CONDENSED CONSOLIDATED STATEMENTS OF INCOME (LOSS) (UNAUDITED) - USD ($) shares in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Revenues	$ 93,257,000	$ 100,346,000	$ 287,291,000	$ 347,498,000
Cost and expenses:
Cost of sales	65,630,000	63,050,000	202,824,000	233,039,000
Selling, general and administrative	31,566,000	27,985,000	83,359,000	85,060,000
Engineering and product development	10,159,000	10,379,000	30,133,000	32,537,000
Impairment and other charges	0	60,968,000	0	60,968,000
Gain on sale of assets	(14,000)	9,000	(5,113,000)	(79,000)
Total costs and expenses	107,341,000	162,391,000	311,203,000	411,525,000
Operating loss	(14,084,000)	(62,045,000)	(23,912,000)	(64,027,000)
Interest income	1,893,000	957,000	5,965,000	2,963,000
Interest expense	(195,000)	(12,000)	(545,000)	(44,000)
Loss before income taxes	(12,386,000)	(61,100,000)	(18,492,000)	(61,108,000)
Income tax provision (benefit)	(2,028,000)	(31,840,000)	2,291,000	(31,959,000)
Net loss	$ (10,358,000)	$ (29,260,000)	$ (20,783,000)	$ (29,149,000)
Loss per common share:
Basic (in dollars per share)	$ (0.28)	$ (0.78)	$ (0.56)	$ (0.78)
Diluted (in dollars per share)	$ (0.28)	$ (0.78)	$ (0.56)	$ (0.78)
Weighted average common shares outstanding:
Basic (in shares)	37,119	37,528	37,349	37,527
Diluted (in shares)	37,119	37,528	37,349	37,527
Products
Revenues	$ 63,246,000	$ 75,885,000	$ 199,010,000	$ 269,570,000
Cost and expenses:
Cost of sales	47,859,000	48,761,000	151,290,000	190,214,000
Services
Revenues	30,011,000	24,461,000	88,281,000	77,928,000
Cost and expenses:
Cost of sales	$ 17,771,000	$ 14,289,000	$ 51,534,000	$ 42,825,000