Annual report pursuant to Section 13 and 15(d)

Income taxes (Narrative) (Details)

v3.19.1
Income taxes (Narrative) (Details) - USD ($)
 1 Months Ended 12 Months Ended
Jan. 31, 2018
Dec. 31, 2018
Dec. 31, 2017
Operating Loss Carryforwards [Line Items]      
Corporate tax rate 21.00%    
Net operating loss carry forwards   $ 117,400,000  
Portion of federal and state net operating loss carryforwards subject to an 80% limitation on taxable income, that do not expire and will carry forward indefinitely   19,100,000  
Increase (decrease) in deferred tax asset valuation allowance   14,800,000 $ (14,000,000)
Federal [Member]      
Operating Loss Carryforwards [Line Items]      
Net operating loss carry forwards   100,300,000  
Foreign [Member]      
Operating Loss Carryforwards [Line Items]      
Net operating loss carry forwards   $ 2,000,000  
Minimum [Member]      
Operating Loss Carryforwards [Line Items]      
Corporate tax rate   21.00%  
Minimum [Member] | Foreign [Member]      
Operating Loss Carryforwards [Line Items]      
Net operating loss carry forwards, expiration date   Dec. 31, 2037  
Maximum [Member]      
Operating Loss Carryforwards [Line Items]      
Corporate tax rate   34.00%  
Maximum [Member] | Federal [Member]      
Operating Loss Carryforwards [Line Items]      
Net operating loss carry forwards, expiration date   Dec. 31, 2037