CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
SALES
Sales	$ 403,627	$ 360,917	$ 325,584
COST OF SALES
Cost of sales (exclusive of depreciation and amortization, shown separately below)	175,282	156,280	147,624
GROSS PROFIT	228,345	204,637	177,960
OPERATING EXPENSES
Selling and marketing	116,920	103,544	79,870
General and administrative	47,652	43,807	40,813
Depreciation and amortization	18,313	16,588	13,868
Research and development	39,706	35,376	30,125
Total operating expenses	222,591	199,315	164,676
INCOME FROM OPERATIONS	5,754	5,322	13,284
OTHER EXPENSE (INCOME)
Interest income	(429)	(319)	(212)
Other expense (income), net	1,139	(190)	822
Interest expense	486	4	48
INCOME BEFORE INCOME TAX (BENEFIT) EXPENSE	4,558	5,827	12,626
INCOME TAX (BENEFIT) EXPENSE	(372)	20,343	1,519
NET INCOME (LOSS)	$ 4,930	$ (14,516)	$ 11,107
NET (LOSS) INCOME PER SHARE - BASIC (in dollars per share)	$ 0.29	$ (0.87)	$ 0.67
NET (LOSS) INCOME PER SHARE - DILUTED (in dollars per share)	$ 0.29	$ (0.87)	$ 0.67
Weighted average shares - Basic (in shares)	17,043,167	16,711,534	16,654,786
Weighted average shares - Diluted (in shares)	17,348,456	16,711,534	16,681,710
Product
SALES
Sales	$ 311,102	$ 277,922	$ 256,010
COST OF SALES
Cost of sales (exclusive of depreciation and amortization, shown separately below)	124,802	110,143	107,965
Service
SALES
Sales	92,525	82,995	69,574
COST OF SALES
Cost of sales (exclusive of depreciation and amortization, shown separately below)	$ 50,480	$ 46,137	$ 39,659