Fair value portion of probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)
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Fair value portion of borrowing which can be exchanged for a specified number of another security at the option of the issuer or the holder, for example, but not limited to, the entity's common stock.

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Face (par) amount of debt instrument at time of issuance.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 55
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-Topic 835
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Measure of dispersion, in percentage terms (for instance, the standard deviation or variance), for a given stock price.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (bbb)
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Fair value of financial and nonfinancial obligations.

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The cash inflow associated with principal collections from a borrowing supported by a written promise to pay an obligation.

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
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Fair Value Measurements Fair Value Measurement - Additional Information (Details) - USD ($)	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016	Aug. 31, 2014
Liabilities:
Receipt of repayment on note receivable	$ 200,000	$ 300,000
2019 convertible senior notes
Liabilities:
Principal amount outstanding	245,000,000		$ 245,000,000
2019 convertible senior notes \| Senior Notes
Liabilities:
Principal amount outstanding				$ 245,000,000.0
Estimated fair value of debt	447,000,000
Recurring
Assets:
Assets, fair value	173,637,000		126,187,000
Liabilities:
Liabilities, fair value	5,695,000		3,388,000
Recurring \| Current contingent liabilities-CyDex
Liabilities:
Liabilities, fair value	86,000		101,000
Recurring \| Long-term contingent liabilities-CyDex
Liabilities:
Liabilities, fair value	1,503,000		1,503,000
Recurring \| Long-term contingent liabilities-Metabasis
Liabilities:
Liabilities, fair value	3,693,000		1,413,000
Recurring \| Liability for amounts owed to former licensees
Liabilities:
Liabilities, fair value	413,000		371,000
Recurring \| Short-term investments
Assets:
Assets, fair value	169,520,000		122,296,000
Recurring \| Note receivable Viking Therapeutics, Inc.
Assets:
Assets, fair value	$ 3,007,000		3,207,000
Liabilities:
Volatility of common stock (as a percent)	75.00%
Recurring \| Investment in warrants
Assets:
Assets, fair value	$ 1,110,000		684,000
Recurring \| Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Assets, fair value	3,863,000		3,738,000
Liabilities:
Liabilities, fair value	413,000		371,000
Recurring \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Current contingent liabilities-CyDex
Liabilities:
Liabilities, fair value	0		0
Recurring \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Long-term contingent liabilities-CyDex
Liabilities:
Liabilities, fair value	0		0
Recurring \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Long-term contingent liabilities-Metabasis
Liabilities:
Liabilities, fair value	0		0
Recurring \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Liability for amounts owed to former licensees
Liabilities:
Liabilities, fair value	413,000		371,000
Recurring \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Short-term investments
Assets:
Assets, fair value	2,753,000		3,054,000
Recurring \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Note receivable Viking Therapeutics, Inc.
Assets:
Assets, fair value	0		0
Recurring \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Investment in warrants
Assets:
Assets, fair value	1,100,000		700,000
Recurring \| Significant Other Observable Inputs (Level 2)
Assets:
Assets, fair value	166,767,000		119,242,000
Liabilities:
Liabilities, fair value	3,693,000		1,413,000
Recurring \| Significant Other Observable Inputs (Level 2) \| Current contingent liabilities-CyDex
Liabilities:
Liabilities, fair value	0		0
Recurring \| Significant Other Observable Inputs (Level 2) \| Long-term contingent liabilities-CyDex
Liabilities:
Liabilities, fair value	0		0
Recurring \| Significant Other Observable Inputs (Level 2) \| Long-term contingent liabilities-Metabasis
Liabilities:
Liabilities, fair value	3,693,000		1,413,000
Recurring \| Significant Other Observable Inputs (Level 2) \| Liability for amounts owed to former licensees
Liabilities:
Liabilities, fair value	0		0
Recurring \| Significant Other Observable Inputs (Level 2) \| Short-term investments
Assets:
Assets, fair value	166,767,000		119,242,000
Recurring \| Significant Other Observable Inputs (Level 2) \| Note receivable Viking Therapeutics, Inc.
Assets:
Assets, fair value	0		0
Recurring \| Significant Other Observable Inputs (Level 2) \| Investment in warrants
Assets:
Assets, fair value	0		0
Recurring \| Significant Unobservable Inputs (Level 3)
Assets:
Assets, fair value	3,007,000		3,207,000
Liabilities:
Liabilities, fair value	1,589,000		1,604,000
Recurring \| Significant Unobservable Inputs (Level 3) \| Current contingent liabilities-CyDex
Liabilities:
Liabilities, fair value	86,000		101,000
Recurring \| Significant Unobservable Inputs (Level 3) \| Long-term contingent liabilities-CyDex
Liabilities:
Liabilities, fair value	1,503,000		1,503,000
Recurring \| Significant Unobservable Inputs (Level 3) \| Long-term contingent liabilities-Metabasis
Liabilities:
Liabilities, fair value	0		0
Recurring \| Significant Unobservable Inputs (Level 3) \| Liability for amounts owed to former licensees
Liabilities:
Liabilities, fair value	0		0
Recurring \| Significant Unobservable Inputs (Level 3) \| Short-term investments
Assets:
Assets, fair value	0		0
Recurring \| Significant Unobservable Inputs (Level 3) \| Note receivable Viking Therapeutics, Inc.
Assets:
Assets, fair value	3,000,000		3,207,000
Recurring \| Significant Unobservable Inputs (Level 3) \| Investment in warrants
Assets:
Assets, fair value	$ 0		$ 0