Condensed Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Mar. 27, 2016	Dec. 31, 2015
Current assets:
Accounts receivable allowance for doubtful accounts	$ 672	$ 672
Stockholders' equity:
Preferred stock, shares authorized (in shares)	2,000,000	2,000,000
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Common stock, par value per share (in usd per share)	$ 0.001	$ 0.001
Common stock, shares authorized (in shares)	120,000,000	120,000,000
Common stock, shares issued (in shares)	80,120,000	79,853,000
Common stock, shares outstanding (in shares)	75,647,000	75,443,000
Treasury stock, shares (in shares)	4,473,000	4,410,000