Summary of significant accounting policies (Details)	3 Months Ended
	Mar. 31, 2020 USD ($) segment subsidiary	Mar. 31, 2019 USD ($) subsidiary	Dec. 31, 2019 USD ($) subsidiary
Summary of significant accounting policies
Number of operating segments | segment	1
Disaggregation of revenue
Revenues	$ 14,493,000	$ 14,634,000
Contract liability	$ 0		$ 0
Product returns
Return time period for expired product prior to expiry date	6 months
Return time period for expired product after expiry date	12 months
Income taxes
Deferred tax assets, net of valuation allowance	$ 0		0
Other Current Assets
Disaggregation of revenue
Contract assets	35,000		$ 27,000
Adzenys XR-ODT
Disaggregation of revenue
Revenues	4,234,000	6,657,000
Cotempla XR-ODT
Disaggregation of revenue
Revenues	8,115,000	5,773,000
Adzenys ER
Disaggregation of revenue
Revenues	190,000	185,000
Generic Tussionex
Disaggregation of revenue
Revenues	$ 1,954,000	$ 2,019,000
Minimum
Intangible assets
Intangible assets - Useful life	10 years
Maximum
Intangible assets
Intangible assets - Useful life	20 years
Wholly-owned subsidiaries
Summary of significant accounting policies
Number of wholly-owned subsidiaries | subsidiary	4	4	4