The estimated fair value of the common stock of a company.

No definition available.

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- Definition

Represents the expense recognized during the period arising from equity-based compensation arrangements (for example, shares of stock, unit, stock options or other equity instruments) with employees, directors and certain consultants qualifying for treatment as employees.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SAB Topic 14.F)
-URI http://asc.fasb.org/extlink&oid=27013229&loc=d3e301413-122809

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 1
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-URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5047-113901

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (h)(1)(i)
-URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901

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- References

No definition available.

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- References

No definition available.

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- Definition

Weighted average period over which unrecognized compensation is expected to be recognized for equity-based compensation plans, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

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- Definition

Unrecognized cost of unvested options awarded to employees as compensation.

+ References

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- References

No definition available.

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- References

No definition available.

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- Definition

The estimated dividend rate (a percentage of the share price) to be paid (expected dividends) to holders of the underlying shares over the option's term.

+ References

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- Definition

The risk-free interest rate assumption that is used in valuing an option on its own shares.

+ References

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- Definition

Weighted average expected volatility rate of share-based compensation awards.

+ References

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- Definition

Gross number of share options (or share units) granted during the period.

+ References

No definition available.

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- Definition

Expected term of share-based compensation awards, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (f)(2)(i)
-URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901

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Significant Accounting Policies, Stock-Based Compensation Expense (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Stock-based Compensation Expense [Abstract]
Stock-based compensation expense	$ 3,942	$ 1,978	$ 7,122	$ 5,168
Unrecognized Compensation Expense [Abstract]
Unrecognized compensation expense related to non-vested stock options	23,000		$ 23,000
Weighted average period for recognition			1 year 6 months
2015 Equity Incentive Plan [Member] \| Employee Stock Options [Member]
Weighted-Average Assumptions [Abstract]
Risk-free interest rate			1.90%	1.60%
Dividend yield			0.00%	0.00%
Volatility			79.40%	69.30%
Expected life			6 years 29 days	6 years 29 days
Fair value of common stock (in dollars per share)			$ 12.12	$ 6.48
2015 Equity Incentive Plan [Member] \| Board of Director Stock Options [Member]
Weighted-Average Assumptions [Abstract]
Risk-free interest rate			1.90%
Dividend yield			0.00%
Volatility			79.40%
Expected life			6 years 3 months
Fair value of common stock (in dollars per share)			$ 12.12
Stock-based Compensation Expense [Abstract]
Options granted (in shares)				0
Ionis 2011 Equity Incentive Plan [Member] \| Employee Stock Options [Member]
Weighted-Average Assumptions [Abstract]
Risk-free interest rate			1.80%	1.50%
Dividend yield			0.00%	0.00%
Volatility			65.80%	59.10%
Expected life			4 years 6 months	4 years 6 months
Research and Development Expenses [Member]
Stock-based Compensation Expense [Abstract]
Stock-based compensation expense	1,919	1,311	$ 3,520	$ 2,147
General and Administrative Expenses [Member]
Stock-based Compensation Expense [Abstract]
Stock-based compensation expense	$ 2,023	$ 667	$ 3,602	$ 3,021