INCOME TAXES - Summary of Net Deferred Tax Assets (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Jun. 30, 2018
Deferred tax assets:
Net operating loss carryforwards	$ 38,486	$ 35,562
Asset reserves	7,211	4,906
Deferred research and development	1,448	1,084
Stock-based compensation	418	661
Other	983	778
Deferred tax assets, gross	48,546	42,991
Deferred tax liabilities:
Intangibles	(6,203)	(6,864)
Deferred tax assets, net	42,343	36,127
Valuation allowance	(42,414)	(36,194)
Deferred tax liabilities, net of allowance	$ (71)	$ (67)