CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Net loss	$ (10,759)	$ (20,501)	$ (18,573)	$ (37,477)
Other comprehensive loss:
Net unrealized losses on available-for-sale securities, net of taxes	(17)	(33)	(18)	(33)
Comprehensive loss	$ (10,776)	$ (20,534)	$ (18,591)	$ (37,510)