Income taxes - Schedule of Effective Income Tax Rate Reconciliation (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Income Tax Disclosure [Abstract]
Federal statutory rate	$ (20,323)	$ (22,344)	$ (10,849)
State income taxes, net of federal benefit	(644)	1,330	(3,810)
Stock compensation	1,271	2,786	185
Foreign rate differential	(2)	0	13
Tax credits	(539)	(539)	(787)
Fair value changes - warrants	(619)	11,192	0
Convertible debt cancellation of indebtedness income	0	15,079	0
Valuation allowance	20,058	(6,812)	14,559
Non-deductible expenses	(2,031)	(485)	0
Other	35	168	690
(Benefit from) provision for income taxes	$ (2,794)	$ 375	$ 1

Effective Income Tax Rate Reconciliation, Cancellation Of Indebtedness Income, Amount

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Effective Income Tax Rate Reconciliation, Changes In Warrant Fair Value, Amount

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Amount of difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying domestic federal statutory income tax rate to pretax income (loss) from continuing operation, attributable to expense for award under share-based payment arrangement. Excludes expense determined to be nondeductible upon grant or after for award under share-based payment arrangement.

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Amount of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

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The amount of income tax expense or benefit for the period computed by applying the domestic federal statutory tax rates to pretax income from continuing operations.

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Amount of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to tax exempt income, equity in earnings (loss) of an unconsolidated subsidiary, minority noncontrolling interest income (loss), tax holiday, disposition of a business, disposition of an asset, repatriation of foreign earnings, repatriation of foreign earnings jobs creation act of 2004, increase (decrease) in enacted tax rate, prior year income taxes, increase (decrease) in deferred tax asset valuation allowance, and other adjustments.

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