FAIR VALUE MEASUREMENTS - Summary of Change in Liability Balance Associated with Liability-Classified Warrants (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Warrant Liability
Change in the Fair Value of Warrants
Balance at beginning of period	$ 1,383	$ 89,169
Warrant exercises	0	(59,907)
Increase (decrease) in fair value	(1,268)	(27,879)
Balance at end of period	115	1,383
Vegas.com LLC | Earnout Payment Liabilities
Contingent Consideration
Balance at beginning of period	990	1,930
Payments	(8)	(1,000)
Change in fair value of contingent consideration	10	60
Interest accrued on unpaid balance	94	0
Balance at end of period	$ 1,086	$ 990