ORGANIZATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - New Accounting Standards (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Jan. 01, 2019
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Operating lease, right-of-use asset	$ 6,900
Present value of lease liabilities	5,095
Operating lease current liability	300
Operating lease noncurrent liability	$ 4,800
Accounting Standards Update 2016-02
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Operating lease, right-of-use asset		$ 7,200
Present value of lease liabilities		5,300
Off-Market Favorable Lease | Accounting Standards Update 2016-02
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Operating lease, right-of-use asset		$ 1,900