Consolidated Statements of Comprehensive Loss (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Statement of Other Comprehensive Income [Abstract]
Net loss	$ (41,303)	$ (30,857)	$ (16,550)
Other comprehensive income (loss):
Foreign currency translation adjustments	0	165	(3)
Reclassification of other-than-temporary loss in marketable securities included in net loss	0	753	0
Unrealized gain (loss) on marketable securities, net of tax	104	(647)	(370)
Other comprehensive income (loss)	104	271	(373)
Total comprehensive loss	$ (41,199)	$ (30,586)	$ (16,923)