INTANGIBLE ASSETS AND GOODWILL (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Nov. 29, 2016
Intangible Assets and Goodwill
Goodwill	$ 90,976	$ 8,965
Finite-lived intangible asset
Accumulated Amortization	(7,799)	(6,802)
Total Intangible Assets
Cost of total intangible assets	89,286	27,596
Intangible Assets, Net (Excluding Goodwill)	81,487	20,794
Amortization expense for intangible assets	997	1,013	$ 1,013
Estimated future amortization expense of intangible assets
2017	900
2018	900
2019	900
2020	900
2021	$ 900
Kolltan
Intangible Assets and Goodwill
Goodwill				$ 82,011
Amgen Amendment
Finite-lived intangible asset
Estimated Life	16 years
Cost	$ 14,500	14,500
Accumulated Amortization	(6,503)	(5,605)
Net	$ 7,997	8,895
Core Technology
Finite-lived intangible asset
Estimated Life	11 years
Cost	$ 1,296	1,296
Accumulated Amortization	(1,296)	(1,197)
Net		99
IPR&D
Indefinite-lived intangible assets:
Indefinite-lived intangible assets	73,490	$ 11,800
IPR&D | CuraGen
Indefinite-lived intangible assets:
Indefinite-lived intangible assets	11,800
IPR&D | Kolltan
Indefinite-lived intangible assets:
Indefinite-lived intangible assets	$ 61,700