Annual and transition report of foreign private issuers pursuant to Section 13 or 15(d)

Warrant Derivative - Summary of Assumptions Used in the Black Scholes Option Pricing Model for Warrants (Details)

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Warrant Derivative - Summary of Assumptions Used in the Black Scholes Option Pricing Model for Warrants (Details)
12 Months Ended
Dec. 31, 2020
year
$ / shares
Dec. 31, 2019
year
$ / shares
Dec. 31, 2018
year
Disclosure of fair value measurement of liabilities [line items]      
Risk-free interest rate 0.34% 1.62% 2.02%
Expected hold period to exercise | year 3.0 3.0 3.0
Expected share price volatility 110.82% 97.90% 81.15%
Warrants      
Disclosure of fair value measurement of liabilities [line items]      
Fair value per warrant (usd per share) | $ / shares $ 1.57 $ 3.89  
Underlying share price (usd per share) | $ / shares $ 2.38 $ 4.76  
Risk-free interest rate 0.10% 1.59%  
Expected hold period to exercise | year 1.0 1.0  
Expected share price volatility 90.00% 90.00%  
Expected dividend yield 0.00% 0.00%  
Dividend Yield, Percent 0.00% 0.00%