Adaptimmune Annual report pursuant to Section 13 and 15(d)

Share-based compensation - Option Plans (Details)

Share-based compensation - Option Plans (Details)										1 Months Ended	12 Months Ended	40 Months Ended
Share-based compensation - Option Plans (Details)	Jul. 01, 2020	Jul. 02, 2019	Jul. 05, 2018	Jun. 22, 2018	Jul. 03, 2017	Nov. 28, 2016	Aug. 11, 2016	Jun. 23, 2016	Mar. 16, 2015 GBP (£) item	Dec. 31, 2014	Dec. 31, 2020 shares	Apr. 30, 2014
Share based compensation
Maximum value of option grants per participant \| £									£ 30,000
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
RSU
Share based compensation
Exercise price \| shares											0.001
Vesting percentage (as a percent)											25.00%
Vesting period (in years)											4 years
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 2011, 2012, 2013, and April 2014
Share based compensation
Contractual term (in years)												10 years
Options granted in December 2014
Share based compensation
Contractual term (in years)										10 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
Non-executive director \| Options granted on July 03, 2017 \| First anniversary
Share based compensation
Vesting percentage (as a percent)					100.00%
Vesting period (in years)					1 year
Non-executive director \| Options granted on June 22, 2018 \| First anniversary
Share based compensation
Vesting percentage (as a percent)				100.00%
Vesting period (in years)				1 year
Non-executive director \| Options granted in July 05, 2018 \| First anniversary
Share based compensation
Vesting percentage (as a percent)			25.00%
Vesting period (in years)			1 year
Non-executive director \| Options granted in July 05, 2018 \| 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 in July 2, 2019 \| First anniversary
Share based compensation
Vesting percentage (as a percent)		100.00%
Vesting period (in years)		1 year
Non-executive director \| Options granted in July 1, 2020 \| First anniversary
Share based compensation
Vesting percentage (as a percent)	100.00%
Vesting period (in years)	1 year