Quarterly Financial Data (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 28, 2019	Sep. 28, 2019	Jun. 29, 2019	Mar. 30, 2019	Dec. 29, 2018	Sep. 29, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 28, 2019	Dec. 29, 2018	Dec. 30, 2017
Quarterly Financial Information Disclosure [Abstract]
Revenue	$ 100,237	$ 103,469	$ 102,296	$ 98,091	$ 95,977	$ 101,484	$ 102,715	$ 98,623	$ 404,093	$ 398,799	$ 385,961
Gross margin	59,293	61,439	60,038	57,652	54,306	58,364	50,248	56,521	238,422	219,439	216,579
Restructuring charges	(55)	252	3,126	1,341	11,854	90	4,376	1,029	4,664	17,349	7,196
Net income (loss)	$ 13,987	$ 13,539	$ 8,559	$ 7,408	$ (7,121)	$ 6,974	$ (20,223)	$ (5,952)	$ 43,493	$ (26,322)	$ (70,562)
Net income (loss) per share - basic (in usd per share)	$ 0.10	$ 0.10	$ 0.06	$ 0.06	$ (0.05)	$ 0.05	$ (0.16)	$ (0.05)	$ 0.33	$ (0.21)	$ (0.58)
Net income (loss) per share - diluted (in usd per share)	$ 0.10	$ 0.10	$ 0.06	$ 0.05	$ (0.05)	$ 0.05	$ (0.16)	$ (0.05)	$ 0.32	$ (0.21)	$ (0.58)