Marketable Securities (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 30, 2017	Dec. 31, 2016
Schedule of Available-for-sale Securities [Line Items]
Term of maturities of investments considered short-term	2 years
Total marketable securities	$ 4,982	$ 10,308
Corporate and government bonds and notes
Schedule of Available-for-sale Securities [Line Items]
Total marketable securities	4,982	10,230
Certificates of deposit
Schedule of Available-for-sale Securities [Line Items]
Total marketable securities	$ 0	$ 78