Annual report pursuant to Section 13 and 15(d)

Shareholders' Equity and Capital Stock - assumptions (Details)

v3.3.1.900
Shareholders' Equity and Capital Stock - assumptions (Details)
12 Months Ended
Dec. 31, 2015
Dec. 31, 2014
Dec. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Expected volatility, Minimum 56.00% 61.00% 61.00%
Expected volatility, Maximum 57.00% 66.00% 66.00%
Expected dividend rate 0.00% 0.00% 0.00%
Restricted Stock Units (RSUs) [Member]      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Forfeiture rate (as a percent)   7.70%  
Maximum      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Risk-free interest rate, Maximum 0.70% 1.40% 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 1 day 3 years 6 months 22 days 3 years 6 months 4 days
Forfeiture rate (as a percent) 5.00% 4.70% 4.40%
Maximum | Restricted Stock Units (RSUs) [Member]      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Forfeiture rate (as a percent) 8.30%   22.30%
Minimum      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Risk-free interest rate, Minimum 0.50% 1.10% 0.90%
Minimum | Employee Stock Option [Member]      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Expected award life (in years) 3 years 7 months 6 days 3 years 5 months 27 days 3 years 1 month 21 days
Forfeiture rate (as a percent) 4.90% 4.50% 4.20%
Minimum | Restricted Stock Units (RSUs) [Member]      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Forfeiture rate (as a percent) 7.80%   12.50%