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Summary Of Significant Accounting Policies - Additional Information (Detail) shares in Thousands, TWD in Thousands, $ in Thousands | 12 Months Ended
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Dec. 31, 2015 USD ($) Customer shares | Dec. 31, 2015 TWD Customer shares | Dec. 31, 2014 USD ($) Customer shares | Dec. 31, 2013 USD ($) Customer shares | Dec. 31, 2012 TWD
Significant Accounting Policies [Line Items] |  |  |  |  |
Consolidated interest acquire in subsidiary | 100.00% | 100.00% |  |  |
Top ten customer sales in percentage | 72.00% | 72.00% | 76.00% | 76.00% |
Number of customers accounted for 10% or more sales | Customer | 1 | 1 | 2 | 2 |
Depreciation and amortization | $ 7,936 |  | $ 6,917 | $ 6,429 |
Warranty period for manufacturing defects of products | 1 year | 1 year |  |  |
Evaluation of tax benefits realized upon settlement | 50.00% | 50.00% |  |  |
Income tax under IBT act effective date | Jan. 01, 2006 | Jan. 01, 2006 |  |  |
Minimum alternative tax on income under IBT act | 10.00% | 10.00% |  |  |
Standard deduction tax amount | TWD |  |  |  |  | TWD 1,000
Standard deduction tax rate |  |  |  |  | 10.00%
Deferred income tax liabilities, noncurrent | $ 0 |  |  |  |
Deferred income tax assets, net | $ 610 |  | 1,521 |  |
Scenario, Previously Reported |  |  |  |  |
Significant Accounting Policies [Line Items] |  |  |  |  |
Deferred income tax assets, noncurrent |  |  | 1,909 |  |
Deferred income tax liabilities, current |  |  | 388 |  |
Scenario, Adjustment |  |  |  |  |
Significant Accounting Policies [Line Items] |  |  |  |  |
Deferred income tax liabilities, noncurrent |  |  | $ 388 |  |
Customers accounted for 10% or more | Net sales |  |  |  |  |
Significant Accounting Policies [Line Items] |  |  |  |  |
Major customers percentage of net sales | 30.00% | 30.00% | 47.00% | 46.00% |
Amended in August 2012 |  |  |  |  |
Significant Accounting Policies [Line Items] |  |  |  |  |
Standard deduction tax amount | TWD |  | TWD 500 |  |  |
Standard deduction tax rate | 12.00% | 12.00% |  |  |
Amendment Effective Date | Jan. 01, 2013 | Jan. 01, 2013 |  |  |
Minimum |  |  |  |  |
Significant Accounting Policies [Line Items] |  |  |  |  |
Short term investment maturity period | 3 months | 3 months |  |  |
Maximum |  |  |  |  |
Significant Accounting Policies [Line Items] |  |  |  |  |
Short term investment maturity period | 1 year | 1 year |  |  |
Held-to-maturity investment maturity period | 1 year | 1 year |  |  |
American Depositary Shares |  |  |  |  |
Significant Accounting Policies [Line Items] |  |  |  |  |
The effect of dilutive securities of employee stock options and restricted stock units | shares | 384 | 384 | 546 | 577 |
Ordinary Shares |  |  |  |  |
Significant Accounting Policies [Line Items] |  |  |  |  |
The effect of dilutive securities of employee stock options and restricted stock units | shares | 1,534 | 1,534 | 2,183 | 2,308 |
Software | Minimum |  |  |  |  |
Significant Accounting Policies [Line Items] |  |  |  |  |
Property plant and equipment estimated useful life | 1 year | 1 year |  |  |
Software | Maximum |  |  |  |  |
Significant Accounting Policies [Line Items] |  |  |  |  |
Property plant and equipment estimated useful life | 5 years | 5 years |  |  |
Development technology | Minimum |  |  |  |  |
Significant Accounting Policies [Line Items] |  |  |  |  |
Intangible asset amortized over estimated useful lives | 3 years 6 months | 3 years 6 months |  |  |
Development technology | Maximum |  |  |  |  |
Significant Accounting Policies [Line Items] |  |  |  |  |
Intangible asset amortized over estimated useful lives | 4 years 6 months | 4 years 6 months |  |  |
Buildings | Minimum |  |  |  |  |
Significant Accounting Policies [Line Items] |  |  |  |  |
Property plant and equipment estimated useful life | 25 years | 25 years |  |  |
Buildings | Maximum |  |  |  |  |
Significant Accounting Policies [Line Items] |  |  |  |  |
Property plant and equipment estimated useful life | 50 years | 50 years |  |  |
Machinery and Equipment | Minimum |  |  |  |  |
Significant Accounting Policies [Line Items] |  |  |  |  |
Property plant and equipment estimated useful life | 3 years | 3 years |  |  |
Machinery and Equipment | Maximum |  |  |  |  |
Significant Accounting Policies [Line Items] |  |  |  |  |
Property plant and equipment estimated useful life | 6 years | 6 years |  |  |
Furniture and Fixtures | Minimum |  |  |  |  |
Significant Accounting Policies [Line Items] |  |  |  |  |
Property plant and equipment estimated useful life | 3 years | 3 years |  |  |
Furniture and Fixtures | Maximum |  |  |  |  |
Significant Accounting Policies [Line Items] |  |  |  |  |
Property plant and equipment estimated useful life | 8 years | 8 years |  |  |
Leasehold And Building Improvement | Minimum |  |  |  |  |
Significant Accounting Policies [Line Items] |  |  |  |  |
Property plant and equipment estimated useful life | 2 years | 2 years |  |  |
Leasehold And Building Improvement | Maximum |  |  |  |  |
Significant Accounting Policies [Line Items] |  |  |  |  |
Property plant and equipment estimated useful life | 6 years | 6 years |  |  |
FCI |  |  |  |  |
Significant Accounting Policies [Line Items] |  |  |  |  |
Consolidated interest acquire in subsidiary | 99.90% | 99.90% |  |  |

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