Interim Financial Statements (Details) (USD $)	1 Months Ended	3 Months Ended		9 Months Ended
	Jul. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012	Dec. 31, 2011
Relistor [Abstract]
Number of countries approved sale of Relistor		50		50
Eligible to receive
License fee receivable on U.S. Marketing approval for subcutaneous Relistor, maximum		$ 40,000,000		$ 40,000,000
License fee receivable on U.S. Marketing approval for oral formulation of Relistor, maximum		50,000,000		50,000,000
Payment receivable on achievement of specified U.S. sales targets		200,000,000		200,000,000
Percentage of royalties, minimum (in hundredths)		15.00%		15.00%
Percentage of royalties, maximum (in hundredths)		19.00%		19.00%
Percentage of upfront, milestone, reimbursement or other revenue (in hundredths)		60.00%		60.00%
Annual U.S. sales, minimum				100,000,000
Public Offering [Abstract]
Proceeds	5,200,000		34,800,000	40,079,000
Public Offering shares issued	1,300,000		8,500,000
Common stock offering price			$ 4.40
Funding and Financial Matters [Abstract]
Cash and cash equivalents at end of period		75,597,000	79,221,000	75,597,000	41,096,000	58,838,000	70,105,000
Increase in cash and cash equivalents		(3,600,000)		16,759,000	(29,009,000)
Minimum number of years cash will fund operations (in years)				1 year
Cash		5,242,000		5,242,000
Money market funds		$ 70,355,000		$ 70,355,000