Stockholders' equity - Preferred Stock (Details)	Dec. 31, 2021 $ / shares shares	Dec. 31, 2020 $ / shares shares	Dec. 31, 2019 $ / shares shares
Class of Stock [Line Items]
Common stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
GDI
Class of Stock [Line Items]
Preferred stock shares, outstanding (in shares) | shares	0	0	1,000,000
Preferred shares, par value (in dollars per share)			$ 0
Preferred stock, conversion ratio			1
Common stock, par value (in dollars per share)			$ 0.0001