ORGANIZATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Other Long-Term Liabilities (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Other long-term liabilities	$ 6,214	$ 2,302
Payments for Tenant Improvements	1,300
Uncertain income tax positions recorded in noncurrent liabilities	200		$ 200
Accrued lease restoration costs	300	400
Severance Costs	400	300
Accrued benefit liability	319	388
Operating Lease, Liability, Noncurrent	5,300
Foreign Plan [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Accrued benefit liability	$ 300	$ 400