Apple recently released several SMC updates, one each for the MacBook Pro, MacBook Pro Retina and MacBook Air that patch a minor issue that some users experienced when draining the battery down to zero. Based on the release notes, the mid-2012 MacBook pro and Retina MacBook Pro models are affected by the update, while the MacBook Air update is applied to mid-2012 and mid-2013 models.
Each of the updates mention the following regarding the now patched issue:
This update addresses rare issues where the battery unexpectedly stops functioning or the system hangs when the battery charge reaches less than one percent.
Source: Apple (Support)