STOCK-BASED COMPENSATION - Schedule of Non-cash Compensation Related to Equity Awards (Details ) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total non-cash compensation	$ 15,080	$ 16,436
Cost of revenue
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total non-cash compensation	393	397
Selling and marketing expense
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total non-cash compensation	2,039	1,802
General and administrative expense
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total non-cash compensation	9,600	12,171
Product development
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total non-cash compensation	1,965	2,066
Restructuring and severance
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total non-cash compensation	$ 1,083	$ 0