13. QUARTERLY FINANCIAL INFORMATION (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended														6 Months Ended		12 Months Ended				172 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2010	Sep. 30, 2010	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2013	Dec. 31, 2012	Jun. 30, 2012	Jun. 30, 2011	Dec. 31, 2013
Quarterly Financial Information Disclosure [Abstract]
Total revenue	$ 0	$ 0	$ 0	$ 0	$ 0	$ 0	$ 0	$ 0	$ 0	$ 0	$ 0	$ 0	$ 0	$ 0
Net loss	$ (5,739)	$ (6,855)	$ (5,257)	$ (4,395)	$ (9,572)	$ (5,858)	$ (8,616)	$ (5,317)	$ (10,127)	$ (10,934)	$ (7,148)	$ (1,633)	$ (2,571)	$ (5,305)	$ (15,430)	$ (21,061)	$ (22,246)	$ (29,362)	$ (34,994)	$ (16,657)	$ (99,441)
Basic and diluted loss per share	$ (0.12)	$ (0.15)	$ (0.12)	$ (0.10)	$ (0.22)	$ (0.13)	$ (0.19)	$ (0.12)	$ (0.23)	$ (0.25)	$ (0.16)	$ (0.04)	$ (0.07)	$ (0.16)	$ (0.35)	$ (0.48)	$ (0.48)	$ (0.66)	$ (0.79)	$ (0.43)