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Revenue by Product Category (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Segment Reporting Information [Line Items]
NET SALES	$ 539,521	$ 457,253	$ 530,348	[1]
Mobile Storage
Segment Reporting Information [Line Items]
NET SALES	532,682	441,700	494,012
Mobile Communications
Segment Reporting Information [Line Items]
NET SALES	0	10,356	30,163
Others
Segment Reporting Information [Line Items]
NET SALES	$ 6,839	$ 5,197	$ 6,173
[1] In 2019 and 2020, revenue billed to Japan was reclassified to others.

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Amount, excluding tax collected from customer, of revenue from satisfaction of performance obligation by transferring promised good or service to customer. Tax collected from customer is tax assessed by governmental authority that is both imposed on and concurrent with specific revenue-producing transaction, including, but not limited to, sales, use, value added and excise.

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