Income Tax Expense - Narrative (Details) $ in Millions	12 Months Ended
	Dec. 31, 2023 USD ($)
Operating Loss Carryforwards [Line Items]
Deferred tax assets, tax deferred expense	$ 1.3
U.S. Federal
Operating Loss Carryforwards [Line Items]
NOL carryforwards	374.0
NOLs utilized	42.6
U.S. Federal | Adamas Pharmaceuticals
Operating Loss Carryforwards [Line Items]
NOL carryforwards	489.9
State
Operating Loss Carryforwards [Line Items]
NOLs utilized	$ 25.7