Discontinued operations - Income Statement and Balance Sheet Disclosures Related to Zohydro (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Dec. 31, 2015
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net loss from discontinued operations	$ (169)	$ (12,696)
Disposal Group, Including Discontinued Operation, Balance Sheet Disclosures [Abstract]
Total current assets of discontinued operations	41		$ 208
Total current liabilities of discontinued operations	2,370		2,906
Zohydro ER
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net product revenue	334	5,006
Cost of product sold	15	1,340
Royalty expense	20	418
Research and development	0	4,808
Selling, general and administrative	468	11,136
Total operating expense	503	17,702
Net loss from discontinued operations	(169)	$ (12,696)
Disposal Group, Including Discontinued Operation, Balance Sheet Disclosures [Abstract]
Prepaid expenses and other current assets	41		208
Total current assets of discontinued operations	41		208
Total assets of discontinued operations	41		208
Accrued expenses	2,370		2,796
Deferred revenue and other current liabilities	0		110
Total current liabilities of discontinued operations	2,370		2,906
Total liabilities of discontinued operations	$ 2,370		$ 2,906