ORGANIZATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Sales Reserves (Details) - Reserve for sales returns - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Year	$ 76	$ 117
Provision related to sales made in current period	1,037	1,198
Adjustment related to sales made in prior periods	31	(10)
Actual returns or credits related to current period	(973)	(1,125)
Actual returns or credits related to prior periods	(103)	(104)
Balance at End of Year	$ 68	$ 76