Collaboration, License and Purchase Agreements - Narrative (Detail) (USD $)	0 Months Ended		1 Months Ended	12 Months Ended			0 Months Ended
	Nov. 05, 2014 payment	Oct. 29, 2014	Jan. 31, 2014 payment	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Oct. 24, 2014
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Number of payments	1
Payment period		15 days
Deferred revenue				$ 8,595,000	$ 0
Mallinckrodt LLC Co-Promotion Agreement [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Incurred service fee expenses				62,000	1,035,000	161,000
Number of annual tail payments			1
Annual tail payment liability				129,000
Carncinogenicity Data [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Royalty agreement, payment period one	3,500,000
Zohydro ER [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Royalty agreement, payment period one		5,000,000
Product exclusivity period		3 years
Royalty period two		5,000,000
Sales threshold to receive royalty payments		5,000,000
Brabant Pharma Limited [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Cash paid in purchase							20,000,000
Additional consideration to acquire businesses							8,718,000
Escrow deposit							2,000,000
Indemnification period							6 months
Issuance of common stock in conjunction with acquisition, shares							11,995,202
Aggregate amount of contingent liabilities							95,000,000
Regulatory Milestones [Member] | Brabant Pharma Limited [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Aggregate amount of contingent liabilities							50,000,000
Sales Milestones [Member] | Brabant Pharma Limited [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Aggregate amount of contingent liabilities							45,000,000
Other Income [Member] | Zohydro ER [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Other income				5,000,000
Royalty Arrangement [Member] | Zohydro ER [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Deferred revenue				$ 5,000,000