Revenue Recognition and Significant Collaborative Research and Development Agreements - Additional Information (Detail) - USD ($)	1 Months Ended	12 Months Ended
	Jun. 30, 2010	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Mitsubishi Tanabe
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Collaborative agreement upfront payment received		$ 30,000,000
Collaborative agreement maximum additional payment to receive		$ 85,000,000
Patent rights period		The longer of ten years or the life of the related patent rights.
Clinical trial cost		$ 12,000,000
Collaborative arrangement right description		Under the terms of the Company’s agreement with Mitsubishi Tanabe, the collaboration effort between the parties to advance NBI-98854 towards commercialization is governed by a joint steering committee and joint development committee with representatives from both the Company and Mitsubishi Tanabe. There are no performance, cancellation, termination or refund provisions in the agreement that would have a material financial consequence to the Company. The Company does not directly control when milestones will be achieved or when royalty payments will begin. Mitsubishi Tanabe may terminate the collaboration at its discretion upon 180 days’ written notice to the Company.
Collaboration termination notice period		180 days
Revenues recognized under collaboration agreement		$ 19,800,000
Deferred revenues under collaboration		$ 10,200,000
AbbVie
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Collaborative agreement upfront payment received	$ 75,000,000
Patent rights period		Ten years or the life of the related patent rights.
Collaborative arrangement right description		The Company will be entitled to a percentage of worldwide sales of GnRH Compounds for the longer of ten years or the life of the related patent rights.
Collaboration termination notice period		180 days
Revenues recognized under collaboration agreement		$ 0	$ 0	$ 0
Amount remains outstanding under collaboration agreement		500,000,000
AbbVie | Development and regulatory event based payments
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Collaborative agreement maximum additional payment to receive		480,000,000
Collaborative agreement payment received		30,000,000
AbbVie | Commercial event based payments
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Collaborative agreement maximum additional payment to receive		$ 50,000,000