Segment Information - General (Details) $ in Millions	3 Months Ended
	Mar. 31, 2024 USD ($) segment	Mar. 31, 2023 USD ($)
Net product sales, cost of product sales and gross profit by product
Number of operating segments | segment	1
Total revenues	$ 677.7	$ 506.9
Cost of sales	72.9	52.3
Gross profit (loss)	604.8	454.6
Tyvaso DPI
Net product sales, cost of product sales and gross profit by product
Total revenues	227.5	118.7
Cost of sales	33.3	20.7
Gross profit (loss)	194.2	98.0
Nebulized Tyvaso
Net product sales, cost of product sales and gross profit by product
Total revenues	145.0	119.7
Cost of sales	8.9	6.2
Gross profit (loss)	136.1	113.5
Remodulin
Net product sales, cost of product sales and gross profit by product
Total revenues	128.0	121.4
Cost of sales	7.9	6.9
Gross profit (loss)	120.1	114.5
Orenitram
Net product sales, cost of product sales and gross profit by product
Total revenues	106.2	88.2
Cost of sales	9.2	7.6
Gross profit (loss)	97.0	80.6
Unituxin
Net product sales, cost of product sales and gross profit by product
Total revenues	58.4	49.1
Cost of sales	3.6	4.7
Gross profit (loss)	54.8	44.4
Adcirca
Net product sales, cost of product sales and gross profit by product
Total revenues	6.4	7.3
Cost of sales	2.6	3.1
Gross profit (loss)	3.8	4.2
Other
Net product sales, cost of product sales and gross profit by product
Total revenues	6.2	2.5
Cost of sales	7.4	3.1
Gross profit (loss)	$ (1.2)	$ (0.6)