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Operating Segment, Geographic and Significant Customer Information - Additional Information (Detail) | 12 Months Ended
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Dec. 31, 2020 Segment | Dec. 31, 2019 Customer | Dec. 31, 2018 Customer
Segment Reporting Information [Line Items] |  |  |
Operating segments | Segment | 4 |  |
Number of customer accounted for more than ten percent of consolidated revenue | Customer |  | 0 | 0
Consolidated Revenue |  |  |
Segment Reporting Information [Line Items] |  |  |
Concentration risk, percentage |  | 10.00% | 10.00%
Semiconductor Test | Consolidated Revenue | Customer Concentration Risk |  |  |
Segment Reporting Information [Line Items] |  |  |
Concentration risk, percentage | 25.00% | 10.00% | 13.00%
Semiconductor Test | Customer 1 | Consolidated Revenue | Revenue from Rights Concentration Risk |  |  |
Segment Reporting Information [Line Items] |  |  |
Concentration risk, percentage |  | 15.00% |
Semiconductor Test | Customer 1 | Consolidated Revenue | Revenue from Rights Concentration Risk | Series of Customer [Member] |  |  |
Segment Reporting Information [Line Items] |  |  |
Concentration risk, percentage | 3.00% | 11.00% |

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- Definition 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. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 280 -SubTopic 10 -Section 50 -Paragraph 42 -URI http://asc.fasb.org/extlink&oid=120311839&loc=d3e9054-108599 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 275 -SubTopic 10 -Section 50 -Paragraph 18 -URI http://asc.fasb.org/extlink&oid=99393423&loc=d3e6351-108592 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 50 -Paragraph 20 -URI http://asc.fasb.org/extlink&oid=121572278&loc=d3e13531-108611 Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 50 -Paragraph 21 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=121572278&loc=d3e13537-108611 Reference 5: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 275 -SubTopic 10 -Section 50 -Paragraph 20 -URI http://asc.fasb.org/extlink&oid=99393423&loc=d3e6404-108592 + Details
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- Definition Number of operating segments. An operating segment is a component of an enterprise: (a) that engages in business activities from which it may earn revenues and incur expenses (including revenues and expenses relating to transactions with other components of the same enterprise), (b) whose operating results are regularly reviewed by the enterprise's chief operating decision maker to make decisions about resources to be allocated to the segment and assess its performance, and (c) for which discrete financial information is available. An operating segment may engage in business activities for which it has yet to earn revenues, for example, start-up operations may be operating segments before earning revenues. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 280 -SubTopic 10 -Section 50 -Paragraph 18 -URI http://asc.fasb.org/extlink&oid=120311839&loc=d3e8672-108599 + Details
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