Stock-based compensation (Tables)
|6 Months Ended|
Jun. 30, 2015
|Stock-based Compensation Tables|
|Stock option plans||
Tabular disclosure of option exercise prices, by grouped ranges, including the upper and lower limits of the price range, the number of shares under option, weighted average exercise price and remaining contractual option terms.
Reference 1: http://www.xbrl.org/2003/role/presentationRef