Collaboration Agreements

12 Months Ended

Dec. 31, 2016

Collaboration Agreements

Collaboration Agreements

15. Collaboration Agreements

Royalty Revenue

In the third quarter of 2014, the Company received a $30.0 million payment pursuant to a Royalty Interest Acquisition Agreement related to the purchase by Healthcare Royalty Partners III, L.P. (HC Royalty), of certain of the Company's rights under the agreement with United Therapeutics Corporation related to the commercialization of Orenitram (treprostinil) Extended-Release Tablets. We will retain full ownership of the royalty rights if and when a certain threshold is reached per the terms of the Agreement. We have recorded a non-recourse liability related to this transaction and have begun to amortize this amount to recognize non-cash royalty revenue as royalties are received by HC Royalty from United Therapeutics. We also recognized non-cash interest expense related to this liability that accrues at an effective interest rate, which is determined based on projections of HC Royalty's rate of return. We recognized royalty revenue of $4.7 million and $3.0 million for the years ended December 31, 2016 and 2015, respectively. We recognized non-cash interest expense of $4.5 million and $3.5 million for the years ended December 31, 2016 and 2015, respectively.

The Company has a license agreement with United Therapeutics Corporation to use one of its proprietary technologies for an oral formulation of Remodulin for the treatment of pulmonary arterial hypertension and potentially for additional indications. The revenue generated in the year ended December 31, 2014 was $2.0 million for a milestone payment.