Lease obligation (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021	Dec. 31, 2021
Operating lease, right-of-use asset			$ 3,005	$ 2,265
Operating lease liabilities			(3,280)	(2,348)
Restricted cash included in deposits and other noncurrent assets	$ 1,515		1,515		$ 1,779
Lease expense	$ 1,000	$ 1,700	$ 3,800	$ 5,400
Weighted average remaining lease term	6 years 3 months 18 days		6 years 3 months 18 days
Weighted average incremental borrowing rate	7.40%		7.40%
75 Sidney Street
Lease term		3 years 3 months 18 days		3 years 3 months 18 days
Operating lease, right-of-use asset	$ 14,500
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