CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (USD $) In Thousands, except Share data, unless otherwise specified	Convertible redeemable preferred stock [Member]	Common stock [Member]	Additional paid-in capital [Member]	Accumulated other comprehensive income (loss) [Member]	Accumulated deficit [Member]	Total
Balance at Dec. 31, 2008	$ 0	$ 703	$ 721,641	$ (2,296)	$ (416,391)	$ 303,657
Balance (in shares) at Dec. 31, 2008	0	70,267				70,267
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock issued upon exercise of stock options and restricted stock, net of tax withholding related to vesting of restricted stock units		7	(820)			(813)
Share-based compensation expense			11,148			11,148
Common stock issued upon exercise of stock options and restricted stock, net of tax withholding related to vesting of restricted stock units (in shares)		733				733
Income tax benefit from share-based compensation			1,409			1,409
Unrealized gain (loss) on investments, net of tax				6,063		6,063
Unrealized gain on hedging contracts, net of tax				0		0
Foreign currency translation adjustment, net of tax				284		284
Net loss					(23,909)	(23,909)
Balance at Dec. 31, 2009	0	710	733,378	4,051	(440,300)	297,839
Balance (in shares) at Dec. 31, 2009	0	71,000				71,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock issued upon exercise of stock options and restricted stock, net of tax withholding related to vesting of restricted stock units		(4)	(1,178)			(1,182)
Share-based compensation expense			9,910			9,910
Common stock issued upon exercise of stock options and restricted stock, net of tax withholding related to vesting of restricted stock units (in shares)		(422)				(422)
Income tax benefit from share-based compensation			96			96
Unrealized gain (loss) on investments, net of tax				(3,090)		(3,090)
Unrealized gain on hedging contracts, net of tax				0		0
Foreign currency translation adjustment, net of tax				415		415
Net loss					(10,233)	(10,233)
Balance at Dec. 31, 2010	0	706	742,206	1,376	(450,533)	293,755
Balance (in shares) at Dec. 31, 2010	0	70,578				70,578
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock issued upon exercise of stock options and restricted stock, net of tax withholding related to vesting of restricted stock units		(2)	(681)			(683)
Share-based compensation expense			8,771			8,771
Common stock issued upon exercise of stock options and restricted stock, net of tax withholding related to vesting of restricted stock units (in shares)		(124)				(124)
Income tax benefit from share-based compensation			36			36
Unrealized gain (loss) on investments, net of tax				211		211
Unrealized gain on hedging contracts, net of tax				826		826
Foreign currency translation adjustment, net of tax				79		79
Net loss					(28,161)	(28,161)
Balance at Dec. 31, 2011	$ 0	$ 704	$ 750,332	$ 2,492	$ (478,694)	$ 274,834
Balance (in shares) at Dec. 31, 2011	0	70,454				70,454