Prepaid Expenses and Other Current Assets and Other Supplemental Assets Information - Prepaid and other current assets (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Prepaid Expenses and Other Current Assets and Other Supplemental Assets Information
Prepaid expenses	$ 8,973	$ 7,372
Income tax receivable	4,800	7,098
Research and development tax credit receivable	3,951	3,610
Current portion of interest rate swap asset	57
Other current assets	767	1,122
Prepaid expenses and other current assets	$ 18,548	$ 19,202