Consolidated Statements Of Operations (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 28, 2012	Sep. 30, 2011	Sep. 28, 2012	Sep. 30, 2011
Sales	$ 69,520	$ 78,704	$ 205,085	$ 238,816
Cost of goods sold	40,667	44,119	117,884	133,489
Gross profit	28,853	34,585	87,201	105,327
Operating expenses:
Research and development and engineering	5,545	6,183	16,933	17,942
Selling, general and administrative	16,125	16,627	49,174	52,037
Amortization of purchased intangible assets	663	874	1,988	2,853
Restructuring, restatement related costs and other	2,728	14	7,396	136
Post-emergence professional fees		63		296
Total operating expenses	25,061	23,761	75,491	73,264
Income from operations	3,792	10,824	11,710	32,063
Interest expense, net	(656)	(3,254)	(2,143)	(10,303)
Foreign exchange transaction gains (losses), net	(685)	731	(957)	(79)
Other income (expense), net	167	(123)	399	1,261
Income from continuing operations before income taxes	2,618	8,178	9,009	22,942
Income tax provision	563	851	1,410	3,870
Income from continuing operations	2,055	7,327	7,599	19,072
Income (loss) from discontinued operations, net of tax	(4,570)	1,489	(3,834)	6,081
Consolidated net income (loss)	(2,515)	8,816	3,765	25,153
Less: Net (income) loss attributable to noncontrolling interest	(19)	29	(45)	(35)
Net income (loss) attributable to GSI Group Inc.	$ (2,534)	$ 8,845	$ 3,720	$ 25,118
Earnings per common share from continuing operations:
Basic	$ 0.06	$ 0.22	$ 0.23	$ 0.57
Diluted	$ 0.06	$ 0.22	$ 0.22	$ 0.57
Earnings (Loss) per common share from discontinued operations:
Basic	$ (0.14)	$ 0.04	$ (0.11)	$ 0.18
Diluted	$ (0.14)	$ 0.04	$ (0.11)	$ 0.18
Earnings (Loss) per common share attributable to GSI Group Inc.:
Basic	$ (0.07)	$ 0.26	$ 0.11	$ 0.75
Diluted	$ (0.07)	$ 0.26	$ 0.11	$ 0.75
Weighted average common shares outstanding-basic	33,803	33,489	33,755	33,472
Weighted average common shares outstanding-diluted	33,912	33,588	33,914	33,572