Number of additional cases filed.

No definition available.

Name:	coll_LossContingencyNumberOfAdditionalCasesFiled
Namespace Prefix:	coll_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Number of demand letters received from purported stockholders.

+ References

No definition available.

+ Details

Name:	coll_LossContingencyNumberOfDemandLettersReceivedFromPurportedStockholders
Namespace Prefix:	coll_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents the stay period before the Federal Drug Administration (FDA) can issue final approval unless the stay is terminated.

+ References

No definition available.

+ Details

Name:	coll_LossContingencyStayPeriodBeforeFinalFederalDrugAdministrationApprovalCanBeIssuedIfPatentInfringementLitigationElected
Namespace Prefix:	coll_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Statutory period of proceedings.

+ References

No definition available.

+ Details

Name:	coll_StatutoryPeriodOfProceedings
Namespace Prefix:	coll_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of loss from litigation settlement for amount awarded to other party. Excludes claims within an insurance entity's normal claims settlement process.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 450
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483076/450-20-50-1

+ Details

Name:	us-gaap_LitigationSettlementLoss
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

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

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 450
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 4
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483076/450-20-50-4

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 450
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 9
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483076/450-20-50-9

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 720
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483359/720-20-50-1

Reference 4: http://www.xbrl.org/2003/role/exampleRef
-Topic 460
-SubTopic 10
-Name Accounting Standards Codification
-Section 55
-Paragraph 27
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482395/460-10-55-27

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 450
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 9
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483076/450-20-50-9

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Topic 450
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 4
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483076/450-20-50-4

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Topic 460
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482425/460-10-50-3

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Topic 450
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483076/450-20-50-1

+ Details

Name:	us-gaap_LossContingenciesLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The total number of new claims filed pertaining to a loss contingency during the period.

+ References

+ Details

Name:	us-gaap_LossContingencyNewClaimsFiledNumber
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Number of another entity's patents that the entity has allegedly infringed.

+ References

+ Details

Name:	us-gaap_LossContingencyPatentsAllegedlyInfringedNumber
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	srt_LitigationCaseAxis=coll_PurduePharmaLimitedPartnershipPatentInfringementMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_LitigationCaseAxis=coll_PurduePharmaLimitedPartnershipPatentInfringementDistrictOfMassachusettsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_LitigationCaseAxis=coll_BdsiAcquisitionLitigationMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_LitigationCaseAxis=coll_AquestiveTherapeuticsIncLitigationMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_IncomeStatementLocationAxis=us-gaap_SellingGeneralAndAdministrativeExpensesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Commitments and Contingencies (Details) $ in Thousands					1 Months Ended	2 Months Ended	18 Months Ended
Commitments and Contingencies (Details) $ in Thousands	Mar. 08, 2023 USD ($)	Feb. 28, 2022 case	Sep. 11, 2020	Mar. 24, 2015 patent	Mar. 31, 2022 stockholder case	Mar. 31, 2022 stockholder	Apr. 30, 2017 patent lawsuit
Xtampza ER Litigation
Commitments and Contingencies
Stay period before FDA can issue a final approval unless it is terminated				30 months
Number of patents allegedly infringed				3			2
Number of lawsuits filed \| lawsuit							2
Statutory period of proceedings			18 months
Xtampza ER Litigation, District of Massachusetts
Commitments and Contingencies
Stay period before FDA can issue a final approval unless it is terminated				30 months
Number of patents allegedly infringed				3
BDSI Acquisition Litigation
Commitments and Contingencies
Number of additional cases filed \| case		2			2
Number of demand letters received from purported stockholders \| stockholder					4	3
Aquestive Therapeutics, Inc Litigation \| Selling, general and administrative expenses
Commitments and Contingencies
Litigation settlement, amount awarded to other party \| $	$ 8,500