OTHER FINANCIAL INFORMATION - Allowance for Doubtful Accounts (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Allowance for Doubtful Accounts Receivable [Roll Forward]
Allowance, beginning of year	$ 711
Allowance, end of year	1,608	$ 711
SEC Schedule, 12-09, Allowance, Credit Loss
Allowance for Doubtful Accounts Receivable [Roll Forward]
Allowance, beginning of year	711	51	$ 36
Provisions	971	713	45
Write offs, net of recoveries	(74)	(53)	(30)
Allowance, end of year	$ 1,608	$ 711	$ 51