INCOME TAX - Components of Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Deferred Tax Assets
Net operating loss carryforwards	$ 38,008	$ 36,090
Deferred income and reserves	0	332
Amortization of intangibles	2,535	2,881
Share-based compensation expense	6,929	7,276
Other	4,000	1,908
Gross deferred tax assets	51,472	48,487
Valuation allowance	(51,455)	(48,487)
Deferred tax assets, net of valuation allowance	17	0
Deferred Tax Liabilities
Depreciation of fixed assets	(17)	0
Gross deferred tax liabilities	(17)	0
Net deferred tax liability	$ 0	$ 0