Consolidated Statements of Comprehensive Income (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Consolidated Statements of Comprehensive Income [Abstract]
Net income (loss)	$ (5,538)	$ 38,059	$ 29,111
Other comprehensive income (loss):
Unrealized gain (loss) on investments, net of taxes	505	(42)	(9)
Unrealized gain (loss) on currency translation	(8)	2	9
Other comprehensive income (loss)	497	(40)
Comprehensive income (loss)	$ (5,041)	$ 38,019	$ 29,111