Condensed Consolidated Statements of Operations (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Income Statement [Abstract]
Revenue	$ 33,727	$ 35,816	$ 91,607	$ 99,605
Cost of revenue	27,357	28,492	74,128	78,420
Gross profit	6,370	7,324	17,479	21,185
Operating expenses:
Selling, general and administrative	9,052	14,565	28,411	36,277
Research and development	5,599	4,909	16,680	14,064
Restructuring and exit costs	(47)	1,251	(26)	2,248
Total operating expenses	14,604	20,725	45,065	52,589
Loss from operations	(8,234)	(13,401)	(27,586)	(31,404)
Interest expense, net	1,252	152	3,275	312
Other components of defined benefit plans, net	(217)	(141)	(649)	(439)
Other (income) loss	34	(14)	(7)	(67)
Foreign currency exchange loss (gain), net	56	(65)	383	50
Loss before income taxes	(9,359)	(13,333)	(30,588)	(31,260)
Income tax provision (benefit)	364	527	(358)	3,117
Net loss	$ (9,723)	$ (13,860)	$ (30,230)	$ (34,377)
Net loss per share
Basic and diluted (in dollars per share)	$ (0.23)	$ (0.37)	$ (0.77)	$ (0.98)
Weighted average common shares outstanding:
Weighted average common shares outstanding, basic and diluted	42,497	37,008	39,381	34,929