Collaboration and Financing Agreements - Additional Information (Detail) (USD $)	0 Months Ended	1 Months Ended			3 Months Ended	0 Months Ended	3 Months Ended					3 Months Ended			0 Months Ended	3 Months Ended	0 Months Ended	3 Months Ended	0 Months Ended	3 Months Ended	0 Months Ended		3 Months Ended		0 Months Ended	3 Months Ended
	Jul. 18, 2011	Jul. 18, 2011	Mar. 31, 2014	Dec. 31, 2013	Mar. 31, 2014 Embedded Derivative Liabilities [Member]	Jul. 18, 2011 Healthcare Royalty Financing Agreement [Member]	Mar. 31, 2014 Healthcare Royalty Financing Agreement [Member]	Mar. 31, 2014 Healthcare Royalty Financing Agreement [Member] Embedded Derivative Liabilities [Member]	Mar. 31, 2013 Healthcare Royalty Financing Agreement [Member] Embedded Derivative Liabilities [Member]	Dec. 31, 2013 Healthcare Royalty Financing Agreement [Member] Embedded Derivative Liabilities [Member]	Jul. 18, 2011 Healthcare Royalty Financing Agreement [Member] Embedded Derivative Liabilities [Member]	Mar. 31, 2014 Healthcare Royalty Financing Agreement [Member] Common Stock Warrant Liabilities [Member]	Mar. 31, 2013 Healthcare Royalty Financing Agreement [Member] Common Stock Warrant Liabilities [Member]	Jul. 18, 2011 Healthcare Royalty Financing Agreement [Member] Common Stock Warrant Liabilities [Member]	Jul. 18, 2011 Healthcare Royalty Financing Agreement [Member] Scenario 1 [Member]	Mar. 31, 2014 Healthcare Royalty Financing Agreement [Member] Scenario 1 [Member]	Jul. 18, 2011 Healthcare Royalty Financing Agreement [Member] Scenario 2 [Member]	Mar. 31, 2014 Healthcare Royalty Financing Agreement [Member] Scenario 2 [Member]	Jul. 18, 2011 Healthcare Royalty Financing Agreement [Member] Scenario 3 [Member]	Mar. 31, 2014 Healthcare Royalty Financing Agreement [Member] Scenario 3 [Member]	Jul. 18, 2011 Minimum [Member] Healthcare Royalty Financing Agreement [Member] Scenario 1 [Member]	Jul. 18, 2011 Maximum [Member] Healthcare Royalty Financing Agreement [Member] Scenario 1 [Member]	Mar. 31, 2014 Mallinckrodt LLC Co-Promotion Agreement [Member]	Mar. 31, 2013 Mallinckrodt LLC Co-Promotion Agreement [Member]	Jun. 27, 2013 Valeant Pharmaceuticals North America LLC Co-Promotion Agreement [Member]	Mar. 31, 2014 Valeant Pharmaceuticals North America LLC Co-Promotion Agreement [Member]	Mar. 31, 2014 Astellas Pharma Us Inc Co Promotion Agreement [Member]	Mar. 31, 2013 Astellas Pharma Us Inc Co Promotion Agreement [Member]	Jul. 31, 2013 Astellas Pharma Us Inc Co Promotion Agreement [Member]
Debt Instrument [Line Items]
Co-promotion agreement termination notice period																									6 months
Agreement Termination Notice Period Net Sales Contingent																									30 days
Agreement Termination Notice Period Change of Control Contingent																									90 days
Sales Revenue, Services, Net																										$ 866,000
Incurred Service Fee Expenses																							100,000	143,000
Tail payment liability related interest expense																											43,000	141,000
Tail payment liability																							559,000				1,174,000		2,032,000
CoPromotion Agreement Additional Term Increments																									12 months
Debt instrument, outstanding						30,000,000
Common stock issued and sold to Healthcare Royalty, amount			140,000	139,000		1,500,000
Common stock issued and sold to Healthcare Royalty, shares			139,539,000	100,809,000		388,601
Common stock issued and sold to Healthcare Royalty, price per share						$ 3.86
Warrant exercisable to Healthcare Royalty, shares	225,000	225,000
Warrant exercisable to Healthcare Royalty, price per share (usd per share)	$ 9.00						$ 9.00
Term of warrant exercisable							10 years
Revenue Interest Rate						0.50%									5.00%		2.50%		0.50%		5.00%	5.75%
Net product sales amount received							10,000,000									75,000,000		75,000,000		150,000,000
Fixed Debt Repayment Dates							January 31, 2015, January 31, 2016 and January 31, 2017
Fixed Payments for Jan 31,2015							10,000,000
Fixed Payments for Jan 31,2016							10,000,000
Fixed Payments for Jan 31,2017							10,000,000
Agreement termination date							Mar. 31, 2018
Intercreditor loan			25,000,000
Terminate payment base amount							75,000,000									52,500,000		45,000,000
Borrowed internal rate of return																19.00%		17.00%
Fair value of embedded derivatives								247,000		233,000
Aggregate net proceed from financing agreement						29,485,000
Financing discounts						476,000					605,000			790,000
Change in fair value					$ 14,000			$ (14,000)	$ (81,000)			$ 122,000	$ (76,000)