Consolidated Balance Sheets (Parenthetical) (USD $) In Thousands, except Per Share data, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
Current assets:
Accounts receivable allowance for doubtful accounts	$ 684	$ 681
Stockholders' equity:
Preferred stock, shares authorized	2,000	2,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value per share	$ 0.001	$ 0.001
Common stock, shares authorized	120,000	120,000
Common stock, shares issued	62,547	54,440
Common stock, shares outstanding	58,366	50,259
Treasury stock, shares	4,181	4,181