Cash equivalent maturity period highly liquid investment.

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- Definition

Change in accounting estimate decrease in revenues.

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- Definition

Change in accounting estimate, increase in income (loss) per share, basic.

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No definition available.

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- Definition

Minimum percentage of likelihood of indefinite lived intangible assets being impaired.

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No definition available.

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- Definition

Organization and summary of significant accounting policies.

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No definition available.

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- Definition

Share based compensation arrangement by share based payment award options and restricted stock units outstanding number.

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No definition available.

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- Definition

Amount of increase (decrease) in the value of a contingent consideration liability, including, but not limited to, differences arising upon settlement.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 30
-Section 50
-Paragraph 4
-Subparagraph (a)(1)
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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.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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-Name Accounting Standards Codification
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- Definition

Amount of impairment loss resulting from write-down of assets, excluding financial assets and goodwill, lacking physical substance and having a projected indefinite period of benefit to fair value.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 30
-Section 50
-Paragraph 3
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=66006027&loc=d3e16373-109275

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- Definition

Revenue from multiple-deliverable arrangements that include licensing fees and services revenue. Licensing revenue is consideration received from another party for the right to use, but not own, certain of the entity's intangible assets. Licensing arrangements include, but are not limited to, rights to use a patent, copyright, technology, manufacturing process, software or trademark. Licensing fees are generally, but not always, fixed as to amount and not dependent upon the revenue generated by the licensing party. An entity may receive licensing fees for licenses that also generate royalty payments to the entity. Services revenue may be derived by providing other, nonspecified, services during the reporting period.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 225
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.1(d),(e))
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- Definition

Amount of cumulative effect of the change in accounting principle or new accounting pronouncement on retained earnings or other components of equity or net assets in the statement of financial position as of the beginning of the earliest period presented.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 250
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=64853466&loc=d3e22580-107794

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-Name Accounting Standards Codification
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-SubTopic 10
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-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (b)(3)
-URI http://asc.fasb.org/extlink&oid=64853466&loc=d3e22499-107794

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- Definition

Number of operating segments. An operating segment is a component of an enterprise: (a) that engages in business activities from which it may earn revenues and incur expenses (including revenues and expenses relating to transactions with other components of the same enterprise), (b) whose operating results are regularly reviewed by the enterprise's chief operating decision maker to make decisions about resources to be allocated to the segment and assess its performance, and (c) for which discrete financial information is available. An operating segment may engage in business activities for which it has yet to earn revenues, for example, start-up operations may be operating segments before earning revenues.

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- Definition

Useful life of long lived, physical assets used in the normal conduct of business and not intended for resale, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Examples include, but not limited to, land, buildings, machinery and equipment, office equipment, furniture and fixtures, and computer equipment.

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- Definition

The amount of compensation earned (contract income) under a research and development arrangement accounted for as a contract to perform research and development for others.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 730
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (b)
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-SubTopic 20
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=6420387&loc=d3e23221-108380

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Organization and Summary of Significant Accounting Policies - Additional Information (Detail) $ / shares in Units, $ in Thousands		1 Months Ended		12 Months Ended
	May 10, 2017 USD ($)	Jan. 31, 2014 USD ($)	Jan. 31, 2012 USD ($)	Dec. 31, 2017 USD ($) Segments shares	Dec. 31, 2016 USD ($) $ / shares shares	Dec. 31, 2015 USD ($) shares
Organization and Summary of Significant Accounting Policies [Line Items]
Liquid investments purchased with original maturities				three months or less
Percentage of likelihood of indefinite lived intangible assets being impaired				50.00%
Impairment charge						$ 1,870
Change in fair value of contingent liability						$ (1,800)
Stock options and restricted stock units outstanding \| shares				8,367,628	9,578,322	9,008,185
Number of operating segments \| Segments				1
Bioverativ Inc [Member]
Organization and Summary of Significant Accounting Policies [Line Items]
Revenue recognized				$ 1,769	$ 2,321	$ 6,176
Up-front payment received from agreement		$ 20,000
Bioverativ Inc [Member] \| Customer Concentration Risk [Member] \| Total revenues [Member]
Organization and Summary of Significant Accounting Policies [Line Items]
Percentage of revenues				34.00%	46.00%
Bioverativ Inc [Member] \| Collaboration Contract Performance Period
Organization and Summary of Significant Accounting Policies [Line Items]
Increase in basic net loss per share \| $ / shares					$ 0.06
Decrease in revenues				$ 4,300	$ 4,300
Pfizer [Member]
Organization and Summary of Significant Accounting Policies [Line Items]
Revenue recognized				17,000
Up-front payment received from agreement	$ 70,000
Pfizer [Member] \| ASU No. 2014-09 [Member]
Organization and Summary of Significant Accounting Policies [Line Items]
Revenue recognized				$ 17,000
Up-front payment received from agreement	$ 70,000
Pfizer [Member] \| Customer Concentration Risk [Member] \| Total revenues [Member]
Organization and Summary of Significant Accounting Policies [Line Items]
Percentage of revenues				47.00%
Dow Agro Sciences [Member] \| Customer Concentration Risk [Member] \| Total revenues [Member]
Organization and Summary of Significant Accounting Policies [Line Items]
Percentage of revenues					26.00%
Shire AG [Member]
Organization and Summary of Significant Accounting Policies [Line Items]
Revenue recognized				$ 2,333	$ 2,181	$ 2,167
Up-front payment received from agreement			$ 13,000
Shire AG [Member] \| Customer Concentration Risk [Member] \| Total revenues [Member]
Organization and Summary of Significant Accounting Policies [Line Items]
Percentage of revenues					17.00%	40.00%
Biogen Inc [Member] \| Customer Concentration Risk [Member] \| Total revenues [Member]
Organization and Summary of Significant Accounting Policies [Line Items]
Percentage of revenues						35.00%
Minimum [Member]
Organization and Summary of Significant Accounting Policies [Line Items]
Estimated useful lives of related assets				3 years
Maximum [Member]
Organization and Summary of Significant Accounting Policies [Line Items]
Estimated useful lives of related assets				5 years
Maximum [Member] \| ASU No. 2014-09 [Member] \| Pro Forma [Member]
Organization and Summary of Significant Accounting Policies [Line Items]
Estimated impact of the adoption of standard				$ 5,000