Revenue recognition - Net Product Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2026	Sep. 30, 2025	Sep. 30, 2026	Sep. 30, 2025
Revenue recognition
Total revenues	$ 357,807	$ 211,007	$ 990,877	$ 1,565,978
United States
Revenue recognition
Total revenues	173,849	56,423	462,549	140,566
Product
Revenue recognition
Total revenues	275,894	130,956	740,286	402,711
Product \| United States
Revenue recognition
Total revenues	173,849	56,423	462,549	140,566
Product \| International
Revenue recognition
Total revenues	102,045	74,533	277,737	262,145
Sephience
Revenue recognition
Total revenues	181,885	19,563	457,746	19,563
Sephience \| United States
Revenue recognition
Total revenues	144,795	14,365	384,385	14,365
Sephience \| International
Revenue recognition
Total revenues	37,090	5,198	73,361	5,198
Translarna
Revenue recognition
Total revenues	48,511	50,665	149,704	196,289
Translarna \| International
Revenue recognition
Total revenues	48,511	50,665	149,704	196,289
Emflaza
Revenue recognition
Total revenues	25,094	35,160	71,206	119,303
Emflaza \| United States
Revenue recognition
Total revenues	25,094	35,160	71,206	119,303
Upstaza/Kebilidi
Revenue recognition
Total revenues	14,553	15,735	35,309	36,283
Upstaza/Kebilidi \| United States
Revenue recognition
Total revenues	3,960	6,898	6,958	6,898
Upstaza/Kebilidi \| International
Revenue recognition
Total revenues	10,593	8,837	28,351	29,385
All other products
Revenue recognition
Total revenues	5,851	9,833	26,321	31,273
All other products \| International
Revenue recognition
Total revenues	$ 5,851	$ 9,833	$ 26,321	$ 31,273