Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 30, 2017	Dec. 31, 2016	Jan. 02, 2016
Net income	$ 47,092	$ 61,494	$ 29,586
Shares used in computing basic earnings per share (in shares)	42,446	41,713	42,309
Effect of dilutive securities:
Stock options and other stock-based awards (in shares)	886	663	636
Shares used in computing diluted earnings per share (in shares)	43,332	42,376	42,945
Earnings per share:
Basic (in dollars per share)	$ 1.11	$ 1.47	$ 0.70
Diluted (in dollars per share)	$ 1.09	$ 1.45	$ 0.69
Shares excluded from computation of diluted earning per share (in shares)	0	100	100
Shares issued upon conversion of principal amount
Earnings per share:
Shares excluded from computation of diluted earning per share (in shares)	0