Income taxes (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022	Dec. 31, 2022
Income Taxes
Income tax expense (benefit)	$ (282,000)	$ 193,000	$ (122,000)	$ 372,000
Interest and penalties accrued	$ 0		$ 0		$ 0