DESCRIPTION OF BUSINESS AND SIGNIFICANT ACCOUNTING POLICIES (Details 2) (USD $) Share data in Thousands, except Per Share data, unless otherwise specified	0 Months Ended		1 Months Ended	3 Months Ended		4 Months Ended		6 Months Ended		12 Months Ended
	Jun. 27, 2013 Country	Jun. 25, 2013	Jul. 31, 2013	Jun. 30, 2013 Tranche	May 31, 2012	Dec. 31, 2012		Jun. 30, 2013 Tranche	May 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		7 years
Number of EU member countries covered by marketing authorization for drug	28
Basis of Presentation [Abstract]
Accumulated losses				$ 175,986,000		$ 135,938,000	[1]	$ 175,986,000
Cash and cash equivalents				74,568,000	17,761,000	36,313,000	[1]	74,568,000	17,761,000			24,732,000
Net cash proceeds received from sales of common stock under ATM offering			11,200,000					23,261,000	352,000
Inventories and Cost of Sales [Abstract]
Inventories				225,000		0	[1]	225,000
Cost of sales				425,000
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	[1]	0
Liabilities
Fair value of common stock warrants				13,500,000	19,100,000			13,500,000	19,100,000
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)								10,549	11,283
Net loss per share, basic and diluted (in dollars per share)				$ (0.43)	$ (0.06)			$ (0.73)	$ (0.35)
Fair value assumptions used based on Black-Scholes option-pricing model [Abstract]
Risk-free interest rate (in hundredths)								0.92%
Expected life								5 years
Volatility (in hundredths)								78.00%
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)								2,213	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)								8,336	6,095
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				69,142,000		35,069,000		69,142,000
Restricted cash				213,000		163,000		213,000
Short-term investments						22,096,000
Total				69,355,000		57,328,000		69,355,000
Liabilities
Fair value of common stock warrants				13,468,000		16,405,000		13,468,000
Total				13,468,000		16,405,000		13,468,000
Recurring [Member] | Level 1 [Member]
Assets
Fair value of cash equivalents				69,142,000		35,069,000		69,142,000
Restricted cash				0		0		0
Short-term investments						22,096,000
Total				69,142,000		57,165,000		69,142,000
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				213,000		163,000		213,000
Short-term investments						0
Total				213,000		163,000		213,000
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				13,468,000		16,405,000		13,468,000
Total				$ 13,468,000		$ 16,405,000		$ 13,468,000

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