Summary of Significant Accounting Policies (Details 5) $ in Thousands	12 Months Ended
	Dec. 31, 2015 USD ($) item	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($) item
Accounts receivable | United States | Credit concentration
Concentrations of Credit Risk, Products, Revenues and Customers
Concentration risk, percentage	50.00%	52.00%
Net revenues | Remodulin | Product concentration
Concentrations of Credit Risk, Products, Revenues and Customers
Concentration risk, percentage	39.00%	43.00%	44.00%
Net revenues | Tyvaso | Product concentration
Concentrations of Credit Risk, Products, Revenues and Customers
Concentration risk, percentage	32.00%	36.00%	39.00%
Net revenues | Orenitram | Product concentration
Concentrations of Credit Risk, Products, Revenues and Customers
Concentration risk, percentage	8.00%	3.00%
Net revenues | United States | Remodulin And Tyvaso And Orenitram | Product concentration
Concentrations of Credit Risk, Products, Revenues and Customers
Number of specialty pharmaceutical distributors	2		3
Concentration risk, percentage	72.00%	74.00%	76.00%
Net revenues | Accredo Health Group, Inc. | Customer concentration
Concentrations of Credit Risk, Products, Revenues and Customers
Concentration risk, percentage	55.00%	58.00%	57.00%
Number of major customers	1
Net product sales | $	$ 807,012	$ 744,765	$ 632,599