Composition of Total Revenue - Schedule of Net Product Sales by Source (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Revenue, Major Customer [Line Items]
License fees and service revenue	$ 17,848	$ 25,705	$ 293
Sales Revenue, Services, Net [Member]
Revenue, Major Customer [Line Items]
Percentage of sales	100.00%	100.00%	100.00%
Servier Canada [Member]
Revenue, Major Customer [Line Items]
License fees and service revenue	$ 6,000	$ 0	$ 0
Servier Canada [Member] | Sales Revenue, Services, Net [Member]
Revenue, Major Customer [Line Items]
Percentage of sales	33.60%	0.00%	0.00%
Co-Promotion With Eagle [Member]
Revenue, Major Customer [Line Items]
License fees and service revenue	$ 9,096	$ 0	$ 0
Co-Promotion With Eagle [Member] | Sales Revenue, Services, Net [Member]
Revenue, Major Customer [Line Items]
Percentage of sales	51.00%	0.00%	0.00%
Mundipharma [Member]
Revenue, Major Customer [Line Items]
License fees and service revenue	$ 1,756	$ 15,144	$ 0
Mundipharma [Member] | Sales Revenue, Services, Net [Member]
Revenue, Major Customer [Line Items]
Percentage of sales	9.80%	58.90%	0.00%
FOLOTYN [Member]
Revenue, Major Customer [Line Items]
License fees and service revenue	$ 927	$ 831	$ 293
FOLOTYN [Member] | Sales Revenue, Services, Net [Member]
Revenue, Major Customer [Line Items]
Percentage of sales	5.20%	3.20%	100.00%
ZEVALIN, MARQIBO, EVOMELA [Member]
Revenue, Major Customer [Line Items]
License fees and service revenue	$ 0	$ 9,682	$ 0
ZEVALIN, MARQIBO, EVOMELA [Member] | Sales Revenue, Services, Net [Member]
Revenue, Major Customer [Line Items]
Percentage of sales	0.00%	37.70%	0.00%
Other License Fees And Service Revenue [Member]
Revenue, Major Customer [Line Items]
License fees and service revenue	$ 69	$ 48	$ 0
Other License Fees And Service Revenue [Member] | Sales Revenue, Services, Net [Member]
Revenue, Major Customer [Line Items]
Percentage of sales	0.40%	0.20%	0.00%