Annual report pursuant to Section 13 and 15(d)

Shareholders' Equity and Capital Stock - assumptions (Details)

v3.6.0.2
Shareholders' Equity and Capital Stock - assumptions (Details)
12 Months Ended
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Expected volatility, Minimum 57.00% 55.00% 61.00%
Expected volatility, Maximum 57.00% 57.00% 66.00%
Maximum      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Risk-free interest rate, Maximum 1.00% 0.70% 1.40%
Maximum | Employee Stock Option [Member]      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Expected award life (in years) 3 years 8 months 19 days 3 years 8 months 1 day 3 years 6 months 22 days
Forfeiture rate (as a percent) 5.60% 5.00% 4.70%
Maximum | Restricted Stock Units (RSUs) [Member]      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Forfeiture rate (as a percent) 6.21% 8.30% 7.70%
Minimum      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Risk-free interest rate, Minimum 1.00% 0.50% 1.10%
Minimum | Employee Stock Option [Member]      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Expected award life (in years) 3 years 8 months 19 days 3 years 7 months 6 days 3 years 5 months 27 days
Forfeiture rate (as a percent) 5.60% 4.90% 4.50%
Minimum | Restricted Stock Units (RSUs) [Member]      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Forfeiture rate (as a percent) 6.21% 7.20%