Accounts Receivable (Tables)

3 Months Ended

12 Months Ended

Mar. 31, 2022

Dec. 31, 2021

Receivables [Abstract]

Schedule of accounts receivable

Accounts receivable consisted of the following:

	December 31, 2021			March 31, 2022
Accounts receivable	$	93,722		$	85,324
Allowance for credit losses		(5,005	)		(5,354	)
Accounts receivable, net	$	88,717		$	79,970

	December 31, 2020			December 31, 2021
Accounts receivable	$	81,345		$	93,722
Allowance for doubtful accounts		(5,047	)		(5,005	)
Accounts receivable, net	$	76,298		$	88,717

Schedule of allowance for doubtful accounts

Movement of allowance for credit losses was as follows:

	Three Months Ended March 31,
	2021			2022
Balance at beginning of the period	$	5,047		$	5,005
Cumulative-effect adjustment upon adoption of ASU2016-13, Financial instruments – Credit losses (Topic 326)		—			866
Reversal of expenses		(514	)		(545	)
Write off		(103	)		—
Exchange difference		(14	)		28
Balance at end of the period	$	4,416		$	5,354

	Year Ended December 31,
	2019			2020			2021
Balance at beginning of the period	$	10,111		$	5,537		$	5,047
(Reserve)/Charge to expenses		(4,250	)		(240	)		721
Write off		(233	)		(493	)		(849	)
Exchange difference		(91	)		243			86
Balance at end of the period	$	5,537		$	5,047		$	5,005