Net Product Sales by Geographic Region and Product Line - Schedule of Product Sales, Net by Product Line (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Sales Information [Line Items]
Product sales, net	$ 38,413	$ 40,096
Percentage of product sales, net	100.00%	100.00%
FUSILEV [Member]
Sales Information [Line Items]
Product sales, net	20,167	22,193
FOLOTYN [Member]
Sales Information [Line Items]
Product sales, net	9,316	10,058
ZEVALIN [Member]
Sales Information [Line Items]
Product sales, net	4,223	6,300
MARQIBO [Member]
Sales Information [Line Items]
Product sales, net	1,893	1,545
BELEODAQ [Member]
Sales Information [Line Items]
Product sales, net	$ 2,814	$ 0
Sales [Member]
Sales Information [Line Items]
Percentage of product sales, net	100.00%	100.00%
Sales [Member] | FUSILEV [Member]
Sales Information [Line Items]
Percentage of product sales, net	52.50%	55.30%
Sales [Member] | FOLOTYN [Member]
Sales Information [Line Items]
Percentage of product sales, net	24.30%	25.10%
Sales [Member] | ZEVALIN [Member]
Sales Information [Line Items]
Percentage of product sales, net	11.00%	15.70%
Sales [Member] | MARQIBO [Member]
Sales Information [Line Items]
Percentage of product sales, net	4.90%	3.90%
Sales [Member] | BELEODAQ [Member]
Sales Information [Line Items]
Percentage of product sales, net	7.30%	0.00%