Comprehensive Loss (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013
Changes in accumulated other comprehensive income (loss) by component
Balance at the beginning of the period	$ 2,745
Other comprehensive income (loss) before reclassifications	(56)
Amounts reclassified from other comprehensive income	0
Net current-period other comprehensive income	(56)
Balance at the end of the period	2,689
Unrealized Gain (Loss) on Marketable Securities, net of tax
Changes in accumulated other comprehensive income (loss) by component
Balance at the beginning of the period	156
Other comprehensive income (loss) before reclassifications	(54)
Net current-period other comprehensive income	(54)
Balance at the end of the period	102
Foreign Currency Items
Changes in accumulated other comprehensive income (loss) by component
Balance at the beginning of the period	2,589
Other comprehensive income (loss) before reclassifications	(2)
Net current-period other comprehensive income	(2)
Balance at the end of the period	$ 2,587