Condensed Consolidated Balance Sheets (Unaudited ) (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012
Allowances, accounts receivable	$ 1,052	$ 1,177
Common stock, par value (usd per share)	$ 0.00001	$ 0.00001
Common stock, shares authorized	100,000,000	100,000,000
Common stock, shares issued	41,739,000	40,856,000
Common stock, shares outstanding	41,739,000	40,856,000
Preferred stock, par value (usd per share)	$ 0.00001	$ 0.00001
Preferred stock, shares authorized	10,000,000	10,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0