The phrase "certain threshold" means a specific point or level that needs to be reached or crossed to trigger a particular action or result. Full definition
Your credit card will be charged periodically throughout the ad campaign, as the outstanding balance reaches certain thresholds. (rogerpacker.com)
The credit is not available to taxpayers whose income exceeds certain thresholds. (taxpolicycenter.org)
They must each also hit certain thresholds to qualify for a city - sanctioned primary debate against de Blasio, of which there can be up to two. (gothamgazette.com)