Commitments and Contingencies - Additional Information (Detail)	1 Months Ended	6 Months Ended		1 Months Ended		6 Months Ended	1 Months Ended	6 Months Ended		1 Months Ended	6 Months Ended	1 Months Ended	6 Months Ended		12 Months Ended		1 Months Ended		12 Months Ended	1 Months Ended	3 Months Ended	6 Months Ended		1 Months Ended
	May 31, 2006 USD ($)	Jun. 30, 2013 USD ($)	Jun. 30, 2013 FOLOTYN [Member] USD ($)	Apr. 30, 2012 ZEVALIN [Member] Licensing Agreements [Member] USD ($)	Apr. 30, 2012 ZEVALIN [Member] Licensing Agreements [Member] EUR (€)	Jun. 30, 2013 ZEVALIN [Member] Licensing Agreements [Member] Country	Sep. 30, 2011 FUSILEV [Member] USD ($)	Jun. 30, 2013 Minimum [Member]	Jun. 30, 2013 Minimum [Member] FOLOTYN [Member] USD ($)	May 31, 2011 Minimum [Member] FUSILEV [Member] USD ($)	Jun. 30, 2013 Maximum [Member] FOLOTYN [Member] USD ($)	Sep. 30, 2011 Maximum [Member] FUSILEV [Member] USD ($)	Jun. 30, 2013 Henderson [Member]	Jun. 30, 2013 Irvine [Member]	Dec. 31, 2010 Irvine [Member] USD ($)	Dec. 31, 2009 Irvine [Member] USD ($)	May 31, 2011 Targent, Inc [Member] USD ($)	Apr. 30, 2011 Targent, Inc [Member]	Dec. 31, 2011 Targent, Inc [Member] USD ($)	Oct. 31, 2008 Allergan [Member] USD ($)	Mar. 31, 2013 Allergan [Member] USD ($)	Jun. 30, 2013 Allergan [Member] USD ($)	Jun. 30, 2013 Nippon Kayaku [Member] USD ($)	Feb. 28, 2010 TopoTarget [Member] USD ($)
Long-term Purchase Commitment [Line Items]
Non cancelable operating lease expiring													Apr. 30, 2014	Jun. 30, 2016
Cost of tenant improvements, agreed																$ 1,500,000
Cost of tenant improvements, required															1,400,000
Cost of tenant improvements, financed															451,000
Payment obligations including commercial milestone to Corixa Corporation		5,000,000
Additional amount paid by RIT to Biogen		5,500,000
Additional milestone payment upon the achievement of an additional FDA approval milestone		10,000,000
Fees paid to Bayer for acquiring licensing rights				25,400,000	19,000,000
Minimum number of countries outside U.S. approved ZEVALIN for treatment						40
Payment to Merck & Cie for the achievement of FDA approval of FUSILEV	100,000
Amount receivable on approval of oral form of FUSILEV	200,000
Shares of common stock, issued																		733,715
Capitalization associated with milestone as intangible assets							10,000,000												6,300,000
Estimated useful life, amortized							8 years 7 months 6 days												8 years 8 months 12 days
First sales milestone										40,000,000
Common stock issued, shares																	577,367
Stock issued for the achievement of first sales milestone																	5,000,000
Second and final sales milestone												100,000,000
Cash paid for sales milestone achieved							5,000,000
Aggregate amount received from first sales milestone							10,000,000
Percentage of royalty on annual worldwide sales under condition one			8.00%
Percentage of royalty on annual worldwide sales under condition two			9.00%
Percentage of royalty on annual worldwide sales under condition three			11.00%
Amount of annual worldwide sales on which royalty is payable under condition one											150,000,000
Amount of annual worldwide sales on which royalty is payable under condition two									150,000,000		300,000,000
Amount of annual worldwide sales on which royalty is payable under condition three									300,000,000
Percentage of royalties on net distributor sales			8.00%
Accrued royalties			1,200,000
Up-front non-refundable payment																				41,500,000
Additional payments based on the achievement of certain development																				245,000,000				313,000,000
Payment related to agreement																				57,500,000			10,000,000
Amount achieved following completion of enrollment in clinical trials																				1,500,000
Deferred revenue																					8,300,000	8,300,000
Upfront fee																							15,000,000
Payment on achievement of commercialization milestones																							126,000,000
Percentage of development cost																								70.00%
Percentage of development cost that is funded by TopoTarget for joint development plan																								30.00%
Percentage of required payment to be paid for the cost incurred																								50.00%
Upfront fee																								$ 30,000,000
Shares of common stock, issued																								1,000,000
Notice period for termination of agreement		180 days
Minimum days required to cancel employment agreement								90 days