The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

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Balance Type:	credit
Period Type:	duration

Schedule of Impact of ASC 606 Adoption on Condensed Consolidated Statement of Cash Flows (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Significant Accounting Policies [Line Items]
Net loss	$ 4,004	$ (33,287)	$ (4,984)	$ (42,127)
Changes in deferred revenue			683	$ (313)
ASC 606 \| Adjustments
Significant Accounting Policies [Line Items]
Net loss			(882)
Changes in deferred revenue			882
ASC 606 \| Balances without adoption of ASC Topic 606
Significant Accounting Policies [Line Items]
Net loss			(4,102)
Changes in deferred revenue			$ (199)