ORGANIZATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Loyalty Deferred Revenue (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Mar. 31, 2020	Sep. 30, 2020	Dec. 31, 2019
Loyalty program
Loyalty deferred revenue, beginning balance	$ 3,127	$ 3,127
Loyalty points forfeited or expired	(4,348)	(2,601)
Loyalty points used	(9,127)	(6,879)
Loyalty points vested	11,320	8,404
Loyalty points unvested	$ 1,051	1,145
Loyalty deferred revenue, ending balance		3,196
Deferred commissions		$ 1,729	$ 1,758