Quarterly report pursuant to Section 13 or 15(d)

Shareholders' Equity and Capital Stock - addl information (Details)

v3.10.0.1
Shareholders' Equity and Capital Stock - addl information (Details)
$ / shares in Units, $ in Thousands
 3 Months Ended 6 Months Ended
Jun. 30, 2018
USD ($)
Mar. 30, 2018
shares
Jun. 30, 2017
USD ($)
Mar. 31, 2017
shares
Mar. 31, 2016
shares
Jun. 30, 2018
USD ($)
shares
Jun. 30, 2017
USD ($)
Jun. 30, 2018
$ / shares
Jun. 30, 2018
USD ($)
$ / shares
shares
Dec. 31, 2017
$ / shares
shares
Stockholder's Equity Note [Line Items]                    
Share-Based Compensation Arrangement By Share-Based Payment Award, Options, Outstanding, Intrinsic Value | $                 $ 414  
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period           183,891        
Stock Issued During Period, Shares, New Issues           1,536,169        
Share Price | (per share)               $ 0.89 $ 0.76  
Payments Of Stock Issuance Costs | $           $ 4 $ 43      
Number of RSUs Vested           80,514        
Stock Issued During Period, Value, New Issues | $           $ (4)        
Percent or RSUs that vest           80,514        
Share-Based Compensation Arrangement By Share-Based Payment Award, Options, Outstanding, Number                 8,954,902 9,459,401
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Number                 6,487,254  
Stock based compensation | $ $ 400   $ 400     $ 566 506      
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested in Period, Fair Value | $           500        
Proceeds from Stock Options Exercised | $           $ 113 $ 348      
Granted, Options           200,000        
Class of Warrant or Right, Exercise Price of Warrants or Rights | $ / shares                 $ 0.95 $ 0.97
Capital Stock                    
Stockholder's Equity Note [Line Items]                    
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period           183,891,000        
Stock Issued During Period, Value, New Issues | $           $ (4)        
In Money Stock Option [Member]                    
Stockholder's Equity Note [Line Items]                    
Share-Based Compensation Arrangement By Share-Based Payment Award, Options, Outstanding, Number                 4,694,331  
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized, Stock Options | $                 $ 700  
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized, Period for Recognition           2 years 4 months 24 days        
Restricted Stock Units (RSUs) [Member]                    
Stockholder's Equity Note [Line Items]                    
Number of RSUs Vested   62,000                
Percent or RSUs that vest   62,000                
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized, Share-based Awards Other than Options | $                 $ 400  
Granted, Options       0 0          
Restricted Stock Units (RSUs) [Member] | Capital Stock                    
Stockholder's Equity Note [Line Items]                    
Number of securities called by each unit                 1  
Grant Date [Member] | Employee Stock Option [Member]                    
Stockholder's Equity Note [Line Items]                    
Share-Based Compensation Arrangement By Share-Based Payment Award, Award Vesting Percentage           10.00%        
Four and One Half Months After Grant [Member] | Restricted Stock Units (RSUs) [Member]                    
Stockholder's Equity Note [Line Items]                    
Stock Option Vesting Period           4 months 15 days        
Four and One Half Months After Grant [Member] | Employee Stock Option [Member]                    
Stockholder's Equity Note [Line Items]                    
Share-Based Compensation Arrangement By Share-Based Payment Award, Award Vesting Percentage           22.00%        
Nine Months After Grant [Member] | Employee Stock Option [Member]                    
Stockholder's Equity Note [Line Items]                    
Share-Based Compensation Arrangement By Share-Based Payment Award, Award Vesting Percentage           22.00%        
Thirteen and One Half Months After Grant [Member] | Restricted Stock Units (RSUs) [Member]                    
Stockholder's Equity Note [Line Items]                    
Stock Option Vesting Period           13 months 15 days        
Thirteen and One Half Months After Grant [Member] | Employee Stock Option [Member]                    
Stockholder's Equity Note [Line Items]                    
Share-Based Compensation Arrangement By Share-Based Payment Award, Award Vesting Percentage           22.00%        
Eighteen Months After Date Of Grant [Member] | Employee Stock Option [Member]                    
Stockholder's Equity Note [Line Items]                    
Share-Based Compensation Arrangement By Share-Based Payment Award, Award Vesting Percentage           24.00%        
First Anniversary [Member]                    
Stockholder's Equity Note [Line Items]                    
Share-Based Compensation Arrangement By Share-Based Payment Award, Award Vesting Percentage           33.30%        
First Anniversary [Member] | Employee Stock Option [Member]                    
Stockholder's Equity Note [Line Items]                    
Stock Option Vesting Period           3 years        
Second Anniversary [Member]                    
Stockholder's Equity Note [Line Items]                    
Share-Based Compensation Arrangement By Share-Based Payment Award, Award Vesting Percentage           33.30%        
Third Anniversary (Member)                    
Stockholder's Equity Note [Line Items]                    
Share-Based Compensation Arrangement By Share-Based Payment Award, Award Vesting Percentage           33.40%