If you gave more than $15,000 in assets
(the value of the stock), you
need to file a gift tax return. That doesn't mean you have to pay a gift tax. It just means you need to file IRS Form 709 to disclose the gift. This amount will count against your lifetime gift allowance, which is currently $11.18 million. If the stock's value is less than $15,000 you don't need to report the gift. Either way, the recipient assumes your cost basis for the stock.
"How do I account for that on my tax return?"
You don't. I assume you give people gifts all the time - birthdays, anniversaries, wedding presents, etc. - and you don't report those on your income tax return. Just because you gifted employees some stock doesn't change that. In you're own records you reduce your basis for this stock - less shares means less basis - and that's it.