Round trip ticket US -Beijing oct 10 days but traveling to third country for several days -visa?

We are us citizens. We have round trip tickets from US to Beijing arriving the 10th and returning the 20th. We are purchasing round trip tickets to Thailand where we will be for 6 days. We will be returning to Beijing to catch our return trip back. We are visiting Beijing for just slightly above 72 hours of our trip in. Would we be okay free transit?