Net product revenues - summary of includes revenues associated with EXONDYS 51 AMONDYS 45 and VYONDYS 53 (collectively the PMO Products and ELEVIDYS (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	$ 309,322	$ 207,774	$ 779,805	$ 607,836
PMO Products [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	240,214	207,774	710,697	607,836
ELEVIDYS [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	69,108	0	69,108	0
United States [Member] | PMO Products [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	198,069	188,346	602,415	548,355
United States [Member] | ELEVIDYS [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	69,108	0	69,108	0
Rest of World [Member] | PMO Products [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	$ 42,145	$ 19,428	$ 108,282	$ 59,481