Stockholders' equity - Warrants (Details) $ in Thousands				3 Months Ended
	Mar. 05, 2020 redeemableWarrant	Mar. 05, 2020 shares	Mar. 05, 2020 commonStock	Mar. 31, 2022 USD ($) shares	Mar. 31, 2021 USD ($) shares	Feb. 17, 2021 shares
Class of Stock [Line Items]
Warrants outstanding (in shares)					4,963,231
Change in fair value of warrants | $				$ 0	$ 859
ChaSerg | Working Capital Sponsor Loan, Equity Units
Class of Stock [Line Items]
Shares issued upon debt conversion (in shares)		53,000
ChaSerg | Working Capital Sponsor Loan, Common Stock
Class of Stock [Line Items]
Shares issued upon debt conversion (in shares)		1
ChaSerg | Working Capital Sponsor Loan, Redeemable Warrant
Class of Stock [Line Items]
Shares issued upon debt conversion (in shares)		0.5
Riverview Group LLC
Class of Stock [Line Items]
Warrant, convertible, conversion ratio						0.3480
Warrant, convertible, common shares (in shares)						2,221,378
Private Warrant
Class of Stock [Line Items]
Warrants outstanding (in shares)				0	346,500
Change in fair value of warrants | $					$ 900
Public Warrant
Class of Stock [Line Items]
Warrants outstanding (in shares)				0	4,616,731	6,383,269
Initial Public Offering | ChaSerg
Class of Stock [Line Items]
Sale of stock, components of units issued in transaction (in shares)	0.5		1
Initial Public Offering | Equity Unit | ChaSerg
Class of Stock [Line Items]
Sale of stock, number of shares issued in transaction (in shares)		22,000,000
Over-Allotment Option | ChaSerg
Class of Stock [Line Items]
Sale of stock, components of units issued in transaction (in shares)	0.5		1
Over-Allotment Option | Equity Unit | ChaSerg
Class of Stock [Line Items]
Sale of stock, components of units issued in transaction (in shares)		640,000