Lease obligation (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022	Dec. 31, 2022	Sep. 30, 2021
Change in operating lease, right-of-use assets			$ (957)	$ (2,556)
Change in operating lease liabilities			(1,385)	(2,647)
Restricted cash included in deposits and other noncurrent assets	$ 1,593		1,593		$ 1,515
Lease expense	$ 900	$ 1,400	$ 1,800	$ 2,800
Weighted average remaining lease term	5 years 6 months		5 years 6 months
Weighted average incremental borrowing rate	7.40%		7.40%
75 Sidney Street
Lease term						3 years 3 months 18 days
Change in operating lease, right-of-use assets		14,500
Change in operating lease liabilities		17,000
Gain on termination of lease		$ 2,500
Restricted cash included in deposits and other noncurrent assets	$ 1,500		$ 1,500