Kolltan Acquisition - Allocations of Assets and Liabilities (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2017	Dec. 31, 2016	Nov. 29, 2016
Summary of fair values of assets acquired and liabilities assumed at acquisition date
Goodwill		$ 90,976	$ 90,976
Kolltan
KOLLTAN ACQUISITION
Goodwill expected to be deductible for income tax purposes				$ 0
Summary of fair values of assets acquired and liabilities assumed at acquisition date
Cash and cash equivalents				8,160
Other current and long-term assets				799
Property and Equipment, Net				2,072
In-process research and development (IPR&D)				61,690
Goodwill				82,011
Deferred tax liabilities, net				(23,393)
Other assumed liabilities				(9,974)
Total				$ 121,365
Pro Forma Financial Information
Net loss	$ 45,300
Basic and Diluted Net Loss Per Common Share	$ (0.39)