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

Financial instruments and fair values (Details)

v3.19.3.a.u2
Financial instruments and fair values (Details)
$ in Thousands
12 Months Ended
Dec. 31, 2019
USD ($)
$ / $
bank
Dec. 31, 2018
USD ($)
$ / $
Foreign exchange rates [abstract]    
Exchange rate, CA$ – US$ | $ / $ 0.770 0.733
Ten percent weakening of CA$ would effect income $ 1,041  
Number of major banks where cash and short term investments are held | bank 3  
Liquidity risk    
Disclosure of credit risk exposure [line items]    
Borrowings, maturity period 1 year  
Interest rate risk    
Disclosure of credit risk exposure [line items]    
Borrowings, maturity period 2 years  
Canada, Dollars | Currency risk    
Disclosure of credit risk exposure [line items]    
Net exposure $ 10,412 $ (1,289)
Foreign exchange rates [abstract]    
Ten percent strengthening of CA$ would increase net loss, amount $ 1,041  
Change in risk variable 10.00%  
Canada, Dollars | Currency risk | Accounts payable and accrued liabilities    
Disclosure of credit risk exposure [line items]    
Net exposure $ (2,332) (1,677)
Canada, Dollars | Currency risk | Cash and cash equivalents    
Disclosure of credit risk exposure [line items]    
Net exposure 12,711 364
Canada, Dollars | Currency risk | Accounts receivable and accrued interest receivable    
Disclosure of credit risk exposure [line items]    
Net exposure $ 33 $ 24
Bottom of range | Liquidity risk | Cash and cash equivalents    
Disclosure of credit risk exposure [line items]    
Cash and cash equivalents instruments, maturity period 30 days  
Top of range | Liquidity risk | Cash and cash equivalents    
Disclosure of credit risk exposure [line items]    
Cash and cash equivalents instruments, maturity period 90 days  
Top of range | Liquidity risk | Bonds and Treasury Notes    
Disclosure of credit risk exposure [line items]    
Short term investments, maturity period 2 years