Condensed Consolidated Balance Sheets (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	Mar. 30, 2014	Dec. 31, 2013
Current assets
Accounts receivable allowance for doubtful accounts	$ 709	$ 704
Stockholders' equity:
Preferred stock, shares authorized	2,000,000	2,000,000
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	120,000,000	120,000,000
Common stock, shares issued	77,618,000	63,384,000
Common stock, shares outstanding	73,437,000	58,727,000
Treasury stock, shares	4,181,000	4,181,000