Commitments and Contingencies - Summaries of Purchase Obligations (Detail) $ in Thousands	Dec. 31, 2017 USD ($)
Commitments and Contingencies Disclosure [Abstract]
Total purchase obligation	$ 431
Payments Due, Less Than 1 Year	431
Payments Due, 2-3 Years	0
Payments Due, 3-5 Years	0
Payments Due, More Than 5 Years	$ 0

No definition available.

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- Definition

Minimum amount of purchase arrangement in which the entity has agreed to expend funds to procure goods or services from a supplier.

+ References

No definition available.

+ Details

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- Definition

Minimum amount of purchase arrangement maturing after the fifth fiscal year following the latest fiscal year. Includes, but not limited to, recorded and unrecorded purchase obligations, long-term purchase commitments, and short-term purchase commitments.

+ References

No definition available.

+ Details

Name:	us-gaap_PurchaseObligationDueAfterFifthYear
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Data Type:	xbrli:monetaryItemType
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- Definition

Minimum amount of purchase arrangement maturing in the fourth and fifth fiscal years following the latest fiscal year. Includes, but not limited to, recorded and unrecorded purchase obligations, long-term purchase commitments, and short-term purchase commitments.

+ References

No definition available.

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- Definition

Minimum amount of purchase arrangement maturing in the next fiscal year following the latest fiscal year. Includes, but not limited to, recorded and unrecorded purchase obligations, long-term purchase commitments, and short-term purchase commitments.

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No definition available.

+ Details

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- Definition

Minimum amount of purchase arrangement maturing in the second and third fiscal years following the latest fiscal year. Includes, but not limited to, recorded and unrecorded purchase obligations, long-term purchase commitments, and short-term purchase commitments.

+ References

No definition available.

+ Details

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