Consolidated Statements of Comprehensive Loss (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Statement Of Income And Comprehensive Income [Abstract]
Net loss	$ (13,665)	$ (27,170)
Other comprehensive loss:
Change in unrealized gain on available-for-sale securities, net		(17)
Other comprehensive loss, net		(17)
Comprehensive loss	$ (13,665)	$ (27,187)