Investment in Aizu Fujitsu Semiconductor Wafer Solution Limited ("AFSW") - Income Statement Information (Details) - Aizu Fajitsu Semiconductor Wafer Solution Limited - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020	Dec. 31, 2019
Summary of Variable Interest Entities [Roll Forward]
Beginning balance	$ (1,466)	$ (1,688)	$ (1,688)	$ (659)
Investment	968	$ 1,500	7,348	2,698
Loss	(1,468)		(6,836)	(3,703)
Effect of exchange rate change	100		(290)	(24)
Ending balance	$ (1,866)		$ (1,466)	$ (1,688)

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Summary of Variable Interest Entities

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Portion of equity (net assets) in a variable interest entity (VIE) not attributable, directly or indirectly, to the parent entity. That is, this is the portion of equity in a VIE that is attributable to the noncontrolling interest (previously referred to as minority interest).

+ References

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The amount of income (loss) from operations derived by the reporting entity during the period from the Variable Interest Entity (VIE).

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-Publisher FASB
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The amount of financial or other support the reporting entity has provided (explicitly or implicitly) to the Variable Interest Entity (VIE) that it was not previously contractually required to provide or that the reporting entity intends to provide, including, for example, situations in which the reporting entity assisted the VIE in obtaining another type of support.

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 810
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