Divestiture and Sale of Zohydro ER business - Narrative (Details) - USD ($)		12 Months Ended
	Apr. 24, 2015	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from divestiture of businesses		$ 0	$ 0	$ 82,984,000
Zohydro ER [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Other income		$ 0	$ 0	5,077,000
Proceeds from divestiture of businesses	$ 80,000,000
Escrow deposit	10,000,000
Consideration received, common stock	10,600,000
Potential cash receipts based on achievement of milestones	283,500,000
Net gain on sale of business	$ 75,400,000
Stock-based compensation				700,000
Depreciation and amortization expense				$ 200,000