Liquidity and Management's Plans - Additional Information (Detail) (USD $)	0 Months Ended		12 Months Ended				0 Months Ended			1 Months Ended		12 Months Ended		1 Months Ended
	Nov. 30, 2013	Jul. 05, 2013	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Nov. 30, 2013 Maximum [Member]	Feb. 07, 2014 Subsequent Event [Member]	Jan. 31, 2014 Subsequent Event [Member]	Feb. 28, 2014 Subsequent Event [Member]	Jan. 31, 2014 Subsequent Event [Member]	Dec. 31, 2013 Subsequent Event [Member]	Jan. 23, 2014 Subsequent Event [Member]	Feb. 28, 2014 Subsequent Event [Member] Equity Option [Member]	Jan. 31, 2014 Subsequent Event [Member] Equity Option [Member]	Nov. 30, 2012 Series A Non-Voting Convertible Preferred Stock [Member]
Liquidity and Management's Plans [Line Items]
Net proceeds from secured loan facility from Midcap			$ 19,800,000
Research and development reimbursements under the Endo agreements			2,782,830
Net royalties under the Meda agreements			1,773,215	1,082,742	2,716,452
Contract revenue from licensing and supply agreement			300,000		300,000
Exercise of Common Stock options			357,281	2,054,100	349,676									2,200,000	2,200,000
Upfront and milestone payments from Endo license agreement				45,000,000
Preferred Stock, par value			$ 0.001	$ 0.001												$ 0.001
Net proceeds from registered direct offering of Common stock and newly designated series				38,400,000					4,000,000
Deferred contract revenue				17,500,000
Exercise of Common Stock warrants			50,000	921,019	1,749,259					2,600,000	2,600,000	50,000
Net proceeds from a private placement offering of Common Stock in March 2011					14,000,000
Research revenues from various contractor agreements				13,375	227,668
Secured loan facility		20,000,000
Net proceeds in the aggregate amount		19,800,000
Company's securities for shelf registration							75,000,000
Common Stock, shares issued			38,204,384	37,497,703				7,500,000	658,489		658,489
Universal shelf registration common stock potential value for utilization at market offering programme	15,000,000
Milestone payment from Endo										10,000,000			10,000,000
Common stock exercised									515,000	515,000	515,000	10,000
Stock options exercised			357,281	2,054,100	349,676									700,000	700,000
Common Stock, shares par value			$ 0.001	$ 0.001	$ 2.91			$ 0.001
Number of common stock shares sold								$ 8.00
Proceeds from sale of common stock								60,000,000
Closing price of the Common Stock, percentage								3.10%
Cash and cash equivalents			23,175,809	63,189,307	10,750,205	18,208,659
Cash from operations			(60,102,816)	12,187,324	(23,274,994)
Stockholders' equity			$ (812,351)	$ 49,777,213	$ 4,120,393	$ 9,786,330