Net (Loss) Income Per Share (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Numerator:
Continuing operations	$ (4,155)	$ 7,197	$ 7,902	$ 14,514
Discontinued operation	110	245	88	222
Net (loss) income	$ (4,045)	$ 7,442	$ 7,990	$ 14,736
Denominator:
Denominator for basic net (loss) income per share-weighted average shares outstanding	51,639,000	50,754,000	51,101,000	50,887,000
Dilutive common equivalent shares:
Employee stock options and other (in shares)		2,223,000	1,142,000	2,230,000
Denominator for diluted net (loss) income per share-weighted average shares outstanding, assuming exercise of potential dilutive common equivalent shares	51,639,000	52,977,000	52,243,000	53,117,000
Basic net income per share:
Continuing operations (in dollars per share)	$ (0.08)	$ 0.14	$ 0.15	$ 0.29
Discontinued operation (in dollars per share)	$ 0.00	$ 0.00	$ 0.00	$ 0.00
Total operations (in dollars per share)	$ (0.08)	$ 0.15	$ 0.16	$ 0.29
Diluted net income per share:
Continuing operations (in dollars per share)	$ (0.08)	$ 0.14	$ 0.15	$ 0.27
Discontinued operation (in dollars per share)	$ 0.00	$ 0.00	$ 0.00	$ 0.00
Total operations (in dollars per share)	$ (0.08)	$ 0.14	$ 0.15	$ 0.28
Antidilutive securities excluded from computation of earnings per share (in shares)	7,800,000	2,600,000	4,600,000	2,300,000