CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Income Statement [Abstract]
Net sales	$ 150,542	$ 151,778
Cost of sales	104,143	108,837
Gross profit	46,399	42,941
Research and development expenses	7,942	7,898
Selling, general and administrative expenses	29,846	26,997
Operating income	8,611	8,046
Interest income (expense), net	(108)	(632)
Other income (expense), net	23	(348)
Income before provision for income taxes	8,526	7,066
Provision for income taxes	1,533	1,220
Net income	$ 6,993	$ 5,846
Earnings per share:
Basic (in dollars per share)	$ 0.51	$ 0.42
Diluted (in dollars per share)	$ 0.49	$ 0.41
Shares used in computing earnings per share:
Basic (in shares)	13,803	13,960
Diluted (in shares)	14,199	14,211