Segment Information - General (Details) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2024 USD ($)	Jun. 30, 2023 USD ($)	Jun. 30, 2024 USD ($) segment	Jun. 30, 2023 USD ($)
Segment Reporting [Abstract]
Number of operating segments | segment			1
Net product sales, cost of product sales and gross profit by product
Total revenues	$ 714.9	$ 596.5	$ 1,392.6	$ 1,103.4
Cost of sales	77.8	64.1	150.7	116.4
Gross profit (loss)	637.1	532.4	1,241.9	987.0
Tyvaso DPI
Net product sales, cost of product sales and gross profit by product
Total revenues	258.3	193.6	485.8	312.3
Cost of sales	37.6	33.0	70.9	53.7
Gross profit (loss)	220.7	160.6	414.9	258.6
Nebulized Tyvaso
Net product sales, cost of product sales and gross profit by product
Total revenues	139.9	125.3	284.9	245.0
Cost of sales	8.4	7.4	17.3	13.6
Gross profit (loss)	131.5	117.9	267.6	231.4
Remodulin
Net product sales, cost of product sales and gross profit by product
Total revenues	147.3	127.2	275.3	248.6
Cost of sales	12.8	7.3	20.7	14.2
Gross profit (loss)	134.5	119.9	254.6	234.4
Orenitram
Net product sales, cost of product sales and gross profit by product
Total revenues	107.1	95.1	213.3	183.3
Cost of sales	5.9	5.7	15.1	13.3
Gross profit (loss)	101.2	89.4	198.2	170.0
Unituxin
Net product sales, cost of product sales and gross profit by product
Total revenues	51.7	44.3	110.1	93.4
Cost of sales	3.8	2.7	7.4	7.4
Gross profit (loss)	47.9	41.6	102.7	86.0
Adcirca
Net product sales, cost of product sales and gross profit by product
Total revenues	5.7	7.5	12.1	14.8
Cost of sales	2.6	3.1	5.2	6.2
Gross profit (loss)	3.1	4.4	6.9	8.6
Other
Net product sales, cost of product sales and gross profit by product
Total revenues	4.9	3.5	11.1	6.0
Cost of sales	6.7	4.9	14.1	8.0
Gross profit (loss)	$ (1.8)	$ (1.4)	$ (3.0)	$ (2.0)