Income Taxes - Summary of Major Tax Jurisdictions and Fiscal Years Open to Examination (Detail)	12 Months Ended
	Jun. 30, 2018
U.S. Federal [Member] | Minimum [Member]
Operating Loss Carryforwards [Line Items]
Fiscal Years Open to Examination	2014
U.S. Federal [Member] | Maximum [Member]
Operating Loss Carryforwards [Line Items]
Fiscal Years Open to Examination	2017
U.S. States [Member]
Operating Loss Carryforwards [Line Items]
Fiscal Years Open to Examination	Various
Foreign Tax Authority [Member] | Minimum [Member] | Australia [Member]
Operating Loss Carryforwards [Line Items]
Fiscal Years Open to Examination	2014
Foreign Tax Authority [Member] | Minimum [Member] | U.K. [Member]
Operating Loss Carryforwards [Line Items]
Fiscal Years Open to Examination	2011
Foreign Tax Authority [Member] | Maximum [Member] | Australia [Member]
Operating Loss Carryforwards [Line Items]
Fiscal Years Open to Examination	2017
Foreign Tax Authority [Member] | Maximum [Member] | U.K. [Member]
Operating Loss Carryforwards [Line Items]
Fiscal Years Open to Examination	2017