ORGANIZATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Dec. 31, 2017
ORGANIZATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES [Line Items]
Percentage of sale returns	1.50%
Revenue, number of performance obligations, product sales	2
Revenue, performance obligations, term of services, online business tools	3 months
Revenue, number of performance obligations, online business tools	3
South Korea
ORGANIZATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES [Line Items]
Net assets	$ 34.4	$ 32.7