Commitments and Contingencies - Additional Information (Detail) - USD ($)		1 Months Ended	3 Months Ended	6 Months Ended
	Jun. 26, 2017	Jun. 30, 2017	Jun. 30, 2017	Jun. 30, 2017	Dec. 31, 2016	Aug. 14, 2015
Indemnification Obligation [Member]
Loss Contingencies [Line Items]
Litigation matters, liabilities		$ 0	$ 0	$ 0	$ 0
Cross-License Agreement [Member]
Loss Contingencies [Line Items]
Total payments due related to license agreement amendment	$ 7,000,000
Payment made related to license agreement amendment		3,500,000
Litigation matters, liabilities					$ 0
Cross-License Agreement [Member] | Cost of Goods Sold [Member]
Loss Contingencies [Line Items]
Accrued royalties		1,400,000	1,400,000	1,400,000
Cross-License Agreement [Member] | General and Administrative Expense [Member]
Loss Contingencies [Line Items]
Accrued expense related to license agreement amendment			3,300,000
Cross-License Agreement [Member] | Other Current Liabilities [Member]
Loss Contingencies [Line Items]
Liability related to license agreement amendment		$ 3,500,000	$ 3,500,000	3,500,000
Cross-License Agreement [Member] | Other Current Assets [Member]
Loss Contingencies [Line Items]
Litigation matters, future obligations of royalty payments				$ 2,300,000
Enzon Litigation [Member]
Loss Contingencies [Line Items]
Damage claim for alleged unpaid licenses						$ 1,500,000
Enzon Litigation [Member] | Cross-License Agreement [Member]
Loss Contingencies [Line Items]
Litigation matters, dismissal date				Jun. 30, 2017