SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Customer Concentration (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020
Concentration Risk [Line Items]
Net revenues	$ 75,248	$ 61,562	$ 157,880	$ 126,305
Accounts receivable, net of allowance for doubtful accounts of $259 and $610 as of June 30, 2021, and December 31, 2020, respectively	44,557		44,557		$ 50,589
Revenue Benchmark | Customer Concentration Risk | Customer A
Concentration Risk [Line Items]
Net revenues	$ 18,280	$ 16,540	$ 38,681	$ 34,883
Concentration risk, percentage	24.30%	27.20%	24.50%	27.70%
Revenue Benchmark | Customer Concentration Risk | Customer B
Concentration Risk [Line Items]
Net revenues	$ 14,651	$ 11,404	$ 31,396	$ 22,422
Concentration risk, percentage	19.50%	18.80%	19.90%	17.80%
Accounts Receivable | Customer Concentration Risk | Customer A
Concentration Risk [Line Items]
Concentration risk, percentage			8.50%		15.00%
Accounts receivable, net of allowance for doubtful accounts of $259 and $610 as of June 30, 2021, and December 31, 2020, respectively	$ 3,789		$ 3,789		$ 7,582
Accounts Receivable | Customer Concentration Risk | Customer B
Concentration Risk [Line Items]
Concentration risk, percentage			13.50%		6.80%
Accounts receivable, net of allowance for doubtful accounts of $259 and $610 as of June 30, 2021, and December 31, 2020, respectively	$ 6,000		$ 6,000		$ 3,447