CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY AND COMPREHENSIVE INCOME (LOSS) (USD $) In Thousands, unless otherwise specified	Total	Common Stock	Common Stock Warrants	Treasury Stock	Additional Paid-in Capital	Retained Earnings	Accumulated Other Comprehensive Income (Loss)
Beginning Balance at Dec. 31, 2008	$ 213,841	$ 204	$ 24,003	$ (147,808)	$ 302,237	$ 58,468	$ (23,263)
Comprehensive income (loss) information:
Net income	19,626					19,626
Other comprehensive income (loss):
Foreign currency translation adjustments	8,398						8,398
Comprehensive income	28,024
Repurchase of common stock	(15,000)			(15,000)
Shares issued and forefeited, net, under stock plans	2,175			4,778	(2,603)
Stock-based compensation	7,645				7,645
Repurchase of restricted stock for tax withholdings	(622)			(622)
Ending Balance at Dec. 31, 2009	236,063	204	24,003	(158,652)	307,279	78,094	(14,865)
Comprehensive income (loss) information:
Net income	27,195					27,195
Other comprehensive income (loss):
Foreign currency translation adjustments	(279)						(279)
Comprehensive income	26,916
Repurchase of common stock	(18,624)			(18,624)
Shares issued and forefeited, net, under stock plans	4,040			6,162	(2,122)
Stock-based compensation	7,790				7,790
Repurchase of restricted stock for tax withholdings	(562)			(562)
Ending Balance at Dec. 31, 2010	255,623	204	24,003	(171,676)	312,947	105,289	(15,144)
Comprehensive income (loss) information:
Net income	45,852					45,852
Other comprehensive income (loss):
Unrealized gain on available-for-sale securities	594						594
Foreign currency translation adjustments	(2,711)						(2,711)
Comprehensive income	43,735
Shares issued and forefeited, net, under stock plans	7,460			9,007	(1,547)
Stock-based compensation	11,254				11,254
Repurchase of restricted stock for tax withholdings	(742)			(742)
Ending Balance at Dec. 31, 2011	$ 317,330	$ 204	$ 24,003	$ (163,411)	$ 322,654	$ 151,141	$ (17,261)