Income Taxes - Valuation allowance (Details)	12 Months Ended
	Dec. 31, 2021 USD ($) jurisdiction audit	Dec. 31, 2020 USD ($)
Valuation allowance
Valuation allowance	$ 130,051,000	$ 77,375,000
Increase (decrease) in valuation allowance	52,676,000	28,468,000
Unrecognized tax benefits	0	0
Accrued interest or penalties related to uncertain tax position	$ 0	$ 0
Number of state jurisdictions in which entity files income tax returns | jurisdiction	4
Number of federal or state audits in progress | audit	0