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Summary of Changes to Prepaid Licensing and Royalty Fees (Detail) - USD ($) $ in Thousands | 12 Months Ended
--- | ---
Dec. 31, 2020 | Dec. 31, 2019 | Dec. 31, 2018
Prepaid Expenses [Line Items] |  |  |
Balance at beginning of year | $ 44 |  |
Addition | (25) | $ (10) | $ (267)
Amortization and usage | (5) | (47) | (36)
Impairment charges (Note 4) | 0 | (85) | (244)
Balance at end of year | 130 | 44 |
Prepaid Licensing and Royalty Fees |  |  |
Prepaid Expenses [Line Items] |  |  |
Balance at beginning of year | 44 | 435 | 459
Addition | 340 | 205 | 968
Amortization and usage | (254) | (511) | (747)
Exchange difference |  |  | (1)
Impairment charges (Note 4) |  | (85) | (244)
Balance at end of year | $ 130 | $ 44 | $ 435

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- Definition Impairment loss on prepaid licensing and royalty fees. + References No definition available. + Details
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- Definition Prepaid expenses. + References No definition available. + Details
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- Definition The aggregate amount of recurring noncash expense charged against earnings in the period to allocate the cost of assets over their estimated remaining economic lives. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 30 -Section 50 -Paragraph 2 -Subparagraph (a)(2) -URI http://asc.fasb.org/extlink&oid=66006027&loc=d3e16323-109275 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 28 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=121586364&loc=d3e3602-108585 + Details
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- Definition The amount of difference between the reported amount and the reporting currency-denominated amount. The default debit balance is based on the reported amount that is greater that the reporting currency-denominated amount. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 830 -SubTopic 30 -Section S99 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6897108&loc=SL6897125-166521 + Details
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- Definition The increase (decrease) during the reporting period in the amount of outstanding money paid in advance for goods or services that bring economic benefits for future periods. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 28 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=121586364&loc=d3e3602-108585 + Details
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- Definition Sum of the carrying amounts as of the balance sheet date of amounts paid in advance for expenses which will be charged against earnings in periods after one year or beyond the operating cycle, if longer. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.17) -URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682 + Details
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