Out-License of ZEVALIN in Certain Ex-U.S. Territories (Details) - USD ($) $ in Thousands		1 Months Ended		3 Months Ended	12 Months Ended
	Nov. 16, 2015	Jan. 31, 2016	Dec. 31, 2015	Dec. 31, 2015	Dec. 31, 2016
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Deferred Revenue			$ 6,513	$ 6,513	$ 3,511
ZEVALIN Ex-U.S. Distribution Rights [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Potential payment	$ 2,000
Payment One [Member] | ZEVALIN Ex-U.S. Distribution Rights [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Total consideration received			$ 15,000
Payment Two [Member] | ZEVALIN Ex-U.S. Distribution Rights [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Total consideration received		$ 3,000
Revenue recognized					1,800
Deferred Revenue					1,300
Total Consideration [Member] | ZEVALIN Ex-U.S. Distribution Rights [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Total consideration received	$ 18,000
Revenue recognized				$ 15,000	1,800
Deferred Revenue					$ 1,300