Segment Information - Geographic Information (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2025	Mar. 31, 2024
Revenues from external customers by geographic area
Total revenues	$ 794.4	$ 677.7
Total Tyvaso
Revenues from external customers by geographic area
Total revenues	466.3	372.5
Tyvaso DPI
Revenues from external customers by geographic area
Total revenues	302.5	227.5
Nebulized Tyvaso
Revenues from external customers by geographic area
Total revenues	163.8	145.0
Remodulin
Revenues from external customers by geographic area
Total revenues	138.2	128.0
Orenitram
Revenues from external customers by geographic area
Total revenues	120.7	106.2
Unituxin
Revenues from external customers by geographic area
Total revenues	58.2	58.4
Adcirca
Revenues from external customers by geographic area
Total revenues	6.0	6.4
Other
Revenues from external customers by geographic area
Total revenues	5.0	6.2
U.S.
Revenues from external customers by geographic area
Total revenues	749.6	641.5
U.S. \| Total Tyvaso
Revenues from external customers by geographic area
Total revenues	441.1	361.2
U.S. \| Tyvaso DPI
Revenues from external customers by geographic area
Total revenues	302.5	227.5
U.S. \| Nebulized Tyvaso
Revenues from external customers by geographic area
Total revenues	138.6	133.7
U.S. \| Remodulin
Revenues from external customers by geographic area
Total revenues	120.2	108.3
U.S. \| Orenitram
Revenues from external customers by geographic area
Total revenues	120.7	106.2
U.S. \| Unituxin
Revenues from external customers by geographic area
Total revenues	56.9	53.4
U.S. \| Adcirca
Revenues from external customers by geographic area
Total revenues	6.0	6.4
U.S. \| Other
Revenues from external customers by geographic area
Total revenues	4.7	6.0
ROW
Revenues from external customers by geographic area
Total revenues	44.8	36.2
ROW \| Total Tyvaso
Revenues from external customers by geographic area
Total revenues	25.2	11.3
ROW \| Tyvaso DPI
Revenues from external customers by geographic area
Total revenues	0.0	0.0
ROW \| Nebulized Tyvaso
Revenues from external customers by geographic area
Total revenues	25.2	11.3
ROW \| Remodulin
Revenues from external customers by geographic area
Total revenues	18.0	19.7
ROW \| Orenitram
Revenues from external customers by geographic area
Total revenues	0.0	0.0
ROW \| Unituxin
Revenues from external customers by geographic area
Total revenues	1.3	5.0
ROW \| Adcirca
Revenues from external customers by geographic area
Total revenues	0.0	0.0
ROW \| Other
Revenues from external customers by geographic area
Total revenues	$ 0.3	$ 0.2