Annual report pursuant to Section 13 and 15(d)

Share based compensation - Option Activity (Details)

v3.20.4
Share based compensation - Option Activity (Details)
£ / shares in Units, $ / shares in Units, £ in Thousands, $ in Thousands
 12 Months Ended
Dec. 31, 2020
GBP (£)
£ / shares
shares
Dec. 31, 2020
GBP (£)
$ / shares
£ / shares
shares
Dec. 31, 2019
£ / shares
shares
Dec. 31, 2019
$ / shares
shares
Dec. 31, 2018
shares
Dec. 31, 2020
USD ($)
$ / shares
shares
Options            
Exercised (in shares) (11,401,390) (11,401,390) (3,549,298) (3,549,298) (5,334,936)  
Stock options            
Options            
Outstanding at the beginning of the period (in shares) 88,878,122 88,878,122        
Granted (in shares) 23,877,526 23,877,526        
Exercised (in shares) (11,401,390) (11,401,390)        
Forfeited (in shares) (9,711,074) (9,711,074)        
Outstanding at the end of the period (in shares) 91,643,184 91,643,184 88,878,122 88,878,122    
Weighted Average Exercise Price Per Option            
Outstanding at the beginning of the period (in dollars per share) | £ / shares £ 0.57          
Granted (in dollars per share) | £ / shares 0.42          
Exercise price (in dollars per share) | £ / shares 0.39          
Forfeited (in dollars per share) | £ / shares 0.58          
Outstanding at the end of the period (in dollars per share) | £ / shares £ 0.55   £ 0.57      
Additional disclosures            
Outstanding - Average Remaining Contractual Term (Years) 6 years 10 months 24 days 6 years 10 months 24 days        
Outstanding - Aggregate Intrinsic Value | £ £ 18,227 £ 18,227        
Exercisable - Options 53,554,476 53,554,476       53,554,476
Exercisable - Weighted Average Exercise Price Per Option | £ / shares £ 0.65 £ 0.65        
Exercisable - Average Remaining Contractual Term (Years) 5 years 9 months 18 days 5 years 9 months 18 days        
Exercisable - Aggregate Intrinsic Value | £ £ 6,455 £ 6,455        
Options granted on market value at grant date            
Options            
Outstanding at the beginning of the period (in shares) 76,646,336 76,646,336        
Granted (in shares) 15,595,374 15,595,374 15,679,383 15,679,383 20,771,970  
Exercised (in shares) (9,077,500) (9,077,500)        
Forfeited (in shares) (7,638,728) (7,638,728)        
Outstanding at the end of the period (in shares) 75,525,482 75,525,482 76,646,336 76,646,336    
Weighted Average Exercise Price Per Option            
Outstanding at the beginning of the period (in dollars per share) | $ / shares   £ 0.66        
Granted (in dollars per share) | $ / shares   0.65        
Exercise price (in dollars per share) | $ / shares   0.49        
Forfeited (in dollars per share) | $ / shares   0.74        
Outstanding at the end of the period (in dollars per share) | $ / shares   £ 0.67   $ 0.66    
Additional disclosures            
Outstanding - Average Remaining Contractual Term (Years) 6 years 7 months 6 days 6 years 7 months 6 days        
Outstanding - Aggregate Intrinsic Value | $           $ 7,611
Exercisable - Options 51,909,485 51,909,485       51,909,485
Exercisable - Weighted Average Exercise Price Per Option | $ / shares           $ 0.67
Exercisable - Average Remaining Contractual Term (Years) 5 years 8 months 12 days 5 years 8 months 12 days        
Exercisable - Aggregate Intrinsic Value | $           $ 5,371
Options with nominal exercise price            
Options            
Outstanding at the beginning of the period (in shares) 12,231,786 12,231,786        
Granted (in shares) 8,282,152 8,282,152        
Exercised (in shares) (2,323,890) (2,323,890)        
Forfeited (in shares) (2,072,346) (2,072,346)        
Outstanding at the end of the period (in shares) 16,117,702 16,117,702 12,231,786 12,231,786    
Additional disclosures            
Outstanding - Average Remaining Contractual Term (Years) 8 years 4 months 24 days 8 years 4 months 24 days        
Outstanding - Aggregate Intrinsic Value | $           $ 10,616
Exercisable - Options 1,644,991 1,644,991       1,644,991
Exercisable - Average Remaining Contractual Term (Years) 7 years 6 months 7 years 6 months        
Exercisable - Aggregate Intrinsic Value | $           $ 1,083