DESCRIPTION OF BUSINESS AND SIGNIFICANT ACCOUNTING POLICIES (Details) (USD $) Share data in Thousands, except Per Share data, unless otherwise specified	0 Months Ended	3 Months Ended		4 Months Ended		9 Months Ended		12 Months Ended
	Jun. 25, 2013	Sep. 30, 2013 Tranche	Aug. 31, 2012	Dec. 31, 2012		Sep. 30, 2013 Tranche	Aug. 31, 2012	Aug. 31, 2012	Apr. 30, 2013 Age	Nov. 30, 2011
DESCRIPTION OF BUSINESS AND SIGNIFICANT ACCOUNTING POLICIES [Abstract]
Minimum age of children for management of nephropathic cystinosis									6
Period of orphan drug exclusivity for PROCYSBI in U.S.	7 years
Period of orphan drug exclusivity for PROCYSBI in EU	10 years
Basis of Presentation [Abstract]
Accumulated losses		$ 193,263,000		$ 135,938,000	[1]	$ 193,263,000
Cash and cash equivalents		88,334,000	23,580,000	36,313,000	[1]	88,334,000	23,580,000	23,580,000		24,732,000
Inventories and Cost of Sales [Abstract]
Net inventories		2,218,000		0	[1]	2,218,000
Raw materials		1,800,000				1,800,000
Work-in-process		300,000				300,000
Finished goods		500,000				500,000
Reserve allowance		400,000				400,000
Cost of sales		425,000,000
Cash and Cash Equivalents [Abstract]
Maximum maturity period for investments considered as highly liquid investments						3 months
Short-term Investments [Abstract]
Short-term investments		0		22,096,000		0
Liabilities
Fair value of common stock warrants		10,300,000	17,300,000			10,300,000	17,300,000	17,300,000
Fixed Assets [Abstract]
Useful life of significant additions and improvements in fixed assets for capitalization, minimum						1 year
Note Payable and Debt Issuance Costs [Abstract]
Total amount of loan		50,000,000				50,000,000
Number of tranches in loan		2				2
Amount of loan per tranche		25,000,000				25,000,000
Annual fixed interest rate (in hundredths)		10.75%				10.75%
Income taxes [Abstract]
Effective tax rate (in hundredths)		0.00%		0.00%		0.00%		0.00%
Accrued interest or penalties related to uncertain tax positions		0				0
Unrecognized tax benefits		0				0
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total potentially dilutive securities (in shares)						9,375	11,313
Net loss per share, basic and diluted (in dollars per share)		$ (0.29)	$ (0.21)			$ (1.01)	$ (0.56)
Fair value assumptions used based on Black-Scholes option-pricing model [Abstract]
Risk-free interest rate (in hundredths)						1.51%
Expected life						5 years
Volatility (in hundredths)						67.18%
Turnover rate (in hundredths)						2.50%
Dividend rate (in hundredths)						0.00%
Period over which current constant maturity treasury bill rates were reviewed						5 years
Term of stock options issued						10 years
Warrants to Purchase Common Stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total potentially dilutive securities (in shares)						1,145	5,188
Options to Purchase Common Stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total potentially dilutive securities (in shares)						8,230	6,125
IP license for PROCYSBI RP103 [Member]
Finite-Lived Intangible Assets [Line Items]
Estimated useful life of intangible assets						20 years
Out license [Member]
Finite-Lived Intangible Assets [Line Items]
Estimated useful life of intangible assets						16 years
Recurring [Member]
Assets
Fair value of cash equivalents		71,434,000		35,069,000		71,434,000
Restricted cash		500,000		163,000		500,000
Short-term investments				22,096,000
Total		71,934,000		57,328,000		71,934,000
Liabilities
Fair value of common stock warrants		10,339,000		16,405,000		10,339,000
Total		10,339,000		16,405,000		10,339,000
Recurring [Member] | Level 1 [Member]
Assets
Fair value of cash equivalents		71,434,000		35,069,000		71,434,000
Restricted cash		0		0		0
Short-term investments				22,096,000
Total		71,434,000		57,165,000		71,434,000
Liabilities
Fair value of common stock warrants		0		0		0
Total		0		0		0
Recurring [Member] | Level 2 [Member]
Assets
Fair value of cash equivalents		0		0		0
Restricted cash		500,000		163,000		500,000
Short-term investments				0
Total		500,000		163,000		500,000
Liabilities
Fair value of common stock warrants		0		0		0
Total		0		0		0
Recurring [Member] | Level 3 [Member]
Assets
Fair value of cash equivalents		0		0		0
Restricted cash		0		0		0
Short-term investments				0
Total		0		0		0
Liabilities
Fair value of common stock warrants		10,339,000		16,405,000		10,339,000
Total		$ 10,339,000		$ 16,405,000		$ 10,339,000

[1] Derived from the Company's audited consolidated financial statements as of December 31, 2012.