the Daily Camera:
Boulder Police Sgt. Robyn VanDerLeest said that police arrested one counterprotester who was throwing firecrackers and detained several others but that overall the demonstration was peaceful.

The left up to their violent tactics again throwing firecrackers is not peaceful. Notice how the DP did not mention these counterprotester lefties dressed up in black hoods were the ones getting arrested. Daddy Soros must be proud.