CONDENSED CONSOLIDATED BALANCE SHEETS (Unaudited) (Parenthetical) (USD $) Share data in Thousands, except Per Share data, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Current assets:
Accounts receivable, allowances for doubtful accounts	$ 270,000	$ 245,000
Stockholders' equity:
Preferred stock, par value (in dollars per share)	$ 0.001	$ 0.001
Preferred stock, shares authorized (in shares)	2,000	2,000
Preferred stock, shares issued (in shares)	883	883
Preferred stock, shares outstanding (in shares)	883	883
Preferred stock, liquidation preference	$ 6,000,000	$ 5,900,000
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized (in shares)	70,000	70,000
Common stock, shares issued (in shares)	32,654	32,471
Common stock, shares outstanding (in shares)	32,654	32,471