Collaboration Agreements (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013
Stendhal License
Collaboration agreement
Amount received to be recognized as revenue on a straight-line basis	$ 1.5
Future milestone payment to be received, based on certain milestones defined in the license agreement	2.3
Deferred revenue	0.1
Collaboration agreements | United Therapeutics
Collaboration agreement
Pre-commercial milestone payments received	1.5
Milestone payments to be received upon launch of Orenitram (treprostinil) product	2.0
Milestone payments to be received upon development of additional treprostinil diethanolamine products for a second indication	4.0
Expiration period from the first commercial sale of each product on a country-by-country and product-by-product basis	12 years 6 months
Collaboration agreements | Stendhal License
Collaboration agreement
Amount received to be recognized as revenue on a straight-line basis	1.8
Future milestone payment to be received, based on certain milestones defined in the license agreement	1.8
Deferred revenue	$ 1.6
Collaboration agreement substantive obligation period	12 years