Business Combinations and Contingent Consideration - Additional Information (Detail) (USD $) Share data in Millions, except Per Share data, unless otherwise specified	1 Months Ended	3 Months Ended	0 Months Ended
	Mar. 31, 2013	Mar. 31, 2015	Jul. 17, 2013	Sep. 05, 2012	Dec. 31, 2014
Business Acquisition [Line Items]
Milestone payments methods		If all sales and regulatory approval milestones are achieved, as summarized below: • $5.0 million upon the achievement of net sales of MARQIBO in excess of $30.0 million in any calendar year • $10.0 million upon the achievement of net sales of MARQIBO in excess of $60.0 million in any calendar year • $25.0 million upon the achievement of net sales of MARQIBO in excess of $100.0 million in any calendar year • $50.0 million upon the achievement of net sales of MARQIBO in excess of $200.0 million in any calendar year • $100.0 million upon the achievement of net sales of MARQIBO in excess of $400.0 million in any calendar year • $5.0 million upon receipt of marketing authorization from the FDA regarding Menadione Topical Lotion
License fees received	$ 3,000,000
Ligand Contingent Consideration		5,091,000			4,901,000
In-process research and development [Member]
Business Acquisition [Line Items]
Estimated cash flow period	10 years
Estimated cash flow discount rate	25.00%
Minimum [Member]
Business Acquisition [Line Items]
Royalties payout percentage on our future net sales of licensed products		20.00%
Milestone Payments [Member]
Business Acquisition [Line Items]
Milestone net sales achievement		66,000,000	5,000,000
Milestone net sales achievement			30,000,000
Ligand Contingent Consideration		6,000,000
Milestone Payment One [Member]
Business Acquisition [Line Items]
Milestone net sales achievement			10,000,000
Milestone net sales achievement			60,000,000
Milestone Payment Two [Member]
Business Acquisition [Line Items]
Milestone net sales achievement			25,000,000
Milestone net sales achievement			100,000,000
Milestone Payment Three [Member]
Business Acquisition [Line Items]
Milestone net sales achievement			50,000,000
Milestone net sales achievement			200,000,000
Milestone Payment Four [Member]
Business Acquisition [Line Items]
Milestone net sales achievement			100,000,000
Milestone net sales achievement			400,000,000
Menadione Topical Lotion [Member]
Business Acquisition [Line Items]
Milestone net sales achievement			5,000,000
Allos Therapeutics, Inc. [Member]
Business Acquisition [Line Items]
Cash consideration				205,200,000
Talon Therapeutics, Inc. [Member]
Business Acquisition [Line Items]
Additional shares business acquisition date		Jul. 17, 2013
Cash consideration			11,300,000
Shares issued in acquisition (shares)			3.0
Common stock value, per share ($ per share)			$ 8.77
Common stock value assigned			26,300,000
Estimated fair value of acquisition			6,500,000
Contingent value rights valuation description		The CVR was valued using a valuation model that probability-weights expected outcomes (ranging from 50% to 100%) and discounts those amounts to their present value, using a discount rate of 25% (these represent unobservable inputs and are therefore classified as Level 3 inputs – see Note 2 (xiii)).
Contingent value rights discount rate			25.00%
Contingent value rights future cash payments		$ 195,000,000	$ 195,000,000
Talon Therapeutics, Inc. [Member] | Minimum [Member]
Business Acquisition [Line Items]
Contingent value rights expected rate			50.00%
Talon Therapeutics, Inc. [Member] | Maximum [Member]
Business Acquisition [Line Items]
Contingent value rights expected rate			100.00%