Revenue Recognition - Customers as Percentage of Total Sales (Detail) - Sales [Member] - Customer Concentration Risk [Member]	3 Months Ended	6 Months Ended
Jun. 29, 2018	Jun. 30, 2017	Jun. 29, 2018	Jun. 30, 2017
Concentration Risk [Line Items]
Total	83.50%	82.80%	85.70%	84.20%
Lam Research Corporation [Member]
Concentration Risk [Line Items]
Total	61.90%	57.10%	64.20%	57.90%
Applied Materials, Inc. [Member]
Concentration Risk [Line Items]
Total	21.60%	25.70%	21.50%	26.30%

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
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Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
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