Common Stock (Tables)

6 Months Ended

Jun. 30, 2017

Equity [Abstract]

Schedule of reconciliation of changes in common shares issued

A reconciliation of changes in common shares issued during the six months ended June 30, 2017 is as follows:

Shares issued at December 31, 2016	59,684,669
Issued as restricted stock award grants	168,756
Issued upon exercise of stock options	651,188
Shares issued at June 30, 2017	60,504,613