Consolidated statements of comprehensive income (loss) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Statement Of Income And Comprehensive Income [Abstract]
Net (loss) income	$ (5,840)	$ 272	$ (15,110)	$ (4,407)
Other comprehensive (loss) income
Unrealized (loss) gain on investments, net of taxes	(208)	638	(692)	681
Unrealized loss on currency translation		(1)	(1)	(5)
Other comprehensive (loss) income	(208)	637	(693)	676
Comprehensive (loss) income	$ (6,048)	$ 909	$ (15,803)	$ (3,731)