Annual report pursuant to Section 13 and 15(d)

Share-based compensation - Option Plans (Details)

v3.6.0.2
Share-based compensation - Option Plans (Details)
1 Months Ended 6 Months Ended 12 Months Ended 48 Months Ended
Nov. 28, 2016
Aug. 11, 2016
Jun. 23, 2016
Mar. 16, 2015
GBP (£)
item
Aug. 31, 2016
director
shares
Dec. 31, 2014
Dec. 31, 2015
shares
Dec. 31, 2016
shares
Jun. 30, 2015
shares
Jun. 30, 2014
shares
Dec. 31, 2009
Dec. 31, 2014
Share based compensation                        
Maximum value of option grants per participant | £       £ 30,000                
Option Exercised (in shares)             0 63,192 0 2,265,000    
Scheme limit, grants as a percentage of fully diluted share capital of the Company immediately following the IPO (as a percent)       8.00%                
Scheme limit, automatic increase percentage (as a percent)       4.00%                
Number of option schemes | item       3                
Accelerated vesting (in shares)         361,222              
Number of non-executive directors | director         2              
Options granted in March 2015 and on May 11,2015                        
Share based compensation                        
Contractual term (in years)       10 years                
Options granted in March 2015 and on May 11,2015 | First anniversary                        
Share based compensation                        
Vesting percentage (as a percent)       25.00%                
Options granted in March 2015 and on May 11,2015 | Monthly installments over the following three years                        
Share based compensation                        
Vesting percentage (as a percent)       75.00%                
Vesting period (in years)       3 years                
Options granted in 2009                        
Share based compensation                        
Vesting percentage (as a percent)                     100.00%  
Vesting period (in years)                     3 years  
Contractual term (in years)                     10 years  
Options granted in 2011, 2012, 2013, and April 2014                        
Share based compensation                        
Contractual term (in years)                       10 years
Options granted in 2011, 2012, 2013, and April 2014 | First anniversary                        
Share based compensation                        
Vesting percentage (as a percent)                       25.00%
Vesting period (in years)                       1 year
Options granted in 2011, 2012, 2013, and April 2014 | Annual installments over the following three years                        
Share based compensation                        
Vesting percentage (as a percent)                       75.00%
Vesting period (in years)                       3 years
Options granted in December 2014                        
Share based compensation                        
Contractual term (in years)           10 years            
Options granted in December 2014 | First anniversary                        
Share based compensation                        
Vesting percentage (as a percent)           25.00%            
Vesting period (in years)           1 year            
Options granted in December 2014 | Monthly installments over the following three years                        
Share based compensation                        
Vesting percentage (as a percent)           75.00%            
Vesting period (in years)           3 years            
Non-executive director | Options granted on June 23, 2016 | First anniversary                        
Share based compensation                        
Vesting percentage (as a percent)     25.00%                  
Vesting period (in years)     1 year                  
Non-executive director | Options granted on June 23, 2016 | Monthly installments over the following two years                        
Share based compensation                        
Vesting percentage (as a percent)     75.00%                  
Vesting period (in years)     2 years                  
Non-executive director | Options granted on August 11, 2016 | First anniversary                        
Share based compensation                        
Vesting percentage (as a percent)   100.00%                    
Vesting period (in years)   1 year                    
Non-executive director | Options granted on November 28, 2016 | First anniversary                        
Share based compensation                        
Vesting percentage (as a percent) 25.00%                      
Vesting period (in years) 1 year                      
Non-executive director | Options granted on November 28, 2016 | Monthly installments over the following two years                        
Share based compensation                        
Vesting percentage (as a percent) 75.00%                      
Vesting period (in years) 2 years