ORGANIZATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Loyalty Deferred Revenue (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2020	Dec. 31, 2019
Loyalty program
Loyalty deferred revenue, beginning balance	$ 3,127	$ 4,231
Loyalty points forfeited or expired	(678)	(4,348)
Loyalty points used	(2,524)	(9,127)
Loyalty points vested	1,959	11,320
Loyalty points unvested	1,159	1,051
Loyalty deferred revenue, ending balance	$ 3,043	$ 3,127