CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (USD $) In Thousands, except Share data, unless otherwise specified	Total	Common stock	Treasury stock	Additional Paid In Capital	Accumulated Deficit	Accumulated Other Comprehensive Income (Loss)
Balance at Dec. 31, 2008	$ 233,557	$ 35	$ (65,064)	$ 315,953	$ (17,367)
Balance (in shares) at Dec. 31, 2008		35,422,678	(4,078,451)
Increase (Decrease) in Stockholders' Equity
Net income	444				444
Share-based compensation	9,725			9,725
Common stock issued under stock option and stock award plans	1,113			1,113
Common stock issued under stock option and stock award plans (in shares)		257,939	(16,855)
Issuance of stock under employee stock purchase plan	2,929	1		2,928
Issuance of stock under employee stock purchase plan (in shares)		392,159
Income tax benefits (charges) realized from employee stock plans	(5,464)			(5,464)
Balance at Dec. 31, 2009	242,304	36	(65,064)	324,255	(16,923)
Balance (in shares) at Dec. 31, 2009		36,072,776	(4,095,306)
Increase (Decrease) in Stockholders' Equity
Net income	4,892				4,892
Share-based compensation	9,015			9,015
Common stock issued under stock option and stock award plans	3,638	1		3,637
Common stock issued under stock option and stock award plans (in shares)		624,916	(25,817)
Issuance of stock under employee stock purchase plan	3,364			3,364
Issuance of stock under employee stock purchase plan (in shares)		451,014
Income tax benefits (charges) realized from employee stock plans	2,001			2,001
Balance at Dec. 31, 2010	265,214	37	(65,064)	342,272	(12,031)
Balance (in shares) at Dec. 31, 2010	33,027,583	37,148,706	(4,121,123)
Increase (Decrease) in Stockholders' Equity
Net income	10,389				10,389
Other comprehensive income	1					1
Share repurchases	(12,573)		(12,573)
Share repurchases (in shares)			(889,511)
Share-based compensation	9,499			9,499
Common stock issued under stock option and stock award plans	2,737	1		2,736
Common stock issued under stock option and stock award plans (in shares)		641,074	(43,174)
Issuance of stock under employee stock purchase plan	4,050			4,050
Issuance of stock under employee stock purchase plan (in shares)		445,965
Income tax benefits (charges) realized from employee stock plans	3,597			3,597
Balance at Dec. 31, 2011	$ 282,914	$ 38	$ (77,637)	$ 362,154	$ (1,642)	$ 1
Balance (in shares) at Dec. 31, 2011	33,181,937	38,235,745	(5,053,808)