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

Derivative warrant liabilities - Assumptions used to estimate fair value of derivative warrant liability (Details)

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Derivative warrant liabilities - Assumptions used to estimate fair value of derivative warrant liability (Details)
12 Months Ended
Dec. 31, 2019
USD ($)
year
$ / shares
Dec. 31, 2018
USD ($)
year
yr
$ / shares
Disclosure of classes of share capital [line items]    
Annualized volatility 52.00% 55.00%
Risk-free interest rate 1.61% 2.04%
Life of warrants in years 4 4
Expected dividend as percentage, warrants options granted 0.00% 0.00%
Bought Deal Public Offering | Warrants    
Disclosure of classes of share capital [line items]    
Annualized volatility 43.00% 55.00%
Risk-free interest rate 1.57% 2.45%
Life of warrants in years | year 1.99 2.99
Expected dividend as percentage, warrants options granted 0.00% 0.00%
Market price (in dollars per share) | $ $ 20.26 $ 6.82
Fair value per Warrant (in dollars per share) | $ / shares $ 17.35 $ 4.39
Private Placement Offering Feb 14 2014 | Warrants    
Disclosure of classes of share capital [line items]    
Annualized volatility   45.00%
Risk-free interest rate   2.56%
Life of warrants in years | yr   0.12
Expected dividend as percentage, warrants options granted   0.00%
Market price (in dollars per share) | $   $ 6.82
Fair value per Warrant (in dollars per share) | $ / shares   $ 3.61