Stock-based compensation (Tables)
|6 Months Ended|
Jun. 30, 2015
|Disclosure of Compensation Related Costs, Share-based Payments [Abstract]|
|Summary of Stock Option Activity Under Stock Option and Incentive Plans||
A summary of the status of stock option awards and changes during the six months ended June 30, 2015 are presented below:
Tabular disclosure of the number and weighted-average exercise prices (or conversion ratios) for share options (or share units) that were outstanding at the beginning and end of the year, vested and expected to vest, exercisable or convertible at the end of the year, and the number of share options or share units that were granted, exercised or converted, forfeited, and expired during the year.
Reference 1: http://www.xbrl.org/2003/role/presentationRef