Consolidated Statements of Operations (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 27, 2013	Sep. 28, 2012	Sep. 27, 2013	Sep. 28, 2012
Sales	$ 85,484	$ 69,520	$ 253,905	$ 205,085
Cost of sales	49,693	40,667	150,452	117,884
Gross profit	35,791	28,853	103,453	87,201
Operating expenses:
Research and development and engineering	6,585	5,545	19,988	16,933
Selling, general and administrative	20,075	16,125	60,933	49,174
Amortization of purchased intangible assets	1,772	663	5,625	1,988
Restructuring costs and other	1,641	2,728	5,893	7,396
Total operating expenses	30,073	25,061	92,439	75,491
Income from operations	5,718	3,792	11,014	11,710
Interest income (expense), net	(839)	(656)	(2,649)	(2,143)
Foreign exchange transaction gains (losses), net	(1,637)	(685)	(866)	(957)
Other income (expense), net	540	167	1,201	399
Income from continuing operations before income taxes	3,782	2,618	8,700	9,009
Income tax provision	1,610	563	4,217	1,410
Income from continuing operations	2,172	2,055	4,483	7,599
Loss from discontinued operations, net of tax	(113)	(4,570)	(848)	(3,834)
Loss on disposal of discontinued operations, net of tax	(281)		(592)
Consolidated net income (loss)	1,778	(2,515)	3,043	3,765
Less: Net (income) loss attributable to noncontrolling interest	12	(19)	(42)	(45)
Net income (loss) attributable to GSI Group Inc.	$ 1,790	$ (2,534)	$ 3,001	$ 3,720
Earnings per common share from continuing operations:
Basic	$ 0.06	$ 0.06	$ 0.13	$ 0.22
Diluted	$ 0.06	$ 0.06	$ 0.13	$ 0.22
Loss per common share from discontinued operations:
Basic	$ (0.01)	$ (0.13)	$ (0.04)	$ (0.11)
Diluted	$ (0.01)	$ (0.13)	$ (0.04)	$ (0.11)
Earnings (loss) per common share attributable to GSI Group Inc.:
Basic	$ 0.05	$ (0.07)	$ 0.09	$ 0.11
Diluted	$ 0.05	$ (0.07)	$ 0.09	$ 0.11
Weighted average common shares outstanding-basic	34,102	33,803	34,058	33,755
Weighted average common shares outstanding-diluted	34,417	33,912	34,325	33,914