Other Income (Expense), Net (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Summary of other income, net
Interest income	$ 470	$ 202
Net gain (loss) on foreign exchange and foreign currency derivative contracts	(933)	22
Net realized gain on sales of short-term investments	3	0
Other non-operating income, net	152	0
Total other income (expense), net	$ (308)	$ 224