Apple Inc. is already "within striking distance" of the leading vendor of wearable devices, according to research firm IDC. Apple marked its entry into the market by shipping 3.6 million units of the Apple Watch in the second quarter, trailing only Fitbit Inc., which shipped 4.4 million units of its wearable devices, IDC's report says. "Although Fitbit outshipped Apple, it's worth noting that Fitbit only sells basic wearables – a category that is expected to lose share over the next few years, leaving Apple poised to become the next market leader for all wearables," an IDC analyst said in a statement.