Nature of Business and Summary of Significant Accounting Policies - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2017 USD ($) Manufacturer Customer $ / shares	Dec. 31, 2016 USD ($) $ / shares	Dec. 31, 2015 USD ($)
Basis Of Presentation [Line Items]
Common Stock, par value | $ / shares	$ 0.001	$ 0.001
Number of contract manufacturers | Manufacturer	3
Percentage of amount due to vendors payable	22.80%	5.60%
Number of customers | Customer	3
FDIC insurance coverage	$ 250,000
Net deposit amount exceeding specified amount under FDIC	$ 21,200,000	$ 32,000,000
Discount for prompt payment	2.00%
Percentage of prompt payment discount, accrued	100.00%
Allowance for prompt payment of discount	$ 200,000	50,000
Allowance for Doubtful Accounts Receivable	0	0
Allowance for Doubtful Accounts Receivable, Write-offs	0.00	20,000	$ 0.00
Inventory obsolescence recorded	243,000	0
Impairment charges recognized on finite lived intangibles assets	0	0	0
Goodwill impairment charges	0	0	0
Product sales	34,922,000	8,266,000	4,157,000
Deferred revenue related to sales	$ 0	1,700,000
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%
Research and development expenses	$ 13,040,000	18,878,000	20,624,000
Advertising expenses	3,800,000	4,200,000	4,900,000
Shipping and handling costs	$ 200,000	$ 50,000	$ 50,000
Sales Revenue, Net [Member] | Customer Concentration Risk [Member]
Basis Of Presentation [Line Items]
Total annual sales percentage	92.00%	91.00%	90.00%
BUNAVAIL [Member]
Basis Of Presentation [Line Items]
Idle equipment net		$ 3,700,000
Impairment loss	$ 0	0
Product sales	7,942,000	8,266,000	$ 4,157,000
Deferred cost of sales	$ 0	1,700,000
BELBUCA [Member]
Basis Of Presentation [Line Items]
Estimated useful lives of equipment	7 years
Idle equipment net	$ 700,000
Product sales	$ 26,980,000	$ 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
Estimated useful lives of equipment	3 years
Accrual to payment cycle period	1 month
Maximum [Member]
Basis Of Presentation [Line Items]
Period of payments from customers	37 days
Estimated useful lives of equipment	10 years
Accrual to payment cycle period	3 months