Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Mar. 29, 2013	Dec. 31, 2012
Current Assets
Cash and cash equivalents	$ 36,337	$ 65,788
Accounts receivable, net of allowance of $641 and $374, respectively	57,285	42,652
Income taxes receivable	16,620	16,540
Inventories	64,902	52,801
Deferred tax assets	7,065	7,583
Prepaid expenses and other current assets	5,991	5,486
Assets of discontinued operations	18,283	17,618
Total current assets	206,483	208,468
Property, plant and equipment, net	33,645	32,338
Deferred tax assets	4,817	3,884
Other assets	8,612	8,172
Intangible assets, net	73,490	40,020
Goodwill	73,271	44,578
Total assets	400,318	337,460
Current Liabilities
Current portion of long-term debt	7,500	7,500
Accounts payable	25,195	18,824
Income taxes payable	4,171	3,317
Deferred revenue	1,104	316
Deferred tax liabilities	376	402
Accrued expenses and other current liabilities	22,356	18,962
Liabilities of discontinued operations	4,716	5,605
Total current liabilities	65,418	54,926
Long-term debt	95,625	42,500
Deferred tax liabilities	770	255
Income taxes payable	2,561	1,764
Other liabilities	9,460	9,809
Total liabilities	173,834	109,254
Commitments and Contingencies (Note 14)
Stockholders' Equity:
Common shares, no par value; Authorized shares: unlimited; Issued and outstanding: 33,920 and 33,796, respectively	423,856	423,856
Additional paid-in capital	22,829	21,924
Accumulated deficit	(206,140)	(208,222)
Accumulated other comprehensive loss	(14,494)	(9,749)
Total GSI Group Inc. stockholders' equity	226,051	227,809
Noncontrolling interest	433	397
Total stockholders' equity	226,484	228,206
Total liabilities and stockholders' equity	$ 400,318	$ 337,460