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Income Taxes - Additional Information (Detail) - USD ($) | 12 Months Ended
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Dec. 31, 2020 | Dec. 31, 2019 | Dec. 31, 2018 | Dec. 31, 2017
Income Tax Contingency [Line Items] |  |  |  |
Corporate income tax rate |  | 20.00% | 20.00% | 17.00%
Change in tax rate for undistributed portion of earnings |  | 5.00% | 5.00% | 10.00%
Unrecognized tax benefits that if recognized would affect the effective tax rate | $ 0 | $ 0 | $ 0 |
Unrecognized tax benefits that if recognized would be offset by a valuation allowance | 0 | 0 | 0 |
Unrecognized tax benefits, income tax penalties and interest expense | $ 0 | $ 0 | $ 0 |
Taiwan | Undistributed Foreign Earnings |  |  |  |
Income Tax Contingency [Line Items] |  |  |  |
Tax loss carryforward period | 10 years |  |  |

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- Definition Amount of expense for interest on an underpayment of income taxes and penalties related to a tax position claimed or expected to be claimed in the tax return. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 50 -Paragraph 15 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=84230637&loc=d3e32718-109319 + Details
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- Definition The total amount of unrecognized tax benefits that, if recognized, would affect the effective tax rate. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 50 -Paragraph 15A -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=84230637&loc=SL6600010-109319 + Details
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