He went out on a limb to support my new idea.
out on a limb
idiomIn a risky, precarious, daring, or uncompromising position, especially one outside of the mainstream; vulnerable.
Origin
disputed originIn reference to the risks of climbing out on the branch or limb of a tree.
She went out on a limb by criticizing the company policy in front of the entire board of directors.
By challenging the established consensus of his peers, the researcher went out on a limb, risking his professional reputation for the sake of his controversial discovery.