SIGNIFICANT ACCOUNTING POLICIES - Schedule of reconciliation of the allowance for doubtful accounts (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Balance, beginning of the period	$ 1,466	$ 1,143	$ 675
Charges to earnings	1,785	1,697	880
Write-off of uncollectible accounts receivable	(1,859)	(1,400)	(435)
Recoveries collected	10	26	23
Balance, end of the period	$ 1,402	$ 1,466	$ 1,143