Concentration of Credit Risk (Tables)

12 Months Ended

Dec. 31, 2017

Concentration of Credit Risk

Schedule of concentration of credit risk related to collaborative partners

	Percentage of Total Milestone and
	Contract Revenues for the
	Years Ended,
	December 31,
	2017		2016		2015
Collaboration Partner A	37	%	40	%	83	%
Collaboration Partner B	63	%	60	%	17	%

Schedule of concentration of credit risk related to specialty pharmacy customers

	Percentage of Total Net
	Product Revenues for the
	Years Ended,
	December 31,
	2017		2016		2015
Customer A	24	%	25	%	28	%
Customer B	15	%	17	%	19	%
Customer C	13	%	13	%	13	%
Customer D	8	%	9	%	9	%