Income Taxes - Unrecognized Tax Benefits (Detail) - USD ($) $ in Thousands	12 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
Income Tax Benefit Expenses [Line Items]
Beginning balance of gross unrecognized tax benefits, Tax	$ 183	$ 148
Increases to unrecognized tax benefits resulting from the generation of additional R&D credits, Tax	38	35
Ending balance of gross unrecognized tax benefits, Tax	221	183
Beginning balance of gross unrecognized tax benefits, Interest	0	0
Increases to unrecognized tax benefits resulting from the generation of additional R&D credits, Interest	0	0
Ending balance of gross unrecognized tax benefits, Interest	0	0
Beginning balance of gross unrecognized tax benefits	183	148
Increases to unrecognized tax benefits resulting from the generation of additional R&D credits	38	35
Ending balance of gross unrecognized tax benefits	$ 221	$ 183