April 2013 Pillar Agreements - Black-Scholes Model to Compute Fair Value of Pillar Warrants (Detail) (USD $)		1 Months Ended
Sep. 30, 2013	May 07, 2013 Pillar I Warrants [Member]	May 07, 2013 Additional Pillar Warrants [Member]
Assumptions used to compute fair value of Pillar warrants [Line Items]
Common stock price	$ 1.55	$ 0.57	$ 0.57
Warrant exercise price		0.61	0.79
Term of warrant (years)		5 years	1 year 1 month 6 days
Expected volatility		62.00%	67.00%
Average risk free interest rate		0.80%	0.10%
Expected dividend yield
Expected percentage of warrants to be exercised		100.00%	100.00%

Name:	idra_AssumptionsUsedToComputeFairValueOfPillarWarrantsLineItems
Namespace Prefix:	idra_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

Fair value assumptions expected percentage of warrants to be exercised.

+ References

No definition available.

+ Details

Name:	idra_FairValueAssumptionsExpectedPercentageOfWarrantsToBeExercised
Namespace Prefix:	idra_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Exercise price per share or per unit of warrants or rights outstanding.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 235

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.4-08.(i)(4))

-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 08

-Paragraph i

-Subparagraph 4

-Article 4

+ Details

Name:	us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights
Namespace Prefix:	us-gaap_
Data Type:	us-types:perUnitItemType
Balance Type:	na
Period Type:	instant

- Definition

Expected dividends to be paid to holders of the underlying shares or financial instruments (expressed as a percentage of the share or instrument's price).

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 820

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (e)

-URI http://asc.fasb.org/extlink&oid=25499696&loc=d3e19207-110258

+ Details

Name:	us-gaap_FairValueAssumptionsExpectedDividendRate
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Period the instrument, asset or liability is expected to be outstanding, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

+ Details

Name:	us-gaap_FairValueAssumptionsExpectedTerm
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Measure of dispersion, in percentage terms (for instance, the standard deviation or variance), for a given stock price.

+ References

+ Details

Name:	us-gaap_FairValueAssumptionsExpectedVolatilityRate
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Risk-free interest rate assumption used in valuing an instrument.

+ References

+ Details

Name:	us-gaap_FairValueAssumptionsRiskFreeInterestRate
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Price of a single share of a number of saleable stocks of a company.

+ References

+ Details

Name:	us-gaap_SharePrice
Namespace Prefix:	us-gaap_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	instant