Condensed Consolidated Statements of Comprehensive Income (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Condensed Consolidated Statements of Comprehensive Income
Net income	$ 4,176	$ (12,180)	$ 8,713	$ 53,091
Other comprehensive loss, net of tax:
Foreign currency translation adjustment during the period	619	(608)	(81)	(999)
Change in fair value of corporate debt securities
Unrealized holding losses on corporate debt securities arising during the period				(98)
Less: Reclassification adjustments for gains included in net income		(1,296)		(1,296)
Change in fair value of corporate debt securities, net		(1,296)		(1,394)
Other comprehensive income (loss)	619	(1,904)	(81)	(2,393)
Comprehensive income (loss)	$ 4,795	$ (14,084)	$ 8,632	$ 50,698