XML 56 R91.htm IDEA: XBRL DOCUMENT v3.20.1

Segment Information - Schedule of Information on Products and Services (Detail) $ in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2019 TWD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2018 TWD ($)	Dec. 31, 2017 TWD ($)
Disclosure of products and services [line items]
Net revenue	$ 20,337,881	$ 679,969	$ 18,480,027	$ 17,940,855
Percentage of total revenue	100.00%	100.00%	100.00%	100.00%
Testing [member]
Disclosure of products and services [line items]
Net revenue	$ 4,257,800		$ 4,790,097	$ 4,838,246
Percentage of total revenue	21.00%	21.00%	26.00%	27.00%
Assembly [member]
Disclosure of products and services [line items]
Net revenue	$ 5,148,877		$ 4,679,676	$ 5,259,281
Percentage of total revenue	25.00%	25.00%	25.00%	29.00%
LCDD [member]
Disclosure of products and services [line items]
Net revenue	$ 6,922,205		$ 5,694,720	$ 4,789,869
Percentage of total revenue	34.00%	34.00%	31.00%	27.00%
Bumping [member]
Disclosure of products and services [line items]
Net revenue	$ 4,008,999		$ 3,315,534	$ 3,053,459
Percentage of total revenue	20.00%	20.00%	18.00%	17.00%

X

- Definition

Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes of the table.

+ References

No definition available.

+ Details

Name:	ifrs-full_DisclosureOfProductsAndServicesLineItems
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

X

- Definition

The percentage of the entity's revenue. [Refer: Revenue]

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name IFRS
-Number 8
-IssueDate 2019-01-01
-Paragraph 34
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=8&code=ifrs-tx-2019-en-r&anchor=para_34&doctype=Standard
-URIDate 2019-03-27

+ Details

Name:	ifrs-full_PercentageOfEntitysRevenue
Namespace Prefix:	ifrs-full_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Expiry date 2020-01-01: The income arising in the course of an entity's ordinary activities. Income is increases in economic benefits during the accounting period in the form of inflows or enhancements of assets or decreases of liabilities that result in an increase in equity, other than those relating to contributions from equity participants. Effective 2020-01-01: The income arising in the course of an entity's ordinary activities. Income is increases in assets, or decreases in liabilities, that result in increases in equity, other than those relating to contributions from holders of equity claims.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 8
-IssueDate 2019-01-01
-Paragraph 28
-Subparagraph a
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=8&code=ifrs-tx-2019-en-r&anchor=para_28_a&doctype=Standard
-URIDate 2019-03-27

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 8
-IssueDate 2019-01-01
-Paragraph 23
-Subparagraph a
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=8&code=ifrs-tx-2019-en-r&anchor=para_23_a&doctype=Standard
-URIDate 2019-03-27

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 8
-IssueDate 2019-01-01
-Paragraph 32
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=8&code=ifrs-tx-2019-en-r&anchor=para_32&doctype=Standard
-URIDate 2019-03-27

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 8
-IssueDate 2019-01-01
-Paragraph 33
-Subparagraph a
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=8&code=ifrs-tx-2019-en-r&anchor=para_33_a&doctype=Standard
-URIDate 2019-03-27

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 8
-IssueDate 2019-01-01
-Paragraph 34
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=8&code=ifrs-tx-2019-en-r&anchor=para_34&doctype=Standard
-URIDate 2019-03-27

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 1
-IssueDate 2019-01-01
-Paragraph 82
-Subparagraph a
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2019-en-r&anchor=para_82_a&doctype=Standard
-URIDate 2019-03-27

Reference 7: http://www.xbrl.org/2003/role/exampleRef
-Name IAS
-Number 1
-IssueDate 2019-01-01
-Paragraph 103
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2019-en-r&anchor=para_103&doctype=Standard
-URIDate 2019-03-27

Reference 8: http://www.xbrl.org/2003/role/exampleRef
-Name IAS
-Number 1
-IssueDate 2019-01-01
-Paragraph 102
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2019-en-r&anchor=para_102&doctype=Standard
-URIDate 2019-03-27

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 5
-IssueDate 2019-01-01
-Paragraph 33
-Subparagraph b
-Clause i
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=5&code=ifrs-tx-2019-en-r&anchor=para_33_b_i&doctype=Standard
-URIDate 2019-03-27

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 12
-IssueDate 2019-01-01
-Paragraph B12
-Subparagraph b
-Clause v
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=12&code=ifrs-tx-2019-en-r&anchor=para_B12_b_v&doctype=Appendix&subtype=B
-URIDate 2019-03-27

Reference 11: http://www.xbrl.org/2003/role/exampleRef
-Name IFRS
-Number 12
-IssueDate 2019-01-01
-Paragraph B10
-Subparagraph b
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=12&code=ifrs-tx-2019-en-r&anchor=para_B10_b&doctype=Appendix&subtype=B
-URIDate 2019-03-27

+ Details

Name:	ifrs-full_Revenue
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

X

- Details

Name:	ifrs-full_SegmentsAxis=imos_TestingMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	ifrs-full_SegmentsAxis=imos_AssemblyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	ifrs-full_SegmentsAxis=imos_LcddMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	ifrs-full_SegmentsAxis=imos_BumpingMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: