Income Taxes - Carryforwards, unrecognized benefits (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Income Taxes [Line Items]
Increase in valuation allowance		$ 28,500	$ 900	$ 900
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Unrecognized tax benefits, beginning balance		670	540	439
Additions based on tax positions related to the current year		161	130	92
Additions based on tax positions related to prior years		172	0	19
Reductions based on tax positions related to prior years		0	0	(10)
Unrecognized tax benefits, ending balance	$ 1,003	1,003	670	$ 540
Unrecognized tax benefits, uncertainty in income taxes	1,100	1,100
Unrecognized tax benefits that would impact effective tax rate	900	900	600
Accrued liability, CARES Act			$ 3,800
Payments for deferred payroll tax, CARES Act	1,900
Accrued liability, current, CARES Act	1,900	1,900
Domestic Tax Authority
Income Taxes [Line Items]
Operating Loss Carryforwards	139,800	139,800
Operating loss carryforwards subject to expiration	102,500	102,500
Operating loss carryforwards not subject to expiration	37,300	37,300
Domestic Tax Authority | Research Tax Credit Carryforward
Income Taxes [Line Items]
Tax Credit Carryforward, Amount	6,100	6,100
Foreign Tax Authority
Income Taxes [Line Items]
Operating Loss Carryforwards	52,800	52,800
Tax Credit Carryforward, Amount	1,200	1,200
State and Local Jurisdiction
Income Taxes [Line Items]
Operating Loss Carryforwards	81,800	81,800
State and Local Jurisdiction | Research Tax Credit Carryforward
Income Taxes [Line Items]
Tax Credit Carryforward, Amount	$ 2,900	$ 2,900