Intangible Asset - Additional Information (Details) - USD ($) $ in Thousands	1 Months Ended				3 Months Ended
	Feb. 28, 2022	Jan. 31, 2021	Nov. 30, 2019	Aug. 31, 2019	Mar. 31, 2022	Mar. 31, 2021
Finite Lived Intangible Assets [Line Items]
License agreement milestone payments paid			$ 75,000	$ 2,000
Amortization expense					$ 5,082	$ 4,579
Net product revenues					85,313	$ 59,674
WAKIX
Finite Lived Intangible Assets [Line Items]
Final payment paid					$ 40,000
Useful life of intangible asset					7 years 7 months 6 days
Remaining useful life					7 years 6 months
WAKIX | United States
Finite Lived Intangible Assets [Line Items]
Net product revenues	$ 500,000
WAKIX | Daytime Sleepiness
Finite Lived Intangible Assets [Line Items]
License agreement milestone payments paid			$ 75,000
Useful life of intangible asset					10 years
Remaining useful life					7 years 6 months
NDA for WAKIX. | Cataplexy
Finite Lived Intangible Assets [Line Items]
License agreement milestone payments paid		$ 100,000
Useful life of intangible asset		9 years
Remaining useful life					7 years 6 months