STATEMENTS OF COMPREHENSIVE LOSS (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
STATEMENTS OF COMPREHENSIVE LOSS [Abstract]
Net loss	$ (17,864)	$ (12,633)	$ (31,674)	$ (22,630)
Other comprehensive income (loss):
Net unrealized gains (losses) on investments available-for-sale	27	168	(1)	207
Reclassification adjustment for gains included in net loss			(615)
Foreign currency translation adjustment	(1,410)		(1,543)
Other comprehensive income (loss)	(1,383)	168	(2,159)	207
Comprehensive loss	$ (19,247)	$ (12,465)	$ (33,833)	$ (22,423)