2-in-1 Sales

The saving grace for the declining tablet market is detachable devices, also called 2-in-1s, that can serve as both a laptop and a separate slate-style tablet.

But the initial successes of detachables by all vendors were not enough to make up for the precipitous decline in tablets. All types of tablets declined 10% in 2015, with pure slate standalone tablets declining by 21%, according to market research firm IDC.

IDC reported Monday that Apple's iPad Pro was the top-selling detachable for the fourth quarter of 2015 with about 2 million sold. Apple was the clear winner even though the company saw an overall decline of 25% in tablet shipments for the quarter compared to the same period a year ago.

Detachables, however, finished with an all-time high of 8 million devices shipped in the fourth quarter, more than doubling their total over the fourth quarter of 2014, which reached 3.1 million, IDC analyst Jitesh Ubrani said in an interview.