CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
SALES
Sales	$ 381,765	$ 403,627	$ 360,917
COST OF SALES
Cost of sales (exclusive of depreciation and amortization, shown separately below)	183,633	182,074	162,235
GROSS PROFIT	198,132	221,553	198,682
OPERATING EXPENSES
Selling, general and administrative	177,378	169,717	152,299
Research and development	44,175	46,082	41,061
Impairment loss	35,213	0	0
Total operating expenses	256,766	215,799	193,360
(LOSS) INCOME FROM OPERATIONS	(58,634)	5,754	5,322
OTHER EXPENSE (INCOME)
Interest income	(714)	(429)	(319)
Other expense (income), net	2,313	1,139	(190)
Interest expense	781	486	4
(LOSS) INCOME BEFORE INCOME TAX EXPENSE (BENEFIT)	(61,014)	4,558	5,827
INCOME TAX EXPENSE (BENEFIT)	1,133	(372)	20,343
NET (LOSS) INCOME	$ (62,147)	$ 4,930	$ (14,516)
NET (LOSS) INCOME PER SHARE - BASIC (in dollars per share)	$ (3.58)	$ 0.29	$ (0.87)
NET (LOSS) INCOME PER SHARE - DILUTED (in dollars per share)	$ (3.58)	$ 0.29	$ (0.87)
Weighted average shares - Basic (in shares)	17,383,415	17,043,167	16,711,534
Weighted average shares - Diluted (in shares)	17,383,415	17,348,456	16,711,534
Selling, general and administrative	$ 177,378	$ 169,717	$ 152,299
Product
SALES
Sales	289,679	320,584	287,248
COST OF SALES
Cost of sales (exclusive of depreciation and amortization, shown separately below)	133,246	130,876	115,761
Service
SALES
Sales	92,086	83,043	73,669
COST OF SALES
Cost of sales (exclusive of depreciation and amortization, shown separately below)	$ 50,387	$ 51,198	$ 46,474