CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Statement [Abstract]
Net sales	$ 753,477	$ 680,241	$ 695,790
Cost of sales	583,274	538,437	530,083
Gross profit	170,203	141,804	165,707
Research and development expenses	29,412	23,815	21,416
Factory transition restructuring charges	0	0	6,145
Selling, general and administrative expenses	125,476	119,654	127,476
Operating income (loss)	15,315	(1,665)	10,670
Interest income (expense), net	(3,918)	(4,690)	(2,534)
Gain on sale of Guangzhou factory	0	36,978	0
Other income (expense), net	(995)	(4,457)	(848)
Income before provision for income taxes	10,402	26,166	7,288
Provision for income taxes	6,772	14,242	17,611
Net income (loss)	$ 3,630	$ 11,924	$ (10,323)
Earnings (loss) per share:
Basic (in dollars per share)	$ 0.26	$ 0.85	$ (0.72)
Diluted (in dollars per share)	$ 0.26	$ 0.85	$ (0.72)
Shares used in computing earnings (loss) per share:
Basic (in shares)	13,879	13,948	14,351
Diluted (in shares)	14,109	14,060	14,351