Balance Sheet Account Detail - Components of Intangible Assets Net of Accumulated Amortization (Detail) - USD ($) $ in Thousands		3 Months Ended	6 Months Ended		12 Months Ended
	May. 29, 2013	Mar. 31, 2015	Jun. 30, 2015	Jun. 30, 2014	Dec. 31, 2014
Product Rights [Line Items]
Historical Cost			$ 305,668		$ 305,668
Accumulated Amortization			(85,507)		(72,383)
Foreign Currency Translation			(4,023)		(2,162)
Impairment			(8,183)		(1,023)
Net Amount			$ 207,955		230,100
Full Amortization Period (months)
Remaining Amortization Period (months)
Intangible asset amortization expense			$ 20,900	$ 11,400
MARQIBO IPR&D (NHL indication) [Member]
Product Rights [Line Items]
Historical Cost			17,600		17,600
Accumulated Amortization			0		0
Foreign Currency Translation			0		0
Impairment			0		0
Net Amount			17,600		17,600
EVOMELA IPR&D [Member]
Product Rights [Line Items]
Historical Cost			7,700		7,700
Accumulated Amortization			0		0
Foreign Currency Translation			0		0
Impairment			0		0
Net Amount			7,700		7,700
BELEODAQ distribution rights [Member]
Product Rights [Line Items]
Historical Cost			25,000		25,000
Accumulated Amortization			(1,875)		(937)
Foreign Currency Translation			0		0
Impairment			0		0
Net Amount			$ 23,125		24,063
Full Amortization Period (months)			160 months
Remaining Amortization Period (months)			148 months
MARQIBO distribution rights [Member]
Product Rights [Line Items]
Historical Cost			$ 26,900		26,900
Accumulated Amortization			(6,384)		(4,225)
Foreign Currency Translation			0		0
Impairment			0		0
Net Amount			$ 20,516		22,675
Full Amortization Period (months)			81 months
Remaining Amortization Period (months)			57 months
FOLOTYN distribution rights [Member]
Product Rights [Line Items]
Historical Cost			$ 118,400		118,400
Accumulated Amortization			(24,752)		(20,030)
Foreign Currency Translation			0		0
Impairment	$ (1,000)		0		0
Net Amount			$ 93,648		98,370
Full Amortization Period (months)			152 months
Remaining Amortization Period (months)			119 months
ZEVALIN distribution rights [Member] | United States [Member]
Product Rights [Line Items]
Historical Cost			$ 41,900		41,900
Accumulated Amortization			(28,871)		(27,134)
Foreign Currency Translation			0		0
Impairment			0		0
Net Amount			$ 13,029		14,766
Full Amortization Period (months)			123 months
Remaining Amortization Period (months)			45 months
ZEVALIN distribution rights [Member] | Ex-U.S. [Member]
Product Rights [Line Items]
Historical Cost			$ 23,490		23,490
Accumulated Amortization			(7,966)		(7,402)
Foreign Currency Translation			(4,023)		(2,162)
Impairment			0		0
Net Amount			$ 11,501		13,926
Full Amortization Period (months)			96 months
Remaining Amortization Period (months)			57 months
FUSILEV distribution rights [Member]
Product Rights [Line Items]
Historical Cost			$ 16,778		16,778
Accumulated Amortization			(7,912)		(6,270)
Foreign Currency Translation			0		0
Impairment			(7,160)		0
Net Amount			$ 1,706		10,508
Full Amortization Period (months)			56 months
Remaining Amortization Period (months)			6 months
FOLOTYN out-License [Member]
Product Rights [Line Items]
Historical Cost			$ 27,900		27,900
Accumulated Amortization			(7,747)		(6,385)
Foreign Currency Translation			0		0
Impairment			(1,023)		(1,023)
Net Amount			$ 19,130		$ 20,492
Full Amortization Period (months)			110 months
Remaining Amortization Period (months)			85 months
FUSILEV [Member]
Product Rights [Line Items]
Impairment		$ (7,200)	$ (7,200)
Intangible asset amortization expense			$ 2,600