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
-Topic 275
-SubTopic 10
-Section 50
-Paragraph 18
-URI http://asc.fasb.org/extlink&oid=99393423&loc=d3e6351-108592

Reference 2: 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=118260190&loc=d3e13531-108611

Reference 3: 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=118260190&loc=d3e13537-108611

Reference 4: 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

Name:	us-gaap_ConcentrationRiskPercentage1
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

Operating Segment, Geographic and Significant Customer Information - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2019 Customer Segment	Dec. 31, 2018 Customer	Dec. 31, 2017
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	10.00%	13.00%	22.00%
Semiconductor Test \| Customer 1 \| Consolidated Revenue \| Revenue from Rights Concentration Risk
Segment Reporting Information [Line Items]
Concentration risk, percentage	11.00%	4.00%
Semiconductor Test \| Customer 2 \| Consolidated Revenue \| Revenue from Rights Concentration Risk
Segment Reporting Information [Line Items]
Concentration risk, percentage			13.00%