SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Significant customer, percentage of revenue (Details) - Customer Concentration Risk	3 Months Ended		12 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2021
Customer A | Revenue
Concentration Risk [Line Items]
Concentration Risk, Percentage	30.00%	0.00%
Customer A | Accounts Receivable
Concentration Risk [Line Items]
Concentration Risk, Percentage	37.00%		0.00%
Customer B | Revenue
Concentration Risk [Line Items]
Concentration Risk, Percentage	11.00%	0.00%
Customer B | Accounts Receivable
Concentration Risk [Line Items]
Concentration Risk, Percentage	1.00%		0.00%
Customer C | Revenue
Concentration Risk [Line Items]
Concentration Risk, Percentage	11.00%	0.00%
Customer C | Accounts Receivable
Concentration Risk [Line Items]
Concentration Risk, Percentage	14.00%		0.00%
Customer D | Revenue
Concentration Risk [Line Items]
Concentration Risk, Percentage	11.00%	0.00%
Customer D | Accounts Receivable
Concentration Risk [Line Items]
Concentration Risk, Percentage	0.00%		0.00%
Customer E | Revenue
Concentration Risk [Line Items]
Concentration Risk, Percentage	11.00%	0.00%
Customer E | Accounts Receivable
Concentration Risk [Line Items]
Concentration Risk, Percentage	5.00%		0.00%
Customer F | Revenue
Concentration Risk [Line Items]
Concentration Risk, Percentage	2.00%	21.00%
Customer F | Accounts Receivable
Concentration Risk [Line Items]
Concentration Risk, Percentage	0.00%		0.00%
Customer G | Revenue
Concentration Risk [Line Items]
Concentration Risk, Percentage	1.00%	18.00%
Customer G | Accounts Receivable
Concentration Risk [Line Items]
Concentration Risk, Percentage	0.00%		0.00%
Customer H | Revenue
Concentration Risk [Line Items]
Concentration Risk, Percentage	0.00%	17.00%
Customer H | Accounts Receivable
Concentration Risk [Line Items]
Concentration Risk, Percentage	2.00%		0.00%
Customer I | Revenue
Concentration Risk [Line Items]
Concentration Risk, Percentage	1.00%	0.00%
Customer I | Accounts Receivable
Concentration Risk [Line Items]
Concentration Risk, Percentage	12.00%		41.00%
Customer J | Revenue
Concentration Risk [Line Items]
Concentration Risk, Percentage	2.00%	0.00%
Customer J | Accounts Receivable
Concentration Risk [Line Items]
Concentration Risk, Percentage	7.00%		26.00%
Customer K | Revenue
Concentration Risk [Line Items]
Concentration Risk, Percentage	1.00%	0.00%
Customer K | Accounts Receivable
Concentration Risk [Line Items]
Concentration Risk, Percentage	1.00%		24.00%