CONDENSED CONSOLIDATED STATEMENTS OF INCOME - USD ($) shares in Thousands	3 Months Ended		9 Months Ended
	Oct. 01, 2021	Oct. 02, 2020	Oct. 01, 2021	Oct. 02, 2020
Income Statement [Abstract]
Net sales	$ 58,352,000	$ 47,081,000	$ 171,471,000	$ 117,462,000
Cost of sales	13,051,000	12,210,000	37,825,000	33,401,000
Gross profit	45,301,000	34,871,000	133,646,000	84,061,000
Selling, general and administrative expenses:
General and administrative	11,018,000	8,589,000	32,671,000	24,406,000
Selling and marketing	18,175,000	12,649,000	50,229,000	34,003,000
Research and development	8,271,000	8,751,000	24,790,000	22,960,000
Total selling, general and administrative expenses	37,464,000	29,989,000	107,690,000	81,369,000
Operating income	7,837,000	4,882,000	25,956,000	2,692,000
Other income (expense), net:
Interest income (expense), net	(23,000)	1,000	(35,000)	237,000
Gain (loss) on foreign currency transactions	(610,000)	468,000	(2,040,000)	388,000
Royalty income	185,000	93,000	496,000	239,000
Other expense, net	(13,000)	(63,000)	(47,000)	(83,000)
Total other income (expense), net	(461,000)	499,000	(1,626,000)	781,000
Income before income taxes	7,376,000	5,381,000	24,330,000	3,473,000
Provision for income taxes	1,356,000	1,489,000	4,751,000	887,000
Net income	$ 6,020,000	$ 3,892,000	$ 19,579,000	$ 2,586,000
Net income per share:
Basic	$ 0.13	$ 0.08	$ 0.42	$ 0.06
Diluted	$ 0.12	$ 0.08	$ 0.40	$ 0.05
Weighted average shares outstanding:
Basic	47,483	45,903	47,064	45,394
Diluted	49,592	48,180	49,448	47,589