v2.4.0.6

Description of the Business (Details)	9 Months Ended
	Sep. 30, 2012
Description of the Business [Abstract]
Number of initial primary target indications	2

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- Definition

Refers to number of initial primary target indications for the product under late-stage clinical trials.

+ References

No definition available.

+ Details

Name:	insm_NumberOfInitialPrimaryTargetIndications
Namespace Prefix:	insm_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

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- Details

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