Income Taxes - Narrative (Details) - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Income Tax [Line Items]
Income tax expense	$ 3,299,000	$ 0	$ 0
Amount of increase in valuation allowance	(150,700,000)
Accrual for interest or penalties on tax matters	0	0	0
Foreign Tax Authority
Income Tax [Line Items]
Income tax expense	3,300,000
Canadian Federal
Income Tax [Line Items]
Scientific research and experimental development expenses deductible for income tax purposes	19,900,000	19,900,000	19,900,000
Net operating loss carry forwards (NOLs)	79,545,000
Canadian Provincial
Income Tax [Line Items]
Scientific research and experimental development expenses deductible for income tax purposes	21,600,000	21,600,000	21,600,000
Net operating loss carry forwards (NOLs)	78,924,000
US Federal
Income Tax [Line Items]
Income tax expense		$ 0	$ 0
Net operating loss carry forwards (NOLs)	1,250,773,000
US Federal | Research Tax Credit Carryforward
Income Tax [Line Items]
Tax credit carryforward	48,500,000
US Federal | Orphan Drug Tax Credit Carryforward
Income Tax [Line Items]
Tax credit carryforward	7,200,000
US State
Income Tax [Line Items]
Net operating loss carry forwards (NOLs)	296,437,000
US State | Research Tax Credit Carryforward
Income Tax [Line Items]
Tax credit carryforward	$ 16,800,000