CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 28, 2018	Sep. 29, 2017	Sep. 28, 2018	Sep. 29, 2017
Income Statement [Abstract]
Revenue	$ 160,794	$ 146,296	$ 458,159	$ 374,372
Cost of revenue	91,160	87,589	261,137	216,082
Gross profit	69,634	58,707	197,022	158,290
Operating expenses:
Research and development and engineering	13,204	11,659	37,744	29,878
Selling, general and administrative	29,147	27,590	87,598	74,274
Amortization of purchased intangible assets	3,947	3,217	11,538	9,413
Restructuring, acquisition and divestiture related costs	2,341	3,834	4,805	6,232
Total operating expenses	48,639	46,300	141,685	119,797
Operating income	20,995	12,407	55,337	38,493
Interest income (expense), net	(2,396)	(2,111)	(7,315)	(4,874)
Foreign exchange transaction gains (losses), net	66	(661)	(164)	(176)
Other income (expense), net	(44)	(138)	(131)	(288)
Gain on acquisition of business				26,409
Income before income taxes	18,621	9,497	47,727	59,564
Income tax provision	3,632	1,131	8,276	6,934
Consolidated net income	14,989	8,366	39,451	52,630
Less: Net income attributable to noncontrolling interest	(435)	(834)	(1,986)	(1,444)
Net income attributable to Novanta Inc.	$ 14,554	$ 7,532	$ 37,465	$ 51,186
Earnings (loss) per common share attributable to Novanta Inc. (Note 5):
Basic	$ 0.61	$ 0.00	$ 1.12	$ 1.15
Diluted	$ 0.60	$ 0.00	$ 1.11	$ 1.13
Weighted average common shares outstanding—basic	34,899	34,833	34,918	34,809
Weighted average common shares outstanding—diluted	35,485	34,833	35,469	35,235