Rambam Hilchot Gneivah 1:2
אָסוּר לִגְנֹב כָּל שֶׁהוּא דִּין תּוֹרָה. וְאָסוּר לִגְנֹב דֶּרֶךְ שְׂחוֹק אוֹ לִגְנֹב עַל מְנָת לְהַחְזִיר אוֹ עַל מְנָת לְשַׁלֵּם הַכּל אָסוּר שֶׁלֹּא יַרְגִּיל עַצְמוֹ בְּכָךְ:
According to the law of the Torah, it is forbidden to steal the smallest amount. It is likewise forbidden to steal in jest, or to steal with the intention of returning the object or paying for it. All this is forbidden, lest one may become addicted to it.
אֵיזֶה הוּא גַּנָּב זֶה הַלּוֹקֵחַ מָמוֹן אָדָם בַּסֵּתֶר וְאֵין הַבְּעָלִים יוֹדְעִים. כְּגוֹן הַפּוֹשֵׁט יָדוֹ לְתוֹךְ כִּיס חֲבֵרוֹ וְלָקַח מְעוֹתָיו וְאֵין הַבְּעָלִים רוֹאִין. וְכֵן כָּל כַּיּוֹצֵא בָּזֶה.
Who is a thief? One who takes a person's property secretly without the owner's knowledge, as when he puts his hand into someone's pocket and takes money out without the awareness of the owner, and so on.
It's apparent from the above, that one is not allowed to take something even if the owner doesn't need the product. While it might not say those words specifically, I believe it's obvious that if one is not allowed to take something from a store even if he has in mind to pay later, then obviously one cannot take something that might not be needed, unless there's explicit permission from the company.