Condensed Conslidated Statements of Comprehensive Income (Loss) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Statement of Comprehensive Income [Abstract]
Net loss	$ (6,576)	$ (7,796)
Unrealized gains (losses) on securities:
Unrealized holding (losses) gains arising during period	(14)	9
Reclassification for recognized gain (loss) on marketable investment securities during the period	7	0
Net unrealized (loss) gain on marketable investment securities	(7)	9
Foreign currency translation (loss) gain	(2)	2
Other comprehensive income	(9)	11
Comprehensive loss	$ (6,585)	$ (7,785)