Organization, Basis of Presentation and Summary of Significant Policies - Additional Information (Detail) - USD ($)	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Basis Of Presentation [Line Items]
Common Stock, par value	$ 0.001		$ 0.001		$ 0.001
Inventory allowances recorded	$ 200,000		$ 200,000		$ 0
Product sales	$ 8,118,000	$ 2,009,000	$ 23,798,000	$ 6,221,000
Sales return maximum duration			18 months
Offered period for sales return prior to expiration			6 months
Offered period for sales return subsequent to expiration			12 months
Discount for prompt payment	2.00%		2.00%
BELBUCA [Member]
Basis Of Presentation [Line Items]
Product sales	$ 6,437,000		$ 17,554,000		$ 0
Endo Agreement [Member]
Basis Of Presentation [Line Items]
Termination agreement date			Dec. 07, 2016
License termination effective date			Jan. 06, 2017
Minimum [Member]
Basis Of Presentation [Line Items]
Period of payments from customers			30 days
Accrual to payment cycle period			1 month
Maximum [Member]
Basis Of Presentation [Line Items]
Period of payments from customers			37 days
Accrual to payment cycle period			3 months