XML 55 R44.htm IDEA: XBRL DOCUMENT v3.21.2
Stock options - Plans narrative (Details) - shares
1 Months Ended 9 Months Ended
Jan. 31, 2021
Jun. 30, 2017
Sep. 30, 2021
Dec. 31, 2020
Stock options        
Number of shares outstanding (in shares)     8,215,549 6,112,948
Stock options        
Stock options        
Vesting period     4 years  
2007 Plan        
Stock options        
Number of shares outstanding (in shares)   3,141,625    
2017 Plan        
Stock options        
Number of shares authorized (in shares)   2,255,000    
Cumulative annual increase in number of shares issuable   4.00%    
Additional shares authorized (in shares) 2,753,651      
Number of shares available for future issuance (in shares)     1,335,946  
Number of options granted in period (in shares)     3,396,186  
2017 Plan | Maximum        
Stock options        
Expiration period     10 years  
Inducement Award Program        
Stock options        
Number of shares outstanding (in shares)     532,500