Composition of Total Revenue - Schedule of Net Product Sales by Product Line (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Segment Reporting Information [Line Items]
Total revenues	$ 29,402	$ 25,268	$ 24,168	$ 30,495	$ 28,570	$ 36,395	$ 34,301	$ 29,101	$ 109,333	$ 128,367	$ 146,444
Product [Member]
Segment Reporting Information [Line Items]
Total revenues									104,466	116,178	128,596
FOLOTYN [Member]
Segment Reporting Information [Line Items]
Total revenues									47,981	43,015	46,245
EVOMELA [Member]
Segment Reporting Information [Line Items]
Total revenues									28,292	35,178	16,169
Beleodaq [Member]
Segment Reporting Information [Line Items]
Total revenues									12,328	12,353	13,368
ZEVALIN [Member]
Segment Reporting Information [Line Items]
Total revenues									7,044	11,759	10,730
MARQIBO [Member]
Segment Reporting Information [Line Items]
Total revenues									5,502	6,573	7,245
Fusilev [Member]
Segment Reporting Information [Line Items]
Total revenues									2,437	7,300	34,839
KHAPZORY [Member]
Segment Reporting Information [Line Items]
Total revenues									$ 882	$ 0	$ 0
Product Concentration Risk [Member] | Sales [Member] | Product [Member]
Segment Reporting Information [Line Items]
Percentage of sales									100.00%	100.00%	100.00%
Product Concentration Risk [Member] | Sales [Member] | FOLOTYN [Member]
Segment Reporting Information [Line Items]
Percentage of sales									45.90%	37.00%	36.00%
Product Concentration Risk [Member] | Sales [Member] | EVOMELA [Member]
Segment Reporting Information [Line Items]
Percentage of sales									27.10%	30.30%	12.60%
Product Concentration Risk [Member] | Sales [Member] | Beleodaq [Member]
Segment Reporting Information [Line Items]
Percentage of sales									11.80%	10.60%	10.40%
Product Concentration Risk [Member] | Sales [Member] | ZEVALIN [Member]
Segment Reporting Information [Line Items]
Percentage of sales									6.70%	10.10%	8.30%
Product Concentration Risk [Member] | Sales [Member] | MARQIBO [Member]
Segment Reporting Information [Line Items]
Percentage of sales									5.30%	5.70%	5.60%
Product Concentration Risk [Member] | Sales [Member] | Fusilev [Member]
Segment Reporting Information [Line Items]
Percentage of sales									2.30%	6.30%	27.10%
Product Concentration Risk [Member] | Sales [Member] | KHAPZORY [Member]
Segment Reporting Information [Line Items]
Percentage of sales									0.80%	0.00%	0.00%