Commitments and Contingencies - Schedule of Future Minimum Lease Commitments Under Non-cancelable Operating Leases and Scheduled Sublease Payments (Detail) $ in Thousands	Dec. 31, 2017 USD ($)
Commitments And Contingencies Disclosure [Abstract]
Gross Payments, 2018	$ 7,438
Gross Payments, 2019	3,753
Gross Payments, Total future minimum lease payments	11,191
Scheduled Sublease Payments, 2018	4,016
Scheduled Sublease Payments, 2019	2,195
Scheduled Sublease Payments, Total future minimum lease payments	6,211
Net Payments, 2018	3,422
Net Payments, 2019	1,558
Net Payments, Total future minimum lease payments	$ 4,980

Operating leases future minimum payments due future minimum gross payments due.

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Operating leases future minimum payments due future minimum gross payments due current.

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Operating leases future minimum payments future minimum sublease rentals due.

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Operating leases future minimum payments future minimum sublease rentals due current.

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Operating leases future minimum payments future minimum sublease rentals due in two years.

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Amount of required minimum rental payments for leases having an initial or remaining non-cancelable letter-terms in excess of one year.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 840
-SubTopic 10
-Section 55
-Paragraph 40
-Subparagraph (Note 3)
-URI http://asc.fasb.org/extlink&oid=82846649&loc=d3e38371-112697

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 840
-SubTopic 20
-Section 50
-Paragraph 2
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=77902758&loc=d3e41502-112717

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Amount of required minimum rental payments for operating leases having an initial or remaining non-cancelable lease term in excess of one year due in the next fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Amount of required minimum rental payments for operating leases having an initial or remaining non-cancelable lease term in excess of one year due in the second fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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