Segment, Customer Concentration and Geographical Information - Company's Customers that Represent 10% or More of Company's Net Revenues (Detail)	3 Months Ended	6 Months Ended
Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Revenues [Member] \| Customer Concentration Risk [Member] \| Wireless [Member] \| Sprint and Affiliates [Member]
Revenue, Major Customer [Line Items]
Customer concentrating on 10% or more of net revenue	81.00%	79.00%	79.00%	78.00%

For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
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Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
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Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
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Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 275
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-Section 50
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-URI http://asc.fasb.org/extlink&oid=99393423&loc=d3e6404-108592

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