CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 28, 2018	Sep. 29, 2017	Sep. 28, 2018	Sep. 29, 2017
Net sales		$ 31,770	$ 23,473	$ 92,768	$ 65,759
Cost of sales		7,910	6,624	24,250	18,859
Gross profit		23,860	16,849	68,518	46,900
Selling, general and administrative expenses:
General and administrative		6,087	4,716	18,054	14,380
Marketing and selling		10,620	6,495	28,733	20,473
Research and development		5,570	4,594	16,323	14,418
Total selling, general and administrative expenses		22,277	15,805	63,110	49,271
Operating income (loss)		1,583	1,044	5,408	(2,371)
Other income (expense):
Interest expense, net		(29)	(27)	(65)	(88)
Gain (loss) on foreign currency transactions		52	444	(545)	738
Royalty income	[1]	159	141	465	400
Other income (expense), net		40	(19)	61	17
Other income (expense), net		222	539	(84)	1,067
Income (loss) before income taxes		1,805	1,583	5,324	(1,304)
Income tax provision		346	410	1,452	697
Net income (loss)		$ 1,459	$ 1,173	$ 3,872	$ (2,001)
Net income (loss) per share:
Basic		$ 0.03	$ 0.03	$ 0.09	$ (0.05)
Diluted		$ 0.03	$ 0.03	$ 0.09	$ (0.05)
Weighted average shares outstanding:
Basic		43,054	41,110	42,065	40,939
Diluted		46,025	42,104	44,618	40,939

[1] Shown as a separate line item in other income, net on the Condensed Consolidated Statements of Operations.