Disaggregated Revenues - Summary of Revenues and Product Sales (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Disaggregation of Revenue [Line Items]
Total revenues	$ 153,880	$ 177,353	$ 443,207	$ 499,910
Net product sales
Disaggregation of Revenue [Line Items]
Total revenues	$ 149,004	$ 172,724	$ 417,915	$ 485,647
Net product sales | Revenue from Contract with Customer Benchmark | Product Concentration Risk
Disaggregation of Revenue [Line Items]
Concentration risk percentage	100.00%	100.00%	100.00%	100.00%
Qelbree
Disaggregation of Revenue [Line Items]
Total revenues	$ 37,081	$ 18,326	$ 93,840	$ 37,708
Qelbree | Revenue from Contract with Customer Benchmark | Product Concentration Risk
Disaggregation of Revenue [Line Items]
Concentration risk percentage	25.00%	11.00%	22.00%	8.00%
GOCOVRI
Disaggregation of Revenue [Line Items]
Total revenues	$ 32,889	$ 27,878	$ 87,650	$ 75,179
GOCOVRI | Revenue from Contract with Customer Benchmark | Product Concentration Risk
Disaggregation of Revenue [Line Items]
Concentration risk percentage	22.00%	16.00%	21.00%	15.00%
Oxtellar XR
Disaggregation of Revenue [Line Items]
Total revenues	$ 29,644	$ 30,528	$ 82,359	$ 88,007
Oxtellar XR | Revenue from Contract with Customer Benchmark | Product Concentration Risk
Disaggregation of Revenue [Line Items]
Concentration risk percentage	20.00%	18.00%	20.00%	18.00%
Trokendi XR
Disaggregation of Revenue [Line Items]
Total revenues	$ 20,625	$ 69,599	$ 74,734	$ 204,033
Trokendi XR | Revenue from Contract with Customer Benchmark | Product Concentration Risk
Disaggregation of Revenue [Line Items]
Concentration risk percentage	14.00%	40.00%	18.00%	42.00%
APOKYN
Disaggregation of Revenue [Line Items]
Total revenues	$ 21,510	$ 18,261	$ 56,324	$ 57,156
APOKYN | Revenue from Contract with Customer Benchmark | Product Concentration Risk
Disaggregation of Revenue [Line Items]
Concentration risk percentage	14.00%	10.00%	13.00%	12.00%
Other
Disaggregation of Revenue [Line Items]
Total revenues	$ 7,255	$ 8,132	$ 23,008	$ 23,564
Other | Revenue from Contract with Customer Benchmark | Product Concentration Risk
Disaggregation of Revenue [Line Items]
Concentration risk percentage	5.00%	5.00%	6.00%	5.00%
Royalty revenues
Disaggregation of Revenue [Line Items]
Total revenues	$ 4,876	$ 4,629	$ 25,292	$ 14,263