GENZYME STRATEGIC TRANSACTION (Details) (USD $)	12 Months Ended							0 Months Ended	1 Months Ended	3 Months Ended		12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Aug. 13, 2012	Dec. 06, 2011	Nov. 10, 2010	Apr. 19, 2010	Jan. 27, 2009 CLP Agreement Genzyme Corporation	Jan. 31, 2009 CLP Agreement Genzyme Corporation	Sep. 30, 2010 CLP Agreement Genzyme Corporation	Mar. 31, 2010 CLP Agreement Genzyme Corporation	Dec. 31, 2012 CLP Agreement Genzyme Corporation	Dec. 31, 2011 CLP Agreement Genzyme Corporation	Dec. 31, 2010 CLP Agreement Genzyme Corporation
License fees
Total agreed consideration amount									$ 18,500,000
Proceeds from Genzyme Collaboration, License and Purchase Agreement			1,896,000						16,650,000	934,250	962,000
Amount subject to holdback									1,850,000
Initial collaboration period (in years)									5 years
Sale of common stock (in shares)	63,909,800	56,624,763						3,000,000
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Price at which share of common stock are sold (in dollars per share)								$ 2.00
Aggregate purchase price								6,000,000
Premium above closing price of common stock at which shares are sold (in dollars per share)								$ 0.51
Closing price of common stock (in dollars per share)	$ 10.59			$ 9.75	$ 8.00	$ 6.00	$ 4.50	$ 1.49
Aggregate premium received over the closing price of common stock								1,530,000
License fee revenue	$ 4,144,000	$ 4,143,000	$ 5,318,000									$ 4,100,000	$ 4,100,000	$ 4,000,000