Annual report pursuant to Section 13 and 15(d)

Shareholders' Equity and Capital Stock - assumptions (Details)

v3.10.0.1
Shareholders' Equity and Capital Stock - assumptions (Details)
12 Months Ended
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Expected volatility, Minimum 54.00% 56.00%  
Expected volatility, Maximum 57.00% 57.00%  
Expected volatility     57.00%
Risk-free interest rate     1.00%
Risk-free interest rate, Minimum 1.90% 1.00%  
Risk-free interest rate, Maximum 2.20% 1.60%  
Expected dividend rate 0.00% 0.00% 0.00%
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
Forfeiture rate (as a percent)     5.60%
Restricted Stock Units (RSUs) [Member]      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Forfeiture rate (as a percent)   6.10% 6.20%
Warrants      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Expected award life (in years) 3 years    
Forfeiture rate (as a percent) 0.00%    
Maximum | Employee Stock Option [Member]      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Expected award life (in years) 3 years 9 months 15 days 3 years 8 months 27 days  
Forfeiture rate (as a percent) 6.00% 6.00%  
Maximum | Restricted Stock Units (RSUs) [Member]      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Forfeiture rate (as a percent) 5.90%    
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 27 days 3 years 8 months 23 days  
Forfeiture rate (as a percent) 5.80% 5.30%  
Minimum | Restricted Stock Units (RSUs) [Member]      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Forfeiture rate (as a percent) 5.50%