In october 2015 , a pharmaceutical company receives cash from the federal government as an incentive to stockpile flu vaccines. In return, the federal government requires the company to be able to deliver vaccines at a moment's notice. If there is a flu outbreak, the company will deliver the vaccines to the CDC. If there is no need for the vaccines by the end of the flu season (usually April of the following year), the company still retains the cash.

When should this company record its revenue ?