Significant Accounting Policies (Details Textual) (USD $) In Thousands, unless otherwise specified	3 Months Ended				6 Months Ended			6 Months Ended
	Jun. 30, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013 Money Market Funds [Member]	Jun. 30, 2013 Maximum [Member]	Jun. 30, 2013 Minimum [Member]	Mar. 09, 2011 JPR Royalty Sub LLC [Member]	Jun. 30, 2013 Shionogi (Japan) [Member] Royalty Receivable [Member]
Significant Accounting Policies (Textual) [Abstract]
Proceeds from non-recourse notes										$ 30,000
Restricted cash	2,129	308			2,129		150				1,979
Maturity of investments								3 months
Maturity period for high-quality marketable securities								3 years
Average portfolio maturity period for high-quality marketable securities								18 months
Maturity period of investments								12 months	3 months
Unrealized gain (loss) on marketable securities available-for-sale	(9)			(9)	(21)
Royalty receipts paid	110				2,034
Average maturity for portfolio investments								18 months
Royalty payment remittance period					2 months
Significant Accounting Policies (Additional Textual) [Abstract]
Cash and Investments	31,254				31,254
Expected net proceeds from common stock					18,500
Expenses reclassified from general and administrative expense to research and development expense				84
Accrued expenses	1,757	6,573			1,757
Accumulated Other comprehensive income loss reclassification					0	0
Royalty payments received			2,848		2,034
Interest expenses	1,165			1,160	2,345	2,320
Amortization of deferred financing costs	110
Cumulative mark-to-market adjustments - gain	1,114			(997)	3,071	(959)
Hedge collateral under the agreement	2,400	5,180			2,400
General and administrative expense, restructuring charges		1,759
Antidilutive effect of shares issued under employee Stock Purchase Plan	978			1,093	852	1,137
Amortization of deferred financing costs	$ 110			$ 110	$ 220	$ 220