CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Income Statement [Abstract]
Net sales	$ 200,724	$ 182,717	$ 578,783	$ 509,938
Cost of sales	154,245	142,401	458,437	405,661
Gross profit	46,479	40,316	120,346	104,277
Research and development expenses	7,930	5,593	21,884	17,703
Selling, general and administrative expenses	32,422	29,994	94,598	90,811
Operating income (loss)	6,127	4,729	3,864	(4,237)
Interest income (expense), net	(784)	(1,177)	(3,088)	(3,526)
Gain on sale of Guangzhou factory	0	0	0	36,978
Other income (expense), net	(148)	(2,282)	(426)	(3,951)
Income (loss) before provision for income taxes	5,195	1,270	350	25,264
Provision for income taxes	2,526	311	3,747	2,233
Net income (loss)	$ 2,669	$ 959	$ (3,397)	$ 23,031
Earnings (loss) per share:
Basic (in dollars per share)	$ 0.19	$ 0.07	$ (0.25)	$ 1.65
Diluted (in dollars per share)	$ 0.19	$ 0.07	$ (0.25)	$ 1.63
Shares used in computing earnings (loss) per share:
Basic (in shares)	13,894	13,836	13,861	13,997
Diluted (in shares)	14,170	13,959	13,861	14,116