Business Combination (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Business Acquisition [Line Items]
Goodwill	$ 17,371	$ 16,864
Viventia Bio, Inc.
Business Acquisition [Line Items]
Cash and cash equivalents	136	136
Prepaid expenses and other assets	1,162	1,162
Property and equipment	867	867
Goodwill	17,371	16,864
Accounts payable	(1,163)	(1,163)
Accrued expenses	(2,001)	(1,494)
Other liabilities	(812)	(812)
Deferred tax liability	(16,335)	(16,335)
Recognized identifiable assets acquired, goodwill, and liabilities assumed, net	59,725	59,725
Viventia Bio, Inc. | U. S. Vicinium
Business Acquisition [Line Items]
In-process research and development	12,200	12,200
Viventia Bio, Inc. | E.U. Vicinium
Business Acquisition [Line Items]
In-process research and development	41,100	41,100
Viventia Bio, Inc. | R.O.W. Vicinium
Business Acquisition [Line Items]
In-process research and development	$ 7,200	$ 7,200