BASIS OF PRESENTATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Recent Accounting Pronouncements (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Increase in deferred tax asset		$ 5,647
Accounting Standards Update 2016-09
Increase in deferred tax asset		$ 5,000
Forecast | Accounting Standards Update 2014-09
Capitalized commission expense	$ 1,000
Retained Earnings | Forecast | Accounting Standards Update 2014-09
Decrease to accumulated deficit	$ (15,000)