Fair Value Measurements - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2016	Sep. 30, 2017	Mar. 31, 2016	Mar. 21, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value, measurement with unobservable inputs reconciliation, recurring basis, asset, transfers, net	$ 0
Change in fair value of liability	0
Contrave | Sales-Based Milestones
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Potential contingent consideration payments required upon achievement of sales-based milestones, minimum		$ 0
Potential contingent consideration payments required upon achievement of sales-based milestones, maximum		110,000,000
0% Convertible Senior Secured Notes due 2020 (2016 Notes)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt instrument, principal amount		$ 1,000	$ 165,000,000	$ 165,000,000
Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value, assets, level 1 to level 2 transfers, amount	0
Fair value, assets, level 2 to level 1 transfers, amount	0
Fair value, liabilities, level 1 to level 2 transfers, amount	0
Fair value, liabilities, level 2 to level 1 transfers, amount	$ 0