Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended
	Apr. 01, 2017	Apr. 02, 2016
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ (2,237)	$ 2,971
Other comprehensive income (loss):
Unrealized gain (loss) on available-for-sale investments, net	(32)	84
Comprehensive income (loss)	$ (2,269)	$ 3,055