CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Income Statement [Abstract]
Net sales	$ 164,698	$ 161,406
Cost of sales	127,496	120,372
Gross profit	37,202	41,034
Research and development expenses	6,051	5,498
Factory transition restructuring charges	0	5,250
Selling, general and administrative expenses	30,247	30,651
Operating income (loss)	904	(365)
Interest income (expense), net	(1,070)	(393)
Other income (expense), net	(587)	583
Income (loss) before provision for income taxes	(753)	(175)
Provision for income taxes (benefit)	(166)	(294)
Net income (loss)	$ (587)	$ 119
Earnings per share:
Basic (in dollars per share)	$ (0.04)	$ 0.01
Diluted (in dollars per share)	$ (0.04)	$ 0.01
Shares used in computing earnings (loss) per share:
Basic (in shares)	14,087	14,449
Diluted (in shares)	14,087	14,717