NOTE PAYABLE (Details) (USD $) In Millions, unless otherwise specified	4 Months Ended
	Dec. 31, 2012
Debt Instrument [Line Items]
Unamortized debt issuance	$ 2.0
Loan Agreement with HC Royalty [Member]
Debt Instrument [Line Items]
Total amount of loan	50.0
Number of tranches in loan	2
Amount of loan per tranche	25.0
Annual fixed interest rate (in hundredths)	10.75%
Interest expense	0.1
Total payment required to terminate loan obligation immediately	97.5
Number of fiscal quarters of net revenues included in total loan payment consideration	4
Threshold net revenues during specified period included in total loan payment consideration	100
Total payment required upon net revenues exceeding threshold during specified period to terminate loan obligation immediately	90
Loan Agreement with HC Royalty [Member] | First Tranche [Member]
Debt Instrument [Line Items]
Draw down on loan	23.4
Royalty rate of first threshold of PROCYSBI and future approved product net revenues for calendar year, Percentage	6.25%
Amount of first threshold of PROCYSBI and future approved product net revenues for calendar year	25.0
Royalty rate of amount between first and second threshold of PROCYSBI and future approved product net revenues for calendar year, Percentage	3.00%
Amount of second threshold of PROCYSBI and future approved product net revenues for calendar year	50.0
Royalty rate for amount in excess of second threshold of PROCYSBI and future approved product net revenues for calendar year, Percentage	1.00%
Loan Agreement with HC Royalty [Member] | Second Tranche [Member]
Debt Instrument [Line Items]
Amount of loan to be cancelled in case of default	$ 25.0