Balance Sheet Account Detail - Schedule of Goodwill (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended	12 Months Ended
Mar. 31, 2015	Dec. 31, 2014
Goodwill [Line Items]
Foreign currency exchange translation effects	$ (448)us-gaap_GoodwillTranslationAdjustments	$ (202)us-gaap_GoodwillTranslationAdjustments
Goodwill	17,949us-gaap_Goodwill	18,195us-gaap_Goodwill
ZEVALIN Ex-U.S. Distribution Rights [Member]
Goodwill [Line Items]
Acquisition	2,525	2,525
Allos Therapeutics, Inc. [Member]
Goodwill [Line Items]
Acquisition	5,346	5,346
Talon [Member]
Goodwill [Line Items]
Acquisition	$ 10,526	$ 10,526

Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

-SubTopic 20

-Section 50

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=35741047&loc=d3e13816-109267

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

-Publisher FASB

-Name Accounting Standards Codification

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Amount of increase in asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized resulting from a business combination.

+ References

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

-Publisher FASB

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Amount of increase (decrease) from foreign currency translation adjustments of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

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