Annual reports filed by certain Canadian issuers pursuant to Section 15(d) and Rule 15d-4

Short term investments - (Details)

v3.19.3.a.u2
Short term investments - (Details)
12 Months Ended
Dec. 31, 2018
USD ($)
yr
Dec. 31, 2019
USD ($)
Dec. 31, 2017
USD ($)
Short-term investment [Abstract]      
Short term investments (note 5) $ 7,889,000 $ 0 $ 7,833,000
Investment [Line Items]      
Financial assets at amortised cost 8,000    
Financial assets at fair value $ 8,000    
Weighted average      
Investment [Line Items]      
Investments, average term of contract | yr 1.69    
Investment interest rate 1.64%    
Canadian Government Bond      
Investment [Line Items]      
Financial assets at amortised cost $ 4,000    
Financial assets at fair value 4,000    
Bank of Nova Scotia Treasury Note      
Investment [Line Items]      
Financial assets at amortised cost 4,000    
Financial assets at fair value $ 4,000