CONDENSED CONSOLIDATED STATEMENTS OF INCOME (LOSS) (UNAUDITED) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Revenues:
Revenues from products and services	$ 93,808		$ 177,718
Leasing	10,000	$ 12,144	20,407	$ 22,810
Total revenues	103,808	94,861	198,125	194,034
Cost of sales:
Total cost of sales	73,867	75,537	143,240	149,023
Selling, general and administrative	22,835	22,869	47,378	50,218
Engineering and product development	5,157	5,302	8,777	9,720
Restructuring and other charges	1,019		3,415
Gain on sale of assets	(1,190)	(5,099)	(1,203)	(5,099)
Total costs and expenses	101,688	98,609	201,607	203,862
Operating income (loss)	2,120	(3,748)	(3,482)	(9,828)
Interest income	2,680	2,275	4,686	4,075
Interest expense		(151)	(121)	(350)
Income (loss) before income taxes	4,800	(1,624)	1,083	(6,103)
Income tax provision	3,119	1,418	5,452	4,318
Net income (loss)	$ 1,681	$ (3,042)	$ (4,369)	$ (10,421)
Income (loss) per common share:
Basic (in dollars per share)	$ 0.05	$ (0.08)	$ (0.12)	$ (0.28)
Diluted (in dollars per share)	$ 0.05	$ (0.08)	$ (0.12)	$ (0.28)
Weighted average common shares outstanding:
Basic (in shares)	35,967	37,615	35,764	37,672
Diluted (in shares)	36,210	37,615	35,764	37,672
Products
Revenues:
Revenues from products and services	$ 77,233	$ 64,719	$ 142,667	$ 135,764
Cost of sales:
Total cost of sales	53,568	57,916	105,110	115,261
Services
Revenues:
Revenues from products and services	16,575	17,998	35,051	35,460
Cost of sales:
Total cost of sales	10,219	8,268	19,455	17,912
Leasing
Cost of sales:
Total cost of sales	$ 10,080	$ 9,353	$ 18,675	$ 15,850