The aggregate amount of write-downs for impairments recognized during the period for long lived assets held for use (including those held for disposal by means other than sale).

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 958
-SubTopic 225
-Section 45
-Paragraph 11
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=68048823&loc=d3e92212-112881

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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-URI http://asc.fasb.org/extlink&oid=6515133

Reference 3: http://www.xbrl.org/2003/role/presentationRef
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-Name Accounting Standards Codification
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Reference 4: http://www.xbrl.org/2003/role/presentationRef
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Describes the periods of time over which an entity anticipates to receive utility from its property, plant and equipment (that is, the periods of time over which an entity allocates the initial cost of its property, plant and equipment).

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Useful life of long lived, physical assets used in the normal conduct of business and not intended for resale, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Examples include, but not limited to, land, buildings, machinery and equipment, office equipment, furniture and fixtures, and computer equipment.

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Summary of Significant Accounting Policies - Summary of Estimated Useful Lives (Detail) - USD ($)	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Property, Plant and Equipment [Line Items]
Impairment of other long-lived assets	$ 0	$ 0
Building
Property, Plant and Equipment [Line Items]
Property, plant and equipment useful life	35 years
Software \| Minimum
Property, Plant and Equipment [Line Items]
Property, plant and equipment useful life	2 years
Software \| Maximum
Property, Plant and Equipment [Line Items]
Property, plant and equipment useful life	3 years
Computers and office equipment
Property, Plant and Equipment [Line Items]
Property, plant and equipment useful life	3 years
Furniture and fixtures
Property, Plant and Equipment [Line Items]
Property, plant and equipment useful life	5 years
Leasehold improvements
Property, Plant and Equipment [Line Items]
Leasehold improvements	Shorter of useful life or remaining term of the lease