Agreements - Biotest (Details) - USD ($)	1 Months Ended	3 Months Ended														6 Months Ended		12 Months Ended
	Sep. 30, 2008	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2017	Dec. 31, 2016	Jun. 30, 2016	Jun. 30, 2015	Dec. 31, 2006
Collaborative Agreements disclosures
Costs related to the research and development services		$ 39,843,000	$ 31,689,000	$ 35,319,000	$ 32,888,000	$ 33,657,000	$ 32,909,000	$ 38,652,000	$ 36,094,000	$ 38,199,000	$ 35,132,000	$ 30,437,000	$ 25,666,000	$ 27,647,000	$ 28,018,000	$ 66,566,000	$ 73,331,000	$ 139,739,000	$ 141,312,000	$ 148,077,000	$ 111,768,000
Biotest
Collaborative Agreements disclosures
Payments received under collaboration agreement																						$ 1,000,000
Potential milestone payments																						35,500,000
Costs related to the research and development services																22,000		41,000		160,000	309,000
Costs related to clinical materials sold																$ 549,000		0		$ 1,800,000	$ 3,000,000
Biotest | Development milestones
Collaborative Agreements disclosures
Payments received under collaboration agreement	$ 500,000
Potential milestone payments																						4,500,000
Biotest | Phase IIb Clinical Trial
Collaborative Agreements disclosures
Potential milestone payments		$ 2,000,000																$ 2,000,000
Biotest | Regulatory milestones
Collaborative Agreements disclosures
Potential milestone payments																						$ 31,000,000