Discontinued Operations - Summary of Assets and Liabilities of Discontinued Operations (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Discontinued operations, current assets	$ 0	$ 5,555
Discontinued operations, non-current assets	0	132,625
Discontinued operations, current liabilities	0	2,311
Discontinued operations, non-current liabilities	$ 0	14,031
Discontinued Operations, Disposed of by Sale [Member] | Product Portfolio [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Inventories		3,550
Prepaid expenses and other assets		2,005
Discontinued operations, current assets		5,555
Intangible assets, net of accumulated amortization		111,594
Goodwill		18,061
Other assets		2,970
Discontinued operations, non-current assets		132,625
FOLOTYN development liability		2,311
Discontinued operations, current liabilities		2,311
FOLOTYN development liability, less current portion		9,686
Acquisition-related contingent obligations		4,345
Discontinued operations, non-current liabilities		$ 14,031