Business concentrations - Additional Information (Details) $ in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2023 USD ($)	Sep. 30, 2023 USD ($)
Mayne Pharma [Member]
Concentration Risk [Line Items]
Customer license revenue percentage	100.00%	100.00%
Royalty receivable short term portion	$ 2.7	$ 2.7
Royalty receivable long term portion	$ 19.1	$ 19.1
Theramex [Member]
Concentration Risk [Line Items]
Customer license revenue percentage	100.00%	100.00%
Royalty receivable short term portion	$ 2.7	$ 2.7