v2.4.0.6

Subsequent Events (Details) (USD $)	9 Months Ended
	Sep. 30, 2012
Subsequent Event [Line Items]
Number of shares of common stock issued (in shares)	6,304,102
Common stock issued, price per share (in dollars per share)	$ 4.07
Subsequent Event [Member]
Subsequent Event [Line Items]
Number of investors included in registered direct financing	3
Number of shares of common stock issued (in shares)	6,304,102
Common stock issued, price per share (in dollars per share)	$ 4.07
Maximum limit of stock issuance specified as percentage of outstanding stock (in hundredths)	20.00%

X

- Definition

This line item represents the maximum limit of stock issuance specified as percentage of outstanding stock pursuant to rules.

+ References

No definition available.

+ Details

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Namespace Prefix:	insm_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

X

- Definition

This line item represents the number of investors included in registered direct financing completed by the entity.

+ References

No definition available.

+ Details

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

X

- Definition

Amount per share assigned to the consideration received for shares issued.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 915

-SubTopic 215

-Section 45

-Paragraph 1

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=6472370&loc=d3e38297-110927

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Balance Type:	na
Period Type:	duration

X

- Definition

Number of new stock issued during the period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 505

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.3-04)

-URI http://asc.fasb.org/extlink&oid=6959260&loc=d3e187085-122770



Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 29, 30

-Article 5



Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher AICPA

-Name Accounting Principles Board Opinion (APB)

-Number 12

-Paragraph 10

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.



Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 04

-Article 3



Reference 5: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 505

-SubTopic 10

-Section 50

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21463-112644

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- Details

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