Summary of Significant Accounting Policies (Details 5) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Accounts receivable | United States | Credit concentration
Concentrations of Credit Risk, Products, Revenues and Customers
Concentration risk, percentage	59.00%	60.00%
Net revenues | Remodulin | Product concentration
Concentrations of Credit Risk, Products, Revenues and Customers
Concentration risk, percentage	44.00%	50.00%	58.00%
Net revenues | Tyvaso | Product concentration
Concentrations of Credit Risk, Products, Revenues and Customers
Concentration risk, percentage	39.00%	36.00%	32.00%
Net revenues | United States | Product concentration
Concentrations of Credit Risk, Products, Revenues and Customers
Number of contracts into which distribution agreements consolidated	1
Net revenues | United States | Remodulin and Tyvaso | Product concentration
Concentrations of Credit Risk, Products, Revenues and Customers
Concentration risk, percentage	76.00%	78.00%	81.00%
Number of specialty pharmaceutical distributors	3
Net revenues | Accredo Health Group, Inc. | Customer concentration
Concentrations of Credit Risk, Products, Revenues and Customers
Concentration risk, percentage	57.00%	56.00%	61.00%
Net product sales	$ 632,599	$ 514,095	$ 455,504
Number of major customers	1