Represents the number of significant partners.

No definition available.

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- Definition

For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" in the equation, this concept represents the concentration percentage derived from the division.

+ References

No definition available.

+ Details

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- Definition

The number of reporting segments previously reported by the entity.

+ References

No definition available.

+ Details

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Namespace Prefix:	isis_
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- Details

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- Definition

For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 275

-SubTopic 10

-Section 50

-Paragraph 20

-URI http://asc.fasb.org/extlink&oid=6927468&loc=d3e6404-108592

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 825

-SubTopic 10

-Section 50

-Paragraph 21

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=6947722&loc=d3e13537-108611

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 825

-SubTopic 10

-Section 50

-Paragraph 20

-URI http://asc.fasb.org/extlink&oid=6947722&loc=d3e13531-108611

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 275

-SubTopic 10

-Section 50

-Paragraph 18

-URI http://asc.fasb.org/extlink&oid=6927468&loc=d3e6351-108592

+ Details

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Period Type:	instant

- Definition

Amount to be collected within one year of the balance sheet date (or one operating cycle, if longer) from customers in accordance with the contractual provisions of long-term contracts or programs including amounts billed and unbilled as of the balance sheet date.

+ References

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 3

-Subparagraph c

-Article 5

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.3(c))

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

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Segment Information and Concentration of Business Risk (Details) (USD $)	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Segment Information and Concentration of Business Risk
Number of reporting segments prior to 2011	2
Concentration of business risk
Contract receivable (in dollars)	6,921,000	1,242,000
Revenue
Concentration of business risk
Significant partners, percent	10.00%
Revenue \| Partner A
Concentration of business risk
Significant partners, percent	73.00%	62.00%	55.00%
Revenue \| Partner B
Concentration of business risk
Significant partners, percent	2.00%	11.00%	8.00%
Revenue \| Partner C
Concentration of business risk
Significant partners, percent			15.00%
Revenue \| Partner D
Concentration of business risk
Significant partners, percent	18.00%	9.00%	2.00%
Contract receivables
Concentration of business risk
Number of significant partners	1	2
Contract receivables \| Regulus Therapeutics Inc.
Concentration of business risk
Percentage of contract receivable from significant partner		44.00%
Contract receivable (in dollars)		544,000
Contract receivables \| Contract receivables, Significant Partner One
Concentration of business risk
Percentage of contract receivable from significant partner	85.00%	30.00%
Contract receivables \| Contract receivables, Significant Partner Two
Concentration of business risk
Percentage of contract receivable from significant partner		15.00%