CONDENSED CONSOLIDATED STATEMENTS OF INCOME (LOSS) (UNAUDITED) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Revenues:
Revenues from products and services	$ 99,735		$ 277,454
Leasing	8,492	$ 12,469	28,899	$ 35,278
Total revenues	108,227	93,257	306,353	287,291
Cost of sales:
Total cost of sales	76,023	71,113	219,271	220,136
Selling, general and administrative	27,962	27,093	75,332	76,711
Engineering and product development	3,754	5,404	12,531	15,124
Restructuring and other charges	546	3,745	3,961	4,345
Gain on sale of assets	(280)	(14)	(1,483)	(5,113)
Total costs and expenses	108,005	107,341	309,612	311,203
Operating income (loss)	222	(14,084)	(3,259)	(23,912)
Interest income	1,906	1,893	6,592	5,965
Interest expense	(26)	(195)	(148)	(545)
Income (loss) before income taxes	2,102	(12,386)	3,185	(18,492)
Income tax provision (benefit)	3,412	(2,028)	8,864	2,291
Net loss	$ (1,310)	$ (10,358)	$ (5,679)	$ (20,783)
Loss per common share:
Basic (in dollars per share)	$ (0.04)	$ (0.28)	$ (0.16)	$ (0.56)
Diluted (in dollars per share)	$ (0.04)	$ (0.28)	$ (0.16)	$ (0.56)
Weighted average common shares outstanding:
Basic (in shares)	35,559	37,119	35,827	37,349
Diluted (in shares)	35,559	37,119	35,827	37,349
Products
Revenues:
Revenues from products and services	$ 81,851	$ 63,246	$ 224,518	$ 199,010
Cost of sales:
Total cost of sales	58,632	53,342	163,750	168,602
Services
Revenues:
Revenues from products and services	17,884	17,542	52,936	53,003
Cost of sales:
Total cost of sales	8,451	9,329	27,906	27,242
Leasing
Cost of sales:
Total cost of sales	$ 8,940	$ 8,442	$ 27,615	$ 24,292